How sound are Swindon speed camera stats?
As the debate rages on at over the road safety effects of speed cameras, much has been made in recent days of the case of Swindon.
The experience in the Wiltshire town has been cited as evidence that the much maligned machines do not actually serve to reduce road accidents.
The Claim
In recent days, an array of news outlets including the BBC, the Sun, and Metro, have all made reference to research conducted after several cameras in Swindon were turned off.
The results, it was reported again and again, showed that the number of accidents had remained stable rather than rising as road safety campaigners had warned.
Given that the Swindon experience is cited as evidence that cutting cameras nationwide would have similar affects, do the statistics stand up to such bold assertions?
Analysis
Full Fact contacted Swindon borough council, who provided us with the data which had been reported. The results are, at best, limited.
The study was based on six cameras covering four stretches of road in the six months after the cameras were first taken out of action, and the same six months a year later.
From August 2008 to January 2009 there were nine accidents, with a similar number the following year.
Crucially, a spokesman for warned that no meaningful conclusion could be drawn for statistics based on a six month study.
“We’ve always said statistically, it’s going to take a long time - possibly up to two years - before you can drawn any meaningful conclusions from these statistics relating those particular site because it’s such a small sample.”
He added: “It’s important to understand that we as a council have never made any claims for how to read into these statistics,” he said.
Conclusion
The way the Swindon statistics have been reported in the media is yet another example of the way that, without scrutiny, claims can be used and repeated in the public debate in ways the original figures do not support.
It is worrying that, whether intentionally or not, the impression given by the way the figures are used is that the research was far more extensive.
Time will tell on how a reduction in speed cameras will affect the level of road traffic accidents. No doubt as further research is released there will be further debate.
We can only hope that in future the arguments are based on stronger figures.
Patrick Casey
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