Consequences of speed

Every year on Western Australian roads, in addition to the 200 people that are killed in road crashes, about 2,800 people are seriously injured as a result of a crash.

The impact of serious injury on our community goes well beyond the statistics reported in the media. It is an extremely sad fact that the effects of serious injuries in road crashes are very far reaching and long term, not only for those directly involved, but also for their loved ones. Serious injuries often lead to ongoing medical problems for the individuals injured. They can also have significant impacts on the injured person’s family and friends.

Of course, the consequences of serious injuries are not only physical and emotional. It is estimated that each serious injury has a financial cost of about $425,000. If we continue to see 2,800 serious injuries a year, over the life of the 'Towards Zero' road safety strategy (2008-2020), the cost to the community will be approximately $14 billion.

Even if the primary cause of a crash is not speed, a crash in a slower vehicle will be less severe. Your chances of surviving and avoiding injury are greater the slower you are driving. The chances of being in a crash approximately doubles for every 5km/h over the limit in a 60km/h zone. For every 1% reduction in average speed, there is on average a 3% cent reduction in casualty crashes.

The physics of a crash

In a crash, it is the amount of kinetic energy that is imparted which causes injuries or death. This kinetic energy increases exponentially with speed.

A doubling of speed is not equal to twice as much kinetic energy, but rather a substantial increase much beyond that and it is much more lethal. A 20% increase in speed is roughly a 45% increase in kinetic energy.

Road toll fatalities