"Speed cameras 'increase risk of serious or fatal crashes','' the Daily Mail tells us, while The Guardian, covering the same report, says "Speed cameras reduce serious road accidents." So you could be forgiven for being more than a little confused.
So what is the picture – do they increase or decrease injuries and fatal crashes?
The main objective of the report published last month by the RAC Foundation was to provide guidance on how speed camera data (which has been publicly available since 2011) should be analysed and interpreted. And not, despite the media’s take on the report, to provide simple figures on the number of collisions and fatalities in the vicinity of each camera.
For this reason, the report mostly consists of detailed discussion into statistical analysis and not real-world outcomes. Though it did provide some data for nine local authorities and road safety partnerships.
The figures for the nine regions reviewed present somewhat mixed results.
Five of the regions showed significant decreases both in the number of fatal or serious collisions (FSCs – decreases ranging from 24–53%), and collisions resulting in personal injury of any severity (PICs – decreases ranging from 20-32%) following introduction of cameras.
However, four of the regions did not find the introduction of cameras to have had a significant effect on FSCs and PICs.
Based on the data provided for the regions studied, we can only conclude that speed cameras have helped to reduce the number of collisions resulting in fatality or injury in some areas. But that in other areas they have had no significant effect.
However, no evidence is presented here to suggest they increase the risk of fatality or injury as was reported in some sections of the UK media.
The report, published last month, titled "Guidance on the use of speed camera transparency data" was conducted by the Royal Automobile Club (RAC) Foundation and authored by Richard Allsop, Professor of Transport Studies, of University College London.
The RAC Foundation is a charity focusing on road safety and transport issues.
The report says that since Summer 2011, data relating to fixed speed cameras has been made available to the public and is presented on the websites of local authorities or road safety partnerships. A list of these websites can be found through on the Department for Transport.
Available data contains information for the period 1990 to 2010 on the number of collisions and casualties near each camera, typically on a 0.4 km to 1.5 km section of road. The RAC have used this information to find, for each camera, the year by year numbers of:
Information is also available from websites regarding:
However, these things were not the focus of this report.
The RAC Foundation considered that the general public needed guidance on how to interpret this data, and this was the focus of the report. The Foundation downloaded data from nine local authorities and road safety partnerships and conducted statistical analysis before submitting their findings for independent peer review. The nine areas covered a mix of metropolitan and shire counties, including Warwickshire, Lincolnshire, Merseyside and Sussex.
The focus of this report was to "discuss a number of ways in which the data can be analysed, and provide users of the data [with] practical advice on the scope and nature of the available data and on their analysis and interpretation". It was not, as the media implied, to produce simple figures on collision and fatality rates.
The hope is that once an agreed method of analysis is reached, simple figures on collision and fatality rates, will be made available.
The report initially raises several practical difficulties of examining the data:
The focus of their report is a fairly complex discussion of how to statistically interpret the data and look at how number of collisions in the vicinity of one camera relates to those in the whole partnership areas, and how numbers of FSC, KSI, PIC and CAS relate to each other.
Since the media focus is on changes in the numbers of collisions and fatalities, below is some of the data presented in appendices.
The following regions demonstrate significant decreases in PICs and FSCs since camera establishment:
Three of the remaining regions showed non-significant changes:
In general, the media's coverage of this report was rather confusing and contradictory.
It appears the media wanted to report on the extent to which speed cameras decrease – or increase – the number road collisions and fatalities.
However, this wasn’t the objective of this report, which was a lot more complex, and focused on guiding people in how to interpret available data on speed cameras.
The Daily Mail’s coverage of the report was particularly poor and arguably disingenuous. The claim that “Speed cameras increase the risk of serious or fatal accidents” is simply not backed up by the data.
The Mail seems to be resorting to what, in academic circles, is known as cherry picking – that is, focusing on the data that supports your argument while ignoring the data that doesn’t.
It was the case that at 21 camera sites the number of accidents went up – though whether this was due to speed cameras remains unproven. Leaving that issue aside, the Mail ignores any data from the remaining 530 camera sites where the number of accidents and fatalities went down.
Such a distortion of evidence is disturbing.
Based on the data provided for the regions studied here we can only conclude that speed cameras have helped to reduce the number of collisions resulting in fatality or injury – or that in some areas they have had no effect. However, no evidence is presented here to suggest that they increase them.