1. Pavement Marking and Safety Research
Iowa Department of Transportation
Sandra Q. Larson, P.E.
Research and Technology Bureau

3. Study the relationship between 5 years of pavement marking retroreflectivity data collected by the Iowa DOT on all state primary roads and corresponding crash and traffic data

4. Overview
Attempt to quantify a relationship between crashes and the quality (measured by retroreflectivity) of pavement markings.

5. Pavement Marking and Crash Data

6. Retroreflectivity Fall 2010

7. Crash & Retroreflectivity Assignment

8. Data Analysis

11. Conclusions
Retroreflectivity was found to be a significant parameter for all line types—at 90% confidence level for white edge lines, at 95% confidence level for yellow edge lines, and at 99% confidence level for yellow center lines. For white edge lines and yellow center lines, crash occurrence probability was found to increase by decreasing values of longitudinal pavement marking retroreflectivity.

12. Pavement Marking and Safety Research
Iowa Department of Transportation
LINK TO REPORT :
TR-580: Pavement Markings and Safety

13. Pavement Marking and Safety Research
Iowa Department of Transportation
Omar Smadi – ,
Neal Hawkins – ,
Mark Dunn – ,
Bob Younie – ,