摘要: |
The primary objective of this study--requested and funded by the National Highway Traffic Safety Administration, the Federal Highway Administration, and the Centers for Disease Control and Prevention--was to review current practice for setting and enforcing speed limits on all types of roads. The study was conducted by a Transportation Research Board committee of experts in traffic engineering, highway design, traffic operations and highway safety, vehicle design and biomechanics, human factors, public health, traffic enforcement, highway users, economics, statistics, political science, and public policy. In addition to reviewing current practice in setting and enforcing speed limits, guidance is provided to state and local governments on appropriate methods of setting speed limits and related enforcement strategies. Following an executive summary, the report is presented in six chapters and five appendices. Chapter 1 provides an introduction. In Chapter 2 the relationship between speed and safety is investigated in depth to help identify the role of speed in crash causation and injury severity. The relationship of speed to travel time and vehicle operating costs is also considered because drivers make tradeoffs among safety, travel time, and other trip-related costs in deciding what speed to travel. Having laid the groundwork for the importance of speed on traffic safety and travel efficiency, Chapter 3 is focused on speed limits--the primary method for managing speed addressed in this study. The theoretical justification for speed limits is elaborated, the strengths and weaknesses of the primary methods of setting speed limits are described, and what is known about the effects of speed limits on driving speeds and safety is summarized. Speed enforcement and adjudication issues are examined in Chapter 4, including the relevance of deterrence theory for speed enforcement and the potential for application of automated enforcement technologies to augment traditional enforcement methods. In Chapter 5, other speed management strategies are discussed briefly, including highway design and infrastructure approaches, highway- and vehicle-related technologies, and interventions for special driver populations. Finally, the committee's guidance on appropriate strategies for both setting and enforcing speed limits is provided in Chapter 6. Appendix A presents a formal treatment of how drivers make tradeoff decisions in selecting driving speeds. Appendices B, C, and D contain literature reviews commissioned to inform the committee deliberations. These papers are entered individually in the TRIS data base. Appendix E is a glossary. |