Government plans to increase the motorway speed limit in England and Wales will have adverse effects on health, outweighing any economic benefits, claims an editorial published on bmj.com today.

The authors, from the London School of Hygiene and Tropical Medicine, criticise government proposals to raise the speed limit on all motorways in England and Wales from 70mph to 80mph by the year 2013.

The government argues that deaths on road in the United Kingdom have fallen by 75% in the past 55 years thanks to advances in car safety and see it fit to increase the speed limit as “almost half of all drivers break the current limit anyway”. They add, furthermore, that since 1967 the number of serious and fatal accidents has continued to fall and as such, the UK now has one of the lowest rates of road deaths in the world.

The authors of the editorial challenge all of these arguments. They question the basis of the suggested economic benefits, given that the higher limit will not extend to heavy good vehicles.

However, their main concern draws on research which links an “exponential” increase in crashes (resulting in injury and death) to a rise in speed limits. In the US, higher speed limits introduced in 1995 resulted in a 16.6% increase in deaths due to vehicle accidents.

The speed limit increase followed a reduction in speed back in 1975 in response to the 1974 oil crisis. The laws on highways and freeways changed from 65mph to 70-75mph and from 55mph to 60-65mph. They also identify other health related reasons for keeping the current limit, including the increase of gas emissions, air pollution and potential rise in obesity due to more people taking advantage of shorter car journeys.

The authors comment: "It is difficult to see how any benefits of an 80mph speed limit would outweigh the costs: past evidence shows that speed limit increases lead to substantial rises in road deaths, as well as other potential negative health and economic impacts."

The authors argue that this proposal appears to be a “populist gimmick” by the coalition government. Given the recent loss of life on the M5 motorway, they challenge the government to produce the evidence to justify their policy with its attendant risks to life.

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