A little speed makes a big difference

Driving just a few kilometres per hour slower can save lives in an accident, experts say, underscoring the danger of speeding in urban areas.

ABU DHABI // When it comes to speed, a little caution can make a big difference. Even a small increase in velocity - from 60kph to 70kph - can cause much more severe injuries in a crash, experts say. "That's the way physics works, and why you get such a big difference to potential impacts and the seriousness of the impacts by increased speeds," said Simon Labbett, the regional director for the Transport Research Laboratory, which has its UAE office in Dubai.

For example, he said, if a pedestrian stepped in front of a car moving 60kph, the posted limit on many urban streets in the UAE, it would take that car about 36.5 metres to stop, assuming the driver's reaction time was one second. By comparison, a car moving at 70kph would still be going 42kph at the point the first car had stopped, he said. "Would 42kph kill somebody? Absolutely," he said. "You only started off with a difference of 10 kilometres.

"That's why in urban crashes, speed has a dramatic effect to the injuries that could be sustained to pedestrians." A study published by the Department of Transport in London found that eight in 10 drivers and passengers die in head-on crashes when the impact speed is 90kph, compared with one in 10 when it drops to 70kph. In side-impact crashes, eight in 10 people die when one car was travelling 70kph, a number that drops to one in 10 when the speed is 50 kph, said the study, The Relationship between Speed and Car Driver Injury Severity.

Even a 1kph reduction in speed would result in a two to three per cent reduction in road crashes, the World Health Organisation (WHO) has found. In Abu Dhabi, where police have identified speed as the top cause of road traffic crashes, 138,919 drivers were caught speeding between January and April 1 this year. That represents 56 per cent of traffic violations. When the WHO released its Global Status Report on Road Safety last month, the UAE's roads were ranked among the most dangerous in the world.

Tami Toroyan, a technical officer with the organisation, has recommended that the UAE Government cut urban road speed limits to 50kph from 60kph. Speed also is an urgent issue for pedestrians, whose chance of survival is 50 per cent when the car that hits them is travelling 45kph. If the same car is driving 30kph, they have a 90 per cent chance of making it through an impact. "We as drivers perhaps with wide roads, perhaps with our air-conditioned comfort cars, low noise, perhaps don't perceive the speed we're travelling at," Mr Labbett said.

"The reality is that speed and speed limits are put there for good safety reasons, and it's only when you actually look at these impact figures that you realise [their impact]. "Next time you're walking down the road, you want people to be keeping to the speed limit, because the chances of you being killed or injured goes up dramatically as the speed increases." Waseen Iqbal, a senior lecturer and assessment examiner at the Emirates Driving Institute in Dubai, noted that other factors, including the physical and mental condition of the motorist and condition of their tyres, can affect stopping distances.

This is why it is important for drivers to follow speed limits and not get too close to vehicles ahead of them, Mr Iqbal said. "They should concentrate on the speed according to the road situation," he said. "If it is a very busy or city road, you can expect there are many hazards around you - you cannot go around 100 kph." A minimum of two seconds behind the next car is a safe following distance under ideal weather conditions, he said, which can be calculated using a fixed reference point.

In adverse weather, such as rain, he recommended a following distance of six seconds. [e-mail]