Speed management is a key component of the Safe System approach. The efficacy, including safety performance, of the various treatments and measures used to reduce vehicle speeds in high-speed environments is not well understood. This project was established to better understand the performance achieved by various types of speed-reducing treatments (or combinations of treatments) for high-speed environments. The project also sought to consider how desired speed can be aligned with a safe, anticipated operating speed with the goal of making high-speed roads more self-explanatory. This is expected to enable treatments to be applied more appropriately and effectively, with consequential benefits in maximising the safety and effectiveness of available funding levels for road improvements in high-speed environments. The project reviewed available literature and Austroads guidance and obtained input from the Austroads Road Design Task Force in order to identify speed reduction treatments and road features influencing speed in high-speed environments. The project was conducted over a two-year period with the first year conducting a broad review of speed reduction treatments applicable to different types of road sections including intersections, transition areas, curves and mid-block sections. The second year of the project focused more specifically on mid-block road segments and considered treatments and road features that influenced speed in high-speed environments. The review of speed reduction treatments in higher-speed environments compiled information on a number of treatments including perceptual countermeasures, transverse rumble strips, vehicle activated signs, gateway treatments, route-based curve treatments, wide median centrelines and sight distance adjustments on intersection approaches. Based on the outcomes of this review, these treatments may merit further consideration for future Austroads research and guidance. On mid-block sections of high-speed roads where the speed environment remains consistent, drivers seek to maintain a desired speed in line with the posted speed limit or design speed applicable to a section of road. There are a number of road features from which drivers obtain cues that may influence their speed. The project has identified a number of these features and has compiled existing research into the effect of individual and combined road features on speed in high speed environments. The research and guidance provided in a number of Austroads Guides on this topic merit further consideration for identifying road features that may aid in making high speed roads more self-explanatory. (Author/publisher)
Samenvatting