Click for next page ( 8


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 7
8 Grants to support the development of strategic plans on crash data collection, whereas a DOT might be more likely to improve traffic records systems. to expend resources to improve data warehousing and link- Grant funds provided to states by FHWA in partnership age. Attempts to balance competing needs can create prob- with NHTSA for the development of strategic plans to lems, or the perception of problems, when trying to make improve their traffic records systems and the develop- changes and improvements to the crash records systems. ment by FHWA of guidelines for the management sys- tems required by ISTEA legislation (14). By 1994, national costs of crash data collection and man- Initiation of the National Governors Association's agement were estimated at $130 million, with data collection project by the Office of Motor Carrier Safety, now the being 60% and data management 40% of that total (19). The FMCSA, to improve the quality and utility of information estimated unit cost was $21 per crash. At that rate, even states concerning crashes involving commercial vehicles (15). with a smaller than average number of crashes can expect to spend millions of dollars to collect and manage these data. As an adjunct to these and other efforts, Congress created a number of incentive mechanisms that provided additional The increased reliance on traffic records information by grant funding to support traffic records improvements if a the highway safety community to develop, manage, and eval- state has not passed certain safety legislation. Individually uate its programs, however, has to be given full considera- and collectively, these efforts encouraged states to improve tion in making a decision to improve crash data collection their traffic records systems, in many cases providing both and management procedures. Traffic records data, particu- the motivation and funding necessary to do so. larly information contained in the police crash report, are the basis for virtually all safety programs, from roadside hazard Over the years, Congress has increasingly viewed traffic removal to the enforcement of traffic safety legislation. Law crashes as a national problem meriting federal involvement; enforcement, traffic engineers, the judiciary, private citizens, therefore, the federal goal in this area has been to provide the medical community, and highway safety program spe- leadership and financial aid to the states as incentives to cialists use traffic records data to initiate actions that ulti- develop a nationally uniform system. One example of federal mately may reduce the frequency and severity of motor vehi- input was the publication in 1990 of an advisory describing cle crashes of all kinds. Understanding and satisfying the traffic records systems and the recommended components of information requirements of the traffic safety and public such systems (16). On the other hand, states have tried to health community is the key to developing usable and acces- retain the maximum degree of flexibility and decentralization sible crash records systems. so that they can respond to their state needs (17). Ironically, the states have the same difficulty in maintaining a uniform crash records system statewide because their local jurisdic- CRASH DATA COLLECTION tions wish to retain the maximum degree of flexibility to meet the needs of their local constituents. In recognition of the need to meet differing local needs with their data collection efforts, the updated NHTSA Traffic NHTSA conducts a periodic survey to identify the custodi- Records Advisory (20) recommends data systems that are ans of the various records systems that comprise each state's flexible enough to receive data from numerous local systems traffic records system. These results were updated with those in a consistent format. Figure 2 shows a data flow diagram obtained from a survey conducted by FMCSA to determine (DFD) from the Advisory. This DFD illustrates the wide num- the types of agencies that serve as the custodians for the ber of data sources needed to complement the crash records statewide crash records system (18). The most recent results system. of those combined surveys indicate the categories of crash custodial agencies as: The highway safety literature has historically documented the causes of, and problems arising from, poor quality crash Thirty agencies that are roadway oriented (e.g., state data. NCHRP Synthesis of Highway Practice 192 (21) cov- DOTs and highway departments). ers this subject well. The causes of poor quality are numer- Eleven agencies that are primarily law enforcement ous but can be generally viewed as errors in form design (i.e., (e.g., Departments of Public Safety, State Police, and the data collection instrument was flawed), reporting errors Highway Patrol). (i.e., the person completing the form made a mistake), and Seven agencies that are primarily financial in nature mismanagement of the records (i.e., the original data were (e.g., Departments of Revenue). somehow corrupted during processing). As shown in the Two agencies that are unknown because of no response DFD, there are numerous steps in the data collection process to either survey. where these errors can occur. The following are some of the issues involved in obtaining quality crash data. The diverse uses and users of these crash systems create an equally large and diverse set of demands. For example, a pub- Uniformity of data--Crash data uniformity is primarily lic safety custodian may place more emphasis and resources a national problem, because most states mandate the

OCR for page 7
9 FIGURE 2 Distributed traffic records systems. use of a uniform crash report form. The federal govern- ance among local reporting policies and thresholds has ment has consistently worked toward national standards implications for the statewide crash database that were for crash data reporting for all states. It has only been once only a problem for national comparisons and analy- since the promotion of MMUCC and the National Gov- ses. These include: ernors' Association commercial truck and bus data vari- Many crashes that may go unreported; ables, supplemented by federal funding initiatives for Driver-only reports, or officer desk reports, which traffic records improvement that substantive advances may not be as reliable as a trained officer's report have been made in uniform reporting. As states make taken at the scene of the crash; and periodic changes in their crash report forms, they are Systematic biases that are introduced into the data if beginning to incorporate the guidelines into their crash drivers report certain kinds of crashes, whereas offi- records systems. In addition, most states follow ANSI cers report others, or if certain types of crashes are standards D-16 and D-20 for crash data reporting. As consistently missing from the database. even more states incorporate MMUCC into their crash reporting standards, the ability to provide meaningful Underreporting or errors in crash reporting affect deci- analyses and draw appropriate conclusions on a national sions regarding the selection of crash countermeasures, law level will be significantly improved. enforcement activities, allocation of funding at state and local Accuracy of data--The more times that crash data are levels, and numerous other traffic safety and transportation interpreted or key entered into a system, the more likely system management activities. that the accuracy of these data is affected. Although inadequate training for law enforcement officers may have contributed to problems of accuracy in the past, Timeliness--In the late 1960s, NHTSA found that crash steps have been taken to improve training programs and data were often several months to a year old by the time to provide automated tools for simpler and more accu- they were available in the crash reporting system. In the rate crash data entry. early 1980s, as crash records systems matured, timeliness Level of reporting--The level of reporting was once a of crash data became less of a problem, with information serious problem only at the national level, owing to the available often within 2 months of the date of the crash different reporting thresholds used by each state. Today, (22). In 1993, a review of nine states showed the time with fewer and fewer resources to commit to crash from crash to crash file as 25 to 210 days (23). Accord- data collection, localities are making their own poli- ing to the survey results for this study, one-quarter of the cies about which crashes they will investigate. This vari- responding states reported that a crash may be entered