Why a 20mph limit is the cure for epidemic of road deaths

Snow and ice has brought gridlock to cities and left many rural roads impassable. However, there is a growing group of people who would like us to lay off the accelerator all year round.

One of them is Professor Danny Dorling, a human geographer and a man who specialises in how we die. According to the University of Sheffield academic, while once the biggest threat to public health was open sewers, followed swiftly by cigarettes, now, he says roads must be recognised as the nation's major killer. The solution, he says, is simple – the introduction of 20mph speed limits.

"Every century comes with a major public health warning about the harm we inflict on ourselves. In Britain in the 19th- century it was the diseases we spread by tolerating open sewers. In the 20th-century it was tobacco that we slowly learnt to love.

"In the 21st-century it is the way we tolerate how cars are allowed to travel on our roads."

Latest research shows that about 30,000 people are killed or seriously injured on Britain's roads every year.

Although the figure is substantially less than it once was, with medical breakthroughs reducing the number of deaths from once deadly diseases, road fatalities now account for an increasing proportion of all deaths, particularly in the case of young children and teenagers.

"The threat isn't diminishing, yet there are simply not enough Government resources directed to the problem," says Prof Dorling. "Roads imprison affluent children at home and in poorer areas they are the scene of many deaths."

By reducing the speed limit to 20mph, not just on residential streets, but on roads leading through towns and city centres which are well-used by pedestrians and cyclists, is according to campaigners, an easy solution to a complex problem.

However, as ever the realisation of such schemes comes down to money. In 2008, when Portsmouth introduced a 20mph limit across the city it came at a cost of 475,000 and with the Department of Transport's road safety budget recently cut from 37m to 17.2m, there is not much cash around.

However, with road traffic accidents putting a major strain on the NHS and police forces, Prof Dorling insists that in the long-term the move would save millions.

"Research in the British Medical Journal shows 20 mph zones cut deaths by 41.9 per cent," he says. "Elsewhere in medicine, you'd get honours and funding for such an effective treatment for an epidemic. Yet there is a collective blind spot on the enormous benefits of 20mph limits – perhaps because directors of public health aren't trained in road safety. In a time of less money it makes even more sense."

A campaign is already underway to introduce 20mph speed limits in York. Under the banner 20's Plenty For Us, residents have joined forces with councillors to reduce the speed limit in the notoriously congested city.

The group claims that if successful, the move would not only reduce the number of deaths and injuries, but would also cut pollution and encourage more people to walk and cycle.

However, not everyone approves of the scheme, which has come under criticism from the Association of British Drivers as being reactive rather than proactive.

"To use a blanket speed limit is a bit like the NHS saying we'll only issue plasters," says an ABD spokesman.

"There is no debate about the fact that in areas of high density the lower your speed limit needs to be. But if you put in a large number of 20mph speed limits where the natural speed limit is higher you end up with a dangerous situation where drivers spend more time concentrating on the limit rather than concentrating on the road."

Prof Dorling has heard such objections before, but insists the arguments against simply don't add up.

Instead, he is advocating a nationwide programme of education, which would make speeding as anti-social as drink-driving and as acceptable as wearing seatbelts.

"Educated people gave up smoking by themselves before a public ban, but the Government does need to take a lead," he says. "If British people care about children and have a soul, they'd want 20 mph residential speed limits.

"Cars may provide instant gratification. But what is one person's convenience, is a town's congestion and a country's major killer."