National Academies Press: OpenBook

Incorporating Travel Time Reliability into the Highway Capacity Manual (2014)

Chapter: Appendix B - STREETVAL User s Guide

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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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Suggested Citation:"Appendix B - STREETVAL User s Guide." National Academies of Sciences, Engineering, and Medicine. 2014. Incorporating Travel Time Reliability into the Highway Capacity Manual. Washington, DC: The National Academies Press. doi: 10.17226/22487.
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142 This appendix provides guidance for the use of the Urban Streets Reliability Engine (USRE), referred to as STREETVAL in the proposed Highway Capacity Manual (HCM) reliability chapters. USRE is a software tool that supports the evaluation of a facility’s reliability of service in terms of its operational performance over an extended time period. The software is distributed as a Microsoft (MS) Excel workbook using the Visual Basic for Applications (VBA) programming language. This user’s guide consists of six sections: • An introduction to the tool and description of its correct use; • The evaluation process in terms of the analysis steps and the data needed for a typical facility evaluation; • Supplemental guidance for assigning reported crashes to intersections and streets; • Computational engine data entry; • Software setup and file description; and • Software installation. Introduction Overview The USRE (hereafter referred to as the “tool”) was developed to predict the operational performance of a facility for each of many small time periods that collectively represent traffic conditions during several consecutive months. The predictions are used to describe the distribution of various performance measures, notably travel time, over the duration of interest. The distribution provides an indication of the degree to which the facility provides reliable service. Two methodologies are implemented in the tool. The first one, reliability methodology, is used to estimate traffic, signal, road, and weather conditions for each of the small time periods. The estimates are based on historic changes in these conditions over time, with the recognition that there is also a random component to these changes in terms of when and where they occur, as well as in their magnitude or duration. The second methodology is that documented in Chap- ters 16, 17, and 18 of the 2010 Highway Capacity Manual (HCM2010) (Transportation Research Board of the National Academies 2010). For this reason, it is referred to as the HCM methodology. It is used to predict facility travel time and other performance measures for each small time period based on its estimated traffic signal, road, and weather conditions. This guide was developed as a companion document for the proposed HCM reliability chapters about the recom- mended methodology for incorporating travel time reliabil- ity into the HCM. These chapters provide the information needed to fully understand and apply the reliability meth- odology. Specifically, they identify the required input data, describe the methodology, provide default values, outline some typical applications, and provide a detailed example problem. Analysts are encouraged to read the proposed HCM reliability chapters before using the tool. Evaluation Scope The tool is intended to be used to quantify the reliability of service provided by an urban street facility in terms of its operational performance over an extended period of time. The evaluation focuses on the performance of automobile and truck traffic and does not directly address the performance of other urban street travel modes. The urban street facility can be either an arterial or collector street. Each segment on the facility is bounded by a signalized intersection. The reliability methodology can be used to evaluate the following sources of unreliable travel time on urban street facilities: • Traffic incidents; • Work zones; • Demand fluctuations; A p p e n d I x B STREETVAL User’s Guide

143 • Special events; • Traffic control devices; • Weather; and • Inadequate base capacity. These sources can result in the formation of oversaturated operation for extended time periods. Traffic demand fluctuations are represented in the reliability methodology in terms of systematic demand volume variation by hour of day, day of week, and month of year. Fluctuations due to diversion are not addressed by the methodology. Traffic control devices are represented in the HCM method- ology in terms of the influence of speed limit and traffic signal operation on facility travel time. This sensitivity can be used to evaluate the quality of the signal timing plan and the relative benefits of pretimed or coordinated-actuated operation. The effect of traffic-responsive or -adaptive signal operation is not addressed by the methodology. Inadequate base capacity is represented in the reliability methodology as the potential for a signalized intersection to act as a bottleneck to traffic flow along the facility. This result may be due to a lane being dropped at the intersection, insufficient numbers of intersection approach lanes, or misallocation of cycle time. The effect of a midsegment lane drop or weaving section is not addressed by the methodology. Limitations The reliability methodology does not address some events (or conditions) that influence urban street operation. The inability to quantify the influence of an event or condition on traffic operation represents a limitation of the methodology. This subsection identifies the known limitations of the reliability methodology. If one or more of these limitations are believed to have an important influence on the performance of a spe- cific facility, then the analyst should consider using alternative evaluation methods or tools. The reliability methodology does not directly account for the effect of the following conditions on facility operation: • Truck pickup and delivery; • Signal malfunction; • Railroad crossing; • Railroad preemption; • Signal plan transition; or • Fog, dust storms, smoke, or high winds. Lane or shoulder blockage due to truck pickup and deliv- ery activities in downtown urban areas can also be considered incidentlike in terms of the randomness of their occurrence and the temporal extent of the event. The dwell time for these activities can range from 10 to 20 min. A signal malfunction occurs when one or more elements of the signal system are not operating in the intended manner. These elements include vehicle detectors, signal heads, and controller hardware. A failure of one or more of these ele- ments typically results in poor facility operation. A railroad crossing the facility at a midsegment location effectively blocks traffic flow while the train is present. Train crossing time can be lengthy (i.e., typically 5 to 10 min) and can cause considerable congestion that can extend for one or more analysis periods. Railroad preemption is used when a train crosses a leg of a signalized intersection. The signal operation is initially disrupted to safely clear the tracks. It then dwells in a speci- fied phase sequence while the train is present. Signal coor- dination may be disrupted for several cycles following train clearance. When a new timing plan is invoked, the controller transi- tions from the previous plan to the new plan. The transition period can last several cycles, during which traffic progression is significantly disrupted. Some weather conditions that restrict driver visibility or degrade vehicle stability are not addressed by the methodology. These conditions include fog, dust storms, smoke, and high winds. They tend to be localized to specific areas of the country and are relatively rare in occurrence. The reliability methodology uses the HCM methodology to quantify facility performance during each scenario. For this reason, the reliability methodology shares the limitations of the HCM methodology. These limitations are described in Section 1 of Chapters 16, 17, and 18 of the HCM2010. Software Limits The tool can accommodate data for eight segments and nine signalized intersections. If a given project exceeds one or more of these limits, the analyst will need to subdivide the project into two or more sections such that each section does not exceed the limits. The tool can address the occurrence of up to seven work zones, special events, or both. The total number of work zones and special events cannot exceed seven. Terminology This section defines many of the terms used in this docu- ment. Those terms that are not listed here are defined in Chapter 9 of the HCM2010. Analysis Period The analysis period is the time interval evaluated by a single application of the HCM methodology.

144 HCM Data Set An HCM data set comprises the input data needed to evalu- ate an urban street facility using the HCM methodology. These data are also needed for the reliability methodology. They are described in Chapter 17 of the HCM2010 and are referred to here as an “HCM data set.” One data set describes the geometry and signal timing conditions for the inter- sections and segments on the facility during one representa- tive study period. The demand volumes recorded in a data set describe conditions for a specified hour of the day and date of the year. Alternatively, they can be stated to represent the average day of the year if they are derived from an annual average daily traffic (AADT) volume. For many reliability evaluations, there will be two or more HCM data sets. One HCM data set describes base conditions. This base data set is required for a reliability evaluation. The base conditions describe demand volume, geometry, and sig- nal timing conditions when work zones and special events are not present. The demand volume for base conditions should be representative of good weather (i.e., it should not represent traffic movement counts during rain or snow storms). Additional HCM data sets are used, as needed, to describe conditions when a specific work zone is present or when a special event occurs. These optional data sets are called alter- native data sets. One alternative data set is used for each time period during the reliability reporting period (RRP) when a specific work zone is present, a specific special event occurs, or a unique combination of these occurs during the study period. Scenario A scenario is a unique combination of traffic demand, geom- etry, and traffic control conditions. It can represent one or more analysis periods, provided that all periods have the same unique combination of demand, capacity, geometry, and traf- fic control. Study Period The study period is a time interval (within a day) that is rep- resented by the performance evaluation. It consists of one or more consecutive analysis periods. Reliability Reporting Period The RRP describes the specific days over which reliability is to be computed, such as all nonholiday weekdays in a year. Special Event Special events are short-term events (e.g., major sporting events, concerts, and festivals) that produce intense traffic demands on a facility for limited periods of time and that may be addressed by temporary changes in the facility’s geometry, traffic control characteristics, or both. Getting Started This section introduces the tool and describes its correct use. It consists of the following six subsections: • Enabling macros: guidance for setting spreadsheet security to enable macros; • Navigation: guidance for selecting and using the worksheets; • Entering data: guidance for entering data in a worksheet; • Reviewing results: guidance for reviewing, saving, and printing results; • Modifying calibration factors and default values: guidance for calibrating the tool to local conditions; and • File management: guidance for saving and deleting files created by the tool. Enabling Macros The tool contains VBA computer code, referred to as macro code in MS Excel, to automate the calculations. It must be enabled when first loading the tool into Excel. The technique for enabling macros varies depending on the version of Excel being used. Enabling Macros in Microsoft ExcEl 2003 The following instruction sequence enables macros for Excel 2003. Open the Excel software. From the main screen, click Tools, and then Options. In the Options panel, click Security, and then click Macro Security. In the Security panel, click Security Level, and then click the radio button adjacent to Medium (the button will show a black circle). Finally, click OK to exit the Security Level panel and click OK to exit the Options panel. This setting should only need to be set once. It will remain effective until this process is repeated and a new security level is selected. Every time the tool is opened in Excel, the pop-up box shown to the right will be displayed. The analyst should click Enable Macros. The tool will finish loading and will function as intended. Enabling Macros in Ms ExcEl 2007 or 2010 The following instruction sequence enables macros for Excel 2007 or 2010. Open the Excel software to the main screen. For Excel 2007, click Office, and a panel will be displayed. In this panel, click Excel Options to bring up the Excel Options panel. For Excel 2010, click File, then click Options to bring up the Excel Options panel.

145 • Calib-Weather: calibration factors and default data for weather; • Calib-Demand: calibration factors and default data for demand volume; • Calib-Incident: calibration factors and default data for incidents; and • Analysis: statistical analysis of results from multiple runs. The Set Up, Facility Evaluation, and Performance Sum- mary worksheets will be used for every evaluation in the order listed. Optionally, the Weather, Demand, or Incident worksheets could be used to examine detailed results for one or more specific analysis periods. The three calibration work- sheets should be used to adjust the calibration factors or replace the default data (or both) to reflect local conditions. Entering Data Data are entered in the Set Up, Facility Evaluation, and Per- formance Summary worksheets. The basic data entry consid- erations are the same for each worksheet. A sample portion of the Set Up worksheet is shown in Figure B.2 to illustrate these considerations. The guidance offered in this section applies to all input worksheets. In all input worksheets, the cells with a light-blue back- ground are for user input. The white cells and gray cells are not for input, so they are locked to prevent inadvertent changes to cell content. The red triangles in the upper-right corner of some cells are linked to supplemental information balloons. Red triangles are shown for five cells in Figure B.2. By positioning the mouse pointer over a red triangle, a balloon will appear. In it will be information relevant to the adjacent cell that will typically explain more precisely what input data are needed. A drop-down list is provided for some cells with a light- blue background. When one of these cells is selected, a gray button will appear on the right side of the cell. Position the For Excel 2007 or Excel 2010, while in the Excel Options panel, click Trust Center, and then click Trust Center Settings to bring up the Trust Center panel. In this panel, click Macro Settings and then click the radio button adjacent to Disable all macros with notification (the button will show a black circle). Finally, click OK to exit the Trust Center panel, and click OK to exit the Excel Options panel. This setting should only need to be set once. It will remain effective until this process is repeated and a new security level is selected. Every time the tool is opened in Excel, a security warning is displayed. It is shown near the top in the following graphic for Excel 2010. A similar message is shown in Excel 2007. In Excel 2007, the analyst should click the Options button, click Enable this content, and then click OK. In Excel 2010, the analyst should click Enable Content (see Figure B.1). Navigation The tool contains 12 worksheets. To navigate among work- sheets, click the worksheet tabs at the bottom of the workbook window. The worksheets are identified in the following list: • Main Menu: includes a foreword, instructions, acknowl- edgment, and disclaimer; • Set Up: basic input data, name of each detailed input data file, start scenario generation; • Facility Evaluation: input data describing evaluation inter- val, start scenario evaluation; • Performance Summary: input data describing measure of interest, start performance summary; • Input Echo: listing of the data in a detailed input data file; • Weather: detailed listing of the predicted weather charac- teristics for each analysis period; • Demand: detailed listing of the demand variation factors applicable to each analysis period; • Incident: detailed listing of the predicted incident charac- teristics for each analysis period; Figure B.1. Urban street scenario generator.

146 before the button is clicked. A numeric counter is shown after the button is clicked. The second gray button, labeled Echo Input, will list the data in a selected input file. The file of interest is identified using the drop-down list just above the Echo Input button. The listing will be displayed in the Input Echo worksheet. Reviewing Results This subsection provides guidance for reviewing and saving the evaluation results. The summary results are shown in the Performance Summary worksheet. In addition to summary results, this worksheet also lists the performance measure for every analysis period (i.e., scenario) in the RRP. Detailed list- ings of the predicted weather characteristics, demand varia- tion factors, and incident characteristics for each analysis period are provided in the Weather, Demand, and Incident worksheets, respectively. mouse pointer over the button and click the left mouse but- ton. After clicking this button, a list of input choices will appear. Use the mouse pointer to select the desired choice, and then click the left mouse button. The section of Figure B.2 titled General Information shows two drop-down windows. On the right side of each list there is a gray button. Position the mouse pointer over the button and click the left mouse button. After clicking this button, a list of input choices will appear. Use the mouse pointer to select the desired choice, and then click the left mouse button. On the right side of Figure B.2 are two gray buttons. One button is labeled Start Calculations. Clicking it will initiate the scenario generation process. A similar process-starting but- ton is provided in the Facility Evaluation worksheet and the Performance Summary worksheet. After clicking a process- starting button, progress through the calculation sequence can be monitored by viewing the counter in the lower left corner of the Excel software (i.e., the status bar). “Ready” is shown General Information Location: Analyst: Nearest city: ok Functional class: Shoulders present on facility? Yes ok Number of analysis periods: 9 Input File Names Number of unique volume scenarios: 9 Path: Computer time estimate, min: 0.0 Base: Date of traffic count: 1/4/2011 Starting hour of count: 7 Work Zone and Special Event File Names Alternative 1: Description: Alternative 2: 1. Select the file you want to echo. Alternative 3: Alternative 4: Alternative 5: 2. Click the button below. Alternative 6: Alternative 7: Basis of alt. traffic vol.: TexasAM2-a1 TexasAM2 Scenario Generation for HCM Urban Street Evaluation Software Texas Avenue, Austin, Texas JHD C:\Documents and Settings\user1\My Documents\user\SHRP L08\Task 7_ Models\input_files\ Echo Input FilesWork zone on EB approach to Int. 2, one lane closed LINCOLN, NE Urban Principal Arterial Start Calculations Base input file Echo Input Figure B.2. Set Up worksheet.

147 Each data set is saved in a file using a file name with a .txt exten- sion. The file name includes the text of the file name associated with the base (or alternative) data set used to create the new data set. In addition, the file name is expanded to include the date and starting time of the corresponding analy sis period. Each file generated in this manner is saved in the same folder, as is the base data set. The typical reliability evaluation will gen- erate several thousand of these files. After the Evaluate Scenarios button is clicked, the tool evaluates each analysis period using the HCM methodology. The results from each evaluation are saved in a file using the same file name as the input value but with the extension .out. Thus, there is one .out file for each .txt file. Each file gener- ated in this manner is saved in the same folder, as is the base data set. The typical reliability evaluation will generate sev- eral thousand of these files. The file name convention and format of these files is described in “Software Setup and File Description” on p. 164. The analysis period data set files and the associated results files should be deleted when the evaluation is complete. Alter- natively, they can be archived using a file compression utility. evaluation process This section describes the activities undertaken during the evaluation of an urban street facility. The first subsection describes the sequence of evaluation activities in the order they are conducted; these activities are outlined as a series of analysis steps. The second subsection describes the data input requirements for the reliability methodology. The third sub- section describes the data entry process using the tool, and the fourth subsection describes the evaluation results. The evaluation requires the creation of a base data set and, optionally, one or more alternative data sets. The Urban Streets Computational Engine (USCE) is used for this pur- pose. The USCE is a software tool that implements the HCM methodology. The software is packaged as a MS Excel work- book using VBA programming language. Guidance for using the USCE to create the base data set is provided in the section titled “Urban Streets Computational Engine Data Entry.” The predicted operational performance is summarized as the last step of the evaluation process. This performance is described in terms of the distribution of a selected perfor- mance measure, such as facility travel time. Improvement strategies can be devised and then evaluated through repeti- tion of this process. Analysis Steps The steps involved in a safety evaluation using the tool are considered to be the routine steps that are used each time a The evaluation results can be saved by saving the entire workbook. The File, Save As menu sequence should be selected, and a new file name entered when prompted (i.e., avoid over- writing the original workbook). Alternatively, the results from the Performance Summary worksheet can be copied and pasted into another worksheet for supplemental data sum- mary, aggregation, or plotting. Modifying Calibration Factors and Default Values The reliability methodology has been developed using data from facilities in several urban areas. In many instances, these data are represented in the tool as calibration factors or default values. Adjusting these factors and values to local conditions will account for any differences between the facilities used for development and those being evaluated and will ensure that the evaluation results are meaningful and accurate for the jurisdiction. The calibration factors and default values are located in the Calib-Weather, Calib-Demand, and Calib-Incident work- sheets (i.e., the calibration worksheets). Most of the variables identified in these worksheets are considered to be default values because they have been found to notably influence the evaluation results, and they are typically available from archi- val databases or simple field measurements. A description of the default values is provided in the proposed HCM reliabil- ity chapters. A few of the variables in the calibration worksheets are considered to be calibration factors either because they have a relatively nominal effect on the evaluation results or they are not readily available or easily measured in the field. Back- ground information about the calibration factors is provided in Appendix H. File Management One base data set and, optionally, up to seven alternative data sets are used by the tool to generate the conditions present for each analysis period (i.e., scenario). The base and alternative data sets are created by the analyst and saved in a folder. The path to this folder is input by the analyst in the Set Up work- sheet. Specifically, it is input in the first row below the section labeled Input File Names, as shown in Figure B.2. The file name for the base file is input in the next row down. The file name for each of the alternative data sets is input in the rows below the subsection labeled Work Zone and Special Event File Names, as shown in Figure B.2. Guidance for setting up the file structure is provided in the section titled “Software Setup and File Description.” After the Start Calculations button is clicked, the tool gen- erates one new data set for each analysis period in the RRP.

148 average conditions for the analysis period during that month. Work zones that exist at the same time as a special event must be described using one alternative data set. In addition to the HCM data sets, the reliability methodology requires some input data to describe the reliability evaluation. These data are needed to define the time period (i.e., temporal scope) of the evaluation, characterize the project location, and describe the crash history of each street and intersection along the facility. The specific data elements needed are described in the section titled “Input Data Requirements,” and the means by which they are entered into the tool are described in “Data Entry.” Step 4. Initiate Calculations and Review Results The calculations proceed in sequence through the scenario generation, facility evaluation, and performance summary stages of the evaluation process. The scenarios are generated first by clicking the Start Calculations button (shown in Fig- ure B.2) in the Set Up worksheet. Once the scenarios have been generated, the analyst moves to the Facility Evaluation worksheet and clicks Evaluate Sce- narios, which initiates the evaluation of each scenario. Finally, the analyst moves to the Performance Summary worksheet and clicks Summarize Results. This action initiates the process of gathering the selected performance measure data from the results files and summarizing them using selected distribution statistics. Additional information about the Set Up, Facility Evalua- tion, and Performance Summary worksheets is provided below under “Data Entry.” When the three stages are complete, the analyst can exam- ine the performance measure summary statistics to eval- uate the overall operational performance of the facility. If more insight is needed about specific time periods, the pre- dicted performance measure for each analysis period is avail- able for examination. Details about the predicted weather, demand volume, or incidents during specific analysis periods can be examined in the Weather, Demand, or Incident work- sheets, respectively. Additional information about the evalu- ations results is provided below under “Results Review and Interpretation.” Input Data Requirements Two types of required input data are needed for the tool. One type of data is that normally needed to apply the urban street segments methodology in Chapter 17 of the HCM2010. These data, which are described in the HCM, are needed to create the base data set and, optionally, the alternative data sets. safety evaluation is undertaken. These steps are identified as follows: 1. Define purpose and scope; 2. Divide facility into individual segments; 3. Acquire input data; and 4. Initiate calculations and review results. Detailed information about each step is provided in the following subsections. Step 1. Define Purpose and Scope The purpose and scope of the evaluation are defined in this step. The purpose defines the nature and extent of the opera- tional problems on the facility and the anticipated use of the information obtained from the evaluation (e.g., quantify prob- lem, diagnose main causes, devise strategies). The scope of the evaluation is used to define the spatial and temporal extent of the evaluation. The spatial extent is char- acterized by the project limits, which define the physical extent of the facility being evaluated (i.e., the number of con- secutive segments). The temporal extent of the evaluation is defined by the duration of the analysis period, the hours of the day spanned by the study period, and the days of the year spanned by the RRP. The RRP is also defined by the days of the week to be considered in the evaluation. Step 2. Divide Facility into Individual Segments Using the project limits identified in Step 1, the facility is divided into segments, with each segment being bounded by a signalized intersection. Segments are internal to the facility and have signalized boundary intersections. The evaluation considers both directions of travel on a segment (when the segment serves two-way traffic flow). Step 3. Acquire Input Data Input data are acquired during this step. Required input data include those data normally needed to apply the methodology in Chapter 17 (Urban Street Segments) of the HCM2010. These data are needed to create the base data set. If work zones or special events occur during the RRP, then additional data are needed. Specifically, one alternative data set is created for each work zone or special event. The analyst must specify any changes to base conditions (e.g., demand, traffic control, available lanes) associated with a work zone or special event, along with a schedule for when the alternative data set is in effect. For example, if a work zone exists during a given month, then an alternative data set is used to describe

149 appropriate traffic volume adjustment factors for each scenario. The functional classes that are considered are identified in the following list: • Urban expressway; • Urban principal arterial street; and • Urban minor arterial street. An urban principal arterial street emphasizes mobility over access. It serves intra-area travel, such as that between a central business district and outlying residential areas, or that between a freeway and an important activity center. It is typi- cally used for relatively long trips within the urban area, or through trips that are entering, leaving, or passing through the city. An urban minor arterial street provides a balance between mobility and access. It interconnects with and aug- ments the urban principal arterial street system. It is typically used for trips of moderate length within relatively small geo- graphic areas (American Association of State Highway and Transportation Officials 2011). Default month-of-year, hour-of-day, and day-of-week adjustment values are provided for each functional class. These values are described in the proposed HCM reliability chapters. Date and Time of Traffic Counts The date and time of the traffic count represented in an HCM data set are used as a basis for estimating the traffic demand volume during each of the various analysis periods that com- prise the RRP. Specifically, the date and time of the count are used to determine the hour-of-day, day-of-week, and month- of-year factors that are then used to convert the volumes in the base data set into average-day-of-year volumes. A similar adjustment is made to the volumes in the alternative data sets. If the traffic demand volumes provided in the base data set (and the alternative data sets) are computed using planning procedures, then they are assumed to represent an average day volume. In this situation, a date does not need to be pro- vided by the analyst. However, the time of day for which the estimated volumes apply is still needed. Peak Hour Factor If a 15-min analysis period is used, the analyst has the option of adding a random element to estimated volume for each movement and analysis period. Including this random element provides a more realistic estimate of performance measure variability. If this option is selected, then the analyst is asked to provide the peak hour factor for each intersection. This factor is then used to randomly adjust the turn-movement volumes at each intersection. The algorithm used for this adjustment The second type of input data is that needed for the reli- ability evaluation. These data are listed in Table B.1 and are the focus of discussion in this section. Nearest City Of interest to the reliability evaluation are the weather statis- tics identified in the following list. The methodology uses these statistics when they are averaged by month of year for a recent 10-year period. • Total normal precipitation (in.); • Total normal snowfall (in.); • Number of days with precipitation of 0.01 in. or more; • Normal daily mean temperature (°F); and • Precipitation rate (in./h). The nearest city input is used to identify the typical weather conditions for the subject facility. Default values are available in the tool for 284 U.S. cities and territories. The first four statistics listed are published by the National Climatic Data Center (2011a), which also publishes the average precipitation rate for these locations in the Rainfall Frequency Atlas (National Climatic Data Center 2011b). The National Climatic Data Center or other weather data sources can be consulted to obtain the necessary weather statistics for cities for which default values are desired but not available in the tool. Precipitation statistics include both rainfall and snowfall, where snowfall is measured by its liquid equivalent. Functional Class The functional class of the subject facility is used to estimate the traffic volume during each of the various scenarios that comprise the RRP. Specifically, it is used to determine the Table B.1. Input Data Category Variable General Nearest city Functional class Traffic counts Date and time of traffic count for base data set Date and time of traffic count for alternative data set Peak hour factor Geometry Presence of shoulders Time period Analysis period duration Study period Reliability reporting period Alternative data set operating period Crash Segment crash frequency Intersection crash frequency Crash frequency adjustment factors

150 the intersection lane assignments and signal timing plan should be the same during the study period. If the facility has two or more time-of-day signal timing plans, then a separate study period should be established for each plan period. Sim- ilarly, if the directional distribution of traffic volume changes significantly during the day, then separate study periods should be established for each time period when the direc- tional distribution is relatively constant. Reliability Reporting Period The RRP represents the specific days over which reliability is to be computed. A typical reporting period for a reliability evaluation is 6 to 12 months. It is specified by start and end dates, as well as the days of week being considered. The RRP is used with the study period to fully describe the temporal representation of the performance measure (e.g., average travel time during weekday periods from 4:00 to 6:00 p.m. for the current year). Alternative Data Set Operating Period One or more alternative data sets are used to describe condi- tions when a specific work zone is present or when a special event occurs. The operating period for each alternative data set is specified by its start and end dates. Segment Crash Frequency The segment crash frequency is used to predict incident occurrence on each of the segments that comprise the facility. The crash frequency that is input represents an estimate of the expected crash frequency for the segment when no work zones are present or special events occur. The estimate should include all severity levels, including property-damage-only crashes. It is provided in units of crashes per year, regardless of the duration of the RRP. The segment crash frequency does not include crashes that occur at the intersection or crashes that occur on the intersec- tion legs and are described in the crash report as “intersection related.” The assignment of crashes to segments is described below under “Urban Streets Computational Engine Data Entry.” The expected crash frequency can be computed using the predictive method in Chapter 12 of the Highway Safety Manual (American Association of State Highway and Trans- portation Officials 2010). If this method cannot be used, then a 3-year crash history for the subject segment can be used to estimate its expected crash frequency. Crashes that occur when work zones and special events are present should be removed from the crash data. In this situation, the expected crash frequency is computed as the count of crashes during times when work zones and special was developed to ensure that the resulting volume variation among analysis periods in a common hour is consistent with that implied by the peak hour factor. Presence of Shoulders The presence of outside (i.e., right-side) shoulders is used to predict incident location. The default distribution of incident lane location is based on facilities with outside shoulders. This distribution is modified when shoulders are not present on the subject facility. For a shoulder to be considered pres- ent, it must be sufficiently wide to store a disabled vehicle without blocking traffic flow in the adjacent traffic lane. If on-street parking is allowed, the analyst will need to determine whether its occupancy during the study period is sufficient to preclude its use as a refuge for disabled vehicles. It is judged that the proportion of on-street parking occupied would need to be less than 30% to provide reasonable assur- ance that there will be opportunity to move a disabled vehicle from the through lanes to an open stall. Analysis Period Duration The analysis period is the time interval considered for the performance evaluation. Its duration is in the range of 15 min to 1 h, with longer durations in this range sometimes used for planning analyses. A shorter duration in this range is typically used for operational analyses. Additional guidance for deter- mining the analysis period duration is provided in Chapter 16 of the HCM2010. A shorter analysis period duration is desirable for reliabil- ity evaluations because it reduces the minimum event dura- tion threshold and thereby increases the number of incidents and weather events that are recognized. In this regard, the structure of the reliability methodology is such that events that are shorter than one-half of the analysis period duration are ignored (i.e., they will not be recognized in the scenario generation process). Thus, the use of a shorter analysis period duration will minimize the number of events that are ignored. Study Period The study period is the time interval (within a day) that is represented by the performance evaluation. It consists of one or more consecutive analysis periods. A typical study period is 1.0 to 6.0 h in duration and is stated to represent specific times of day and days of the week (e.g., weekdays from 4:00 to 6:00 p.m.). If congestion occurs during the study period, then at least the first analysis period should be uncongested. The maximum study period duration is 24 h. The geometric design elements and traffic control features of the facility must be unchanged during this period. Thus,

151 worksheets can also be changed if appropriate local data are available. Guidance for using the USCE to create an HCM data set is provided in the section titled “Urban Streets Computa- tional Engine Data Entry.” The analyst should confirm that he or she has enabled macro operation in the workbook before starting the data entry process. The procedure for enabling macros is described in the section “Getting Started.” Data Entry Basics The worksheet cells are used for data entry. Some cells accept numeric data, which can be typed in directly using the key- board. Some cells provide a drop-down list of text choices. In this case, the analyst should use the mouse pointer to select the applicable choice. If a numeric entry is not within an allowed range, or if it does not match one of the drop-down list of text choices, then a message box indicating “Out of Range!” is displayed. The analyst can click Retry and reenter the data, or click Cancel and return to the cell’s previous content. Set Up Worksheet The Set Up worksheet is divided into six sections. The first five sections are used for data entry; the sixth is used to dis- play advisory information. gEnEral inforMation The organization of this section is shown in Figure B.2. The Location data entry field is used to describe the project being evaluated, and the Analyst data entry field is used to identify the person conducting the evaluation. These entries are not used by the reliability methodology. They are optional data entry fields that will accept any desired combination of numeric and character data. The Nearest City data are entered using a drop-down list. This information is used to identify the typical weather con- ditions for the subject facility. If the weather for the city near- est to the subject site does not adequately describe the weather of the subject site, then the Calib-Weather worksheet can be modified to include weather statistics for the location of interest. The analyst will need to select for replacement one of the cities shown in the worksheet (i.e., one row). The data in this row are then deleted. Next, the city name should be entered in each of Columns C, U, AM, BE, and BW. The monthly average weather statistics for this city should be entered in the corresponding row for each of the five tables. The Functional Class data are entered using a drop-down list. This information is used to estimate the traffic volume during each of the various scenarios that comprise the RRP. Functional class defines the month-of-year and hour-of-day events are not present divided by the time period when work zones and special events are not present. Thus, if there were 15 crashes reported during a recent 3-year period and five of these crashes occurred during a 6-month period when a work zone was present, then the expected crash frequency is estimated as 4.0 crashes per year ([15 - 5] / [3 - 0.5]). Intersection Crash Frequency The intersection crash frequency is used to predict incident occurrence at each of the intersections within the limits of the facility. The crash frequency that is input represents an esti- mate of the expected crash frequency for the intersection when no work zones are present or special events occur. The estimate should include all severity levels, including property- damage-only crashes. It is provided in units of crashes per year, regardless of the duration of the RRP. Guidance for obtaining this input data is provided in the preceding subsec- tion, “Segment Crash Frequency.” Crash Frequency Adjustment Factor The crash frequency adjustment factor is used to estimate the expected crash frequency when a work zone or special event is present. This factor is multiplied by the expected crash fre- quency for the segment and intersection, as appropriate. Their product represents the expected crash frequency if the work zone or special event were present for 1 year. Two adjustment factors are needed for each alternative data set. One factor applies to segment-related crashes, and the other factor applies to intersection-related crashes. The pair of factors is applied to all segments and intersections on the facility, regardless of whether the work zone is on a small portion of the facility or if it extends for the entire length of the facility. The factor value should include consideration of the effect of the work zone or special event on traffic volume and crash risk. For example, the volume may be reduced due to diver- sion, and changes to the geometry and signal operation may increase the potential for a crash. To illustrate this concept, consider a work zone that is envisioned to increase crash risk by 100% (i.e., crash risk is doubled) and to decrease traffic vol- ume by 50% (i.e., volume is halved). In this situation, the crash frequency adjustment factor is 1.0 (2.0 × 0.5). The analyst’s experience with similar types of work zones or special events should be used to determine the appropriate adjustment factor value for the subject facility. Data Entry This section describes the data entry process for the tool. Data are entered primarily in the Set Up worksheet. However, the default values and calibration factors in the calibration

152 analysis period is selected, then additional input data are needed in the Supplemental Input Data section (discussed later in this section). The tool monitors the Analysis Period entry. Depending on the value entered, the tool will either highlight the appropriate data entry cells in the Supplemental Input Data section with a light-blue background, or it will change the cells to white, which indicates that the supplemen- tal data are not needed. There are two cells for the Study Period data entry. The data in the first cell define the starting hour of the study period in terms of hours since midnight. A value of 0 corre- sponds to midnight; a value of 13.5 corresponds to 1:30 p.m. The data in the second cell indicate the duration of the study period. The Reliability Reporting Period field also has two cells. The data in the first cell define the start date using a month- day-year format. The data in the second cell indicate the duration of the RRP. There are two cells for each alternative data set. The data in the first cell define the start date of the work zone or special event using a month-day-year format. The data in the second cell indicate the duration of the RRP. The Days of Week Considered data entry consists of seven cells. One cell is associated with one day of the week. A Yes or No is entered in each cell. If Yes is entered, then the associated day is considered in the reliability analysis. crash Data The data entry fields associated with the crash data are shown in Figure B.4. The upper portion of the Crash Data section is used to enter the crash frequency for the segments and intersections that comprise the urban street facility. The eight light-blue cells in the upper-left portion are used to enter the segment crash frequency. One cell is associated with each segment. The segment numbers are defined when the base data set is created using the USCE. volume adjustment factors. The Calib-Demand worksheet can be modified if the analyst has factors that are more repre- sentative of the subject site. input filE naMEs The Path data entry field is used to define the location of the HCM data set files. This path also defines the location of the data sets generated by the tool. The path must exist on the stor- age drive (i.e., it will not be created if it does not exist). The Base data entry field is used to record the file name of the base data set. This file includes turn-movement volumes for each intersection on the facility. The date that these vol- umes were counted is entered in the Date of Traffic Count field. If this field is left blank, then the volumes are assumed to represent an average day’s volume, as may be derived from the AADT volume. Similarly, the starting hour of this count is entered in the Starting Hour of Count field. A starting hour of 1:30 p.m. is entered as 13.5. Seven rows are available to enter alternative data sets; one row is used to describe each data set. The file name is entered in the Alternative field. A description of the work zone or special event is provided in the Description field. The infor- mation in this field is not used by the reliability methodology; it is an optional data entry field that will accept any desired combination of numeric and character data. The Basis of Alternative Traffic Volume field is used to indicate the date associated with the volumes in the alterna- tive data sets. The analyst can specify the same date as that associated with the base data set. Alternatively, if the field is left blank, then the volumes are assumed to represent an aver- age day volume. tiME pErioD Data The data entry fields associated with the analysis time period data are shown in Figure B.3. The Analysis Period data entry field allows the analyst to indicate a 0.25-h or a 1.0-h analysis period. If a 0.25-h Time Period Data Time Periods Start Duration End Time Period Checks Analysis period, h: 0.25 ok Study period, h: 7 3 10 ok Reliability reporting period, day: 1/1/2011 365 12/31/2011 ok Alternative 1 operating period, day: 1/2/2011 3 1/4/2011 ok Alternative 2 operating period, day: . . Alternative 3 operating period, day: . . Alternative 4 operating period, day: . . Alternative 5 operating period, day: . . Alternative 6 operating period, day: . . Alternative 7 operating period, day: . . Days of week Sunday Monday Tuesday Wednesday Thursday Friday Saturday considered: No Yes Yes Yes Yes Yes No Figure B.3. Set Up worksheet: Time Period Data section.

153 number data entry cell is used for weather predictions, another for demand prediction, and a third for incident pre- diction. A unique sequence of events is predicted for a given seed number. One, two, or three of the seed numbers can be changed to generate a different set of conditions, if desired. For example, if the seed number for weather events is changed, then a new series of weather events is created and, to the extent that weather influences incident occurrence, a new series of inci- dents is created. Similarly, the seed number for demand varia- tion can be used to control whether a new series of demand volumes is created, and the seed number for incidents can be used to control whether a new series of incidents is created. When evaluating different improvement strategies, it is likely that the analyst will use one set of seed numbers as a variance-reduction technique. In this application, the same seed numbers are used for the evaluation of each strategy. With this approach, the results from an evaluation of one strategy can be compared with those from an evaluation of another strategy. Any observed difference in the results can be attributed to the changes associated with the strategy (i.e., they are not due to random changes in weather or incident events among the evaluations). The nine light-blue cells in the upper-right portion are used to enter the intersection crash frequency. One cell is associated with each signalized intersection. The intersection numbers are defined when the base data set is created using the USCE. The lower portion of the Crash Data section is used to enter the work zone and special event crash frequency adjust- ment factors. Two data entry cells are available for each alter- native data set. One cell is used to enter the adjustment factor for all segments on the facility. The second cell is used to enter the adjustment factor for all intersections on the facility. supplEMEntal input Data The data entry fields associated with the supplemental data are shown in Figure B.5. Light-blue data entry fields are avail- able when a 0.25-h analysis period is used. A Yes or No is entered in the Randomize Demand data entry field. If Yes is entered, then nine light-blue cells are displayed. The peak hour factor is entered for each intersection in the associated light-blue cell. If No is entered, then these cells are white, and no additional data entry is necessary. Three Seed Numbers data entry cells are shown on the right side of the Supplemental Input Data section. One seed Crash Data see note Segment Number 1 2 3 4 5 6 7 8 Work Zone and Special Event Crash Frequency Adjustment Factors see note Segment Intersection Alternative 1 1.1 1.2 Alternative 2 Alternative 3 Alternative 4 Alternative 5 Alternative 6 Alternative 7 8 to 9 3 to 4 5 to 6 7 to 8 4 to 5 18 6 to 7 20 19 Segment cr/year Boundary 2 to 3 16 1 to 2 Frequency 7 8 9 38 17 15 Crash Intersections Intersection Number 1 2 3 4 5 6 Crash Frequency, cr/year 32 33 34 35 36 37 Figure B.4. Set Up worksheet: Crash Data section. Supplemental Input Data Randomize demand among 15-min analysis periods within hour: Yes Seed Numbers PHF PHF Weather: 82 0.99 0.96 Demand: 11 0.92 0.97 Incident: 63 0.93 0.94 0.955 Intersection Number Intersection Number 6 7 8 9 1 2 3 4 Figure B.5. Set Up worksheet: Supplemental Input Data section.

154 Alternatively, the analyst can chose to evaluate every scenario for every other day (i.e., enter 2). This choice will reduce the evaluation time by a factor of two (by evaluating only one- half of the scenarios). More generally, the analyst can specify any integer number for the evaluation interval. The value that is entered is checked by the tool to ensure that it will not bias the results or produce an unacceptably small sample. If the check indicates that an unacceptable outcome will occur, then a warning message is displayed just to the right of the cell specifying the number of days in the scenario evaluation interval (i.e., in cell F5 as shown in Figure B.6). The Engine Path data entry field is used to define the loca- tion of the executable file that implements the HCM2010 urban streets methodology. Performance Summary Worksheet Three drop-down lists in the Performance Summary worksheet accept input from the analyst (see Figure B.7). Information input in these lists is used to determine the scope of the perfor- mance summary. The Direction of Travel list is used to indicate which of the two travel directions is of interest to the analysis. One direction is the eastbound (EB) or northbound (NB) travel direction; the other is the westbound (WB) or southbound (SB) direction. The USCE defines the EB or NB directions to coincide with Phase 2 of the National Electrical Manufacturers Association (NEMA). It defines the WB or SB directions to coincide with NEMA Phase 6. One evaluation of each strategy using the same set of random-number seeds is called a replication. Multiple replica- tions are needed to quantify the best estimate of the desired per- formance measure and its associated confidence interval. Each replication would use a different set of seed values. The Analysis worksheet can be used to compare strategies based on two or more replications. This worksheet uses statistics to compare strategies by quantifying (1) the expected change in perfor- mance and (2) the level of confidence that can be placed in a claim that one strategy has a different performance than another. Advisory MessAges The Advisory Messages section is used to report software- generated warning messages to the analyst. The analyst should check this section after the calculations are completed and before moving on to the Facility Evaluation worksheet. If a message is shown, then the analyst should make the requested corrections and repeat the calculations. If this section is blank, then the analyst can move to the Facility Evaluation worksheet and continue the analysis. Facility Evaluation Worksheet The Facility Evaluation worksheet has two data entry fields: the Scenario Evaluation Interval field and the Engine Path field (see Figure B.6). The Scenario Evaluation Interval uses units of days; it is used to minimize the total evaluation time. The analyst can chose to evaluate every scenario for every day (i.e., enter 1). Figure B.6. Facility Evaluation worksheet. Figure B.7. Performance Summary worksheet. Input Data Direction of travel to be evaluated: System component to be evaluated: Performance measure of interest: Advisory Messages Performance Summary for HCM Urban Street Evaluation Software EB or NB direction (NEMA 2) Facility Travel time

155 Results Review and Interpretation This section describes the output data provided by the tool. These data are provided in the following four worksheets: • Performance Summary; • Weather; • Demand; and • Incident. Performance Summary Worksheet The output data in the Performance Summary worksheet are specific to the direction of travel, system component, and performance measure requested by the analyst. They are dis- played in three locations in the worksheet. The first location, in the upper-left portion of the worksheet, describes sum- mary statistics of the performance measure distribution. These statistics are displayed near the top of the Performance Summary worksheet in the Summary Statistics section (see Figure B.8). The data shown correspond to the facility travel time for a 1-year RRP and a 3-h study period. Three columns of data are shown in the Summary Statis- tics section. The base free-flow speed and base free-flow travel time are shown in the left column. These statistics are always reported, regardless of the performance measure requested by the analyst. They are relevant to the evaluation of travel time data and the calculation of a TTI. The middle and right columns of data in the Summary Statistics section summarize the performance measure requested by the analyst. The middle column lists the average, standard deviation, skewness, and median statistics. The right column lists a selected set of percentile values. The second location for output data is just to the right of the Summary Statistics section. It includes a figure that shows the frequency distribution of the requested performance measure. An example frequency distribution is shown in Figure B.9. This figure shows the facility travel time distribution correspond- ing to the statistics summarized in Figure B.8. The third location for output data, just below the Summary Statistics section, lists in chronological order the performance measure for each analysis period. A sample of these data for the performance measure of facility travel time is shown in Figure B.10. Measures are listed by date, month, day of week, The System Component list is used to indicate whether the performance summary is based on the entire facility or just one segment. Any one of the segments can be individually selected to facilitate a detailed examination of segment performance. The Performance Measure list is used to specify the follow- ing performance measures of interest: • Travel time; • Travel speed; • Stop rate; • Running time; • Through delay; and • Total delay. With one exception, all the measures in the list above describe the performance of the major-street through move- ment. The last measure describes the total delay (in vehicle hours) at one or more intersections. If Facility is selected as the system component, then the total delay is computed for all intersections. If Segment is selected as the system compo- nent, then the total delay is computed for the inter section at the end of the segment in the direction of travel evaluated. For a given intersection lane group, total delay is computed as the product of the analysis period duration, lane-group vol- ume, and lane-group control delay. The lane-group total delay is computed for all intersection lane groups, and then these values are added to obtain the intersection total delay. If travel time is the selected performance measure, then the vehicle miles traveled (VMT) is computed. VMT is computed for each segment and in each scenario and added for all seg- ments on the facility and all scenarios in the RRP. This statis- tic describes overall facility utilization for the RRP. If travel time is the selected performance measure, then the reliability rating is also computed. The reliability rating describes the percentage of VMT on the facility associated with a travel time index (TTI) less than 2.5. A facility that satisfies this criterion during a given scenario is likely to pro- vide a level of service D or better for that scenario. The TTI is computed using the average travel speed (as opposed to a per- centile value). The TTI and VMT are computed for each seg- ment in each scenario. The VMT for those segments and scenarios with a TTI less than 2.5 is summed for all segments on the facility and all scenarios in the RRP. This VMT is then used to compute the reliability rating. Summary Statistics Scenario evaluation interval: 1 Average: 443.74 5th percentile: 344.97 Base free-flow speed, mi/h: 41.08 Standard deviation: 309.41 10th percentile: 347.63 Base free-flow travel time, s: 262.90 Skewness: 7.20 80th percentile: 412.72 Reliability rating: 93.2 Median: 371.85 85th percentile: 431.13 Total vehicle-miles travel (1,000's): 2260 Number of obs.: 3120 95th percentile: 783.82 Figure B.8. Performance Summary worksheet: Summary Statistics section.

156 shown in Figure B.11 so that the figure text could be kept at a readable size. The second location for output data, just below the weather statistics, lists in chronological order the predicted weather conditions for each analysis period. A sample of these data is shown in the lower portion of Figure B.11. The first six columns define the date and time of the analysis period. The remaining columns describe the weather condi- tions. A snow event is shown to occur starting at 7:00 a.m. on January 5, 2011. The precipitation amount in the second to the last column describes the liquid equivalent of the snowfall rate. Demand Worksheet The Demand worksheet provides supplemental output data (see Figure B.12) that consist of the demand volume adjust- ment factors that were read from the Calib-Demand work- sheet. These factors represent the distribution of volume by hour of day, day of week, and month of year. Data are located in two sections of the Demand worksheet. The upper portion of the worksheet lists the adjustment fac- tors that are applicable to the base data set and the alternative data sets. These factors are used to convert the turn-movement volumes in the data set to AADT volume estimates. The infor- mation in Figure B.12 indicates that the turn-movement volumes in the base data set are based on 1-h counts taken on January 4, 2011, starting at 7:00 a.m. The data entry fields for this date and time are provided in the Set Up worksheet, as shown in Figure B.2. and start time of the analysis period. The day of week is numeric; Sunday is Day 1. Weather Worksheet The Weather worksheet provides supplemental output data (see Figure B.11). Data are located in two sections of the Weather worksheet. The top portion of the worksheet lists the weather statistics for the city nearest to the subject facility. These statistics were read from the Calib-Weather worksheet and reported back to the Weather worksheet for the analyst’s convenience. One set of weather statistics is provided for each month of the year. The statistics for October, November, and December are not 0 200 400 600 800 1000 1200 1400 31 0.0 36 6.0 42 2.0 47 8.0 53 4.0 59 0.0 64 6.0 70 2.0 75 8.0 81 4.0 87 0.0 Performance Measure Value Fr eq ue nc y Figure B.9. Performance Summary worksheet: frequency distribution. Period Day of Start Perf. Number Day Date Month Week Time Measure (hr) (s) 1 3 1/3/2011 1 2 7.00 366.6 2 3 1/3/2011 1 2 7.25 367.5 3 3 1/3/2011 1 2 7.50 363.3 4 3 1/3/2011 1 2 7.75 367.1 5 3 1/3/2011 1 2 8.00 351.5 6 3 1/3/2011 1 2 8.25 356.2 7 3 1/3/2011 1 2 8.50 348.2 8 3 1/3/2011 1 2 8.75 347.3 9 3 1/3/2011 1 2 9.00 332.8 10 3 1/3/2011 1 2 9.25 333.0 11 3 1/3/2011 1 2 9.50 333.9 12 3 1/3/2011 1 2 9.75 332.9 13 4 1/4/2011 1 3 7.00 369.8 14 4 1/4/2011 1 3 7.25 365.7 15 4 1/4/2011 1 3 7.50 370.5 16 4 1/4/2011 1 3 7.75 368.5 17 4 1/4/2011 1 3 8.00 350.5 18 4 1/4/2011 1 3 8.25 348.6 19 4 1/4/2011 1 3 8.50 349.3 Figure B.10. Performance Summary worksheet: analysis period results.

157 The Incident worksheet lists in chronological order the incident type and location for each analysis period. One group of 12 columns is dedicated to each intersection and to each segment on the facility. For a given intersection or segment, the 12 columns collectively describe the incident type, lane location, and severity. Each row of the worksheet corresponds to one analysis period. If all the cells are blank for a given analy- sis period (i.e., row), then no incident was predicted to occur. If a cell has a value, then an incident is indicated to exist for that time period. The lower portion of the Demand worksheet lists in chrono- logical order the adjustment factors used for each analysis period. These factors are used to convert the AADT estimates into turn-movement volumes corresponding to the specific analysis period. Incident Worksheet The Incident worksheet provides supplemental output data (see Figure B.13). Location: LINCOLN, NE JAN FEB MAR APR MAY JUN JUL AUG SEP Normal precipitation, in/month 0.67 0.66 2.21 2.9 4.23 3.51 3.54 3.35 2.92 Snowfall, in/month 6.6 6 5.7 1.5 0.1 0 0 0 0 Days with precip./month 5 5 8 9 11 9 9 8 7 Average temp, degrees 22.4 28.3 39.4 51.2 62 72.7 77.8 75.4 66 Precip. per event, in/event 0.13 0.13 0.28 0.32 0.38 0.39 0.39 0.42 0.42 Total analysis periods with weather effects: 144 Total analysis periods: 3120 Total periods with rain events: 76 Total periods with snow events: 33 Period Day of Start Rain Wet Snow Snow or Precip. Number Day Date Month Week Time Amount Pavement Amount Ice on Amount (h) (in/h) (in/h) Pavement (in/h) Total 19 4 1/4/2011 1 3 8.50 0.00 no 0.00 no 0.00 20 4 1/4/2011 1 3 8.75 0.00 no 0.00 no 0.00 21 4 1/4/2011 1 3 9.00 0.00 no 0.00 no 0.00 22 4 1/4/2011 1 3 9.25 0.00 no 0.00 no 0.00 23 4 1/4/2011 1 3 9.50 0.00 no 0.00 no 0.00 24 4 1/4/2011 1 3 9.75 0.00 no 0.00 no 0.00 25 5 1/5/2011 1 4 7.00 0.00 no 0.79 YES 0.08 1 26 5 1/5/2011 1 4 7.25 0.00 no 0.79 YES 0.08 1 27 5 1/5/2011 1 4 7.50 0.00 no 0.79 YES 0.08 1 Figure B.11. Weather worksheet. Location: LINCOLN, NE Functional Class: Urban Principal Arterial Day of Start Hr of Day Day of Wk Month of Date Month Week Time (h) Factor Factor Yr Factor Date of traffic count 1/4/2011 1 3 7 0.071 0.980 0.831 Basis of alt. traffic vol.: Ave.day 7 0.059 1.000 1.000 Day of Week: 1:Sun | 2:Mon | 3:Tue | 4:Wed | 5:Thr | 6:Fri | 7:Sat Total analysis periods with unique factors: 720 Total analysis periods: 3120 Period Day of Start Hr of Day Day of Wk Month of Number Day Date Month Week Time Factor Factor Yr Factor (h) Total 1 3 1/3/2011 1 2 7.00 0.071 0.980 0.831 1 2 3 1/3/2011 1 2 7.25 0.071 0.980 0.831 1 3 3 1/3/2011 1 2 7.50 0.071 0.980 0.831 1 4 3 1/3/2011 1 2 7.75 0.071 0.980 0.831 1 5 3 1/3/2011 1 2 8.00 0.058 0.980 0.831 1 6 3 1/3/2011 1 2 8.25 0.058 0.980 0.831 1 7 3 1/3/2011 1 2 8.50 0.058 0.980 0.831 1 8 3 1/3/2011 1 2 8.75 0.058 0.980 0.831 1 9 3 1/3/2011 1 2 9.00 0.047 0.980 0.831 1 Figure B.12. Demand worksheet.

158 in the Highway Safety Manual (American Association of State Highway and Transportation Officials 2010). Intersection crashes include crashes that occur at an inter- section (i.e., within the curb limits) and crashes that occur on the intersection legs and are intersection related. All crashes that are not classified as intersection or intersection-related crashes are considered to be segment-related crashes. Figure B.14 illustrates the method used to assign crashes to segments or intersections. As shown, all crashes that occur within the curb line limits of an intersection (i.e., Region A) are assigned to that intersection. Crashes that occur outside the curb line limits of an inter- section (i.e., Region B) are assigned to either the segment on which they occur or an intersection, depending on their char- acteristics. Region B represents the roadway between two inter- sections. Crashes that are classified on the crash report as intersection related or have characteristics consistent with an intersection-related crash are assigned to the intersection to which they are related; such crashes would include rear-end crashes related to queues on an intersection approach. Crashes that occur between intersections and are not related to an intersection are assigned to the roadway segment on which they occur. In some jurisdictions, crash reports include a field that allows the reporting officer to designate the crash as intersec- tion related. When this field is available on the crash reports, crashes should be assigned to the intersection or the segment based on the way the officer marked the field on the report. In jurisdictions where there is not a field on the crash report that allows the officer to designate crashes as intersec- tion related, the characteristics of the crash may be consid- ered to help determine whether the crash should be assigned to the intersection or the segment. Other fields on the report, such as crash type, number of vehicles involved, contribut- ing circumstances, weather condition, pavement condition, The incident location is indicated by determining in which group of 12 columns the nonblank cell exists. That is, if a group of 12 columns has one or more cells with a value in it, then this condition indicates that the associated intersection or seg- ment was predicted to experience an incident. If the location is an intersection, then the cell value indicates the intersection approach location of the incident. The cell value represents the NEMA number of the phase that serves the affected intersec- tion approach. If the location is a segment, then the cell value indicates the direction of travel associated with the incident. The value is the NEMA number of the phase that serves the direction of travel. The NEMA phase-numbering scheme for the subject facil- ity is defined in the USCE and communicated to the tool using the HCM data set. The USCE defines the EB or NB directions to coincide with NEMA Phase 2. It defines the WB or SB directions to coincide with NEMA Phase 6. It defines the NB or WB directions to coincide with NEMA Phase 8. It defines the SB or EB directions to coincide with NEMA Phase 4. For example, the data in Figure B.13 indicate that a crash occurred on the Phase 2 approach of Intersection 1 at 8:00 a.m. on May 10, 2011. The crash was a fatal or injury crash that blocked two or more lanes for a 2-h period. Supplemental Guidance for Assigning Reported Crashes The reliability methodology requires an estimate of the expected average crash frequency for intersections and for segments on the facility. One source of this estimate is reported crash history data. However, these crashes must be properly assigned to the location of their occurrence. The assignment process requires differentiation of each crash as either an intersection-related crash or a segment-related crash. This sec- tion describes the crash assignment procedure recommended Total analysis periods with incidents: 156 Total analysis periods: 3120 Expected Segment Intersection Total Total Total crash incidents: 4 13 17 11.6 Total non-crash incidents: 6 27 33 24.6 Period Day of Start Fatal or Inj PDO Fatal or Inj PDO Fatal or Inj PDO Brkdwn Other Brkdwn Other Brkdwn Other Number Day Date Month Week Time 2 0 8 0 4 0 5 0 4 0 4 0 1093 130 5/10/2011 5 3 7.00 1094 130 5/10/2011 5 3 7.25 1095 130 5/10/2011 5 3 7.50 1096 130 5/10/2011 5 3 7.75 1097 130 5/10/2011 5 3 8.00 2 1098 130 5/10/2011 5 3 8.25 2 1099 130 5/10/2011 5 3 8.50 2 1100 130 5/10/2011 5 3 8.75 2 1101 130 5/10/2011 5 3 9.00 2 1102 130 5/10/2011 5 3 9.25 2 1103 130 5/10/2011 5 3 9.50 2 1104 130 5/10/2011 5 3 9.75 2 1105 131 5/11/2011 5 4 7.00 Crash Non-Crash One lane Two+ Lanes Shoulder One lane Two+ Lanes Shoulder Intersection 1 Figure B.13. Incident worksheet.

159 • Segment 6: input data describing the segment located between Intersections 6 and 7; • Segment 7: input data describing the segment located between Intersections 7 and 8; and • Segment 8: input data describing the segment located between Intersections 8 and 9. The segment and intersection numbers are defined sequen- tially in the EB or NB direction of travel. The data entered in each segment worksheet describe both the road between the intersections and the downstream signalized intersection. The data entered in each segment worksheet are identical, so only the data entry for the Segment 1 worksheet will be described in this section. If the facility has fewer than eight segments, then data are entered only for those segments that exist. Many input values and parameters are associated with the USCE. The meaning of each value or parameter is described in Chapter 17 or 18 of the HCM2010. The data entry cell for each parameter is populated with a default value in the USCE. After the data are entered, the analyst should return to the Set Up worksheet to save the data in an HCM data set. Click- ing the button labeled Write Data to File saves the data to a file. This button is located in the upper-right corner of the worksheet. The next section describes where the analyst can enter the file name. Set Up Worksheet The data entry fields in the Set Up worksheet are divided into six sections. The input data fields in each section are described in the following paragraphs. General Information The General Information section shown in Figure B.15 is located near the top of the Set Up worksheet. traffic control malfunction, and sequence of events can pro- vide helpful information in making this determination. If the officer’s narrative and a crash diagram are available, they can also assist in making the determination of a crash’s inter- section relationship. The following crash characteristics are indicative of an intersection-related crash: • A rear-end crash in which both vehicles were going straight approaching an intersection or in which one vehicle was going straight and struck a stopped vehicle; and • A crash in which the report indicates a signal malfunction or improper traffic control at the intersection contributed to the crash. Urban Streets Computational engine data entry This section describes the data entry process for the USCE, which implements the urban streets methodology described in Chapter 16 of the HCM2010. The 10 input worksheets in the USCE are as follows: • Set Up: general input data to describe overall characteris- tics of the facility and start calculations; • Intersection 1: input data describing the first signalized intersection encountered in the EB or NB travel direction; • Segment 1: input data describing the segment located between Intersections 1 and 2; • Segment 2: input data describing the segment located between Intersections 2 and 3; • Segment 3: input data describing the segment located between Intersections 3 and 4; • Segment 4: input data describing the segment located between Intersections 4 and 5; • Segment 5: input data describing the segment located between Intersections 5 and 6; Segment Length All crashes that occur within this region are classified as intersection crashes. Crashes in this region may be segment or intersection related, depending on the characteristics of the crash. B A A A B B B B B B B Figure B.14. Definition of roadway segments and intersections.

160 parameters can be entered in the Supplemental Urban Street Parameters section that is located at the bottom of the Set Up worksheet (not shown). Default values are provided for these parameters. Basic Segment Information The Basic Segment Information section is shown in Fig- ure B.16. The names of the two streets that bound the segment are listed in Columns 2 and 3. The name of the street crossed when departing the segment in the WB (or SB) direction is shown in Column 2. The name of the street crossed when departing the segment in the EB (or NB) direction is shown in Column 3. The Location, Analysis Period, and Analyst data entry fields are used to describe the project being evaluated. These entries are not used by the reliability methodology. They are optional data entry fields that will accept any desired combi- nation of numeric and character data. The File Name data entry field is used to define the path location and name of the HCM data set files. The path must exist on the storage drive (i.e., it will not be created if it does not exist). Urban Street Parameters The data entry fields in the Urban Street Parameters section are shown in the lower portion of Figure B.15. Two additional Figure B.15. USCE Set Up worksheet: General Information and Urban Street Parameters sections. General Information Location: Analysis Period: File name: Analyst: JHD Urban Street Parameters Start-up lost time (l1), s 2.0 Stored vehicle lane length, ft 25 Extension of effective green, s 2.0 Number of calculation iterations 15 Analysis time period (T), h 0.25 Length of left-turn bay (access point), ft 250 Critical merge headway, s 3.7 Right-turn equivalency factor (signalized) 1.18 Deceleration rate (access point), ft/s2 6.7 Sneakers per cycle, veh: 2.0 Right-turn speed (access point), ft/s 20 Base saturation flow rate, pc/h/ln 1900 Deceleration rate (signal), ft/s2 4.0 Distance between stored vehicles, ft 8.0 Acceleration rate, ft/s2 3.5 Left-turn equivalency factor (signalized) 1.05 Headway of bunched vehicle stream, s/veh 1.5 Critical headway for major left (access pt.), s 4.1 Maximum headway in a platoon, s/veh 3.6 Follow-up headway for major left (access pt.), s 2.2 Stop threshold speed, mph 5.0 Right-turn equivalency factor (access point) 2.2 C:\Documents and Settings\TexasAM2 Texas Avenue, Austin, Texas 7:15 am to 7:30 am Figure B.16. USCE Set Up worksheet: Basic Segment and Coordination Information sections. Basic Segment Information Segment Segment Number EB WB EB WB Length, ft 1 First Avenue Second Avenue 35 35 2 2 1800 2 Second Avenue Third Avenue 35 35 2 2 1800 3 Third Avenue Fourth Avenue 35 4 Fourth Avenue Fifth Avenue 5 Fifth Avenue Sixth Avenue 6 Sixth Avenue Seventh Avenue 7 Seventh Avenue Eighth Avenue 8 Eighth Avenue Ninth Avenue No. Intersections: 3 Total, mi: 0.68 Coordination Information 22 Travel direction for Movement 2 at all intersections Cycle Length, s: 100 Origin–Destination Seed Proportions Upstream Origin Downstream Cross St. Major St. Cross St. Mid-Seg. Destination Left Turn Through Right Turn Entry Left Turn 0.02 0.10 0.05 0.02 Through 0.91 0.78 0.92 0.97 Right Turn 0.05 0.10 0.02 0.01 Mid-Segment Exit 0.02 0.02 0.01 0.00 Through Lanes Street to West Cross Street Names Street to East Speed Limit, mph EB

161 entry. This schematic is repeated at the top of the Intersection worksheet and at the top of each Segment worksheet. Origin–Destination Seed Proportions The data entry fields in the Origin–Destination Seed Propor- tions section are used to enter the proportion of upstream traffic (by movement) that arrives at each downstream desti- nation movement. The values in these cells represent default values and will not likely need to be modified for most reli- ability evaluations. Intersection 1 Worksheet The data entered in the Intersection 1 worksheet is catego- rized in three sections. The data entry fields in each section are described in the following paragraphs. There is also an Advisory Messages section near the bottom of this work- sheet (not shown) that should be consulted after all data are entered in this worksheet. Advisory messages will be posted when the data entered are contradictory, missing, or out of range. Signalized Intersection Input Data The data entered in the Signalized Intersection Input Data section are shown in Figure B.18. This section describes the data entry fields for the individual movements at the inter- section. One column is provided for data entry for the left- turn, through, and right-turn movements on each intersection This section is also used to inform the USCE about the num- ber of intersections on the facility. This number is reported in the last line of this section. It is based on the count of segments for which the analyst has provided speed limit, lane, and seg- ment length data in the rows above. The number of inter- sections is equal to one more than the number of segments. The data shown in Figure B.16 indicate that there are two segments and three intersections on the subject facility. The speed limit for the WB approach to Intersection 3 (at Fourth Avenue) is 35 mph. This approach is external to the facility (i.e., it serves through vehicles, but it is not on one of the seg- ments). If the facility has eight segments, then the speed limit for the WB approach to Intersection 9 (at Ninth Avenue) is entered in the Segment 8 worksheet. Similarly, the EB approach at Intersection 1 is external to the facility. The speed limit for this approach is entered in the Intersection 1 work- sheet. Based on these data entry rules, the reader will note that there will always be one more speed limit entry in the WB column than in the EB column whenever there are fewer than eight segments. Coordination Information The Coordination Information section is used to define the direction of travel associated with NEMA Phase 2, which is the same as Movement 2. The direction that is chosen is then used to establish the association between the intersection number, segment number, phase number, and travel direction. A street schematic of the facility is shown in Figure B.17; the inter- section and segment numbers are established by the data Intersection No.: 1 2 3 4 5 6 7 8 9 N Segment No.: 1 2 3 4 5 6 7 8 Downstream intersection in red circle. Street Schematic Figure B.17. USCE Set Up worksheet: Intersection and Segment Numbers. Figure B.18. USCE Intersection 1 worksheet: Signalized Intersection Input Data section. Signalized Intersection Input Data (In each column, enter the volume and lanes data. For all other blue cells, enter values only if there is one or more lanes.) Approach Movement L T R L T R L T R L T R Movement number 5 2 12 1 6 16 3 8 18 7 4 14 Volume, veh/h 200 1000 10 200 1000 10 100 500 50 100 500 50 Lanes 1 2 1 1 2 1 1 2 0 1 2 0 Turn bay length, ft 200 200 200 200 200 200 Sat. flow rate, veh/h/ln 1800 1800 1800 1800 1800 1800 1800 1800 1800 1800 Platoon ratio 1.000 1.333 1.000 1.000 1.333 1.000 1.000 1.000 1.000 1.000 Initial queue, veh 0 0 0 0 0 0 0 0 0 0 Speed limit, mph 35 35 35 35 35 35 35 35 35 35 35 35 Stop line det. length, ft 40 40 40 40 40 40 Max. allow. hdwy, s/veh 3.9 3.9 3.9 2.9 3.9 2.9 Opp. rt-turn lane influence Yes Yes Yes Yes Signalized Intersection 1 Eastbound Westbound Northbound Southbound

162 fwid = saturation flow rate adjustment factor for approach width; freduce = saturation flow rate adjustment factor for reducing lanes during work zone presence; aw = approach lane width during work zone (total width of all open left-turn, through, and right-turn lanes plus any setback distance to adjacent curb or work zone traffic control devices), ft; no = number of left-turn and through lanes open during normal operation; and nwz = number of left-turn and through lanes open during work zone presence. Equation B.1 produces values less than 1.0 for a wide range of conditions. However, when the approach has many lanes open while a work zone is present (or a few wide lanes), then Equation B.1 can mathematically produce a value that exceeds 1.0. In these few instances, a value of 1.0 is recommended as an upper bound on the factor value. One factor value is computed for each approach with a work zone present. The computed factor is then used to esti- mate the saturation flow rate for the through movement, as well as the left- and right-turn movements from exclusive lanes, on this approach. Platoon Ratio The Platoon Ratio data entry field is provided for all intersec- tion movements. However, with a few exceptions, the values provided for Movements 2 and 6 will be ignored. One of the exceptions is the EB (or NB) Movement 2 at Intersection 1. This movement is an external movement. Its platoon ratio and speed limit need to be entered in this section. The other exception is for the WB (or SB) Movement 6 at the last intersection on the facility. This movement is also an external movement. In this case, the platoon ratio for this movement will need to be entered in the Segment worksheet associated with the last intersection. Phase Sequence and Left-Turn Mode The Phase Sequence and Left-Turn Mode section is shown in Figure B.19. Drop-down lists are used to describe the phase sequence and left-turn mode for the major street and the cross- street approaches. The left-turn mode can be permitted, protected–permitted, or protected only. The USCE requires approach. Separate groups of three columns are provided for each of the four intersection approaches. In each column, the volume and lanes data are entered for the associated movement. For all other blue cells, values are entered only if there is one or more exclusive lanes serving the movement. If two or more movements share a lane, then their combined data are entered in the column for the through movement. Saturation Flow Rate The Saturation Flow Rate data entry field is used to describe the adjusted saturation flow rate for every movement with one or more lanes. The value entered should reflect the effect of lane width, heavy-vehicle presence, grade, parking activity, local buses that stop, area type, lane utilization, pedestrian conflicts, and bicycle conflicts. If the movement does not exist, then the cell should be left blank (i.e., cell contents should be deleted). The procedure in Chapter 18 of the HCM2010 (i.e., Step 4) can be used to estimate the adjusted saturation flow rate. How- ever, for left-turn (or right-turn) movements, the saturation flow rate entered should be based on a left-turn (or right-turn) adjustment factor of 1.0 (i.e., do not adjust for permitted or protected–permitted operation). If a work zone is present on an intersection approach, then an additional saturation flow rate adjustment factor fwz is computed using Equation B.1. This factor is then multiplied by the saturation flow rate obtained from Chapter 18 of the HCM2010 to obtain the value to be entered in the USCE worksheet. Equations B.2 and B.3 are used to calculate the saturation flow rate adjustment factors for approach width and reducing lanes during work zone presence, respectively. = × × ≤0.858 1.0 (B.1)wz wid reducef f f with ( )= − − 1.0 1.0 0.0057 12 (B.2)widf aw ( )= + − 1.0 1.0 0.0402 (B.3)reduce wz f n no where fwz = saturation flow rate adjustment factor for work zone presence; Phase Sequence and Left-Turn Mode Major street sequence Cross street sequence (movement numbers shown) (movement numbers shown) Major street left-turn mode Cross street left-turn mode (movement numbers shown) (movement numbers shown) 5/1 Protected-Only 3/7 Protected+Permitted 5 & 1 left leading 3 & 7 left leading Figure B.19. USCE Intersection 1 worksheet: Phase Sequence and Left-Turn Mode section.

163 not be discussed in this section. The remaining two sections are described in the following paragraphs. There is also an Advisory Message section near the bot- tom of this worksheet (not shown) that should be consulted after all data are entered in this worksheet. Messages will be posted when the data entered are contradictory, missing, or out of range. Free-Flow Speed Input Data The Free-Flow Speed Input Data section is shown in Figure B.21. The data entered in this section are used to compute the free- flow speed for the segment. A speed is computed for each direction of travel. The values in the white cells were entered in the Set Up worksheet and are repeated here for convenience. A Supplemental Segment Data section (not shown) located just to the right of the Free-Flow Speed Input Data section allows the analyst to enter any midsegment delay to through that both approaches on a given street have the same left-turn mode. Phase sequence choices are identified in the following list: • No exclusive phase; • Lead/lead left-turn phases; • Lead/lag left-turn phases; and • Lag/lag left-turn phases. Phase Settings The Phase Settings section is shown in Figure B.20. The phase numbers referenced in this figure correspond to the move- ment numbers shown in Figure B.18. Segment 1 Worksheet The data entered in the Segment 1 worksheet are categorized in five sections. The data entry fields in three of these sections are the same as in the Intersection 1 worksheet, so they will Phase Settings Approach Phase number 5 2 1 6 3 8 7 4 Movement L T+R L T+R L T+R L T+R Lead/lag left-turn phase Lead -- Lead -- Lead -- Lead -- Left-turn mode Prot. -- Prot. -- Pr/Pm -- Pr/Pm -- Passage time, s 2.0 -- 2.0 -- 2.0 2.0 2.0 2.0 Minimum green, s 5 -- 5 -- 5 5 5 5 Yellow + red clear, s 3.0 4.0 3.0 4.0 3.0 4.0 3.0 4.0 Phase split, s 20 35 20 35 20 25 20 25 Recall -- -- Dual entry Ref. Phase Offset, s: 0 Offset Ref.: Force Mode: Cycle, s: 100 Enable Simultaneous Gap-Out? Enable Dallas Left-Turn Phasing? Phase Group 1,2,5,6: Phase Group 3,4,7,8: Phases 1,2,5,6: Phases 3,4,7,8: Eastbound Westbound Northbound Southbound No No No No No No No Yes No Yes No Yes No Yes End of Green Fixed2 Figure B.20. USCE Intersection 1 worksheet: Phase Settings section. Figure B.21. USCE Segment 1 worksheet: Free-Flow Speed Input Data section. Input Data EB WB Basic Segment Data Number of through lanes that extend the length of the segment: 2 2 Speed limit, mph 35 35 Segment Length Data Length of segment (measured stopline to stopline), ft 1800 1800 Width of upstream signalized intersection, ft 50 50 Adjusted segment length, ft 1750 1750 Length of segment with a restrictive median (e.g., raised-curb), ft 0 0 Length of segment with a non-restrictive median (e.g., two-way left-turn lane), ft 0 0 Length of segment with no median, ft 1750 1750 Percentage of segment length with restrictive median, % 0 0 Access Data Percentage of street with curb on right-hand side (in direction of travel), % 70 70 Number of access points on right-hand side of street (in direction of travel) 4 4 Access point density, access points/mi 24 24 Free-Flow Speed Computation

164 Software Description The software used for a reliability evaluation consists of two Excel workbooks and one executable file. These files are described in this section. USRE Workbook The USRE workbook supports the evaluation of a facility’s reliability of service in terms of its operational performance over an extended time period. The software is distributed as a MS Excel workbook using VBA programming language. This workbook is used to guide the reliability evaluation and implement the reliability methodology. It interacts with other software and creates data files as needed for the evaluation. Guidelines for using this workbook are provided below. The file name for this workbook is USRE-XY.xls. The letters X and Y are used to convey the software version. USCE Workbook The USCE workbook implements the urban streets methodol- ogy described in Chapter 16 of the HCM2010. This workbook is used to create the HCM data set that includes the input data needed to evaluate an urban street facility using the HCM. The file name for this workbook is C17_A06-4_G06-4_ V2010_L08.xls. L08 is added to the file name to indicate that this workbook is an enhanced version of the HCM workbook implementing the methodology in HCM2010, Chapter 17. The workbook has been enhanced to explicitly model the effect of spillback on intersection operation. HCM Executable This executable file is a compiled version of the VBA code in the USCE workbook. It is called the USRE workbook, and it is vehicles traveling along the segment that is due to sources other than turns at the access points (as described in the next section). These other sources of delay may include curb park- ing, pedestrian crossings, double parking, and so forth. Access Point Input Data The Access Point Input Data section is shown in Figure B.22. The data entered in this section are used to compute the delay to through movements as a result of vehicles turning from the major street into an access point. The access points described in this section are sufficiently busy that they are likely to result in some delay to the major-street through movement. Data for a maximum of six access points can be entered. These data are entered in order from top to bottom as they occur in an EB or NB direction of travel. Access point location represents the distance measured from the stop line of the upstream signalized intersection to the equivalent stop line at the downstream access point in the subject direction of travel. If several low-volume access points exist and none are going to be entered as a separate access point, they can be combined into one surrogate access point. The volume for each minor movement at the surrogate access point should equal the sum of the corresponding minor movements for all access points being combined. The location of the surro- gate access point should represent the average of the dis- tances to each of the individual access points that were combined. Software Setup and File description This section describes the software and data files associated with the USRE workbook and summarizes the process for setting up the file structure for a typical application. Figure B.22. USCE Segment 1 worksheet: Access Point Input Data section. Access Point Input Data Access Approach Point Movement L T R L T R L T R L T R Location,ft Movement number 1 2 3 4 5 6 7 8 9 10 11 12 600 Volume, veh/h 80 1050 100 80 1050 100 80 0 100 80 0 100 West end Lanes 0 2 0 0 2 0 1 0 1 1 0 1 1200 Volume, veh/h 80 1050 100 80 1050 100 80 0 100 80 0 100 Lanes 0 2 0 0 2 0 1 0 1 1 0 1 Volume, veh/h 0 0 0 0 0 0 0 0 0 0 0 0 Lanes 0 2 0 0 2 0 0 0 0 0 0 0 Volume, veh/h 0 0 0 0 0 0 0 0 0 0 0 0 Lanes 0 2 0 0 2 0 0 0 0 0 0 0 Volume, veh/h 0 0 0 0 0 0 0 0 0 0 0 0 Lanes 0 2 0 0 2 0 0 0 0 0 0 0 Volume, veh/h 0 0 0 0 0 0 0 0 0 0 0 0 East end Lanes 0 2 0 0 2 0 0 0 0 0 0 0 Eastbound Westbound Northbound Southbound

165 The file name for this file is yyyymmdd-HHhh.out. The file naming convention is the same as that for the sce- nario data set file as described in the previous section. The scenario data set files are saved in the same folder as the HCM data set file. The file is a comma-delimited text file and can be read using any word processing software program (e.g., Notepad). It can also be opened in an Excel worksheet. Sample content of this file is shown in Figure B.23. The units are shown on the right-hand side of the figure for each variable listed. The text for the units is shown here for convenience; it is not included in the text file. The first three entries in the scenario output file shown in Figure B.23 are defined as follows: • FileName: the first line lists the name of the subject sce- nario output file. • NbrSegments: the number of segments for which data are provided in the file. The data for Segment 1 begin in the third row (the data for Segment 2 are not shown). • SEGMENT: the values in this section describe the perfor- mance of the through movement on Segment 1. Each value represents an average for the analysis period. This section is repeated for each numbered segment. The fourth line identifies the two vehicle movements (by number) representing the major-street through movements. Each movement is associated with one travel direction along the major street. Movement 2 (i.e., EB or NB) is listed first. Movement 6 (i.e., WB or SB) is listed second. This is a header line because it defines the order of presentation for the values listed in the subsequent rows for the segment. Specifically, the first value listed corresponds to Movement 2, and the second value listed corresponds to Movement 6. For example, the row with the segment through delay (SegThruDelay) shows 20.369 seconds per vehicle (s/veh) for Movement 2 travel direction and 20.043 s/veh for Movement 6 travel direction. The movement numbers are shown in Figure B.24. Other entries in the scenario output file shown in Fig- ure B.23 are defined as follows: • SegLength: This is the length of the segment, which is the same in each direction of travel. • SYSTEM: The values in this section describe the perfor- mance of the through movement on the facility. They are computed from the through movement values for each segment. Each value represents an average for the analysis period. • NbrIntersections: The number of intersections for which data are provided in the file. The data for Intersection 1 begin with the next row (the data for Intersections 2 and 3 are not shown). used to evaluate the data set associated with each scenario. It is compiled to minimize the time required to evaluate a data set. The file name for this file is engine17.exe. The path to this engine is input to the USRE workbook in the Facility Evaluation worksheet. Data File Description The three data files associated with the use of the USRE work- book are described in this section. HCM Data Set File The HCM data set files are created using the USCE work- book. The base data set is used to describe the urban street when there are no work zones or special events present. One or more alternative data sets are used to describe the urban street when a work zone, special event, or both are present. The file name for this file is specified by the analyst using any characters acceptable to the Windows operating system. The file extension is “.txt”. The base and alternative data sets are created by the analyst and saved in a folder. The path to this folder is input by the analyst in the Set Up worksheet of the USRE workbook. Scenario Data Set File The USRE workbook creates one scenario data set file for each scenario. This data set is created from the HCM data set, but it is modified to reflect the demand levels, speed, and saturation flow rate, as they may be influenced by the events predicted for the specific scenario. The file name for this file is yyyymmdd-HHhh.txt. The file name describes the date and time associated with the scenario. The letters yyyy are used to indicate the year, mm indicates the month, and dd indicates the day of the month. HH indicates the hour associated with the start of the scenario (in military time); hh indicates the percentage of an hour associated with the start of the scenario. Values used are 00%, 25%, 50%, and 75%, which correspond to 00, 15, 30, and 45 min, respectively. For example, 1825 indicates the sce- nario start time is 6:15 p.m. The scenario data set files are saved in the same folder as the HCM data set file. Scenario Output File The USRE workbook creates one scenario output file for each scenario. This data set contains the output from the HCM executable file; that is, it contains the predicted delay and queue length at each intersection, as well as the travel time and travel speed for each segment and for the overall facility.

166 "FileName:","TexasAM2.out" "NbrSegments",2 "SEGMENT:",1 " 02 06" "SegLength",1800............................................................................. (ft) "SegBaseFreeFlowSpeed",40.78,40.78......................................................... (mi/h) "SegRunningTime",33.46,33.43.................................................................. (s) "SegRunningSpeed",36.67,36.71.............................................................. (mi/h) "SegThruDelay",20.369,20.043.............................................................. (s/veh) "SegTravelSpeed",22.8,22.95................................................................ (mi/h) "SegThruStops",.596,.585.............................................................. (stops/veh) "SegSpatialStops",1.75,1.72............................................................ (stops/mi) "SegThruVolume",968.35,949.29............................................................. (veh/h) "SYSTEM" "SystemTravelTime",107.3,107.3................................................................ (s) "SystemTravelSpeed",22.87,22.87............................................................ (mi/h) "SystemSpatialStops",1.73,1.73......................................................... (stops/mi) "SystemBaseFreeFlowSpeed",40.78,40.78...................................................... (mi/h) "NbrIntersections",3 "INTERSECTION:",1 "TimerPhaseAssign0",1,2,3,4,5,6,7,8 "Left Lane Group" "TimerPhaseAssign",1,0,3,0,5,0,7,0............................................................... "TimerGroupVolume",189.9,0,100,0,200,0,100,0.............................................. (veh/h) "TimerGroupUniformDelay",46.875,0,30.966,0,42.179,0,30.966,0.............................. (s/veh) "TimerGroupIncDelay",2.534,0,.601,0,3.436,0,.601,0........................................ (s/veh) "TimerGroupD3Delay",0,0,0,0,0,0,0,0....................................................... (s/veh) "TimerGroupUniformStops",.952,0,.716,0,.851,0,.716,0.................................. (stops/veh) "TimerGroupIncStops",.03,0,.013,0,.04,0,.013,0........................................ (stops/veh) "TimerGroupH3Stops",0,0,0,0,0,0,0,0................................................... (stops/veh) "TimerGroupFinalQue",0,0,0,0,0,0,0,0........................................................ (veh) "Middle Lane Group" "TimerPhaseAssign",0,2,0,4,0,6,0,8............................................................... "TimerGroupVolume",0,1000,0,278.6,0,949.3,0,278.6......................................... (veh/h) "TimerGroupUniformDelay",0,12.58,0,38.907,0,18.971,0,38.907............................... (s/veh) "TimerGroupIncDelay",0,1.469,0,1.876,0,1.072,0,1.876...................................... (s/veh) "TimerGroupD3Delay",0,0,0,0,0,0,0,0....................................................... (s/veh) "TimerGroupUniformStops",0,.358,0,.826,0,.566,0,.826.................................. (stops/veh) "TimerGroupIncStops",0,.025,0,.023,0,.019,0,.023...................................... (stops/veh) "TimerGroupH3Stops",0,0,0,0,0,0,0,0................................................... (stops/veh) "TimerGroupFinalQue",0,0,0,0,0,0,0,0........................................................ (veh) "Right Lane Group" "TimerPhaseAssign",0,12,0,14,0,16,0,18........................................................... "TimerGroupVolume",0,10,0,271.4,0,9.5,0,271.4............................................. (veh/h) "TimerGroupUniformDelay",0,13.86,0,38.95,0,13.684,0,38.95................................. (s/veh) "TimerGroupIncDelay",0,.035,0,1.998,0,.027,0,1.998........................................ (s/veh) "TimerGroupD3Delay",0,0,0,0,0,0,0,0....................................................... (s/veh) "TimerGroupUniformStops",0,.415,0,.827,0,.408,0,.827.................................. (stops/veh) "TimerGroupIncStops",0,.025,0,.024,0,.02,0,.024....................................... (stops/veh) "TimerGroupH3Stops",0,0,0,0,0,0,0,0................................................... (stops/veh) "TimerGroupFinalQue",0,0,0,0,0,0,0,0........................................................ (veh) Figure B.23. Sample scenario output file content. Major Street Minor Street Vehicle Movements 5 2 12 3 8 18 1 6 16 7414 Figure B.24. Intersection traffic movements and numbering scheme. • INTERSECTION: The values in this section describe the performance of all movements at Intersection 1. Each value represents an average for the analysis period. This section is repeated for each numbered intersection. • TimerPhaseAssign0: This variable lists the phase sequence using a dual-ring controller structure. The first four num- bers indicate the sequence for Ring 1, as presented in the order listed. The last four numbers indicate the sequence for Ring 2. The numbers listed are the movement numbers associated with the through and left-turn movements. • Left Lane Group: This text defines the section containing the data for the left-lane groups at the intersection. This lane group is used to describe the performance of any lane groups that serve a left-turn movement in one or more exclusive lanes. If there are no exclusive-lane left-turn lane groups,

167 rename it to create a new workbook; one workbook should be created for each strategy being considered. Specifically, modify the workbook file name by attach- ing a suffix to indicate the specific strategy to which this workbook will apply (e.g., C17_A06-4_G06-4_V2010_ L08_s1.xls). Step 3. Create one folder for the USRE workbook that is specific to the facility being considered (e.g., C:\Users\ ksmith\Documents\USRE\10thStreet\ex). Save the USRE workbook in this folder. Modify the workbook file name by attaching a suffix indicating the specific replication to which this workbook will apply (e.g., USRE-XY_ex-rep1. xls). Copy the USRE workbook and rename it to create a new workbook; create one workbook for each replication being considered. If one or more improvement strategies are being consid- ered, create one folder for each strategy being considered (e.g., C:\Users\ksmith\Documents\USRE\10thStreet\s1). Save a copy of the USRE workbook in this folder. Modify the workbook file name by attaching a suffix indicating the specific strategy and replication to which this workbook will apply (e.g., USRE-XY_s1-rep1.xls). Copy the USRE workbook and rename it; create one workbook for each replication being considered. Step 4. Create one folder for the data files that is specific to the facility and replication identified in Step 3 (e.g., C:\ Users\ksmith\Documents\USRE\10thStreet\ex\rep1). Repeat this step to create one folder for each replication (e.g., C:\Users\ksmith\Documents\USRE\10thStreet\ex\ rep2, and so forth). If one or more improvement strategies are being con- sidered, create one folder for the data files that is specific to the facility, strategy, and replication identified in Step 3 (e.g., C:\Users\ksmith\Documents\ USRE\10thStreet\s1\ rep1). Repeat this step to create one folder for each unique combination of strategy and replication (e.g., C:\Users\ ksmith\Documents\USRE\10thStreet\s1\rep2). Step 5. Use the USCE comparator workbook set up in Step 2 to create an HCM data set for the base conditions on the facility (i.e., no work zones, no special events). Save this base data set to each of the replication folders created in Step 4 for the comparator facility. If a work zone, special event, or both occur during the RRP, then use the USCE workbook set up in Step 2 to create one HCM data set for each unique occurrence. Save this alternative data set to the same replication fold- ers in which the base data set was saved. Each USCE workbook used to create an alternative data set may be renamed and saved, if desired (e.g., C17_A06-4_G06-4_ V2010_L08_ex-wz1.xls). If one or more improvement strategies are being considered, then the process outlined in the preceding then this lane group is used to describe the shared lane serv- ing left-turn and through movements. This lane group is also used to describe the case for which there is only one lane on the approach. • TimerPhaseAssign: This is a header row because it defines the order by which the values are listed in the subsequent rows for the specified lane group. For example, the row with the uniform delay (TimerGroupUniformDelay) shows 46.875 s/veh for Movement 1, 30.966 s/veh for Movement 3, and so forth. • Middle Lane Group: This text defines the section contain- ing the data for the middle-lane groups at the intersection. This lane group is used to describe the performance of any lane groups that serve a through movement in one or more exclusive lanes. • Right Lane Group: This text defines the section contain- ing the data for the right-lane groups at the intersection. This lane group is used to describe the performance of any lane groups that serve a right-turn movement in one or more exclusive lanes. If there are no exclusive-lane right-turn lane groups, then this lane group is used to describe the shared lane serving right-turn and through movements. Software Installation This section describes the steps involved in installing the reliability evaluation software. The installation process con- sists of establishing the folder structure for the software and saving the software in the appropriate folder. The installa- tion process does not require administrative access to the computer. It does not make changes to the Windows regis- try, nor does it add any shortcuts to the desktop or program directory. The steps for installing the reliability evaluation software are as follows: Step 1. Create a folder for the HCM executable file (e.g., C:\ Users\ksmith\Documents\USRE). Save the HCM executable file in this folder. Step 2. Create a folder for the USCE workbook that is spe- cific to the facility being evaluated (e.g., C:\Users\ksmith\ Documents\USRE\10thStreet). Save the USCE workbook in this folder. Modify the workbook file name by attaching a suffix to indicate that it applies to the facility (e.g., C17_ A06-4_G06-4_V2010_L08_ex.xls). In the context of evalu- ating various improvement strategies, this workbook would describe the comparator facility (typically, the comparator is the “existing” facility). Enter data in this workbook. If one or more improvement strategies are being considered, copy the USCE comparator workbook and

168 results from each run will be saved in the appropriate rep- lication folder. After each run, the appropriate replication folder should contain one scenario data set file and one scenario output file for each analysis period associated with that replication. Step 7. Use the Analysis worksheet in the USRE workbook to evaluate the results from the set of replications for each alternative. Step 8. At the conclusion of the evaluation, archive (or delete) the files associated with this evaluation. As a mini- mum, the data files in the replication folders should be archived (or deleted) due to their large number. References American Association of State Highway and Transportation Officials. Highway Safety Manual, 1st ed. AASHTO, 2010. American Association of State Highway and Transportation Officials. A Policy on Geometric Design of Highways and Streets. AASHTO, Washington, D.C., 2011. National Climatic Data Center. Comparative Climatic Data for the United States Through 2010. National Oceanic and Atmospheric Administration, Asheville, N.C. http://www.ncdc.noaa.gov. Accessed Sept. 21, 2011(a). National Climatic Data Center. Rainfall Frequency Atlas of the U.S.: Rain- fall Event Statistics. National Oceanic and Atmospheric Administra- tion, Asheville, N.C. http://www.ncdc.noaa.gov/oa/documentlibrary/ rainfall.html. Accessed Sept. 21, 2011(b). Transportation Research Board. Highway Capacity Manual 2010. TRB of the National Academies, 2010. paragraphs is repeated for each strategy. This process is described as follows: a. For a given strategy, use the USCE workbook set up in Step 2 to create an HCM data set for the base conditions on the facility (i.e., no work zones, no special events). Save this base data set to each of the replication folders created in Step 4 for the specified strategy. b. For a given strategy, if a work zone, special event, or both occur during the RRP, then use the USCE work- book set up in Step 2 to create an HCM data set for each unique occurrence. Save this alternative data set to the same replication folders in which the base data set was saved. Each USCE workbook used to create an alterna- tive data set may be renamed and saved, if desired (e.g., C17_A06-4_G06-4_V2010_L08_s1-wz1.xls). Step 6. Run the USRE comparator workbooks set up in Step 3. One workbook was set up for each replication. Each work- book should be coded so that the results from each run are saved in the appropriate replication folder. After each run, the appropriate replication folder should contain one sce- nario data set file and one scenario output file for each analysis period associated with that replication. If one or more improvement strategies are being consid- ered, then the process outlined in the preceding paragraph is repeated for each strategy. This process is described as fol- lows: for a given strategy, run the USRE workbooks set up in Step 3, in which one workbook was set up for each rep- lication. Each workbook should be coded so that the

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TRB’s second Strategic Highway Research Program (SHRP 2) Report S2-L08-RW-1: Incorporation of Travel Time Reliability into the Highway Capacity Manual presents a summary of the work conducted during the development of two proposed new chapters for the Highway Capacity Manual 2010 (HCM2010). These chapters demonstrated how to apply travel time reliability methods to the analysis of freeways and urban streets.

The two proposed HCM chapters, numbers 36 and 37, introduce the concept of travel time reliability and offer new analytic methods. The prospective Chapter 36 for HCM2010 concerns freeway facilities and urban streets, and the prospective supplemental Chapter 37 elaborates on the methodologies and provides an example calculation. The chapters are proposed; they have not yet been accepted by TRB's Highway Capacity and Quality of Service (HCQS) Committee. The HCQS Committee has responsibility for approving the content of HCM2010.

SHRP 2 Reliability Project L08 has also released the FREEVAL and STREETVAL computational engines. The FREEVAL-RL computational engine employs a scenario generator that feeds the Freeway Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived. The STREETVAL-RL computational engine employs a scenario generator that feeds the Urban Streets Highway Capacity Analysis methodology in order to generate a travel time distribution from which reliability metrics can be derived.

Software Disclaimer: This software is offered as is, without warranty or promise of support of any kind either expressed or implied. Under no circumstance will the National Academy of Sciences or the Transportation Research Board (collectively "TRB") be liable for any loss or damage caused by the installation or operation of this product. TRB makes no representation or warranty of any kind, expressed or implied, in fact or in law, including without limitation, the warranty of merchantability or the warranty of fitness for a particular purpose, and shall not in any case be liable for any consequential or special damages.

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