Doctors have joined the chorus of attacks on 4x4 vehicles with a warning that owners are recklessly putting other road users at risk by flouting laws over the use of mobile phones and seat belts.
Researchers who studied the behaviour of drivers of the all-terrain vehicles say that they took more risks because they felt safer than drivers of smaller cars. Scornfully known as Chelsea tractors due to their increasing appearance on urban streets, few 4x4s have seen more mud than can be picked up on a private school sports field. Teachers have tried to ban them and politicians want to impose penal tax rates on them - up to £2,000 a year, 10 times the normal road tax, in the latest proposal from the Liberal Democrats. They have been widely condemned as gas-guzzling, road-hogging and environmentally damaging. And the new front opened by the medical profession is bound further to inflame the debate on Britain's most controversial vehicle.
Although passengers in a 4x4 are less likely to suffer harm in an accident than those in a smaller vehicle, their owners are increasing the risk of injury to themselves and others by their failure to observe common safety measures, according to research from Imperial College, London, which is published in the British Medical Journal.
The pattern is an example of "risk compensation", where the safer a person feels the riskier the behaviour they indulge in.
A record 187,000 4x4s were sold in Britain last year, double the number a decade ago. One in seven cars on the road is now a 4x4, according to the Department of Transport.
However, the Energy minister, Malcolm Wicks, hit out at the vehicles recently, saying: "There will come a time when it will be irresponsible for those [4x4s] to be on sale."
They have also incurred the wrath of the London Mayor, Ken Livingstone, who lambasted urban owners as "complete idiots". The presenter of BBC's Top Gear, Jeremy Clarkson, described them as "clinically insane".
For the study by researchers from Imperial College, drivers of passenger cars were observed passing three different points in Hammersmith, west London, in February 2004.
The vehicles were monitored for an hour in the morning and an hour in the evening during weekdays. More than 38,000 vehicles were studied, including almost 3,000 4x4s.
The researchers found drivers of 4x4s were almost four times more likely to be seen using hand-held mobiles. They were also less likely to use seat belts.
Those who broke one law, on using a mobile or not using a seat belt, were more likely also to break the other. Overall, one in six drivers (15.3 per cent) was not wearing a seat belt and one in 40 (2.5 per cent) was using a mobile.
Lesley Walker and colleagues say in the BMJ: "Our data show a worryingly high level of non-compliance with laws on seat belts and hand-held mobile phones by drivers in London. Our observation that almost one in six drivers was not wearing a seat belt is a public health concern."
Last October the BMJ published an American study showing that 4x4s were more dangerous to pedestrians than normal cars. Tests showed that people who were hit by the vehicles in accidents were four times more likely to die than those hit by other cars.
Previous studies have shown that drivers using mobile phones have four times the risk of an accident. On that basis, 4x4 drivers are at 16 times the risk of having an accident, given that they are four times more likely to use a mobile compared with other drivers.
Dr Walker said: "In general 4x4s reduce the risk for their occupants but increase the risk for everyone else. In using a 4x4, instead of a normal car, one's chance of death or serious injury falls by four in 1,000 but the chance of killing or injuring others rises by 11 in 1,000, with a resulting cost to the community."
Bruce Thompson, charity executive, 54: 'It uses no more space than a saloon'
"We own two vehicles, a Land Rover Discovery TD5, and a high performance four-wheel-drive saloon car. The Land Rover ferries my wife to work every day, takes the family on holiday and tows a two-ton horse trailer.
"The alternative, if we want to pursue our hobby, is to buy another vehicle, which would be more harmful as the more damaging effects on the environment come from manufacture, not usage.
"It uses up no more road space than a typical, largish saloon car, and it has an engine no bigger than a typical saloon car. My wife does a round trip of 50 miles a day to the school where she teaches and does not go off-road and I drive to central London with it when I occasionally visit.
"I get cross about uninformed critics of 4x4 users and people who jump on the bandwagon and think that by banning the 4x4 there will be salvation for the planet. I find that the Land Rover encourages a more relaxed, non-aggressive approach to driving.
"I accept that you can't see past it easily, and for other road users that's annoying. I don't have a lot of sympathy with people who only buy them for the school run and never put them to the use for which they were designed."
Counting the cost
Driving a 13mpg 4x4 rather than a 25mpg car for a year will waste more energy than leaving the fridge open for seven years, leaving the TV on for 32 years or leaving the light on for 34 years.
Alliance Against Urban 4x4s
Range Rovers with a 4.4-litre engine have an urban mpg of 12.2 and emit 389g carbon dioxide per kilometre. In contrast, a Ford Mondeo 2-litre fuel-injected saloon has an urban mpg of 25 and emits 190g carbon dioxide. A Smart car emits 138g carbon dioxide.
Alliance Against Urban 4x4s
Urban 4x4s are involved in 25 per cent more accidents than saloon cars and do far more damage.
4x4 drivers are 27 per cent more likely to be at fault in the event of an accident than saloon car drivers.
If a pedestrian is hit by a 4x4 they are twice as likely to be killed than if they were hit by a saloon car.
Only 5 per cent of 4x4s are ever taken off-road.
Alliance Against Urban 4x4s
Sales of 4x4s grew by 12.8 per cent in 2004, to 179,000, more than double the number sold a decade ago.
Department of Transport, 2005
Drivers of 4x4s are most likely to have been in an argument with traffic wardens (22 per cent), compared with 6 per cent of saloon car drivers.
RAC Foundation, 2004
The risk of a fatal roll-over crash is twice as high for 4x4s as it is for a saloon car.
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