1 / 18

Low Cost Safety Improvements Pooled Funds Study Increasing Retroreflectivity of STOP Signs Results

Low Cost Safety Improvements Pooled Funds Study Increasing Retroreflectivity of STOP Signs Results. Dr. Bhagwant Persaud, Persaud and Lyon, Inc. Overview. Introduction Objective Study Design Data Collection Results Economic Analysis Conclusions. Background on Strategy.

erek
Download Presentation

Low Cost Safety Improvements Pooled Funds Study Increasing Retroreflectivity of STOP Signs Results

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Low Cost Safety Improvements Pooled Funds StudyIncreasing Retroreflectivity of STOP SignsResults Dr. Bhagwant Persaud, Persaud and Lyon, Inc

  2. Overview • Introduction • Objective • Study Design • Data Collection • Results • Economic Analysis • Conclusions

  3. Background on Strategy • Identified by TAC, not in Guides • Low-cost, short-term implementation • Target crashes • Right-angle • Other STOP sign violation

  4. Literature Review • Legibility effects of increasing the retroreflectivity of freeway guide signs (Carlson and Hawkins) • No studies on increased retroreflectivity levels of STOP signs

  5. Objective • To estimate the safety effectiveness of increasing the retroreflectivity of STOP signs as measured by crash frequency • To assess cost-effectiveness • Questions of interest • Do effects vary by traffic volumes? • Do effects vary by land use (i.e., urban/rural) • Do effects vary by type of interest (i.e., 3 versus 4-leg)

  6. Study Design • Sample Size • Minimum 1,076 intersection years per period to detect a 20percent reduction in right angle crashes • Desirable 2,036 intersection years per period to detect a 10percent reduction in all crashes • Assumes 0.44 crashes per intersection per year before strategy of which 0.17 are right angle crashes

  7. Data Collection

  8. Data Collection

  9. Data Collection

  10. Aggregate Evaluation Results

  11. Aggregate Evaluation Results(Continued)

  12. Disaggregate Evaluation Results: Urban versus Rural

  13. Disaggregate Evaluation Results 3-leg versus 4-leg

  14. Disaggregate Evaluation: Effect of Minor ADT

  15. Economic Analysis • FHWA cost per crash for unsignalized intersections • $13,238 for rear-end • $61,114 for right angle • $66/year crash savings per intersection required for a 2:1 benefit cost ratio • Requires 0.005 rear-end crashes saved per intersection per year • Target seems easily achievable – especially under favorable circumstances identified in the disaggregate analysis

  16. Conclusions • Significant reduction (17.5percent) in rear-end crashes in South Carolina • Strategy is more effective at lower volumes on the minor approaches • Urban versus rural – Strategy tended to be more effective at: • Rural installations in Connecticut • Urban installations in South Carolina

  17. Conclusions • Strategy was more effective at 3-legged intersections • No detectable effects for nighttime crashes • Strategy has potential to reduce crashes cost-effectively, particularly in situations identified

  18. QUESTIONS???

More Related