In its report, the IAM said that its analysis of government data has found that the number of serious accidents on 20mph roads has increased by over a quarter (26%) last year. Slight accidents on 20mph roads increased by 17%.
In the same year, there was a decrease in the number of serious and slight accidents on 30mph roads and 40 mph roads. Serious accidents went down 9% on 30mph roads and 7% on 40mph roads. There was a 5% reduction in slight accidents on 30 mph roads and a 3% decrease on 40mph roads.
In response, 20's Plenty for Us – a “not for profit” organisation that campaigns for 20mph to become the default speed limit on residential and urban streets – has said the IAM’s conclusions show ‘a woeful lack of understanding of statistics’.
The organisation said the reason why casualties on 20mph roads have increased is mainly because many UK towns and cities are changing the limit on roads from 30mph to 20mph. As a result the total length of 20mph roads is increasing and 30mph decreasing.
Responding back, IAM chief executive Simon Best said: ‘The 20's Plenty campaign have deliberately misinterpreted our press release. At no point do we say, or imply, that a 20mph limit increases danger. Our release contains findings using statistics released by the DfT.
‘Our point is that there is no evidence that 20mph limits on their own are reducing casualties and more attention needs to be given to the design of the road and other measures where there is a proven casualty problem. That is completely valid. The 20's plenty’s response is based on a bogus reading of our press release.’
