Before-and-After Safety Study of Roadways Where New Medians Have Been Added.

摘要

The main objective of the study was to evaluate the safety impact of median conversion from two-way left-turn lanes (TWLTLs) to raised medians in Florida. Based on segment length and data availability, 18 locations totaling 17.51 miles were selected for before-and-after analysis. Police reports of all the crashes before and after median conversion were reviewed to correct miscoded crash types and obtain additional detailed crash information. The safety performance of individual locations varied in terms of crash type and crash severity. Overall, the results showed a 30.3 percent reduction in the total crash rate after median conversion. Median conversion was particularly effective in reducing rear-end, angle, left-turn, and right-turn crash rates. Further review of three locations that performed particularly poorly revealed that the majority of crashes that occurred after conversion could not be attributed directly to raised medians.