How does speed affect chances of survival?
Road safety data provided by state governments says a reduction of 5km/h in average travel speed would reduce ‘urban’ crashes by about 25 per cent.
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 in the time it takes for the driver to react; and
- The distance travelled once the brakes have been applied.
The faster a car is travelling, the longer it takes to stop. In an emergency, the average driver takes about 1.5 seconds to react. Stopping distances increase exponentially the faster the car is travelling.
At 40 km/h, on a dry road a driver takes about 26 metres to stop in an emergency. At 50km/h on a dry road a vehicle takes 35 metres to stop in an emergency.
The risk of pedestrian death rises exponentially with crash speeds above 30 km/h.
It is estimated that less than 10% of pedestrians would die when struck by a vehicle travelling at 30 km/h, compared with fatality rates of 26% at 40 km/h and over 80% at 50 km/h.
Consultation has concluded
