Guidance on Use of Speed Camera Transparency Data (revised Nov ’13)

In 2011, local authorities were required to provide data on offences, collisions, casualties and speeds at fixed camera sites in response to the Coalition Government’s drive for transparency. The information mounted in response to this requirement is now available for the public and professionals to view, analyse and interpret.

Although the data as mounted is now in the public domain, there is no guidance for the general public, media or practitioners on how to use it in a robust and consistent way.
In the absence of any formal guidance, the RAC Foundation commissioned Prof. Richard Allsop of University College London to provide a view on how available speed camera data can be best analysed.

The first edition of this report, published in June 2013, gave rise to both media
attention and extensive technical exchanges with the author. Constructive
criticism, debate and revision are essential to scientific progress and Professor
Allsop was able to improve his advice in one respect which will be useful to
some users of the data, and he has reworked his example calculations.

The second edition incorporates these improvements and readers will be able to see the differences in the illustrative results: the estimates of reductions in collisions attributable to the cameras are still substantial though the reworking leads to somewhat smaller estimates.

The process of scrutiny and revision in response to comment strengthens confidence in the overall conclusion: the evidence is that on the average speed cameras are effective in reducing collisions and saving lives.

Revisions to the report have been informed by comments and analysis from Professor Mike Maher, and comments by Dave Finney and Idris Francis.