Speed limit setting and the safe system principle

The Safe System policy dictates that speed limits for the road and traffic system use human biomechanical and human competency as the design parameter to set the values. Taking crash injury severity factors into account research into the physics of crashes has determined when the physical forces will be too great for the human body to tolerate. Despite the formal adoption of the Safe System principles by all Australian Governments in 2004, no Australian State has adopted recommended Safe System speed limits. While most Australian States are not yet fully applying Safe System principles to speed zoning, this paper analyses New South Wales practices as an example. The current NSW Speed Zoning Guidelines, while transitionally moving towards a Safe System approach, explicitly aim to guide the setting of speed limits to “ensure that they are practical and balance mobility, road safety and community concerns.” Part of the problem for governments introducing safe speed limits is the amount of vocal opposition to lowering the limits. This paper identifies a number of specific departures from the Safe System approach inherent in the setting of speed limits as well as some of the ways that community attitudes might be shifted to promote better acceptance of safer speeds.