Speed in Queensland is managed in accordance with the methodology provided in the Manual of Uniform Traffic Control Devices (MUTCD) Part 4, which is based on Australian Standard 1742.4. The methodology considers the function of road, prevailing speed, road and roadside environment and crashes. For sections of road that have lower crash risks, provision in the MUTCD can be applied for implementing higher speed limits for ensuring transport efficiency. For sections of road with significant road and roadside deficiencies and a history of high crash rates, the current MUTCD provides for implementing reduced speed limits which are appropriate for safe mobility. However, these provisions rely heavily on experiential judgements that can be influenced by variations in practitioners’ knowledge and experience. In some cases, opportunities to manage crash risks through speed management may not be taken because the current methodology is not providing clear guidance to practitioners to support the implementation of safe speed.
This paper outlines the three-stage speed management method proposed for use in Queensland. The method includes important additional triggers which would call for a change in the speed limit, and captures both infrastructure risks and crash risks proactively and collectively in a very objective manner. The suggested method is analytical and prescriptive, yet flexible enough to allow practitioners to develop recommendations based on their experience and local knowledge. It’s simple, yet robust enough to explain the likelihood of potential risks in a statistically acceptable manner. The method advances the speed limit setting method in Queensland one step closer to adopting Safe System speed.