Guidelines for Selection of Speed Reduction Treatments at High-Speed Intersections: Supplement to NCHRP Report 613 (2008)

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APPENDIX B

NCHRP 3-74 Appendix B Selection of Speed Reduction Treatments at High-Speed Intersections Literature Review The following document summarizes the critical concepts and general information outlined in each task of the Amplified Research Plan. These bullet points will be used as criteria to screen and prioritize the sources that we have gathered thus far. A source that does not provide insight on one of the following criteria may not have specific relevance to our research goals. The concepts have been categorized by task and sub-task in order to refer back to the original Amplified Research Plan for further detail on each topic if needed. B.1 TASK 1 – ANALYZE POTENTIAL TREATMENTS • Relationship between frequency and/or severity of crashes based on speed • Factors that affect intersection safety and speed • Speed transition areas • Impacts of treatments on speed and safety o Effectiveness of treatments • Evaluation criteria for treatments, safety and speed reduction (1.2, 1.3) • Case studies that discuss experience with applying various treatments to different roadway environments (1.2) • Types of speed reduction techniques (1.4) o Beyond the list shown in the research plan • Effectiveness of speed enforcement on intersection approaches (1.5) o With or without particular geometric or traffic control treatments • Relationship between geometric design speed reduction techniques and non-design treatments (1.5) B.2 TASK 2 – CHARACTERISTICS FACTORS OF HIGH RISK INTERSECTIONS • Characteristics of intersections with high crash rates • Characteristics of high-speed intersections with a history of severe crashes • Categorization of potential speed reduction treatments o Visual, physical, operations • Factors that contribute to speed (2.1) o Conflicts and friction, roadside impedances, roadside environment, etc. • Speed characteristics and trends (2.2) o Based on facility type, roadway environment, climate, traffic control devices, etc. Kittelson& Associates, Inc. Page B-1 Appendix B Literature Review - Document Screening

Appendix B NCHRP 3-74 Literature Review Selection of Speed Reduction Treatments at High-Speed Intersections • Safety characteristics of the factors that influence speed (2.3) o A low volume, high-speed road could experience a low frequency of severe crashes, whereas a high volume, low speed facility could experience a high number of low severity crashes • Relationship between human factors and intersection safety and speed (2.3) o How does human behavior influence speed? B.3 TASK 3– RECOMMEND TREATMENTS • Performance measures of speed reduction treatments • Relationship between roadway facility characteristics and speed and safety (3.1) • Relationship between speed differentials and the risk of crashes (3.2) • Evolution of speed characteristics on a specific facility or area (3.2) o Volume growth o Adjacent land uses changing • Amount of speed reduction (3.2) B.4 TASK 4 – OUTLINE GUIDELINES • Guidelines for mitigating high risk intersection with speed reduction treatments • Case studies that discusses experience with applying a roundabout or roundabout design principles to a conventional intersection • How to define “target” speeds for treatments and/or roadway environments (4.2) • Duration and/or distance of speed reduction (4.2) • Relationship between roadway system and isolated treatments (4.3) • Impacts of treatment on safety of non-auto road users (4.3) B.5 TASK 5 – DEVELOP TESTING PLAN • Ability to implement and test a specific speed reduction treatment • Effectiveness of using driver simulators to test treatments • Treatment testing methodology Page B-2 Kittelson & Associates, Inc.