The main purpose of this project was to review recent road engineering safety research (substantive safety evidence) to enable the Austroads Road Design Task Force to verify or otherwise recommend changes to Austroads geometric design criteria. The project reviewed quality research sources such as Austroads, National Cooperative Highway Research Program (NCHRP) and American Association of State Highway and Transportation Officials (AASHTO) programs, and selected references based on the robustness of their methods and their applicability to the project. The authors selected and reviewed crash modification factors (CMFs) for 20 geometric road design criteria, including horizontal curvature, lane and sealed shoulder widths, sag and crest design values and various longitudinal sight distance requirements. The review of findings by the Project Advisory Group, consisting of the Task Force members, largely resulted in verification of the current design criteria values and their application as published in the Guide to Road Design Part 3: Geometric Design (Third Edition, Austroads 2016). The Advisory Group suggested further investigations of selected design criteria, e.g. economic analysis of the provision of wider shoulders on curves, values of the sideways friction coefficient for curves, and human factors associated with longitudinal sight distance. Investigation of the use of the Australian National Road Assessment Model (ANRAM) and Interactive Highway Safety Design Model (IHSDM) in detailed road design in Australia and New Zealand suggested that it was feasible, but both would require further adaptation. The report also provides a compendium of recent and robust evidence on the relationships between key geometric design criteria and safety outcomes. (Author/publisher)
Samenvatting