Wiltshire Council dragging its feet on 20mph zones

Despite the fact that many communities around the county have asked for 20mph speed limits in villages and residential areas WC is refusing to move forwards except at a very slow pace, saying it prefers to wait for more guidance from the government, and for the results of trials in a small number of villages.

In December 2009 The Department for Transport consulted with all local highway authorities on proposed changes to Circular 01/06 'Setting Local Speed Limits'. This draft document outlined likely changes to the previous guidance on 20mph speed limits and zones and set the course for councils to adopt a less prescriptive and more flexible approach.

Previously 20mph speed restrictions have typically fallen into two categories; zones and limits. 20mph zones were first introduced in 1991 and covered mainly street lit residential areas and incorporated physical engineering measures such as road humps to encourage reduced vehicle speed. Zones are well established in the United Kingdom and make up over 90% of all 20mph schemes. Evidence has demonstrated that during the last 20 years they have proved to be extremely successful in reducing pedestrian casualties as well as providing wider community benefits.

In contrast 20mph limits remain less common and rely solely on the use of signing to enforce the limit. Previous guidance contained in Circular 05/99 advised caution in the use of 20mph limits as the weight of evidence at the time showed that in the absence of traffic calming, such limits had little or no effect on traffic speed.

In recent years a number of authorities such as Portsmouth, Hull and Bristol have sought to undertake their own trials to establish the effectiveness of 20mph 'sign only' limits. Early evidence of the Portsmouth trial confirms that 20 mph limits reduced average traffic speeds by less than that achieved in 20 mph zones. However, the Portsmouth scheme did indicate that where average traffic speeds before the installation of 20 mph limits were above 24 mph, average speeds were significantly reduced, by around 6-7 mph. Early evidence also suggests that overall casualty reductions above the national trend are likely.

Over recent months the government has issued a number of press releases promoting the revised changes to the guidance on 20mph limits and zones, although as yet no date for formal publication has been given. Faced with an ever increasing number of requests for 20mph limits and the likelihood of a relaxation of the conditions by which authorities could introduce such limits, Wiltshire Council made the decision to undertake its own pilot study.

The villages participating in the trial are Westwood, Limpley Stoke, Great Cheverell, Biddestone and Great Bedwyn.

The 20mph limits have been implemented on an experimental basis for eighteen months. During this time regular traffic data monitoring will take place. Towards the end of the trial there will also be a village survey.

WC intends that the results of the trial sites will form the basis of a policy that may allow the introduction of 20mph limits to other locations around the County. However no further limits will be introduced until the results have been obtained and analysed.