The single biggest road safety issue in New Zealand today is speed – drivers travelling too fast for the conditions.
Speed affects all crashes. It can be a factor in causing them and it has a direct effect on the damage done in a crash. It is clear from the crash statistics that many people underestimate how changing conditions, such as wet weather, can increase road risk.
In 2014, speeding was a contributing factor in 78 fatal crashes, 357 serious injury crashes and 995 minor injury crashes.
Many drivers aren’t aware that they can be travelling at the speed limit and still be driving unsafely.
The speed limit is the maximum legal speed that you can travel at on a road in perfect conditions.
However, road conditions are rarely perfect. As a safe driver, you’ll have to look out for changes in traffic, road and weather conditions, and reduce your speed accordingly.
Traffic conditions that you might need to reduce your speed for include:
high volumes of traffic on the road
pedestrians, joggers and cyclists
holiday times when there are lots of visitors on the road
Road conditions you should reduce your speed for include:
bumpy or narrow areas on the road
wet, icy or gravel road surfaces
signs warning of hazards such as sharp curves or a slippery surface.
Weather conditions you should reduce your speed for include:
rain, snow and ice
The faster you drive, the more likely you are to crash. As your speed increases:
the distance you need in order to stop increases
there is a greater probability that you will be going too fast if you meet an unexpected change in road conditions
there is a greater chance that other road users will misjudge how fast you are travelling.
The severity of injuries resulting from a crash is directly related to the impact speed of the vehicle – whether or not speeding was a factor in the crash.
When a vehicle crashes, it undergoes a rapid change of speed. However, the occupants keep moving at the vehicle’s previous speed until they are stopped – either by hitting an object or by being restrained by a safety belt or airbag.
Human bodies are not designed to be hurled against objects at speed, and the faster the speed, the more severe the injuries.
If a pedestrian is hit by a vehicle, the severity of their injuries is related to the impact speed. The probability of death for a pedestrian rises steeply from 10% at an impact speed of 30km/h to 70% at 50km/h.
The risks for vulnerable pedestrians, such as the elderly and young children, are higher.
The number of crashes is substantially reduced when speed cameras are used. A study of crash data in the 20 months following the introduction of speed cameras in New Zealand in 1993 found a 23% reduction in fatal and serious crashes at urban speed camera sites and an 11% reduction in fatal and serious crashes at rural speed camera sites.
International experience shows that speed cameras are a highly cost-effective speed management tool. This means they save a lot of lives for the cost of putting them in place and operating them.
Speed cameras are sited on stretches of road that have a lot of speed-related crashes. The police consult with councils, NZ Transport Agency and the local AA when deciding where to locate speed cameras.
Information on ‘speeding instances’ of more than 100km/h recorded by GPS units fitted to vehicles in the NZ Transport Agency’s corporate fleet for the 2015/16 calendar year is available here [XLSX, 11 KB].
The NZ Transport Agency publishes GPS speed data from our corporate fleet vehicles in order to encourage safe driving by our staff, and to demonstrate transparency and accountability for our role in road safety leadership.
The GPS units record speed data continuously, with data reported once for every 500 metres travelled. If a vehicle is exceeding 100km/h at the point in time when the speed is measured during a 500 metre travel segment it is recorded as a ‘speeding instance’. This means that a single trip by a single driver where speeds exceed the 100km/h speed limit may account for multiple recorded instances of speeding.