Sir – Some clarification is needed regarding the so-called Barton ‘boulevard’ proposals. Self-evidently, the A40 no longer passes by communities — it cuts through them; it is simply not a bypass. It was downgraded from trunk road status years ago.

Nevertheless, past Barton it carries motorway-speed traffic, blighting residential communities with motorway-standard noise and pollution, and forming a ‘Berlin wall’ between them.

The city council seems to accept that the only effective solution to these problems of noise, pollution and disconnection is the transformation of the character of the A40. The objective of creating a genuinely successful, vibrant and attractive new community at Barton, integrated with and connected to the rest of the city, cannot be achieved without this fundamental alteration of the character of the road, the most essential element of which is a reduction in vehicle speed.

This needs more than just speed limit signs; however, widespread evidence shows that drivers do respond rationally to perceptions of their environment.

The so-called ‘boulevard’ proposals are not an end in themselves, but are intended to create an environment, including active frontages in the development and appropriate landscaping, in which 40mph is perceived as an appropriate speed.

Screens of trees alone do nothing for noise attenuation, pollution reduction or severance of communities; acoustic barriers have limited effect, sterilise development space and exacerbate isolation.

Simple arithmetic shows that a 40mph limit between Headington and Marston would increase travel time by about 30 seconds, in perfect conditions.

More realistically, delay here would be compensated for by shorter queues at Headington and Cutteslowe, where, incidentally, reduced speeds would also be of huge benefit to the community.

Peter Thompson, Chairman, Oxford Civic Society