Transport for London (TfL) is standing by its claim that fixed speed cameras have cut killed and serious injuries (KSIs) by 58%, despite a prominent academic concluding that the cameras have delivered no casualty benefit (Local Transport Today (LTT)).
The LTT article (subscription only), published on 11 December, says TfL officials were told their claims were incorrect in 2014 by Mike Maher, an honorary professor at University College London, and member of the Institute of Mathematics and its Applications.
Writing in LTT, Mr Maher said: “What TfL did not say was that this percentage fall in KSIs at camera sites matched that across London generally over the same period; that is, no allowance was made for trend.”
Mr Maher’s article suggests that TfL has repeatedly claimed that the capital’s fixed speed cameras have delivered, on average, a 58% reduction in KSIs at camera sites and helped prevent 500 deaths or serious injuries annually.
He adds that TfL has used this claim to help justify an investment programme to replace hundreds of wet film fixed cameras with new digital equipment.
The papers Mr Maher presented to TfL officials, which have been released following a Freedom of Information request, highlight findings from his analysis of casualty data for hundreds of fixed camera sites in the capital.
Mr Maher concluded: “Although the estimates of the average camera effect from these variants of the basic model are different, they all agree that there is no discernible beneficial effect from the fixed cameras on either slight (casualties) or KSIs.”
Mr Maher told LTT he is “very neutral” on the issue of speed cameras and is not an “anti-camera lobbyist”. He also says there is evidence of “significant benefit” from the use of red light cameras, with a 17-20% reduction in KSIs as a result of their deployment.
In a statement to LTT, TfL said: “On average, a reduction of 58% in fatal and serious collisions was observed in the three-year (after) period compared to the three-year period before safety cameras were installed and this was the figure quoted in papers seen by TfL’s finance and policy committee.
“We value the contribution made by Professor Mike Maher to the debate on speed camera effectiveness. We disagree that the effect of speed cameras is negligible but we are of course interested in any new statistical analysis on this topic.”