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posted by janrinok on Tuesday November 21 2017, @07:25PM   Printer-friendly
from the er-yes-no-maybe dept.

Speed cameras have been the focus of motorists' anger and frustration for years, although we are told repeatedly that they are an effective means of reducing death and injury on the roads. But is this really the case?

Whether speed cameras actually do save lives seems an easy assertion to test: measure the numbers of casualties at a site over a period, say two years; introduce a speed camera; re-measure the number of casualties over an equal period, and any reduction is due to the camera. But it's not really that simple. Many other factors are at play that might make cameras appear to be more effective than they really are. And these factors are often ignored when evaluating the performance of speed cameras at improving road safety.

Do speed cameras actually save lives?

[...] In road safety data, there is a general tendency for collision incidents at a site to reduce anyway following a short-term rise in their number, without any treatment (such as a speed camera) being applied. In statistics, this is known as regression-to-the-mean (or RTM). We also know that the long-term trend in collisions has generally been downward due to factors such as improved vehicle safety and better driver education[PDF].

So if we observe a reduction in casualties at a site following the installation of a camera, we need to ask how much of this reduction would have happened anyway (the RTM effect)? How much is due to general trends in road safety? And how much can we actually attribute to the camera itself?

[...] To make matters worse, half of the UK's fixed speed cameras may not even be turned on. So the situation is far from simple.

Methods to accurately account for RTM and trend often require knowledge of advanced statistics which may not always be available within a road safety team, and so it is likely that these confounding factors are not being considered consistently across the country.

[...] So, do speed cameras save lives? The answer is almost certainly yes, but probably not always to the extent that people are led to believe.

https://theconversation.com/do-speed-cameras-really-save-lives-87701


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  • (Score: 1) by Didz on Thursday November 23 2017, @06:52AM (1 child)

    by Didz (1336) Subscriber Badge on Thursday November 23 2017, @06:52AM (#600542) Homepage

    In South Australia there is no camera warning signs for mobile cameras and any signs for fixed cameras do not have a speed limit sign next to them like other states do.

    School zones are 25kmph when children present. Not only is it slower than other states it is a grey area about what what 'children present' means or even if you see one at all.

  • (Score: 2) by MostCynical on Thursday November 23 2017, @08:02AM

    by MostCynical (2589) on Thursday November 23 2017, @08:02AM (#600551) Journal

    In NSW, school days are the days published in the NSW Government Gazette. Pupil free days (teachers only, or no one at all at schools) are also 40km/h.

    At least they are putting flashing lights at the start of school zones (Well "one set per school" - too bad if the school has lots of roads around it)
    http://roadsafety.transport.nsw.gov.au/stayingsafe/schools/flashinglights/index.html [nsw.gov.au]

    --
    "I guess once you start doubting, there's no end to it." -Batou, Ghost in the Shell: Stand Alone Complex