I WOULD like to pick up on the point made by AJ Wood (Postbag, January 16) regarding seemingly contradictory evidence presented in relation to 20mph speed limits.

A reduction in casualty rates of 46 per cent was reported after the introduction in 1999 of the 20mph zone in Salisbury city centre. The relevant report is still available on Wiltshire Council’s website (in the meeting papers for the Salisbury Joint Transportation Committee meeting of February 15, 2007).

Wiltshire Council’s more recent conclusions regarding the effectiveness of 20mph limits arise from trials undertaken in 2011 involving 20mph limits in selected village locations across the county.

The report on these trials indicated that: “It is too early to evaluate the effect of the new limits on collision rates; however this should become clearer in the next few years following regular monitoring and trend analysis.

“Despite some reported reductions elsewhere in the country, there still appears to be little conclusive or proven statistical evidence that overall casualty rates have fallen following the introduction of 20mph limits.”

There are a number of reasons why there are differences between the findings – the size and scale of the scheme and existing accident rates would all be factors. Also importantly, the Salisbury city centre scheme was a 20mph zone – with various features such as road narrowings being introduced to encourage slower traffic speeds. Wiltshire’s village trials were 20mph limits where signage alone was being used.

In formulating its lacklustre 20mph policy Wiltshire Council has focused on the unremarkable results from the trials in villages and chosen to ignore the rather more positive earlier results from Salisbury city centre.

Particularly in an urban area such as Salisbury, I believe there are multiple benefits to be gained from lower traffic speeds including reduced noise and pollution as well as a safer environment for pedestrians and cyclists.

Cllr Margaret Willmot, Fisherton & Bemerton Village Ward, Salisbury