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Traffic Safety Evaluation of Nighttime and Daytime Work Zones (2008)

Chapter: Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods

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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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Suggested Citation:"Chapter 5 - Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods." National Academies of Sciences, Engineering, and Medicine. 2008. Traffic Safety Evaluation of Nighttime and Daytime Work Zones. Washington, DC: The National Academies Press. doi: 10.17226/14196.
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50 Introduction Highway agencies are beginning to recognize the value of having access to comprehensive crash and other supporting (i.e., exposure) data for work zones. These data can be used to develop work zone crash rates and to assess work zone operating characteristics such as traffic, delays, and travel speeds/times. These crash rates and operating characteristics could be used by the agencies to determine statewide work zone safety and mobility trends and/or the need to modify or enhance work zone traffic control plans. FHWA rulemaking finalized in 2004 increases the impor- tance of this issue. Specifically, it requires highway agencies to collect and analyze work zone data, including crash data (71): (c) Work zone data. States shall use field observations, available work zone crash data, and operational information to manage work zone impacts for specific projects during implementation. States shall continually pursue improvement of work zone safety and mobility by analyzing work zone crash and operational data from multiple projects to improve State processes and proce- dures. States should maintain elements of the data and informa- tion resources that are necessary to support these activities. Previously, highway agencies and others have indicated a sig- nificant concern that police accident reports frequently do not accurately or consistently indicate work zone involvement in traffic crashes, which can significantly impact the results of any analyses performed on that data (72, 73). The majority of police crash report forms used by states now include some explicit field or code to identify whether a crash occurs within the limits of a highway work zone. However, although some improvements in crash reporting for work zones are evident, more is still needed. Highway agencies have expressed a number of concerns re- garding work zone crash data, which can generally be grouped into the following categories: • Lack of consistency and accuracy of police crash databases, • Lack of interoperability between databases, • Lack of timely data, • Lack of work zone information, • Lack of identification of work zone limits, • Lack of ability to know whether or not the work activity had any effect on the crash, and • Lack of identification and assessment capabilities of worker injuries/fatalities. Categories of Critical Data Elements While a number of state crash reporting forms include a way to identify work zone crashes—and a few do include some additional fields to capture work zone characteristics— most do not obtain sufficient information to fully assess the relationship of a crash to common work zone features. A num- ber of suggestions have been made by state highway agencies as to the types of safety performance measures that would be useful in assessing and comparing work zone crash experi- ences and improvement initiatives (74): • Crashes per day of work activity per hours of work; • Crashes per day the work zone traffic control is in place; • Crashes per work zone mile; • Crashes per type of work zone or work zone activity; • Crashes per vehicle-miles traveled; • Crashes per million entering vehicles; and • Number of crashes per location in work zone (e.g., num- ber of crashes in queues, number of crashes in the advance warning area, etc.). However, the ability to perform a meaningful analysis is based on the availability of sufficient data that adequately de- scribe the crash and the characteristics of the work zone where it occurred, as well as other information about the project and traffic characteristics. Some of the types of data considered desirable include: • Description of the traffic control devices in the area of the crash; C H A P T E R 5 Recommended Work Zone Crash Data Elements, Collection Techniques, and Analysis Methods

• Type of work activity (e.g., construction or maintenance, permanent or temporary, specific activity, etc.); • Location of the crash in the work zone (e.g., advance warn- ing area, transition, etc.); • Money spent on construction/maintenance projects; • Duration of work zone; • Total number of miles of work zone; • Number of work zones per type of roadway; • Volume of traffic through the work zone; • Hours of work zone activity without positive protection; • Queue lengths per type of roadway; • Running speed or other traffic operational measures about the work zone; • Frequency of motorists exceeding the posted speed limit; and • Number of erratic/conflict maneuvers in work zones. A detailed list of data elements for work zone crashes is dis- cussed at the end of this chapter. The most basic data com- ponents needed to address these objectives can be grouped into the following categories. 1. Basic crash characteristics—Information such as the basic nature of the crash, location, time and date, vehicles and persons involved, resulting injuries, and basic roadway characteristics is included in sufficient detail in most state crash report forms. All of this information is critical in assessing crash causation and severity and is equally im- portant for work zone crashes. 2. Work-zone-specific crash characteristics—The involvement of workers, work vehicles and equipment, and other work zone features is important to address various work zone objectives. 3. Work zone characteristics—Information describing work zone characteristics is critical to assess the effectiveness of work zone procedures and to identify needed improve- ments. Desirable information includes work zone type (lane closure, crossovers, etc.), devices and safety features present, location of devices and safety features, presence of work operations/equipment/workers, when work activity was occurring (day, night, weekends, etc.), whether lanes were being closed, and other information to fully describe the work zone at the location and time of the crash. 4. Basic project characteristics—This includes the project type (pavement overlay, reconstruction, widening, bridge re- pairs, etc.), length and duration of the project, project lim- its (mainline and intersecting roads), project budget, etc. 5. Traffic operating characteristics—Several data elements are needed to develop exposure rates and assess traffic opera- tions. These include traffic volumes, operating speeds, speed limits, queues, delays, and travel times. These data elements are needed to establish crash rates and to stratify crashes during certain operating conditions of the work zone (such as crashes during periods of queuing). 6. Other work zone non-crash accidents—While work zone crashes involving traffic are a major safety concern for the traveling public, workers are at risk both from traffic crashes and from industrial accidents that occur in work zones. These include falls, electrical contacts, struck by work vehicles/equipment, etc. Data elements needed for such accidents are similar to those needed for work zone crashes but involve industrial accidents rather than traffic crashes. Worker injury data from industrial accidents may be a major cost factor in highway programs, and its avail- ability can be useful in the overall safety management of highway programs. Review of Work Zone Crash Data Sources and Systems The discussion above clearly establishes the importance of access to detailed work zone crash data, and this importance is recognized by state highway agencies. It also establishes that there is little consistency among the systems used to compile work zone data and that the systems in use entail a range of shortcomings. There are a number of systems and approaches currently in use to record and compile work zone crash data on a statewide or national basis. The three most basic systems currently in use are described as follows. State Crash Reports In most states, crash reporting is coordinated by a central- ized state agency, with the crash reports generated and sub- mitted by police agencies and in some cases by the motorists involved in the crash. This system typically includes the use of a state standard reporting form. Many state crash report- ing forms and procedures currently in use do provide a way to identify crashes occurring in work zones. However, in most cases, only very limited data elements are compiled con- cerning the work zone and its involvement. Furthermore, there is little consistency in the forms and procedures used between states, and even within states in some cases. Crash reports are used by a number of states to summarize work zone crashes within the state. However, in most cases, the level of detail captured is limited, and in most cases it does not permit the examination of specific work zone parameters. Because of the state-to-state differences, it is difficult to com- bine data on a nationwide basis to address issues of national concern beyond very simple measures such as total work zone crash fatalities. MMUCC Guideline-Based Enhancements to State Crash Reports The Model Minimum Uniform Crash Criteria (MMUCC) guideline defines a dataset for describing crashes of motor 51

vehicles that will generate the information necessary to im- prove highway safety within each state and nationally and provides recommendations of data elements to be included on state crash report forms (75). The MMUCC provides for recording more extensive work zone data than what is now obtained in most existing state crash reporting forms. With some relatively minor revisions to the present MMUCC, states that adopt these elements into their state crash report form could be successful in capturing a great deal of the work zone crash information considered important. The biggest drawback to the guideline is that it has not been widely imple- mented to its fullest extent nationally, and it does not appear that it will be in place in more than a handful of states in the foreseeable future. For those states that do adopt the work- zone-related data elements recommended in the MMUCC, it would be possible to combine data from multiple states to assess work zone issues of national significance, and it would also permit the comparison of certain work zone safety per- formance measures between states. State DOT Agency-Based Work Zone Crash Data Reporting Some state DOTs have established an internal crash re- porting mechanism in place to capture work zone crash data above and beyond data available from the statewide crash re- porting system. A state can have a system in place to capture crash data on selected types of projects, or in some cases on all projects for fatal crashes or other limited categories of crashes. These procedures rely on data collection and report prepara- tion by highway agency personnel, typically at the project level. These project-initiated reports are typically supplemented by standard state-level crash reports and may be linked to other agency data such as traffic volumes, project characteristics, etc. This system may include industrial accidents in addition to work zone crashes. However, it may be less successful in capturing crashes and industrial accidents that occur on nights and weekends and at other times when project staff are not present. Comparison of Crash Data Sources Table 22 below summarizes the comparative advantages and disadvantages of these three sources of data. Selecting a Work Zone Crash Data Source As shown in Table 22, each of the three approaches to collecting work zone crash data offers distinct advantages and disadvantages. The adoption of a single uniform system nationwide, based on the MMUCC guideline or a revised ver- sion of it, would offer a distinct advantage in that it would permit pooling of work zone crash data on a national basis and would provide more detailed work zone crash data char- acteristics for analysis purposes than the data that are now available in most states. However, even if national imple- mentation of the MMUCC recommendations is achieved, which seems highly unlikely in the foreseeable future, there will still be some shortcomings relative to all of the ideal objec- tives of a work zone crash reporting system. Ultimately, the selection of which crash reporting system to use will be made at the agency level, as is appropriate. In most cases, it is reasonable to expect that this decision will be made by the state highway agency, in conjunction with input from other state agencies involved in the crash reporting system including police agencies responsible for traffic law enforcement and crash investigation on highway projects. It is also reasonable to expect that each state’s FHWA Division Office will provide input in the decision of how to obtain crash data. Specific considerations for the adoption of each of the three available systems are discussed below. Use of Existing State Crash Reports Use of existing statewide crash report forms to track and evaluate work zone safety programs is likely the least costly option for most states. Unfortunately, unless the state has in- corporated additional data elements concerning work zones into the form (such as is recommended in the MMUCC guideline), the manner and extent to which these data can be used is fairly limited. Going forward, a number of terms and conditions can be stated that should be present to allow these data to be considered an acceptable option for purposes of meeting the intent of the FHWA safety and mobility rule re- garding the collection and review of work zone safety data. These terms and conditions are as follows: • The statewide crash reporting form must allow identifica- tion of crashes that occur within a work zone or that are likely related to work zone activities (i.e., at the end of a work zone queue). • The statewide crash reporting form must also contain basic crash characteristics (severity, manner of collision, etc.). • The report form should include at least the most essential work zone characteristics, as is discussed in the section that follows. • The ability should exist for work zone crash reports to be forwarded to the highway agency in a timely manner as requested. Such critical reports would typically include fatal crashes within a work zone and serious crashes directly involving the work operation or personnel. • A good level of cooperation must exist between the high- way agency, the agency that compiles the reports, and the police agencies that investigate the crashes and prepare the 52

individual reports. This would assume that revisions to the reporting form and procedures can be considered from time to time to meet specific needs of the highway agency. • The crash reporting procedure should include a reasonably low reporting threshold so that most work zone crashes are captured. • The highway agency should consider developing a supple- mental reporting system to capture serious non-crash worker industrial accidents occurring on project sites. These would include serious injuries to workers (hospital treatment may be a useable threshold), accidents resulting in substantial property damage or environmental damage, and “near- miss” accidents that did not result in serious consequences but clearly had the potential to be much more severe. A typ- ical example would be the overturning of a large crane that missed workers and vehicles traveling through the project, or the rupture of a large natural gas transmission line. • Adequate training must be provided to law enforcement personnel that respond to crashes to ensure that the work zone and other data entered into the forms are correct and consistent. • The highway agency should develop clear-cut procedures as to how the crash report form data are to be extracted, analyzed, and used to guide decisions and changes to work zone policies, procedures, and practices. If data concerning non-crash worker industrial accidents are to be collected, efforts should be made to ensure that the requirements are understood by all agency staff that have responsibility for its implementation. • Buy-in to this system is obtained from the state division of- fice of FHWA. Adoption of MMUCC Work Zone and Related Data Elements on the State Crash Report Form The MMUCC guideline identifies several work zone data elements recommended for inclusion on state crash report forms. Overall, the recommendations represent a substantial improvement over the crash reporting forms used in many states and offer the potential to provide good uniformity of reporting among the states where it is used. However, it appears that only a handful of states have implemented the 53 State Crash Reports MMUCC Guideline Enhancements to State Crash Reports Highway Agency-Generated Work Zone Crash Reports Advantages Already in place in all states Would help make forms uniform across states Can provide best work zone detail Most states provide basic field to identify a crash as occurring in a work zone Includes other good work zone details Can capture non-crash accidents Captures most non-minor crashes Supported by key national agencies – FHWA, NHTSA, etc. Can help improve timely reporting to DOT Includes good basic crash characteristics Identifies additional crash data elements that may be useful in work zone analyses High level of DOT control Can be revised at state level to add elements as needed May be improved at state level to add elements Can be customized to meet specific needs May be linked to roadway, project, and traffic data May be linked to roadway, project, and traffic data May be linked to roadway, project, and traffic data May provide better information that is useful in defense of legal claims Disadvantages Not uniform between states No AASHTO involvement Not uniform between states Requires ongoing enforcement training Requires more training for enforcement personnel Requires development of state procedures Omits industrial accidents Overlooks most minor crashes May miss some events— nights, weekends Most contain few, if any, work zone characteristics Omits industrial accidents Requires DOT staff training Overlooks most minor crashes Work zone terminology needs “tweaking” Requires DOT management commitment Access to data by DOT is often delayed Access to data by DOT is often delayed Added cost to DOT May lack uniformity within state Should be supplemented by state crash report Table 22. Advantages and disadvantages of available work zone crash data sources.

1998 version of the MMUCC relative to the work zone data elements, and it is not known at this time if any have adopted the latest 2003 version. For state highway agencies that rely on the state crash reporting system to collect work zone crash data, implementation of the MMUCC at the state level will provide essentially all of the advantages those states now re- alize in terms of obtaining work zone crash data through their state crash reporting system, but with the significant added advantage of capturing more detailed and more consistent work zone characteristics in the reports. For the data elements to be available, the state agency re- sponsible for the statewide crash data form must first imple- ment the MMUCC. Once this is in place, the MMUCC will provide the specific major advantage of collecting much more detailed work zone crash data than most of the non-uniform state systems now in place. While the MMUCC will provide a greatly improved level of data in most cases, the other necessary terms and conditions listed above for the existing state report forms are also applicable to use the MMUCC data. State Highway Agency-Based Crash Data Collection and Reporting Currently, some states have internal systems in place for collecting work zone crash data elements using their own per- sonnel or contractor personnel at the project sites. In at least one case, non-crash worker industrial accidents are collected as well. Development of a work zone crash data collection and archival system within an agency does appear to provide the most effective means to compile complete data on work zone crashes. When combined with the availability of police crash reports based on the MMUCC guideline and the ability to link crashes to project, program, and traffic characteristics, such a system can provide the complete range of information needed for an agency to determine statewide work zone crash trends, and/or the need to modify or enhance work zone poli- cies, procedures, temporary traffic control plans, etc. When non-crash worker industrial accidents are included in the sys- tem, it also provides the ability to assess the overall safety of the agencies’ construction and maintenance programs. While this approach offers the opportunity to obtain the most detailed work zone crash and characteristics data, tai- lored to the specific needs of an agency, it is not without a few disadvantages, mostly related to increased costs and efforts by the highway agency to implement and continuously manage. Furthermore, if this type of approach is to be successful in al- lowing comparisons across states, it will be necessary for AASHTO or a follow-up NCHRP effort to promote the use of a uniform set of work zone data elements (as described in the next section) by highway agencies (an approach that is similar in concept to the MMUCC effort). As was the case for the state crash report form approach, there are a number of terms and conditions that can be stated that are essential for this approach to be considered an effec- tive option: • The highway agency must develop comprehensive report- ing forms for reporting crashes and accidents occurring on agency projects. These forms can standardize the coding and entry of data elements needed about the crash or acci- dent not captured on the standard state crash report form. • As part of the collection process, a mechanism is needed to match the highway agency’s collected data on its report form with the data collected on the state crash report form (relevant for all traffic crashes investigated). • Agency management must commit to providing the re- sources needed to collect the work zone crash and accident data, to analyze it in a timely manner, and to utilize it effec- tively to manage work zone safety and mobility. • Mechanisms are needed to ensure that the agency-collected work zone crash reports are forwarded to the highway agency in a timely manner, and individual crash reports should be available to the highway agency personnel on a near-immediate basis for critical crashes when requested. Such critical reports would typically include fatal crashes within a work zone and serious crashes directly involving the work operation or personnel. • The crash reporting procedure should include a reasonably low reporting threshold such that most work zone crashes are captured in the police crash reports. • The reporting system should include provisions to capture serious non-crash accidents occurring on project sites. These would include serious injuries to workers (hospital treatment may be a useable threshold), accidents resulting in substantial property damage or environmental damage, and “near-miss” accidents that did not result in serious consequences but clearly had the potential to be much more severe. A typical example would be the overturning of a large crane that missed workers and vehicles traveling through the project, or the rupture of a large natural gas transmission line. • The highway agency must develop clear-cut procedures to ensure the collection and dissemination requirements of the work zone crash report data are known and correctly followed by all agency staff having responsibilities for its implementation. Typically, this includes training of the in- volved staff as needed and ensuring that adequate quality control procedures are established. • A critical quality control component needed is the establish- ment of back-up procedures to alert project staff to crashes and work accidents that occur on nights and weekends and at other times when agency staff are not present. A close working relationship with law enforcement personnel at 54

the project level can be critical to capture such crashes. Contract provisions can be included to require contractors to report non-crash accidents and incidents directly to agency staff to permit the agency to follow up with its re- porting procedures. • Buy-in to this approach will need to be obtained from the state division office of FHWA. • Finally, a periodic agency summary of the work zone crashes and accidents should be prepared and circulated through- out the agency as a way to distribute lessons learned and to gain a consensus on needed changes in agency-level work zone policies and procedures. Recommended Model Work Zone Crash Report Data Elements, Attributes, and Definitions MMUCC Guideline Data Elements and Attributes—2003 Edition The 2003 MMUCC criteria include much of the informa- tion that is considered desirable to document work zone crashes in a manner that makes it feasible to manage traffic safety and some aspects of mobility in work zones. A full list of all 111 MMUCC data elements appears in Appendix C; those thought to be most directly critical to work zone man- agement are identified in the column “Work Zone Critical.” Several of the 111 elements actually include several sub- fields, such that the total number of data elements is con- siderably more than 111. Each of the 111 data elements and associated subfields includes a range of specific data attri- butes that are fully described in the MMUCC guideline. Sev- eral data elements relate directly to work zones, and several others address various work zone attributes in a less direct manner. These elements and attributes are discussed in this section. Only one of the 111 data elements in the MMUCC is used solely to describe work zone attributes. Data element C19 is defined as follows: C19. Work Zone-Related (Construction/Maintenance/Utility): Definition: A crash that occurs in or related to a construction, maintenance, or utility work zone, whether or not workers were actually present at the time of the crash. ‘Work zone-related’ crashes may also include those involving motor vehicles slowed or stopped because of the work zone, even if the first harmful event occurred before the first warning sign. Combined with definitions of work zone and work zone crash also provided in the MMUCC, this definition of “work zone related” describes what would typically be regarded as work zone crash events. To further clarify this definition, Fig- ure 6C-1 of the Manual on Uniform Traffic Control Devices (MUTCD), “Component Parts of a Temporary Traffic Control Zone,” is reprinted as an MMUCC appendix. Minor revisions to these definitions are discussed in the next section. Four sets of attributes are provided with this data element C19 to provide specific detailed information relating the crash to the work zone and its specific characteristics. Subfield #1 indicates whether or not the crash occurred in or near a work zone, given the choices of “yes,” “no,” and “unknown.” When the attribute is “yes,” three additional sub- fields are used to enter additional information. Subfield #2 defines the location of the crash, with the choices of: • Before the First Work Zone Warning Sign, • Advance Warning Area, • Transition Area, • Activity Area, and • Termination Area. Subfield #3 identifies the type of work zone, given the fol- lowing choices: • Lane Closure, • Lane Shift/Crossover, • Work on Shoulder or Median, • Intermittent or Moving Work, and • Other. Subfield #4 addresses the presence of workers, providing the choices of “yes,” “no,” and “unknown.” Several other data elements can also be used to provide data addressing work zone conditions, although all of them apply to crashes in general and are not limited to use in work zone crashes. These other elements and the attributes that may be applicable are presented in Table 23. In addition to those discussed in the table, the MMUCC guideline includes numerous other data elements that are use- ful in describing the characteristics of work zone crashes. These include such elements as C8—Manner of Crash/Collision Impact, C12 – Light Conditions, and several elements describ- ing injuries resulting from a crash, characteristics of persons and vehicles involved, and others that are potentially valuable in addressing work zone safety concerns. Overall, this guide- line provides a very detailed and comprehensive description of highway crashes that includes much of the information considered important to effectively manage work zone safety and, to some extent, mobility. Even so, there are a number of specific revisions that can be suggested to enhance its useful- ness for managing work zone safety. With consideration of the revisions discussed in the next section, this guideline can become even more effective as a system for recording work zone crash data. 55

Suggested Revisions to MMUCC Guideline Definitions The first category of suggested revisions to the MMUCC ad- dresses a number of definitions that are not consistent with commonly used highway terminology, and in some cases are in- consistent with the MUTCD and other highway guidelines and standards. The first of these is the basic definition of the work zone itself. The guideline definition of “work zone,” which very closely parallels the definition in the MUTCD, is given as: Work Zone—An area of a highway with highway construc- tion, maintenance, or utility work activities. A work zone is typ- ically marked by signs, channelizing devices, barriers, pavement markings, and/or work vehicles. It extends from the first warning sign or flashing lights on a vehicle to the END ROAD WORK sign or the last traffic control device. A work zone may exist for short or long durations and may include stationary or moving activities. This definition is very consistent with the MUTCD, although shortened slightly. A slight revision to “flashing lights on a work vehicle” would clarify this definition and make it even more consistent with the MUTCD definition. A second critical definition is that of “work zone crash,” stated in the guideline as: Work Zone Crash – A Work Zone Crash is a traffic crash in which the first harmful event occurs within the boundaries of a 56 Element Number Element Name Attribute Discussion C6 First Harm ful Event This elem ent includes attributes to describe various collision and non-collision events. The attribute “ thrown or falling object ” could be used to describe the involvem ent of construction debris falling from a bridge or from construction vehicles or equipm ent. The attribute “ collision with work zone/maintenance equipment ” and the attribute “ collision with a pedestria n ” could apply to highway workers, including flaggers. Also included are “ collision with impact attenuator/crash cushion ” and “ collision with other traffic barrier. ” C13 Roadway Surface Condition One of the available attributes is “ mud, dirt, gravel , ” which can be used to describe conditions sometim es encountered in work zones. C15 Contributing Circum stances, Road One of the available attributes is “ work zone (construction/maintenance/utility) , ” which can be used to identify possible contribution of a work zone to the occurrence or outcom e of a crash. V2 Motor Vehicle Type and Num ber This elem ent contains a choice of attributes to identify vehicle type, including “ working vehicle/equipment. ” This attribute can be used to identify vehicles and equipm ent involved in the work zone operation. V17 Traffic Control Device Type One of the available attributes is “ person (including flagger, law enforcement, crossing guard, etc.) , ” which can be used to identify work zones where flagger traffic control was present at the crash location. V20 Sequence of Events This data element includes several attributes that can be used to identify safety features co mm only found in work zones. These attributes include “ traffic sign support, impact attenuator/crash cushion, concrete traffic barrier, and work zone/maintenance equipment .” V21 Most Harmful Event for This Motor Vehicle This data elem ent includes the sam e attributes as V20. P3 Person Type This element includes several attributes that can be used to characterize highway workers involved in crashes, including “ motor vehicle driver and passenger, and non-motorist categories including pedestrian and occupant of motor vehicle not in transport (parked, etc.) . ” P22 Non-m otorist Action Prior to Crash Attributes include “ working, approaching or leaving motor vehicle, and playing or working on motor vehicle. ” Several other attributes may also be used to describe worker actions prior to a crash. P23 Non-m otorist Action at Ti me of Crash Attributes include “ in roadway (standing, on knees, lying, etc.) ” and several others that may be useful to describe worker actions at the time of a crash. P25 Non-m otorist Location at Ti me of Crash The list of attributes for this element can be used to describe the location of a worker at the tim e of a crash, in term s of standard highway term inology. Available choices include “ in roadway (not in crosswalk or intersection), shoulder, sidewalk, roadside, and outside trafficway, ” as well as several others. P26 Non-m otorist Safety Equipm ent Attributes include “ helmet and reflective clothi ng (jacket, backpack, etc.) , ” which can be used to identify worker use of hardhats and high-visibility apparel. RL2-9 and 11-18 Roadway Elements These data elem ents all describe co mm on highway design elem ents, safety features, and operating characteristics and highway classifications that may be of considerable interest in ma naging work zone safety and m obility. Included are such attributes as lane and shoulder widths, intersection characteristics, access control, roadway lighting and pavem ent markings, and traffic volumes. Table 23. MMUCC data elements relevant to describing work zone traffic crashes.

work zone or on an approach to or exit from a work zone, result- ing from an activity, behavior or control related to the movement of the traffic units through the work zone. Includes collision and non-collision crashes occurring within the signs or markings in- dicating a work zone or occurring on approach to, exiting from or adjacent to work zones that are related to the work zone. For ex- ample: 1) An automobile on the roadway loses control within a work zone due to a shift or reduction in the travel lanes and crashes into another vehicle in the work zone, 2) A van in an open travel lane strikes a highway worker in the work zone, 3) A highway con- struction vehicle working on the edge of the roadway is struck by a motor vehicle in transport in a construction zone, 4) A rear-end collision crash occurs before the signs or markings indicating a work zone due to vehicles slowing or stopped on the roadway because of the work zone activity, 5) A pickup in transport loses control in an open travel lane within a work zone due to a shift or reduction in the travel lanes and crashes into another vehicle which exited the work zone, 6) A tractor-trailer approaching an intersec- tion where the other roadway has a work zone strikes a pedestrian outside the work zone because of lack of visibility caused by the work zone equipment. Excludes single-vehicle crashes involving working vehicles not located in trafficway. For example: 1) A high- way maintenance truck strikes a highway worker inside the work site, 2) A utility worker repairing the electrical lines over the traf- ficway falls from the bucket of a cherry picker. This definition is very comprehensive and includes all types of crashes involving vehicles either within a work zone or upstream of the advance warning area if the crash was in- fluenced by traffic backups and queues or other activity within the work zone. However, this definition could be fur- ther clarified by adding a sentence stating: “This definition in- cludes all crashes that occur within a work zone, whether or not workers are present and work is actively underway.” While all of the examples included in the definition are clearly work zone crashes, all of them involve motor vehicles, and it is not clear if accidents involving a pedestrian, bicyclist, or other non-motor vehicles would be considered a work zone crash unless a motor vehicle is also involved. It is desir- able that this issue be clarified to include any events involving a pedestrian, bicyclists, or other non-motor vehicle traveling through a work zone as a work zone crash, regardless of whether or not a motor vehicle is involved. Managing such events is an important aspect of work zone safety manage- ment, especially in urban areas where pedestrians and bicy- cles are common, and data concerning these accidents are an important part of a crash data system. It is expected that this definition can be easily revised to ad- dress this issue. However, whereas police response to vehicle crashes is typically expected, this may not always be the case for accidents involving pedestrians and bicycles unless a more serious injury with a motor vehicle is involved. While revising this definition may result in capturing some of these events, it is likely that the MMUCC guideline will be less sensitive to pedestrian and bicycle accidents than to crashes involving motor vehicles, and a highway-agency-based reporting system may be better able to capture such events. A third critical definition is that of “work zone related crashes,” which is stated as: Work Zone-Related Crash—A crash that occurs in or related to a construction, maintenance, or utility work zone, whether workers were actually present at the time of the crash or not. Work zone-related crashes may also include those involving motor vehicles slowed or stopped because of the work zone, even if the first harmful event was before the first warning sign. This definition is consistent with the definition typically ap- plied by most highway agencies and does not require revision. In addition to these three basic definitions, 18 other defi- nitions were identified that involve work zone features. Some of these are not inconsistent with standard terminology in the MUTCD and other highway-related standards, and others need to be expanded or clarified to clearly describe common work zone features. These additional definitions are discussed in Appendix D. Suggested Revisions to MMUCC Data Elements and Attributes In addition to the suggested revisions to guideline defini- tions, there are also a number of data elements and attributes that would benefit from minor revisions such that they can more adequately describe work zone features and character- istics. These revisions are summarized in Table 24. Inherent Limitations in the MMUCC Guideline In addition to the suggested revisions to the 2003 edition of the MMUCC guideline, three inherent limitations were identified that impact its usefulness for managing some as- pects of work zone safety, and these limitations may be diffi- cult to overcome within the existing framework of the MMUCC guideline. The most critical limitation is that this guideline focuses entirely on work zone crashes and does not address non-crash events. Non-crash events that are routinely of interest to highway agencies in managing the overall safety and impacts of highway work include: • Industrial accidents occurring in a work zone (falls, work- ers struck by equipment, trench collapse, etc.); • Near-miss accidents resulting in only minimal injuries or property damage but with clear potential for more severe consequences; • Worker exposure to toxic materials; • Contacts with utilities (electrical transmission lines, gas mains, etc.) with the potential to cause injuries or property damage or disrupt service; and • Harmful environmental events such as release of hazardous waste or debris into the environment. 57

The MMUCC does not currently address any of these types of events, unless they are related to a traffic crash, and even then, detailed information about the event is not included as attrib- utes that would be collected via the MMUCCC guideline. Given the goals and objectives of the current guideline and its existing format and structure, a major revision would be required to ad- dress such events. It is considered more practical to address such needs through agency-based reporting systems and other sources of event reporting that are already in place to address such events through such venues as the Occupational Safety and Health Administration (OSHA) reporting requirements, insur- ance company and construction company records, and report- ing requirements of various other state and federal agencies. A second limitation, which may be problematic for some work zone events, is the focus on events involving motor vehicles, while not clearly including non-vehicle events in- volving pedestrians or bicycles. This limitation may be addressed to some extent by revising the existing guideline, but even with the suggested revisions, it appears that these non-vehicle events may not be addressed as completely as would be desired. This limitation is discussed above under the suggested revisions to the definition of “work zone crash.” The third significant limitation is that most of the linked roadway data elements RL1–RL18 provide information on roadway features that are also of interest in work zone crashes. However, because these data elements are obtained 58 Element Number Element Name Suggested Attribute Revisions C6 First Harmful Event • While the attribute “thrown or falling object” can be used to describe construction debris, it would be helpful to add an additional new attribute “construction debris/material” for this purpose. • Likewise, the attribute “pedestrian” would presumably include highway workers and flaggers. However, it would be helpful to include this as a separate attribute “construction/maintenance worker/flagger.” • The existing attribute “work zone/maintenance equipment” should be revised to read “work zone/maintenance equipment or vehicle.” It is suggested that an additional attribute “work vehicle with portable crash cushion attached” be added to permit tracking crashes involving shadow vehicles equipped with truck-mounted attenuators. • The definition associated with the attribute “impact attenuator/crash cushion” does not distinguish between permanent and work zone devices. It would be helpful to revise this attribute to “impact attenuator/crash —permanent” and to add a new attribute “impact attenuator/crash cushion—work zone.” • The attribute “other traffic barrier” as currently defined can be used to include a wide range of work zone safety devices but is not consistent with standard highway terminology. A revised definition of this attribute is provided in Appendix D. In addition, it is suggested that two additional attributes be added to identify commonly used work zone barriers. These are “temporary work zone concrete barrier—non-moveable” and “temporary work zone concrete barrier—moveable.” • It is suggested to add a new attribute under fixed objects: “construction features—excavation/trench/material stockpile, etc.” C19 Work Zone- Related (Construction/ Maintenance/ Utility) • Under Subfield 2, location of crash includes attributes for each of the work zone areas, as well as for before the first work zone sign. It would be helpful to revise the current attribute for “activity area” to three new attributes including “activity area—traffic space,” “activity area—workspace,” and “activity area—buffer space.” Definitions for each of these attributes should be added to the definitions, using the current definitions in MUTCD Figure 6C-1. • Under Subfield 3, the attribute “lane shift/crossover” should be separated into two distinct attributes because these are not similar work zone types. • A new Subfield 5 is recommended for “workspace intrusion,” with three attributes provided as “yes,” “no,” and “unknown.” • A definition for work zone intrusion should be added, as noted in Appendix D. V20 Sequence of Events • The attribute “work zone/maintenance equipment” under “collision with person, motor vehicle, or non-fixed object” should be expanded to “work zone/maintenance vehicle or equipment.” V21 Most Harmful Event for This Motor Vehicle • The attribute “work zone/maintenance equipment” under “collision with person, motor vehicle, or non-fixed object” should be expanded to “work zone/maintenance vehicle or equipment.” P26 Non-motorist Safety Equipment • Under Subfield 1, revise the attribute “helmet” to “helmet or hardhat.” Table 24. Recommended enhancements and revisions to MMUCC data elements and attributes.

by linkage to roadway inventory files, it is expected that the attributes recorded will be those normally present when no work zone is present. However, some or all of these attributes may be changed during some or all of the time the work zone is present. Reliance on this linked data thus has a high likeli- hood of providing incorrect data for work zone crashes. A major revision would be required to the guideline to address this limitation, and it does not appear likely that it can be addressed within the existing framework. Considering these limitations, reliance exclusively upon the MMUCC data elements and state crash report forms may not generate all work zone crash and accident data elements deemed essential to managing work zone safety. Even if all the MMUCC data elements and attributes are adopted by a state and all enhancements suggested in this report to better cap- ture work zone crash data are also adopted, a highway-agency- based reporting system may still be desirable to better capture the full range of data elements considered important. Data Element Considerations of Highway-Agency-Based Crash Reporting Systems Some states have implemented work zone crash and acci- dent reporting within the highway agency. Examples of re- porting forms for three such states (Florida, Maryland, and Louisiana) are provided as examples in Appendix E. These data are supplemented by police accident reports. NYSDOT has implemented a much more comprehensive system for reporting work zone crashes and other accidents that occur on its construction projects. Termed the “Con- struction Accident Reporting Program,” this system was initiated in the mid-1980s and has been expanded and refined several times to increase the information compiled and improve timeliness of reporting and analysis of the data for use in agency-wide management of work zone safety and mobility. This system requires a major commitment of re- sources by the agency and is believed to represent the most comprehensive database of this nature now available nation- ally. While it addresses many of the crash and accident data needs discussed in the preceding sections, a potential major drawback of this system is that it is unique to this agency and does not utilize the MMUCC guideline or any other stan- dardized reporting format. This will make it difficult to com- bine and compare data between states. Such a capability would be extremely helpful to projects such as this one and other efforts to examine work zone safety and mobility ques- tions and issues on a national basis. It is noted that this sys- tem is applicable to crashes and construction accidents that occur on department-administered construction projects, whether on the state highway system or local highways, and also any crashes or accidents involving Construction Division employees, regardless of the location. It also includes crashes and accidents on highway permit work sites administered by the Construction Division. A separate, less detailed system not directly linked to this one is used to report crashes and ac- cidents in maintenance work zones staffed by agency mainte- nance employees. This system is not applicable to work zones administered by toll roads or by local highway agencies in New York State. The basic requirements for the latest iteration of this system, implemented in 2004, are set forth in that agency’s construc- tion procedures manual (5). It defines the purpose of this reporting system as “to keep executive management informed of developing situations, to define the scope of safety related problems, and to identify corrective action.” This system pro- vides for electronic reporting directly by project field office staff of crashes and accidents meeting the criteria in the ref- erenced procedure. Individual reports are maintained in project files, regional office files, and the central office where they are used to generate various reports for use in managing work zone and construction safety, including the preparation of annual reports to summarize safety-related issues. Reporting requirements for this system address nearly all crashes and accidents that occur on an agency construction contract, as well as all accidents involving Construction Divi- sion employees, regardless of where they occur. The following describes event types that are covered by this reporting system: Immediate Notification Required • Any injuries to NYSDOT construction employees, • All accidents involving state-owned vehicles and private vehicles used on state business, • Any fatal or hospital transportation to consultant or con- tractor employee directly related to construction activity, • Traffic accidents resulting in fatal or multiple (three or more) personal injuries, if directly related to construction activity or the maintenance and protection of traffic, • Any utility incidents, and • Any accident resulting in media attention. Notification Required as Soon as Possible • Any traffic accident involving maintenance and protection of traffic, but not resulting in fatal or multiple (three or more) personal injuries, • Any traffic accident within the project limits resulting in a fatality or personal injury, but not related to construction activity or within limits of active M&PT, • Any construction-related accident resulting in minor worker injury or damage to private property, and • Any near miss accident. A user manual defines the procedure for entering crash and accident data into the electronic Construction Accident 59

Reporting Program, written in Visual Basic/Crystal Reports. It also details how reports are to be transmitted and stored within the agency, and periodic management reports gener- ated by the system track the completion and follow-up of individual accident reports. This manual provides a partial list of the data elements and attributes included in the pro- gram, but it does not provide an overall comprehensive list. Appendix D provides a list of the NYSDOT data elements and attributes compiled from the user manual and the database itself. The NYSDOT Construction Accident Reporting Program, in its current form, offers a number of specific advantages for the management of work zone safety and mobility: • It is based on management’s commitment to the report- ing of all crashes, accidents, and other incidents related to the agency’s construction program, and use of the data to manage and improve safety in the construction program. • Procedural guides and user manuals have been developed to assist in the uniform implementation of the program. • The program provides for immediate or rapid reporting of all such incidents up through the agency chain of command. • An electronic reporting program provides for data entry at the field office. The overall system provides for distribution of reports throughout the agency as appropriate and gener- ation of various management reports on a systematic basis. • Other reports, such as police accident reports, are appended to these reports. • An extensive “accident file” is assembled for serious acci- dents to assist in defense of any claims, to develop corrective measures, and for various other purposes. • This system provides for statewide data availability and analysis for the preparation of agency-wide summary reports. • In addition to traffic crashes involving vehicle collision, this system captures virtually all harmful or potentially harmful events that occur on construction or permit proj- ects, or involving Construction Division employees. This includes construction accidents; accidents or crashes in- volving pedestrians, bicycles, and motorcycles; incidents involving damage to or contacts with utility infrastructure; and off-site accidents involving Construction Division employees. • The reporting program includes detailed data elements and attributes designed to provide specific information considered necessary to the management of the agency’s construction program. • These reports can be linked to other data available within the agency such as traffic volumes, roadway inventory, construction program attributes, and others as deemed necessary. In spite of the significant strengths of this program, it appears that it also entails a number of potential weaknesses, especially in terms of the development and implementation of the elec- tronic reporting system: • The user manual provided for the reporting system ap- pears to omit specific instructions for some portions of the system. Based on a review of the reports submitted since the current reporting system was implemented, there are clearly inconsistencies in how some of the elements are reported. • The methodology of using true/false attributes for a num- ber of data elements is cumbersome and confusing. For ex- ample, rather than providing a single data element for “manner of crash,” followed by a list of several allowable attributes defining the various manners of crash, the cur- rent program includes several elements that use a true/false attribute. Adding further to the confusion, these elements are not grouped together within the system. • The data elements in the system do not provide a compre- hensive list of all possible manners of crash, consistent with those in the MMUCC guideline. • A number of closely associated data elements are not lo- cated together in the form, increasing the risk of incorrect or inconsistent reporting. • The data element for work zone intrusion is inconsistent in that it appears to classify both workspace intrusions and certain other crashes involving workers and work vehicles/ equipment as intrusions even when they do not occur in the workspace. • The records do not clearly indicate the involvement of most work zone traffic control devices and safety features in a crash, except as noted in the narratives. This may pre- clude automated sorting of the records to identify all such crashes and may even fail to identify some of these crashes. • The unique and cumbersome coding system included in the current program makes it extremely difficult to com- bine the New York data with data available from other states and other work zone crash data sources. • The coding system also makes it extremely cumbersome to query the database to identify specific crash and accident types and characteristics, other than those specific data elements and attribute factors now included in the report- ing program. • There are no specific data elements and lists of attributes to describe construction accidents involving workers. While this information can be obtained from the narrative de- scriptions, a specific data element to identify construction accident attributes would be a very helpful feature. • A number of other potential concerns are mentioned in the discussion of the individual data elements and attributes provided in Appendix F. 60

Data Element Considerations of Work Zone Exposure Information The previous discussion notes the importance of capturing roadway and certain work zone characteristic information present at the time of a crash; this information is typically not captured in agency roadway inventory databases because of the temporary nature of the work zone. In addition to these types of event-based data elements, there is a need for agen- cies to begin to establish mechanisms to gather and organize data pertaining to work zone exposure information. These exposure data elements are needed to properly normalize crashes into appropriate rate-based measures so that they can be consolidated across multiple work zones and compared in various ways. The data elements needed or desired for exposure estima- tion purposes include those pertaining to traffic and to specific characteristics of the work zone itself. Suggested elements and attributes include the following: • Traffic volumes and characteristics (ADTs, hourly volumes, and vehicle mix); • Work zone length (overall and by sections with similar geometric features); • Work zone duration (duration of phases, hours of work ac- tivity, and times and durations of capacity restrictions); and • Highway worker and equipment exposure (number of workers and equipment present, and location of workers/ equipment within the work zone). Currently, few agencies actively collect work zone traffic data, although the increased use of work zone ITS technologies now provides an opportunity to do so with greater frequency. On the other hand, much of the proposed data pertaining to work zone exposure are already within the potential grasp of many highway agencies. Daily project diaries already provide spaces to document times of work activity, equipment and workers present, locations of work activities, etc. As agencies move toward electronic storage of daily project information (using the AASHTO Trns•port SiteManager or other con- struction management software), the opportunity does exist to more easily extract this type of data for use in exposure estimation. The challenge will be in ensuring adequate docu- mentation levels of these data elements. As part of this re- search, thousands of pages of such diaries were reviewed. The extent to which those elements were consistently reported in the diaries varied widely. Other data elements, most notably lane closures that tem- porarily restrict the capacity of the roadway, do not have a specific field in the inspector diary but are typically docu- mented in the narrative portion of the diary. Capturing these data at the present time is thus extremely time consuming. Modification to project diary pages to specifically request lane closure information, and the inclusion of this item in con- struction management software where project diary data are kept, would be an important first step. Recommended Work Zone Crash Data Analysis Methods In the most general terms, work zone crash data can be used for ongoing monitoring functions or for detailed after- the-fact (post-hoc) investigations to quantify and/or test the statistical significance of various crash-related hypotheses. The monitoring function can be for a particular project, or it can be for a particular crash type across a district, region, or even state. For example, project engineers often maintain an informal awareness of the crashes occurring in their particu- lar project (either informally by discussions with local law enforcement or by regularly obtaining actual hard copies of crash reports occurring in the work zone) as a way of check- ing for any obvious safety problems that need immediate attention in the work zone. Likewise, some states maintain a running total of the number of fatalities or the number of cer- tain types of crashes occurring in work zones throughout the year to compare against similar year-to-date totals in previ- ous years. Meanwhile, post-hoc investigations are typically carried out to determine the amount of crash increase occur- ring in work zones overall or of a particular type, to evaluate the effect of a particular design feature or operating strategy upon crashes, or to evaluate the effectiveness of a particular countermeasure implemented to address a particular crash issue. The analyses performed as part of this research are examples of these post-hoc investigations. The Ohio Department of Transportation is one agency that has formalized its efforts to monitor crashes in its significant work zones (76). For those work zones selected for monitor- ing, the agency divides the projects into 0.5-mi segments and compares crashes occurring in each segment with the average rate of crashes that had occurred in those segments in the pre- vious 3-year time period. Those segments where crashes ap- pear abnormally high are targeted for further assessments of the possible underlying factors that may be contributing to the higher-than-normal crash frequencies. An example of the type of analysis generated through this effort is provided in Figure 29. Crashes are examined both by location and by time to identify unusual trends. A key component of this process is the commitment of personnel resources by the Ohio DOT to manually collect hard-copy crash reports from the law en- forcement office at each project every 2 weeks and to enter that data into the spreadsheets used for analysis. A comparison of some of the opportunities and challenges associated with monitoring and post-hoc investigations of work zone crashes is provided in Table 25. Review of the 61

points presented in the table illustrates that both approaches have a significant role within highway agencies as they strive to improve safety within the work zones under their jurisdiction. Perhaps more importantly, there is a degree of synergy between the two main analysis approaches. Monitoring efforts are best suited to identify possible safety issues at the project level that may be quickly mitigated by the agency or the con- tractor. Monitoring efforts can be an effective method of identifying possible work zone design features, operating strategies, etc. that may be unduly contributing to crashes occurring in work zones and so need to be modified. Post- hoc investigations are more suited to actually quantifying the extent to which those features and operating strategies are con- tributing to work zone crashes and to quantifying the extent that any modifications made to them are actually reducing crash risk. Summary Although no work zone crash data system currently in use fully addresses the needs of effective work zone safety manage- ment, it appears that such a system can be developed by com- bining the desirable features of the MMUCC with an agency construction accident reporting program similar in concept to the one now in use at NYSDOT. However, revisions and improvements to both of these are considered essential to achieve the goal of providing comprehensive, timely, and consistent data for crashes, construction accidents, and other 62 0 5 10 15 20 25 30 148 137 2004 Work Zone Crashes Pre Work Zone 3-Yr Average 1 2 3 4 5 6 7 8 9 Pre Work Zone 3-Year Monthly Average: 18 Crashes HAM-IR-75 Work Zone vs. Non Work Zone Crash Comparison HAM-IR-75 Count of Crashes in Work Zone by Month Month (Numerical Value) N um be r o f C ra sh es 0 20 40 60 80 100 120 140 160 N um be r o f C ra sh es 0 10 20 30 40 50 60 70 0 7 34 19 30 64 3 3 38 31 39 19 10 8 Boxes Contain Pre Work Zone 3-Year Averages by Section (April 1 - November 30) Crash Logpoint (MP 14.2 - 17.4) HAM-IR-75 Work Zone Crash Location-Frequency Chart N um be r o f C ra sh es Exception Location: Review Crash Reports and Field Review Exception Location: Review Crash Reports and Field Review 14 .2 7 - 1 4. 76 14 .7 7 - 1 5. 26 15 .2 7 - 1 5. 76 15 .7 7 - 1 6. 26 16 .2 7 - 1 6. 76 16 .7 7 - 1 7. 26 17 .2 7 - 1 7. 76 Figure 29. Example of work zone crash analysis performed by Ohio DOT (76).

harmful events in and related to highway work zones. Specif- ically, the following actions would be needed: • The MMUCC guideline needs to be implemented by more states to permit sharing of data between states. • Minor modifications to the MMUCC guideline should be made to address the weaknesses and inconsistencies dis- cussed in the preceding sections. • Some roadway data elements in the MMUCC guideline are recorded in the field, while others are obtained through linkage to other roadway databases. Because roadway char- acteristics are frequently temporarily changed in work zones, the linked roadway data included in the MMUCC may be invalid for work zone crashes. Therefore, it appears necessary to verify these linked roadway elements in the field at the time of a work zone crash, or to establish pro- cedures that would allow work zone roadway element fea- tures present at the time of the crash to be determined via construction plans, project diary documentation, or other mechanisms. • While the NYSDOT system is conceptually sound, there are inherent weaknesses in it that need to be corrected. These involve revising some data elements and attributes and adding others. The reliance on true/false attributes should be replaced by standard attributes associated with specific data elements to facilitate use of the database. • A nationally supported research effort either by FHWA or through the NCHRP program appears to be the most prac- tical means to develop a model state system, using the NYSDOT program as a starting point, and revising and expanding it to address its weaknesses. The proposed list of data elements and attributes for work zone crashes addresses specific characteristics of work zone crashes and accidents using attributes based on generally accepted terminology. The MMUCC data elements are clas- sified into four major groups – crash, motor vehicle, person, and roadway data. With the corrections and revisions dis- cussed in the previous sections, the MMUCC data elements would be sufficient to provide much of the information needed for vehicle-involved crashes. However, it includes no data elements to address work zone accidents by pedestrians and bicycles but not involving a vehicle, and no elements for construction accidents. In addition, there are insufficient elements to identify all of the specific types of work zone traf- fic control devices and safety features present or involved in the crash, other than a few included in other data elements such as “Traffic Control Device Type.” In addition, there are no elements to describe work vehicles, equipment, and work operations. These lacking data elements can best be addressed by de- veloping a comprehensive list of data elements and attributes to be incorporated into a work zone crash/accident reporting program to be implemented by highway agencies as a supple- ment to MMUCC or similar crash reports. Such a compre- hensive list should have a strong consensus of support from highway agencies in this country. These data elements would include the following four groups: • Project and crash identification elements—A series of ele- ments would identify the date, time, and location of the event and the contract or permit where the event occurs. An element could be included to identify agency region or district as well as project type (reconstruction, bridge re- habilitation, safety improvement project, etc.). Involved contractors, subcontractors, and consultants would also be identified. A tracking number would be included for each event. • Work zone elements—These elements would identify com- monly used work zone traffic control devices, traffic safety 63 Crash Monitoring Post-Hoc Investigations Opportunities • Allows for near real-time identification of possible safety problems (features, strategies, etc.) • Demonstrates a culture of diligence about work zone safety by the agency (potentially useful for litigation purposes) • Allows for quantification of influence of work zone feature(s), operating strategies, and safety countermeasures implemented • Allows experiences from multiple work zones to be properly consolidated and interpreted (useful for periodic assessment of agency policies and processes) Challenges • Requires commitment by the agency to collect and process data in a timely manner • Difficult to determine relative contributions of multiple features or strategies to a possible safety problem • Difficult to know what feature(s) or operating strategies are the highest priority to investigate • Typically requires more data to perform correctly • Often a significant time lag exists between when a crash occurs and the time it is available for analysis Table 25. Comparison of monitoring and post-hoc crash analysis approaches.

features, and construction safety features and devices. Also included would be elements to describe work vehicles and equipment involved and the related work operations. • Supplemental person elements—These elements would pro- vide information about workers involved, including job title, employer, etc. • Report tracking elements—These elements would identify persons involved in preparing and reviewing the report, report dates, etc. They would be used for internal agency management purposes and are not directly associated with crash or accident safety management. In addition to these data elements to be addressed solely in the work zone crash/accident reporting program, the pro- posed system will also rely on numerous data elements in- cluded in the MMUCC. To the extent that the MMUCC or equivalent accident reports are available in a timely manner to supplement the agency internal report, this information could be available as needed. In reality, however, some delay will be encountered in obtaining MMUCC or other similar reports prepared by police agencies, and more critically not all crashes and events will generate a police report. Therefore, it is important to duplicate certain data elements from the MMUCC into the work zone crash/accident reporting pro- gram to ensure that the necessary information is available in a timely manner for all events. These elements are identified in the column “Work Zone Related” in Appendix C. While the above categories of elements are thought to in- clude those most relevant to work zone safety management, individual highway agencies could have the option to add any additional elements considered important for internal purposes. 64

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Traffic Safety Evaluation of Nighttime and Daytime Work Zones Get This Book
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TRB's National Cooperative Highway Research Program (NCHRP) Report 627: Traffic Safety Evaluation of Nighttime and Daytime Work Zones explores the crash rates for nighttime and daytime work zones and examines management practices that promote safety and mobility in work zones. The report also highlights work-zone crash reporting suggestions designed to help improve the data collected on work zone crashes.

The following appendices to NCHRP Report 627 are available online:

Appendix A: Data Collection, Reduction, and Analysis in California, North Carolina, Ohio, and Washington

Appendix B: EB Crash Analysis

Appendix C: MMUCC Guideline Data Elements

Appendix F: NYSDOT Accident Reporting Program - Data Elements and Attributes

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