A leading road safety data analyst has criticised a new report into the effectiveness of speed cameras for showing a “lack of independence” and a “clear bias against speed enforcement”.
The remarks were made by Richard Owen, operations director at Road Safety Analysis, in response to a report published by Dave Finney, an electronics engineer, whom he describes as “a long time anti speed camera campaigner”.
Mr Finney’s report investigates the effect that mobile speed cameras had on the number and severity of collisions and casualties at sites in Thames Valley (Oxfordshire, Buckinghamshire and Berkshire).
Mr Finney claims that this is the first speed camera report to contain measurements of the "regression to the mean" effect at speed camera sites.
In the report, Mr Finney says: “The entire KSI casualty reduction that occurred at the mobile speed camera sites was due to regression to the mean, with the mobile cameras having provided no benefit whatsoever.”
He concludes that: “The evidence suggests that the policy of using mobile speed cameras has contributed to more collisions, more serious injuries and more deaths.
“The decision not to perform scientific trials, and the subsequent failure of official reports to demonstrate that they have completely excluded the effects of regression to the mean from their results, has resulted in there not being any good quality evidence that speed cameras have produced a positive benefit for road safety.”
In response, Richard Owen said: “I find Mr Finney’s research of interest as the data being used was provided by the Thames Valley Safer Roads Partnership (TVSRP) while I was the operations manager in charge of day-to-day running of the partnership.
“Mr Finney and I have had many long conversations about the analysis of camera statistics over the years and I have voiced concerns about the methods he has used in the past.
“In order to inform the road safety community about the validity of this new research I have prepared a summary of his latest report.
“Truly independent analysis requires the forming of a hypothesis, devising the methodology and then analysing the results. By adapting a theory to match the results Mr Finney has shown a lack of an independent approach and demonstrates clear bias against speed enforcement.
“Independent analysis of published statistics is to be welcomed and Mr Finney’s perseverance is to be commended. It is unfortunate that in his pursuit of ‘the truth’ he has followed a path that leads to an analytical cul-de-sac with the only option to turn back and start again.
“There are many published reports into the effectiveness of speed camera enforcement and Mr Finney would do well to study these, their methodologies and analytical techniques, before re-attempting to analyse the Thames Valley dataset.”