Speed cameras reduce collisions and deaths, study finds

14.45 | 19 February | | 11 comments

Photo: Albert Bridge – licensed for reuse under the Creative Commons Licence.

Deploying an additional 1,000 speed cameras on British roads could save up to 190 lives each year, a study has concluded.

The London School of Economics research, published in October 2017, analysed collision outcomes before and after speed cameras were installed at 2,500 sites in England, Scotland and Wales.

The analysis found that from 1992 to 2016, the number of ‘accidents’ fell by between 17% and 39% – and fatalities by between 58% and 68% – within 500 metres of speed cameras.

In addition to the reduction in fatalities, lead researcher Cheng Keat Tang says that adding another 1,000 cameras would produce annual savings of up to 1,130 collisions and 330 serious injuries.

However, the report points out that the benefits of speed cameras are ‘highly localised’ and dissipate over distance – with a slight increase in collisions observed at distances beyond 1.5kms from the camera sites.

The report says this could be due to a ‘kangaroo’ effect as drivers ‘brake suddenly before the camera to avoid fines’ and ‘speed up beyond camera surveillance’.

Cheng Keat Tang said: “Although the study found a slight increase in accidents away from the camera, the overall reduction in road accidents and deaths around the camera more than makes up for this increase.

“Given the huge number of fatal accidents that take place on our roads every year, the introduction of more cameras could save hundreds of lives annually and make our roads safer for users.”


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    Idris – have you ever published a peer reviewed paper on your findings? If so would you share it?


    Dan, Exeter
    Agree (7) | Disagree (4)
    +3

    As a engineer seeking all the facts Idris, just to clarify, have you examined in detail the collisions as I suggested, or are you not going to bother? It’s just that you’ve just said you’d analysed 1.1 million collisions, but then suggested it would be absurd to actually look at them in detail – so, it sounds to me as if you haven’t actually analysed them at all – could be some uncomfortable truths in there no doubt. Non-specific and incomplete Stats 19 data is however, probably more useful when trying to reach a pre-determined, impartial conclusion I would imagine.


    Hugh Jones
    Agree (7) | Disagree (3)
    +4

    I have driven at least 2 million miles in my lifetime and I’m not quite 60 yet.

    Speed cameras do what they do but far too many so called beneficial additional effects on driver behaviour has been attributed to them. My experience is that driving has not improved in the last 30 years. The opposite is true. Other factors that would have existed without speed cameras have reduced KSI rates.

    I would like to know the number of convictions for non speeding motoring offences compared to 1988. My guess is that far less drivers find themselves in court for due care and attention offences…..and that won’t be because less drivers are breaking that rule. It will be because there are very few police vehicles on patrol and those that are don’t bother with traffic violations.

    It has reached the stage where I cannot now drive in my town for more than 5 minutes without seeing some kind of inept driving causing other road users to take avoiding action.


    Nicholas Elmslie, New Milton
    Agree (14) | Disagree (0)
    +14

    Even in relation to speed cameras I have never read as absurd a proposition as Hugh’s, that one observer at camera sites can better judge what happens than another who analyses 1.1m collisions within 1m of 3,800 speed cameras. Or that I should look in detail at all of those collision reports!

    As a former engineer I deal with facts not opinions. Mr. Tang found significant increases in collisions more than 1km from cameras, albeit only on the particular roads on which cameras were located.

    My analysis of 2km diameter sites found even larger increases more than 500m from the cameras, including on roads which suffered some of the 40 or so adverse effects identified more than 10 years ago, many of which could clearly extend well beyond narrowly-defined site boundaries. My results are consistent, logical and unequivocal


    Idris Francis, Petersfield
    Agree (5) | Disagree (8)
    --3

    Equally sorry Idris, but to be really sure, you will need to look in detail at all the individual collision reports you’ve referred to, plus… spend many hours at camera sites and observe what actually happens, not what it is presumed happens. I suspect you’ve spent too much time reading data and not enough time observing driver behaviour out on the roads as I have, where it all happens.


    Hugh Jones
    Agree (7) | Disagree (8)
    --1

    Sorry Hugh, you are wrong again. My very large volume of Stats19 data that identifies (to within 10m and up to 1km) the distance from a collision to the nearest cameras consistently clearly shows significant increases in collisions near but outside the narrowly-defined official boundaries of camera sites, especially from the 2nd year after installation onwards.

    I have to wonder whether any of the 6 who “disagree” believe that cameras can be justified by a supposed 4% difference between benefit and cost despite each parameter involved in estimating both is subjective and subject to margins of error far greater than 4%


    Idris Francis, Petersfield
    Agree (9) | Disagree (7)
    +2

    I think what is described as the ‘kangaroo effect’ is a bit of an urban myth….something that it is said happens, but has never been witnessed, nor could it be easily witnessed anyway.


    Hugh Jones
    Agree (4) | Disagree (8)
    --4

    As this item relates to a paper published 4 months ago it seems likely that it was triggered by an article and my accompanying letter in last week’s Local Transport Today,reporting my formal complaint to the most senior levels of the LSE about the innumerable errors of fact and analysis that make nonsense of its findings. My detailed assessment covers 14 pages so in brief:

    • wildly exaggerated ‘costs’ of collisions, contribution of speeding to accident causation and and claims of reductions achieved.

    • incorrect definition of serious injuries

    • failure to realise that some 63% or non-fatal collisions are never reported to the authorities.

    • restricting analysis to the narrow confines of the particular roads on which cameras are located, thereby ignoring the many adverse effects which can (and do) increase collisions outside those boundaries.

    • using calendar year collision totals and camera installation dates, thereby reducing accuracy and making it impossible to monitor accurately the quite sudden reductions which should occur shortly after installation.

    • failing to understand and correct or long-term trends (and even claiming that effectiveness continues to increase year after year after year.

    • claiming net benefit per camera per year of £21,119, the difference between estimated total benefit of £439,279 and estimated to total costs of £418,160 despite that 4% difference being greater than the margin of error of each of the many estimates involved.

    It is entirely unacceptable that a failed speed camera policy should again be supported by such flawed analysis and wishful thinking so I have asked the LSE to withdraw it.


    Idris Francis, Petersfield
    Agree (8) | Disagree (11)
    --3

    Wow! Another study that says that cameras “work”. Of course they do, but that isn’t the point.

    Dr Helen Wells has explained why the approach is a poor one, and Sir Alker Tripp – decades ago – explained how we should approach traffic management.

    Dr Oliver Carsten and his colleagues have spent a great deal of their academic lives in providing us with a congenial answer.

    NCAP now awards points for it, so what is the “road safety community” waiting for:
    https://www.youtube.com/watch?v=SoZLrZTnUGs

    Or do we really prefer cameras, humps, chicanes, sign proliferation and punishment?


    Andrew Fraser, Stirling
    Agree (2) | Disagree (10)
    --8

    There is enough of a problem trying to find the money to maintain the existing cameras. (If anyone needs reminding, the camera income goes to the Treasury). I don’t see any of our various governments in the UK putting their hand in their pocket to pay for lots more cameras. Or to expand the support and enforcement network that would also be required on an annual revenue budget after the capital cost.


    Pat, Wales
    Agree (9) | Disagree (3)
    +6

    Over the years there have been numerous analysis and reports on speed cameras – but why? Speeding is an offence anyway…. why do the authorities and academics feel the need to have to keep justifying the enforcement of one particular offence? If an analysis of speed limit infringement enforcement was felt necessary at all by the LSE (why the LSE anyway?), then the results from the various police forces’ routine speed enforcement via police patrols and roadside checks should be thrown into the mix as well.


    Hugh Jones
    Agree (8) | Disagree (6)
    +2