Author(s)

N. HUSSEIN & R. HASSAN Swinburne

Abstract

Crash records for a sample of signalized intersections have been analysed to assess the effect of surface treatment. Analysis of crash data (all types and severity levels) for 3–5 years before and after resurfacing year showed a reduction in rate. Effectiveness of treatment in achieving statistically significant reduction in crashes was confirmed by Empirical Bayes (EB) approach. Overall trends of crash frequency before and after treatment against surface condition in terms of roughness, rut depth and skid resistance were also investigated. The results showed that the trend of crash rate correlates positively with roughness and negatively with skid resistance and rut depth. This trend was true for both before and after crash data. Time of day and moisture condition of the surface proved to strongly influence crash frequency with wet surface during night-time being associated with lower frequency than dry surface at daytime.

Keywords

crash frequency, crash rate, Empirical Bayes, roughness, rutting, safety effectiveness, signalized intersection, skid resistance