Speed cameras are useless: here’s the proof

05 September 2014

Idris Francis is an electrical engineer who ran his own specialist electronics company for 30 years. He sold the business in 1994 and has spent an estimated 10,000 hours studying speed camera data and claims made for camera effects.

Regression to the mean (RTM) has been well understood for a hundred years and is clearly visible in any graph of road accidents, so the fact that supposedly expert authors of successive reports deliberately ignored its contribution to observed falls in the DfT’s eight area trial of speed cameras was inexplicable, inexcusable and, I believe, culpable.

In my 54 years as an engineer (when being that badly wrong would have bankrupted my company) I never saw such a pig’s ear made...