Sir – I hope Oxfordshire County Council will reinstate road safety cameras next April. Good evidence informed each camera’s installation, so their withdrawal was false economy. Some extremists are not satisfied.

They want dwindling police resources diverted to enforce Oxford’s indiscriminate 20mph limit, and our County Council’s reduced budget squandered to introduce 20mph limits to other Oxfordshire towns.

Cyclox claims a 6.7 per cent fall in casualties in Oxford in the first nine months of the 20mph limit “proved” it works (Report, September 9). Gert Westermann demands police not only enforce 20mph but also impound vehicles from anyone who breaks it (Letters, November 4).

But Oxfordshire’s serious road casualties are mostly on faster non-urban roads. What casualties occur in towns are mostly on busy main roads, which Oxford’s 20mph limit largely omits. Oxford’s 20mph limit wasted £300,000 on roads that were already the safest. Nine months’ data is a meaninglessly short statistical basis for Cyclox’s claims.

And only casualty rates, rather than numbers, can show which safety measures really work. Traffic numbers are needed to calculate casualty rates, but Oxfordshire’s 2010 traffic data will not be published until 2011. Until then pro-20mph claims are wishful guesswork. However, we know road traffic in inner Oxford fell by 8.3 per cent from 2005 to 2009. The most cost-effective casualty reduction may be the low-carbon option: keep reducing traffic! Constabularies are required to reduce budgets by 16 per cent in four years. Thames Valley Chief Constable Sara Thornton fears any reduction of more than ten per cent “could lead to noticeable reductions in service”.

Seven months ago I asked what policing Cyclox wanted reduced to fund enforcement of 20mph limits (Letters, March 25). Cyclox has never answered, but nevertheless continues its ill-founded, unaffordable demands.

Hugh Jaeger, Oxford