Vehicle travel speeds affect both the risk of crash involvement and the severity of crashes, and subsequent injuries. Speed is a critical factor in every serious crash, and speeding was identified as a contributing factor in an estimated 36% of fatal crashes (2007-2011). Reductions in travel speed save lives and injuries. Reductions in the average travel speed across the network is the most effective and swift way to reduce road trauma and would produce significant and immediate road safety benefits.
Why is speeding a problem?
If we all do the right thing and drive within the speed limit, lives will be saved and serious injuries will be prevented. A reduction of 5 km/h in average travel speed would reduce rural casualty crashes by about 30% and urban crashes by about 25%. This is a significant saving of lives and injuries for South Australians.
A critical factor in the relationship between speed and crashes is stopping distance. There are two components to stopping distance:
- The distance travelled by the vehicle during the time it takes for the driver to react; and
- The distance travelled once the brakes have been applied.
The impact of speeding on crash risk
The risk of a casualty crash approximately doubles with each 5km/h increase in speed on a 60km/h speed limited road, or with each 10km/h increase in speed on 110km/h roads.
It is illegal to drive at any speed above the speed limit.
Vehicle travel speeds affect both the risk of crash involvement and the severity of crashes, and subsequent injuries.
Driving over the speed limit:
- increases your chances of being involved in a crash
- means you have less time to react to avoid a crash
- takes longer to stop the vehicle to avoid a crash
- increases the severity of injury in a crash.