Study: 4x4 drivers most lawless

"We looked at risk behaviour and showed that four-wheel drivers take more risks," Lesley Walker from Imperial College, London, told Reuters Health.

Roughly 19% of four-wheel drivers were not wearing seat belts and use of a mobile phone was four times higher than in those driving other cars.

The findings are based on observations of driving behaviour in three busy areas of London during the morning, afternoon and evening.

Walker and colleagues made their first observations during a "grace" period regarding use of hand-held mobile phones, during which the police only cautioned offenders. They repeated their observations one month later, after police started ticketing offenders for using hand-held cell phones while driving.

The researchers observed a total of 38 182 conventional cars and 2 944 four-wheel drive vehicles.

A little more than 8% of four-wheel drivers were seen using hand-held phones compared with just 2% of drivers of other cars; 19.5% of four-wheel drivers were seen driving without a seatbelt compared with 15% of drivers of other cars.

Levels of non-compliance with both cell phone and seat belt laws were slightly higher during the penalty phase of observation than during the grace period and flouting one law increased the odds of flouting the other law.

There is evidence to suggest, Walker said, that using a cell phone while driving reduces concentration and speed of reaction, increasing the odds of crashes.

"Two studies found a fourfold increase in crashes in drivers using a mobile phone," Walker said.

"Therefore, four-wheel drivers have a 16 fold increase if you consider they are four times more likely to use the phone and that risk has a four-fold increase in having a crash."

"By increasing the risk of a crash, four-wheel drivers are putting other road users (including cyclists and pedestrians - especially the elderly and children) at a greater risk of serious injury," Walker said. Due to the size and weight of these vehicles, the resulting impact is much greater.

One of the sites where Walker and colleagues observed driving behaviour was by three schools. The non-compliance rates were much greater at the schools, "suggesting it is parents dropping off and collecting children who are also taking these risks," Walker told Reuters Health.

SOURCE: British Medical Journal Online First, June 23, 2006