More research needs to be done before 20 miles an hour zones are rolled out across the country, according to a study that will be unveiled today. Elizabeth Dainton, Research Development Manager from the RAC Foundation will tell a conference at Aston University that policy development should not rush ahead of understanding, local considerations and public acceptance.

She will present a paper from the Foundation showing that 95 per cent of pedestrian casualties and almost the same level of cyclist casualties are killed or injured on built up roads with speed limits of less than 40mph. She will argue that speed is not the issue behind the accidents, with driver behaviour, which includes speed, being a factor in 26 per cent of cases. Failing to look is in fact the biggest cause of collisions, responsible for more than two thirds of them, so Ms Dainton will point to driver training and education being as important as reducing speed to reduce road casualties.

The Foundation says that although casualty reductions for current 20mph zones are impressive, Ms Dainton will highlight limits to their use, including the issue of enforcement. Traffic calming measures are unpopular and expensive and physical enforcement is the only option available due to low levels of traffic police and a lack of camera enforcing technology. On the issue of acceptability of the zones to the public she will say no research is available to assess whether a more comprehensive network of zones would be welcomed, although three quarters of people support 20mph zones in residential areas. She will argue, too, that it is essential that local areas have ‘roads for movement’ and that a network of 20mph zones is not viable or desirable.

“Reducing road casualties in the UK must remain a priority, and speed limits as well as 20mph zones have an important role to play. It does not follow that 20mph zones should be implemented in residential areas without adequate consideration being given to local circumstances and public opinion. One-size fits all policies are rarely successful. Twenty mph zones are no different,” Ms Dainton said.