TRB’s National Cooperative Highway Research Program (NCHRP) Report 617: Accident Modification Factors for Traffic Engineering and ITS Improvements explores the development of accident modification factors (AMFs) for traffic engineering and intelligent transportation system improvements. AMFs, also known as crash reduction factors, are designed to provide a simple and quick way of estimating the safety impacts of various types of engineering improvements, encompassing the areas of signing, alignment, channelization, and other traffic engineering solutions.
The following appendices to NCHRP Report 617 are available online:
* Appendix A: Methodology for Determining Crash-Harm Rating for Treatments
* Appendix B: Effects of Converting Rural Intersections from Stop to Signal Control
* Appendix C: Safety Effects of Four-Lane to Three-Lane Conversions
* Appendix D: Safety Effects of Improving Pavement Skid Resistance
* Appendix E: Evaluation of the Safety Effectiveness of Urban Signal Treatments
* Appendix F: An Empirical Examination of the Relationship Between Speed and Road Accidents
* Appendix G: Accident Modification Factors for Median Width
Two AMF treatment summaries that appear in the printed version of NCHRP Report 617 contain incorrect information. These treatments are “Add Intersection Lighting” and “Add Roadway Segment Lighting.” The information in these two AMF treatment summaries has been corrected in the online version of the report.