London School of Hygiene & Tropical Medicine

From the pages of the BMJ, the authors 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 since deaths on road in the United Kingdom have fallen by 75% in the past 55 years thanks to advances in car safety it can be safe 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.

In their editorial, the authors question the basis of the suggested economic benefits, given that the higher limit will not extend to heavy good vehicles. Also, their main concern draws on research which links higher speed limits with an “exponential” increase in crashes (resulting in injury and death).

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.

Dr Lopez Bernal comments: "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. This proposal appears to be a populist gimmick, especially given the recent loss of lives on the M5 motorway. The Government should provide the evidence to justify their policy."

Other health-related reasons in support of the lower limit include the increase of gas emissions and air pollution as well as a potential rise in obesity due to more people taking advantage of shorter car journeys.