Recent articles in the Telegraph and Local Transport Today (LTT) both scrutinise casualty reduction claims made by Transport for London when it announced plans to upgrade the capital’s speed camera network.
In September 2014, when announcing the upgrade from wet film to digital speed cameras, TfL said: “At locations where safety cameras operate in the capital, research shows that the number of people killed or seriously injured (KSI) fell by an average of 58%, meaning that the cameras help to prevent 500 deaths or serious injuries each year”.
However, on 13 December, the Telegraph columnist Christopher Booker said: “Mayor Johnson’s traffic officials have embarked on a scheme that will do little or nothing for road safety”.
Then, on 23 January, LTT asked whether “Transport for London’s speed camera investment programme is based on a flawed understanding of the evidence about their effectiveness in reducing casualties”.
Both articles originate from information provided by Idris Francis, who has long argued that speed cameras do little to reduce casualties. Both quote data provided by Mr Francis which suggests that the TfL figures “ignore the influence of factors such as regression to the mean and trend”.
Leon Daniels, TfL’s managing director of surface transport, wrote to Mr Francis rejecting his claims. LTT quotes an extract from the letter which says: “The effectiveness of safety cameras in reducing casualties at the locations where they are implemented is well established.
“Our position is supported by a number of studies, including the detailed four-year evaluation of the National Safety Camera Programme, produced for the DfT by University College London and Dr Mountain of Liverpool University in 2005.
“Importantly, this study shows that safety cameras are effective in reducing casualties, even after trend effects and regression towards the mean are taken into account.”
Mr Francis, who has produced a series of graphs plotting the decline in reported fatal and serious injuries across London and at camera sites, told LTT: “As you can see there has been no meaningful difference between the rate at which KSI fell at your (camera) sites and the rate at which they fell elsewhere.”
Christopher Booker in the Telegraph describes the result as “unequivocal”, adding: “The two graphs, though very slightly apart, showed exactly the same rate of decline. In other words, any evidence that cameras affected the accident rate was virtually nil.”
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