Rural highways are typically undivided, have high operating speeds, carry high traffic volumes and are often designed to minimum geometric standards. Head-on and cross-over-the-centreline crashes are of the most severe crash types that occur on rural highways. They are disproportionally represented in crashes resulting in fatalities, yet undivided rural highways provide no separation between opposing traffic lanes. One possible countermeasure to these crash types is a continuous narrow painted median strip. Narrow painted median strips are a relatively new and innovative road safety treatment aimed at reducing the incidence and severity of head-on and crossover-the-centreline crashes on undivided roads. This is achieved by increasing the separation between vehicles travelling in opposite directions and warning drivers that have strayed from their lane with noise and vibration inside the vehicle. Previous research suggests audio-tactile centreline-marking to be an effective countermeasure to these crash types however, the added benefit of combining audio-tactile line-marking with a narrow painted median has notbeen thoroughly evaluated. This research quantifies the safety benefit following installation of a 1.0 m wide continuous painted median strip utilising audio-tactile line-marking on the Bruce Highway in Queensland, Australia. Data was analysed for a 56 km section of the highway before and after installation of the painted median. An Empirical Bayes statistical analysis procedure was used for evaluation due to the short period of before and after data available. This method accounts for the regression to the mean bias that is prevalent when short data collection periods are available or when sites with a higher than normal crash history are being analysed. Findings indicate significant reductions for all crash types that were analysed in this study. Head-on crashes were reduced by 75% (SD = 7.0%), Run-off-road-left crashes were reduced by 59% (SD = 14.5%) and Total crashes were reduced by 59% (SD = 8.8%). The results of this study add to the limited body of knowledge that is published on narrow painted median strips as a road safety treatment. The narrow painted median strip provides significant safety benefits, by means of crash reduction, and has relatively low installation costs. These preliminary yet encouraging results give justification to the future consideration or implementation of a continuous narrow painted median strip as a road safety countermeasure. (Author/publisher)
Samenvatting