Sir — The county council is to be congratulated on its proposal to reduce speed limits in Oxford city to 20mph.

Not only can this reduce emissions by getting people out of their cars, it can really improve accident statistics. According to county council data, Oxford city pedestrians and cyclists are three times more likely to be involved in an accident than residents of neighbouring council areas.

But self enforcement — relying on a few signs — may not work for all streets. The council should offer to do what Portsmouth has done in its successful experiment which is to promise to consider engineering solutions if speeds in particular communities are still too high. In its consultation material, the figure of £250,000 is mentioned as the basic cost. While we don't want to spend unnecessarily, Portsmouth has spent much more than this in its trial.

We very much hope that the county will not spoil the scheme by not being prepared to allocate whatever is needed to make our streets safer. Finally, there can be little certainty that a self-enforcement scheme will work. We would like to see the council collecting the baseline data in order to carry out a real pilot over, say, two years. During this time it would collect data on traffic levels, speeds, and people switching their travel modes, both before and after the trial.

We very much look forward to the results of the consultation and seeing this initiative get started in Oxford.

Sam Clarke, Oxford Friends of the Earth