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G uideline for Marked and Unmarked Pedestrian Crosswalks at Unsignalized Intersections. LAURA ZHAO Graduate Research Assistant Center for Advanced Transportation Education and Research Department of Civil & Environmental Engineering University of Nevada, Reno. Email: yuezhao118@gmail.com.
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Guideline for Marked and Unmarked Pedestrian Crosswalks at Unsignalized Intersections LAURA ZHAO Graduate Research Assistant Center for Advanced Transportation Education and Research Department of Civil & Environmental Engineering University of Nevada, Reno Email: yuezhao118@gmail.com
Outline • Background • Guideline Development • Case Study • Conclusions
Background • Marked Crosswalks • Increase pedestrian MOBILITY • With perhaps a deceived sense of SECURITY • With HIGHER pedestrian crash rates (e.g. California, Florida, and Texas.) • UnMarked Crosswalks • With no clear PATH for pedestrian • With no specific WARNING for driver • With LOWER pedestrian crash rates Typical Marked and Unmarked Crosswalks at TWSC Intersections
Background • Critical issues • Whether crosswalk should be marked or not? • Under what conditions marked crosswalks should be used?
Background • Existing Guidelines • Qualitative statement; Single dominate factor; Flowchart; e.g. MUTCD, FHWA etc. • Major Issue: lack a balanced consideration and interpretation of all potential impact factors. • Objectives: • Develop a guideline to assist decision making, i.e. help determine the installation of marked crosswalk
Guideline Development • Guideline Development Decision Making Process • Attain a decision through the combination of impact factors simultaneously. • Conceptual Guideline • Multi-Criteria Analysis Problem • Alternatives: Mark, Unmark • Multi-criteria decisive variables: Speed Limit, Number of Travel Lanes etc.
Mark/Unmark Choice Tool Inner Computational Engine Combination of PROMETHEE &AHP
Mark/Unmark Choice Tool 1 2 3 4
Case Study • 24 unsignalized intersections: 50% marked crosswalks + 50% unmarked crosswalks Mark/Unmark Choice Tool FHWA Guideline Existing Crosswalk
Case Study Phase I: Comparison of Developed Tool Recommendation and Existing Conditions • Approximate 72%of all proposals match actual field data. • Explanation I: No consideration regarding pedestrian-related crash factor in agencies when the crosswalk was installed. • Explanation II: Final preference scores are not divided into absolute two categories, mark and unmark, but the engineering judgment category is highly recommended when the difference between two final scores is less than 20%.
Case Study Phase II: Comparison of Developed Tool Recommendation and FHWA Guideline • 60% of FHWA recommendations confirm actual crosswalk type. • 64% of developed tool recommendations met FHWA recommendations. • If merely considering combinations of vehicle ADT, speed limit, number of travel lanes and median type which are the core of FHWA guideline, the developed guideline will provide the same results as FHWA guideline. • By complementing pedestrian volume, crash data and engineer preference factors, developed tool could accommodate more practical and insightful suggestions pertaining to crosswalk type.
Conclusions • Crosswalk marking is a useful traffic control device. • It is very important to realize the positive as well as the negative consequences of marking crosswalks. • The developed Mark/Unmark Choice Tool can help engineers make sound decisions for the placement of marked crosswalks and interpret the dilemma of crosswalk markings.