Areas of the UK road network covered by permanent average speed cameras have more than doubled since 2013.
New figures released by the RAC Foundation showed that by the end of 2015 the UK had 51 stretches of road covered by the technology, a total of 261 miles. In 2013, that total was 127 miles.
Much of the current coverage is focused on Scotland, in particular a 99-mile stretch of the A9 between Dunblane and Inverness that was installed in 2014. Since the cameras were installed, road deaths on the A9 have dropped by 30 percent. The research does not include roads with temporary average speed cameras, such as those installed to monitor roadworks.
Experts have cautiously welcomed improved compliance with speed limits in average speed camera zones, but warned that the technology is not a catchall solution to road safety.
Average speed cameras work out the time it takes vehicles to between several set points, unlike traditional speed cameras, which take a snapshot of vehicle speeds at one location.
Richard Owen of Road Safety Analysis, which carried out the research, said a reduction in the cost of average speed camera technology was behind the rise in usage. It costs around £100,000 per mile, compared to £1.5m per mile in the early 2000s.
“Some of the old fixed speed cameras have been around for 25 years and they are based on 35mm film,” Mr Owen said. “They are coming to the end of their life and are starting to be replaced, in some cases with average speed camera systems.”
Steve Gooding, director of the RAC Foundation, called for more research into the wider effects of average speed cameras on accident and casualty rates.
“The acid test is whether accident and casualty rates have also fallen,” he said. “That is what the next part of this research project should tell us. Rightly or wrongly many motorists perceive the current ‘spot’ speed cameras to be more about raising revenue for the Treasury than saving lives, but average speed cameras have greater potential to bring drivers onside. Clearly a high compliance rate means a very low penalty rate and hence both road safety and drivers wallets could benefit from greater use of these systems in appropriate places.”
A spokesman for the AA told Autocar that speed was only one factor in road safety, and he hoped that authorities weren’t looking at average speed cameras as a default solution.
“It’s not the silver bullet for road safety,” he said. “We don’t want speed cameras to always be the knee-jerk reaction to road safety. There are other ways of making roads safer through engineering, and Highways Authorities should be looking at all options.
“We would urge that proper analysis of types of accidents takes place, and if there are clear patterns that aren’t necessarily speed related, then they should be addressed as well.”