Sir – The speed limit in the London Road, in Headington, is 20mph. Car and van drivers make some effort to stay (roughly) within this limit. But what use is this when coaches, buses and taxis dangerously overtake them on the inside lane going more like 40mph?

Until the limit is enforced on all vehicles, none of us will be inclined to observe it more carefully. Nor will pedestrians and cyclists reap the benefit of the lower limit.

Nancy Kenny, Headington