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59 8.4.7 Do Not Attempt to Use a Black Box be adequate to simply know that, for example, two-thirds of Approach the system operate at acceptable levels under peak conditions, or that a proposed operational improvement covering a sig- Sophisticated tools that build a prioritized list of improve- nificant portion of the system (stepped-up freeway patrols, for ment projects may appeal to technical staff, but more rarely example) might reduce congested miles by several percentage are appreciated by decision makers and the public. It is criti- points. Conversely, for the decision-maker or elected official cal to work with the stakeholders during the evaluation with budget concerns, knowing the absolute number of con- process, and to explain the strengths and weaknesses of the gested miles may be useful as it highlights more dramatically tools during the entire planning process. Otherwise, the first the extent of the problem and immediately conveys at least a time a credible source provides a negative critique of the tools gross sense of the size of undertaking and resources required used, decision makers may lose faith or withdraw support for to address the problem. the entire set of recommendations. Indexing a quantity (e.g., annual hours of delay) to some Ultimately, integrating performance results into planning baseline quantity, such an area's population or miles of travel and decision making takes time. A review and revision/ may help to normalize the influence of background popula- enhancement of each tool and product may be required. But tion growth when comparing current to future congestion small steps can yield superior results that only can help en- levels, as demonstrated in the previous example from SCAG. force the overall commitment to the concept. This information may be more meaningful to agencies study- ing conditions at the corridor or regional level, for example, hours of delay per lane-mile of road, person hours of delay 8.5 Using Travel Time, Delay, per 1,000 person miles traveled, or hours per 1,000 travelers. and Reliability in Planning The general public may not gain much added benefit from Applications these variant measures since it is more difficult to relate to This section and the subsequent section summarize how personal travel decisions or travel experience to some of the the detailed methods and approaches described in Chapters indexed quantities. 2 through 7 can be applied to typical transportation planning Again, the analyst should be guided by the primary audience analysis in support of decisions. The material in Chapter 2 for the performance data and choose accordingly. The con- provides guidance for the selection of performance measures cepts and calculations are similar regardless of the variant, and suitable for particular applications, and Chapter 3 provides most analysts will be readily able to adapt measures to suit their data collection steps and actual equations for calculating the particular needs. various measures. Chapters 4 through 7 describe specific analyses that can be performed using travel time and delay 8.6 Typical Planning Applications data. Exhibit 8.3 presents a recommended short list of measures This section describes applications for measures of travel for reporting travel time, delay, and reliability. These measures time, delay, and reliability in the planning process. Six typical are organized according to whether they report primarily planning applications were selected, based upon review of the travel time, congestion-related delay, or reliability in planning research conducted for this project and the needs of practi- applications. This table also indicates which component of tioners as perceived by the research team and project panel: congestion is reported, and the geographic area(s) best addressed by each measure. In fact, many measures can be 1. Evaluate trends in travel time, delay, and reliability; applied at multiple scales (e.g., region, subarea, section, and 2. Identify existing deficiencies; corridor), which makes the measures useful for multiple 3. Evaluate the actual effectiveness of improvements (before- applications (e.g., long-range planning), as well as corridor- after study); specific alternatives analysis. 4. Predict future conditions/identify future needs and defi- There are numerous variants to the recommended meas- ciencies; ures that may be useful depending upon the audience and 5. Alternatives analysis; and application. For example, some measures may be expressed as 6. Improve fleet operations and productivity. an absolute number, as well as a percentage (e.g., percent or number of system lane miles operating at or below the defined These six applications address a very large percentage of threshold of congestion). The raw number of congested miles, the situations in which a planner or analyst might want to in this example, may not give the lay person adequate sense of apply measures of travel time, delay, and reliability in order the magnitude of the problem, since they are unlikely to know to shed more light on a trend or need, discern differences the total extent of the system mileage. For that person it may between alternative courses of action, etc. Each of these

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60 Recommended Congestion Performance Component Geographic Area Measures Addressed Addressed Typical Units Reported Travel Time Measures Travel Time Duration Region Person-minutes/day, person-hours/year Total Travel Time Duration Region Person or vehicle hours of travel/year Accessibility Extent, Intensity Region, Subarea # or % of "opportunities" (e.g., jobs) where travel time < target travel time Delay and Congestion Measures Delay per Traveler Intensity Region, Subarea, Person-minutes/day, person-hours/year Section, corridor Total Delay Intensity Region, Subarea, Person- or vehicle-hours of delay/year Section, Corridor Travel Time Index or Intensity Region, Subarea, Dimensionless factor that expresses ratio of travel Travel Rate Index Section, Corridor conditions in the peak period to conditions during free-flow (e.g., TTI of 1.20 = congested trip is 20% longer than free-flow trip) Congested Travel Extent, Intensity Region, Subarea Vehicle-miles under congested conditions Percent of Congested Duration, Extent, Region, Subarea Congested person-hours of travel (PHT) as % or Travel Intensity ratio of total PHT Congested Roadway Extent, Intensity Region, Subarea # (or %) of miles of congested roadway Misery Index Duration, Intensity Region, Subarea, Proportion or percentage (e.g., 1.50) (expressing Corridor time difference between the average trip and the slowest 10 percent of trips) Reliability Measures Buffer Index Intensity, Region, Subarea, % extra time to be allowed to ensure on-time Variability Section, Corridor arrival, e.g., "BI of 30%" Percent On-Time Variability Facility, Corridor, % of trips meeting definition of "on time" Arrival System Planning Time Index Intensity, Region, Subarea, Dimensionless factor applied to normal trip time, Variability Section, Corridor e.g., PTI of 1.20 x 15-min. off-peak trip = 18-min. travel time for travel planning purposes Percent Variation Intensity, Region, Subarea, % of average travel time required for on-time Variability Section, Corridor arrival of given trip, similar to Planning Time Index 95th Percentile Duration, Section or Corridor Trip duration in minutes and seconds Variability Exhibit 8.3. Recommended measures for reporting travel time, delay, and reliability. applications involves one or more fundamental tasks, such additional investment to serve growing demand in developing as identifying the most suitable measures, data collection, areas. The analyst also typically will use the existing and pro- forecasting performance under a hypothetical or future con- jected future performance data to identify probable cause of dition, reporting the results, etc. These building blocks are the failures, as well as to suggest potential solutions to be eval- each addressed in Chapters 2 through 7, and several of these uated in a subsequent alternatives analysis. The description of building blocks might be used in each of the above planning this particular planning application identifies five distinct applications. steps to be taken: For example, the fourth example application is prediction of future conditions. This is typically conducted in order to Step 1. Determine agency performance standards, identify corridors, facilities, or specific locations that at some Step 2. Determine scope of analysis, future point will fail to meet an agency's standards or require Step 3. Select forecast approach,

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61 Step 4. Conduct forecasts, and Decide on length of analysis periods and time slices within Step 5. Process results. analysis period. (Chapter 2) Each of these steps then is covered in detail in a particular chapter (e.g., Chapters 2 and 5 contain guidance for identify- ing and quantifying agency standards, and Chapter 6 de- Step 3. Determine Sampling Plan scribes various methods for estimating or forecasting future Determine if suitable data already exist or if sampling is values of travel time depending upon the data available). required; This modular approach is offered because the six planning Decide on number of days, hours, seasons of year for which applications share many common steps (e.g., identification data desired; and of desired measures, data collection, and forecasting future Determine which hours, days, and weeks to sample. values of input variables to the performance measures). (Chapter 3) Presenting these steps or building blocks in discrete chapters eliminates the need to repeat the steps for multiple planning applications. This format also allows the planner or analyst Step 4. Prepare Data Collection Plan to assemble various steps, as appropriate, to conduct a plan- Determine required accuracy (confidence interval) of results. ning application other than the six defined in this guidebook. Estimate minimum samples required. The six applications described here will cover a large percentage of applications that might be found in a trans- Identify segments, facilities to be sampled. portation planning context, and with slight modification can Determine if the available data covers the necessary geo- be extended to cover most all situations. graphic areas, facilities, time periods, days, seasons of the years needed for the analysis. If necessary data not available, select one of the following 8.6.1 Application 1: Evaluate Trends in to supplement or fill gaps in available data: Travel Time, Delay, and Reliability Step 4A. Data collection technology (loop detectors, The objective of this application is to identify and track GPS/AVI vehicles); or overall trends in travel time, delay, and reliability for the pur- Step 4B. Estimation methodology (sketch planning, poses of preparing a report on agency performance. Many HCM, or BPR curve). agencies regularly do this, and the typical reporting agency Estimate data collection (and/or estimation) costs and per- might be a MPO, congestion management agency, state sonnel required. DOT, or transit operator, but also could be city or county Revisit study bounds and accuracy requirements, and tech- transportation units, freight operators, or a national DOT. nology if resources insufficient. The report may be prepared monthly, quarterly, or annually. (Chapter 3) In some cases, the reports are directed at high-level decision makers and stakeholders; and in other cases, may be intended for a broader audience of lay system users or taxpayers. Step 5. Conduct Baseline Data Collection The following is an overview of the recommended proce- For field data collection methods see appropriate data col- dure. References are given to the appropriate chapters for the lection guide (e.g., Travel Time Data Collection Handbook, necessary technical guidance. Within those chapters, addi- FHWA Traffic Monitoring Guide, etc.); and tional references are given, where appropriate, to more specific Simultaneously collect weather and incident logs for times technical background on a particular subject. and locations of data collection (to be used later to address outlier data). Step 1. Identify Desired Metrics (Chapter 3) Select metrics for travel time, delay, and/or reliability, depending upon issues, audience, and availability of real- Step 6. Process Baseline Results time data. (Chapter 2) Set reasonableness bounds for data and eliminate outliers; Set travel time standard (free-flow, speed limit, or other) against which additional travel time is considered delay; Step 2. Determine Study Bounds Compute mean and variance for travel time and delay; Decide if O-D times, facility times, or segment times Compute confidence intervals for mean travel time and desired; and mean delay;

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62 Compute desired metrics, selecting from initial list; and taller, darker-colored bars) represents the additional propor- Prepare report and graphics. tion of time travelers should add to a typical free-flow travel (Chapter 3) time when a 95 percent likelihood of on-time arrival is de- sired. As defined in Chapter 2, the PTI differs from the TTI, Step 7. Conduct Trend Data Collection as it is based on the 95th percentile trip time or rate, rather than the average rate. The PTI compares near-worst case See Step 5, Conduct Baseline Data Collection for guidance. travel time to light or free-flow travel time, whereas the TTI (Chapter 3) compares average (measured or estimated) travel time (or rate) to free-flow conditions. Step 8. Process Trend Results In this example, reporting both the TTI and PTI in a com- parative graph may help in interpreting the underlying causes See Step 6, Process Baseline Results for guidance. of change in the measures. The trend data suggest that the ob- (Chapter 3) served reduction in TTI in the final year of data (2003) may be due in large part to a decrease in the longest trip times, as Step 9. Compare Trend to Baseline indicated by the even sharper drop in the PTI. The PTI will Determine extent to which differences between base and be more sensitive to the 95th percentile trip time (or rate) trend year are due to sampling error; value, indicating the longest trip times have declined meas- Fit trend line to data; and urably since the previous year of data. This type of result may Prepare report and graphics. have been the effect of an improved systemwide incident (Chapters 3 and 8) management program, or other system-level improvement that had a more significant impact in reducing the amount of Exhibit 8.4 shows how results from two related measures nonrecurring or incident-generated delay. This reduces the can be compared to one another to help tell a more complete spread between the average trip time and the slowest trips on story of trends. This figure illustrates four-year trends in the the system. The PTI uses a different standard of performance travel-time index and the planning-time index at the system than the TTI and indicates that travelers need to allow a larger level. The TTI (represented by the shorter, lighter-colored margin than would be suggested by the TTI; it indicates the bars) shows that the typical (i.e., average observed) peak- amount of time that must be planned for important trips. Ex- period trip takes about 30 percent to 40 percent longer than hibit 8.4 also includes the miles of freeway included each year the same trip at FFS, and that trends may be improving in the in the system-level analysis, and while this information is not most recent year presented. The planning time index (PTI, essential, it provides the user with a yardstick to confirm that Index Value 1.9 1.85 1.8 1.75 1.7 1.66 1.6 1.54 1.5 1.42 1.39 1.4 1.35 1.29 1.3 1.2 192 miles 412 miles 412 miles 411 miles 1.1 1.0 2000 2001 2002 2003 Year Exhibit 8.4. Use of congestion and reliability measures to exhibit two differing trends.

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63 system miles have not changed notably in the final three years Step 3. Prepare Data Collection Plan of data, and thus average trip times (as indicated by the TTI) Determine whether real-time detector data exists; have not changed simply as a result of expanded system miles. Determine required accuracy (confidence interval) of results; In a planning application such as identifying the likely fu- Estimate minimum samples required; ture impact of a proposed solution, travel demand model Identify facilities and segments to be included; outputs of travel time and congestion will typically not Determine if the available detector data covers the neces- include the component of nonrecurring delay. In these cases, sary geographic areas, facilities, time periods, days, seasons the TRI (see Section 2.4) is used, which does not include in- of the years needed for the analysis; cident-generated delay. The TRI is also the appropriate meas- If necessary detector data is not available, select data ure when travel-time runs are conducted to estimate travel collection technology (loop detectors, GPS/AVI vehicles) rates, since those runs affected by incident conditions are or estimation methodology (sketch planning, HCM, or normally removed from the data set. The TTI and PTI are BPR curve) to supplement or fill gaps in available detector most appropriate where continuous data streams allow for data; direct measurement that includes incidents. Estimate data collection costs and personnel required; and Revisit study bounds and accuracy requirements, and tech- nology if resources insufficient. 8.6.2 Application 2: Identify Existing (Chapters 3 and 5) Deficiencies The objective of this application is to identify and diagnose Step 4. Conduct Data Collection existing deficiencies in travel time, delay, and reliability for the purposes of determining appropriate agency actions. The For field data collection methods see Introduction to Traf- outcome of the analysis is usually a report identifying fic Engineering - A Manual for Data Collection (8) or ITE facilities and locations failing to meet the agencies' perform- Manual of Traffic Engineering Studies (9); and ance standards, and identifying the probable causes of the Simultaneously collect weather and incident logs for times failures. The report may even go on to recommend specific and locations of data collection (to be used later for diag- improvements. However, the development of these recom- nosis). mendations will be covered under the alternatives analysis (Chapters 3 and 5) application, which is described later. The typical agency may be a transit operator, freight Step 5. Process Results operator, city, county, MPO, congestion management agency, state DOT, or a national DOT. The analysis may be Set reasonableness bounds for data and eliminate outliers; performed when the agency first becomes aware of a problem Set travel time standard (free-flow, speed limit, or other) or may be done annually, or linked to some other regular pe- against which additional travel time is considered delay; riod (e.g., a budget cycle, a long-range plan update, etc.). Compute mean and variance for travel time and delay; Compute confidence intervals for mean travel time and mean delay; Step 1. Determine Agency Performance Standards Compute desired reliability metrics; and Identify deficient segments and facilities Select metrics for travel time, delay, and reliability; (Chapter 5) Decide if agency performance will be measured in terms of O-D times, facility times, or segment time delay and/or re- liability; and Step 6. Diagnose Causes of Deficiencies Determine agency performance standards for each metric. Cross-tabulate incident log against measured performance (Chapters 2 and 5) deficiencies; Note geometric constraints; Identify volume increase locations; Step 2. Determine Sampling Plan for Determining Identify cause of deficiency; and Compliance Prepare report. Decide on number of days, hours, seasons of year for which (Chapters 5 and 8) data desired; and Determine which hours, days, and weeks to sample. Exhibit 8.5 presents an example of trend data plotted against (Chapter 3) agency performance standards. In this case the measure is the

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64 Percent of Lane Miles 100 92.2% 90.7% 88.4% 88.2% 88.1% 90 85.2% 83.4% 83.1% 83.4% 81.3% 81.1% 81.7% 80.6% 80 78.1% 73% Long-Term Target 74.1% 70 61% 70.6% 71.0% 70.4% Long-Term Target 60 50 1996 1997 1998 1999 2000 2001 2002 2003 2004 Calendar Year Percent of Arterial Lane Miles with Volumes < 10,000 Vehicles per lane, per day (78% Short-Term Target; 73% Long-Term Target) Percent of Freeway Lane Miles with Volumes < 20,000 Vehicles per lane, per day (66% Short-Term Target; 61% Long-Term Target) Exhibit 8.5. Comparison of trend to agency performance standard. Percent- age of lane miles with average annual volumes below congested levels. percentage of lane miles that are operating at uncongested lev- each improvement evaluated, rather than on an ongoing or els. The agency performance standard is set as a minimum (i.e., periodic basis. Chapter 4 contains specific guidance on the they want to see no less than 73 percent of their lower-volume before/after type of application. roads, and no less than 61 percent of their higher-volume roads), operating at uncongested levels. The trend data indi- Step 1. Identify Desired Metrics cate that although both lower- and higher-volume roadways still exceed the agency performance standard, there has been a Select metrics for travel time, delay, and reliability. In this steady downward trend (i.e., negative) over the years data is particular application where comparison of before and after presented. Depending upon the underlying causes for the grad- performance is required, special attention must be given to ual degradation in performance (e.g., rising VMT and density measure selection to ensure that data and measures from the per highway lane mile), the data suggest that more aggressive two time periods are in fact comparable. This constraint may countermeasures, possibly both capital and operating, will be limit the range of measures available for the comparison, needed to maintain above-target performance over the long particularly if the decision to conduct the before/after analy- term. sis was not made until after implementation of the improve- ment, in which case, the analyst is limited to data on-hand 8.6.3 Application 3: Evaluation representative of the before-project conditions. It is always of Effectiveness of Improvements preferable, though not always possible, to develop the be- fore/after analysis framework and data collection plan before The objective of this application is to determine if an im- any construction on the improvement has taken place. plemented improvement or action actually resulted in the de- (Chapters 2 and 4) sired improvement in travel time, delay, or reliability. This type of analysis allows an agency to better assess the cost ef- Step 2. Determine Study Bounds fectiveness of specific actions and also to assess the effective- ness of their planning analysis and decision processes. Any Decide if O-D times, facility times, or segment times de- typical agency with responsibility and accountability for ex- sired; and penditure of funds for system improvements and operations Decide on length of analysis periods and time slices within may at times need to conduct a careful before/after analysis analysis period. such as this. The report would be prepared one time only for (Chapter 2)

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65 Step 3. Determine Sampling Plan Step 8. Process After Results Decide on number of days, hours, seasons of year for which See Step 6, Process Baseline Results for guidance. data desired; and (Chapter 3) Determine which hours, days, and weeks to sample. (Chapter 3) Step 9. Compare Before and After Results Step 4. Prepare Data Collection Plan Determine extent to which differences between base and trend year are due to sampling error; Determine desired lag time between implementation of the Conduct hypothesis tests of before/after results improve- facility or system improvement and the measurement of its ments to determine statistical significance of results; success or failure; Prepare report and graphics; and Identify segments and facilities to be sampled; Revise monitoring plan for future analyses. Determine if the available detector data covers the necessary (Chapter 4) geographic areas, facilities, time periods, days, and seasons needed for the analysis; Determine required accuracy (confidence interval) of 8.6.4 Application 4: Prediction of Future results; Conditions Estimate minimum samples required; The typical objective of this application is to identify and If necessary detector data not available, select data collection technology (loop detectors, GPS/AVI vehicles) or estima- diagnose future deficiencies in travel time, delay, and/or reli- tion methodology (sketch planning, HCM, or BPR curve) to ability for the purposes of determining appropriate agency supplement or fill gaps in available detector data; actions. The outcome of the analysis is usually a report iden- Estimate data collection (and/or estimation) costs and tifying facilities and locations failing to meet the agencies' personnel required; and standards at some future date, and identifying the probable Revisit study bounds and accuracy requirements, and causes of the failures. technology if resources insufficient. The performance report may go on to recommend specific (Chapter 3) improvements to address deficiencies. However, the devel- opment of these recommendations will be covered later under the alternatives analysis application. Step 5. Conduct Baseline (Before) Data Collection For field data collection methods, see ITE Data Collection Step 1. Determine Agency Performance Standards Guide; and Simultaneously collect weather and incident logs for times Select metrics for travel time, delay, and reliability; and locations of data collection (to be used later to address Decide if agency performance will be measured in terms of outlier data). O-D times, facility times, or segment times delay and/or re- (Chapter 3) liability; and Determine agency performance standards for each metric. Step 6. Process Baseline Results (Chapter 2) Set reasonableness bounds for data and eliminate outliers; Set travel time standard (free-flow, speed limit, or other) Step 2. Determine Scope of Analysis against which additional travel time is considered delay; Determine temporal scope of analysis; Compute mean and variance for travel time and delay; Decide on number of days, hours, seasons of year for which Compute confidence intervals for mean travel time and results desired; mean delay; Determine which existing and forecast years, hours, days, Compute desired reliability metrics; and Prepare report and graphics. and weeks to evaluate; Determine geographic scope of analysis; (Chapter 3) Determine which trip O-Ds, which facilities, and/or which segments of facilities to evaluate; and Step 7. Conduct "After" Data Collection Determine required outputs of analysis and accuracy (con- See Step 5, Conduct Baseline Data Collection for Guidance. fidence interval) of results. (Chapter 3) (Chapters 2 and 3)

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66 Step 3. Select Forecast Approach The typical agency may be a transit operator, freight operator, city, county, MPO, congestion management Determine resources (funds, time, personnel) available for agency, state DOT, or a national DOT. The analysis may be analysis; performed when the agency first becomes aware of a prob- Select desired analytical approach (e.g., sketch planning, lem, usually as the outcome of a periodic monitoring of sys- 4-step, mezoscopic, HCM, micro-simulation); and tem performance, such as might be produced by Application Revisit accuracy requirements, proposed analytical ap- 2: Identification of Deficiencies. Many agencies also conduct proach, and number of candidate improvements if inade- regional system or corridor analyses to identify projected quate resources or time. future deficiencies and test the efficacy of different capital and (Chapter 6) operating strategies. Step 4. Conduct Forecasts Step 1. Conduct Studies to Identify and Diagnose For 4-step model approach, see the FHWA Guide on Travel Existing and Future Deficiencies Forecasting; These studies should be completed prior to conducting the For microsimulation, see the FHWA Guide on Micro- alternatives analysis: Application 2: Identification of Exist- simulation; For HCM analysis, see HCM; and ing Deficiencies and Application 4: Predictions of Future For sketch planning, see NCHRP 398: Congestion Mea- Conditions. surement. (Chapter 6) Step 2. Determine Candidate Improvements The analyst should consult a number of sources to identify Step 5. Process Results potential solutions that address the identified deficiencies. Set reasonableness bounds for forecasts and eliminate Chapter 7 presents in table format a collection of typical outliers; problems, likely causes, and improvement strategies and Set travel time standard (free-flow, speed limit, or other) actions. It also references several published reference doc- against which additional travel time is considered delay; uments that can guide the analyst to strategies and actions Compute mean and variance for travel time and delay; that are specifically appropriate for reducing travel time, Compute confidence intervals for mean travel time and delay, and variability. mean delay; (Chapter 7) Compute desired reliability metrics; Identify deficiencies; and Step 3. Determine Scope of Analysis Prepare report and graphics. (Chapter 3) Determine temporal scope of analysis; Decide on number of days, hours, seasons of year for which results desired; 8.6.5 Application 5: Alternatives Analysis Determine which existing and forecast years, which hours, The objective of this application is to develop and evaluate which days, which weeks to evaluate; a set of alternative actions to improve facility or system Determine geographic scope of analysis; performance. Presumably, the operator already has con- Determine which trip O-D's, which facilities and/or which ducted Application 2: Identification of Existing Deficiencies, segments of facilities; and and has diagnosed the underlying causes of the existing prob- Determine required outputs of analysis and accuracy (con- lems. The operator also should have conducted a future fidence interval) of results. analysis (Application 4) and identified future deficiencies and (Chapters 2 and 3) their projected causes. The outcome of the alternatives analysis is usually a report Step 4. Select Evaluation Approach identifying facilities that currently fail and/or in the future will fail to meet the agency's standards, reviewing the probable Determine resources (funds, time, personnel) available for causes of the failures, and recommending actions by the agency analysis; (and potentially other agencies) to alleviate the existing and/or Select desired analytical approach (e.g., sketch planning, future deficiencies. 4-step, mezoscopic, HCM, micro-simulation); and

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67 Revisit accuracy requirements, proposed analytical ap- or perhaps as the outcome of periodic monitoring of system proach, and number of candidate improvements if inade- performance, such as might be produced by Application 2: quate resources or time. Identify Existing Deficiencies. (Chapter 3) Step 1. Conduct Studies to Identify and Diagnose Step 5. Evaluate Improvements Deficiencies Estimate mean travel time, delay, reliability before and These studies should be completed prior to conducting after improvement (The methodology provided here will the alternatives analysis: Application 2: Identification of vary according to the selected approach in the prior step.); Existing Deficiencies and Application 4: Predictions of Compute reliability metrics as desired; Future Conditions. Determine confidence intervals for results; Estimate cost-effectiveness of each candidate improve- Step 2. Determine Candidate Improvements ment; Determine if candidate improvements are sufficient to Exhibit 7.1 in Chapter 7 may be used to identify appropriate meet operator standards; and candidate improvements to consider for solving the identi- Select final list of improvements. fied deficiencies, particularly if the deficiencies are related to (Chapter 3) roadway system capacity, and are impacting movement of trucks or transit vehicles on the general purpose highway network. For deficiencies specific to the fleet operation itself Step 6. Develop Improvement Program (e.g., maintenance, route designation and run scheduling), Determine funds available for improvements; more specialized resource materials, outside of the scope Determine desired timeline and sequence for improve- of this effort, should be consulted. Suggested references include TCRP Report 95: Traveler Response to Transportation ments; System Changes, and TCRP Report 100: Transit Capacity and Prioritize and schedule improvements; Level of Service Manual. These reports are available on-line Determine needed funding schedule; at TRB.org/TRB/publications. Prepare report and graphics; and Revise monitoring plan for future analyses. (Material not explicitly presented in this Guidebook.) Step 3. Determine Scope of Analysis Determine temporal scope of analysis; 8.6.6 Application 6: Improve Fleet Decide on number of days, hours, seasons of year for which Operations and Productivity results desired; Determine which existing and forecast years, which hours, The objective of this application is to develop a set of actions which days, which weeks to evaluate; to improve fleet operations and productivity. Presumably, the Determine geographic scope of analysis; operator already has conducted Application 2: Identification Determine which trip O-D's, which facilities and/or which of Existing Deficiencies, and has diagnosed the existing causes segments of facilities; and of the problems. The operator may have arrived at this point Determine required outputs of analysis and accuracy (con- after conducting a future analysis (Application 4) and identi- fidence interval) of results. fying future deficiencies. (Chapters 2 and 3) The outcome of the analysis for Fleet Operations and Productivity is usually a report identifying vehicle routes that currently fail and/or in the future will fail to meet the operator's Step 4. Select Evaluation Approach standards, reviewing the probable causes of the failures, and rec- Determine resources (funds, time, personnel) available for ommending actions by the operator (and potentially other analysis; agencies) to alleviate the existing and/or future deficiencies. Select desired analytical approach (e.g., sketch planning, The typical fleet operator may be a transit operator or a 4-step, mezoscopic, HCM, micro-simulation); and freight operator, or a planning agency with responsibility for Revisit accuracy requirements, proposed analytical ap- oversight of transit performance. proach, and number of candidate improvements if inade- The analysis may be performed when the agency first quate resources or time. becomes aware of a problem, either through customer feedback (Chapter 3)

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68 Step 5. Evaluate Improvements Select final list of improvements. (Chapters 3 and 4) Estimate mean travel time, delay, reliability before and after improvement (the methodology provided here will vary according to the selected approach in the prior Step 6. Develop Improvement Program step); Determine funds available for improvements; Compute reliability metrics as desired; Determine desired timeline and sequence for improvements; Determine confidence intervals for results; Prioritize and schedule improvements; Estimate cost-effectiveness of each candidate improve- Determine needed funding schedule; ment; Prepare report; and Determine if candidate improvements are sufficient to Revise monitoring plan for future analyses. meet operator standards; and (Material not explicitly presented in this guidebook.)