Too fast for these conditions? Factors influencing drivers’ choice of speed

This paper introduces a selection of the technical findings under Austroads safety program project ST1870, which sought to identify effective infrastructure improvements to reduce motorcycle crash risk and crash severity, based on how riders perceive, respond and react to infrastructure they encounter.
The project commenced with a literature review of national and international guides, publications and research papers commenced the project, which also enabled the identification of knowledge gaps and areas where further detail was required.
A crash analysis was undertaken to demonstrate the relationship between motorcycle crashes, travel period, vehicle configuration (i.e. motorcycle only and multiple vehicle crashes involving a motorcycle), road geometry, road layout (e.g. intersection type) and crash types. For comparative purposes, vehicle crashes at the same location were also analysed.
Explanations of why, and how, road infrastructure elements influence motorcycle crash risk were researched and are provided within this paper. This primarily involved identifying how the design and condition of road infrastructure elements can influence either the likelihood of a crash occurring or the resulting severity of a crash. Where a number of elements that would increase the likelihood or severity of a crash were present concurrently, the proportionate increase in risk was demonstrated using the AusRAP model.
The study has built up a compendium of treatments, presented in such a way that engineering decisions to manage these elements can be justified, even if outside of existing design warrants, and asset management and maintenance practice.
The research highlights that motorcycles should be identified as an individual road user group and considered as a ‘design vehicle’ during road design and asset management and maintenance practices.
It is concluded that motorcycle crash risk can be managed, but requires changes in practice, in design, asset management funding and routine maintenance performance contracts. One example is in the identification of road sections and/or routes that pose the highest crash risk to motorcyclists, so that they can be managed and maintained appropriately. In addition, the author advocates proactive motorcycle specific network safety assessments and road safety audits, as well as fine tuning in design parameters for roads carrying significant volumes of motorcyclists (e.g. horizontal geometry, sight lines, lane and shoulder width, intersection types, intersection quality and controls). It is also suggested that the range and detail of mitigation measures be expanded.
This paper introduces a selection of the technical findings under Austroads safety program project ST1870, which sought to identify effective infrastructure improvements to reduce motorcycle crash risk and crash severity, based on how riders perceive, respond and react to infrastructure they encounter.
The project commenced with a literature review of national and international guides, publications and research papers commenced the project, which also enabled the identification of knowledge gaps and areas where further detail was required.
A crash analysis was undertaken to demonstrate the relationship between motorcycle crashes, travel period, vehicle configuration (i.e. motorcycle only and multiple vehicle crashes involving a motorcycle), road geometry, road layout (e.g. intersection type) and crash types. For comparative purposes, vehicle crashes at the same location were also analysed.
Explanations of why, and how, road infrastructure elements influence motorcycle crash risk were researched and are provided within this paper. This primarily involved identifying how the design and condition of road infrastructure elements can influence either the likelihood of a crash occurring or the resulting severity of a crash. Where a number of elements that would increase the likelihood or severity of a crash were present concurrently, the proportionate increase in risk was demonstrated using the AusRAP model.
The study has built up a compendium of treatments, presented in such a way that engineering decisions to manage these elements can be justified, even if outside of existing design warrants, and asset management and maintenance practice.
The research highlights that motorcycles should be identified as an individual road user group and considered as a ‘design vehicle’ during road design and asset management and maintenance practices.
It is concluded that motorcycle crash risk can be managed, but requires changes in practice, in design, asset management funding and routine maintenance performance contracts. One example is in the identification of road sections and/or routes that pose the highest crash risk to motorcyclists, so that they can be managed and maintained appropriately. In addition, the author advocates proactive motorcycle specific network safety assessments and road safety audits, as well as fine tuning in design parameters for roads carrying significant volumes of motorcyclists (e.g. horizontal geometry, sight lines, lane and shoulder width, intersection types, intersection quality and controls). It is also suggested that the range and detail of mitigation measures be expanded.