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5 CHAPTER ONE INTRODUCTION The government are very keen on amassing statistics. They col- roadways. Without improvements in the quality and utility of lect them, add them, raise them to the n-th power, take the cube these data, it may not be possible to sustain the gains in safety root, and prepare wonderful diagrams. But you must never for- get that every one of these figures comes in the first instance that have been made or to achieve further gains. from the village watchman, who just puts down what he damn pleases. As shown in Figure 1, the fatality rate per 100 million vehicle-miles traveled (VMT) essentially has flattened in --Comment of an English judge quoted by Sir Josiah Stamp in Some Economic Matters in Modern Life the United States, after experiencing steady improvement for many years (1). In 1990, 44,599 fatalities occurred, for a rate of 2.08 per 100 million VMT. In 2002, 42,815 fatal- BACKGROUND ities occurred, for a rate of 1.51 per 100 million VMT. State traffic records assessments promoted by NHTSA and The U.S.DOT and other major stakeholder groups have FHWA, as well as a recent evaluation of states for possible adopted as their goal to reduce fatalities to a rate of 1.0 per inclusion in FHWA's Highway Safety Information System, 100 million VMT by 2008. To meet this goal, it is more crit- have discovered a disturbing trend. The completeness and ical than ever to be able to analyze state safety data to make quality of the safety databases of many states are eroding. informed decisions on the best methods for reducing fatalities. With reductions in staff and other resources, a smaller pro- portion of motor vehicle crashes is reported to state crash The incentive to improve the quality and utility of traffic databases than ever before. Crash thresholds are increasing records systems, in particular motor vehicle crash data, is to the point that any meaningful analyses are problematic, undertaken against a backdrop of diminished state resources and data entry backlogs result in information that is outdated and increased demands for scarce financial resources. The by the time the data are available for use. Although states are costs of collecting crash data continue to be a substantial bur- increasing their use of geographic information systems (GIS) den to all states. In addition, the time required to collect crash technology, they are not adequately maintaining or linking a data and the costs of doing so compete with demands for record of the roadway characteristics associated with specific other police work, including more recently, homeland secu- locations. Core data elements such as location control, num- rity duties. ber of lanes, lane widths, shoulder widths, median type, and median width are missing in many systems that define road- Consequently, over the past two decades, some states have way characteristics. Items such as horizontal curve, vertical eliminated some data from their crash report forms rather than grade, intersection features, and interchange features are vir- adding to the existing information to satisfy emerging needs. tually nonexistent. Other states have altered reporting criteria to reduce the num- ber of crashes that police investigate or implemented "self An increasing emphasis on traffic records is not without report" forms for crashes in which no one is injured. At a time justification. It has become apparent over time that appro- when more and better information is needed, these trends can priate, accurate, and timely information describing various have a disastrous effect on the quality and utility of crash data. aspects of the transportation system (including its crash expe- Conversely, these trends are also the genesis for attempts to rience) are needed to improve traffic safety and mobility. use advanced information collection capabilities in the form of Data on fatalities are not enough. National samples of police- laptop, notebook, and hand-held computers, global position- reported crash data are not enough. To manage its safety pro- ing system (GPS) devices, pen-based entry systems, and other grams effectively, each state needs to analyze an increasingly technologies that have the potential to improve the process of wide variety of information about the design characteristics collecting and automating crash and other transportation data. of its road system, the behavior of traffic on that system, and the crash experiences of its users. This need for improved Crash data are the basis for many decisions regarding traf- data arises in part from a growing awareness that significant fic safety, highway design, operations, and research. These improvements in safety have and will come from state actions data are used to help identify specific problems, to develop to control the crash experience of road users. More than ever and prioritize remedial actions, and to establish goals and per- states need detailed information about both urban and rural formance measures to evaluate whether the desired results