The way our road and road side networks are planned and designed is one of the key contributors to improving road safety.
Road infrastructure is a long-term investment, balancing the multiple objectives of safety, reducing congestion, and ensuring life cycles of up to 50 years. It must meet the needs of the many different road users who use it for many different reasons. Road agencies need to design for a Safe System and the future, for example to support the arrival of connected and automated vehicles.
Australia’s road network is around 877,651 km in total. The Australian Government, along with state, territory and local governments, continually invest in new and upgraded roads around Australia. This presents the opportunity to ensure road safety is included in future investment as a priority, making sure roads are planned, designed and built to be as safe as they can be. Under the National Partnership Agreement on Land Transport Infrastructure Projects, state and territory governments agreed to have regard for Safe System principles and road safety treatments when considering road infrastructure investment proposals.
Road infrastructure and design challenges
Governments invest in roads for multiple reasons, including to improve asset condition, enable economic development, increase productivity, improve reliability and accessibility, and improve road safety. Road infrastructure projects can be complex and balance multiple objectives. Safety outcomes are not always prominent in project lifecycle considerations and sometimes, when they are included, are value engineered out during construction. The result being that roads can and are still being built that are not as safe as they could be. Governments at all levels; local, state and territory and federal contribute to investments in road safety and as resources are finite, they must be targeted.
There is an opportunity to adopt the Safe System thinking in projects that upgrade the road network. A Safe System approach acknowledges that the human body is fragile; and when mistakes happen, infrastructure should be engineered and designed to counteract people being killed or injured when they do make a mistake.
A proactive approach will help to prevent future crashes, particularly for the length of corridors on regional roads.
A Safe System approach requires that where conflicts between vehicles and road users cannot be avoided and crashes occur, the speed environment should be managed so the outcome will not result in a death or serious injury.
Speed is a major contributor to increasing the severity of a crash.
Speed limit reductions by as little as 10 km/h have provided the lowest cost, greatest value for reducing fatalities and serious injuries on roads. As kinetic energy increases exponentially with speed, there is a rapid increase in the probability of a fatal (and serious injury) crash outcome as speed increases.
Australia has a very large road network with relatively high speed limits across much of its network. Crash risk remains high on many higher speed roads, particularly in more regional and remote areas, and in many cases it is not feasible to address this risk with infrastructure improvements alone.
All states and territories have implemented 40 km/h speed limits in areas with high pedestrian and cycle use and some states have introduced 30 km/h or lower speed limits. These lower speed areas reduce the severity of collisions and provide drivers with more time to perceive and react to hazards, reducing the likelihood of collision.
Many urban intersections have high traffic volumes, with speed limits up to 100 km/h. Side impacts can lead to serious crash outcomes, as the chance of survival decreases rapidly when impact speeds exceed 50 km/h. Pedestrians, cyclists and motorcyclists are particularly vulnerable at intersections and make up over 45 per cent of these fatalities. Infrastructure treatments to reduce vehicle speeds at points of conflict in intersections, including roundabouts and raised intersection platforms, align with Safe System principles and have proven effective.
What is a safe road?
People make mistakes. A safe road is where system designers responsible for the design of the road transport system have made allowances in the road design to counteract people being killed or injured on the road when they make a mistake.
A number of factors need to be taken into account to create a safe road. The function of the road and vehicle speeds are two key factors reflected in the Movement and Place approach developed to support safe transport of all types in line with the place-making desirability of a road and its location. On high speed roads that carry freight and high volumes of traffic, there should be features present that separate opposing traffic directions, clear delineation and forgiving allowances to support staying in or re-entry into the travel lane, and barriers to absorb crash forces and prevent run-off-road and head-on crashes. In residential areas, lower speeds, traffic calming infrastructure and the separation of pedestrians and bike riders from motorised vehicles assists in the prevention of fatal and serious injuries. Intersection crashes can be reduced through roundabouts (noting roundabouts may not support safe pedestrian and cyclist movements), raised platforms, traffic separation and rumble strips, reducing the speed limit on the approach to the intersection and by providing safe pedestrian crossings.
For more information on the Movement and Place approach, read the fact sheet on speed management through the Movement and Place approach