The telematics-based insurance provider Wunelli has published a study in which more than 8,800 UK car journeys were analysed, collecting over a billion miles of driving behaviour data.

It has been discovered that the number of ‘hard braking events’ at speed camera locations is an average of six times higher than at other areas which made up the journeys. In some speed camera locations studied, the number of hard braking events is 11 times higher than the average elsewhere.

In this study, a hard braking event is defined as a decrease in speed of 6.5mph or more over a one-second time period – abrupt enough to send items placed on the car seats, such as bags, tumbling into the footwell.


The worst speed camera location in terms of frequency of hard braking events was found to be the M4 near Boston Manor rail station. That’s followed closely by the speed camera area on Rochdale Road in Middleton, Greater Manchester and the A4146 Leighton Buzzard Road in Hemel Hempstead.

It has also been found in the study that at as many as 80 per cent of speed camera locations, there is a spike in the number of hard braking events.

The founding director of Wunelli, Paul Stacy, commented: “I’m not in favour of speeding and not averse to speed cameras.

“But these findings really put into question the value of speed cameras as a road safety tool. Instead they appear to encourage poor driving behaviour.

“After hard braking drivers often speed up again. Questions must be asked about the long-term effectiveness of these cameras."