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Safety cameras: more, not fewer, saves lives
  1. Mark Stevenson
  1. Correspondence to Professor Mark Stevenson, Monash University Accident Research Centre, Monash Injury Research Institute, Monash University, Melbourne, Victoria 3800, Australia; mark.stevenson{at}

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There is consensus among scientists, government officials and the general public that the energy transferred at the time of a motor vehicle crash (namely kinetic energy) results in the trauma that we observe presenting to our hospitals. We also know that the greater the speed at impact, the greater the kinetic energy and hence severity of injury. Clearly, anything that reduces the kinetic energy ipso facto reduces the level of trauma. In fact, we know from research in Scandinavia that even a 10% reduction in speed across the road network equates to 30–40% reduction in road fatalities.1 It is not surprising therefore that managing or containing travel speeds so that they reflect the road environment is merely ensuring that we can contain the kinetic energy in the unlikely event of a crash. This is the most fundamental tenet of road safety and one of the most effective ways of managing the burgeoning incidence of road injury.

Management of speed is the success story of road injury prevention, and much of this success can be attributed to the widespread roll-out of overt (such as red light) and covert (anytime anywhere or mobile) speed cameras. In combination, overt and covert cameras act as a specific deterrent, encouraging offenders not to re-offend, and a general deterrent, whereby they target all road users irrespective of whether they have previously offended.2 The deterrence approach, which is based on deterrence theory,3 has been extensively used in road safety campaigns, including those against unlicensed driving, drink driving and drug driving,4 with the success associated with speed cameras attributed to the implementation of both specific and general deterrence (ie, extensive use of both overt and covert cameras), and thereby ensuring that an increasing number of drivers are detected.

The evidence of the effectiveness of overt speed cameras is overwhelming, with recent evaluations of red light and fixed cameras in the State of Victoria, Australia, for example, highlighting a 47% reduction in casualty crashes, with a cost saving to the community of over A$8 million per annum.5 Similar cost savings per population have been reported in the UK, with an estimated £221 million benefit to society accrued over a 3-year period from overt cameras.6 The effectiveness of covert or mobile speed cameras is equally compelling, with a further 21% reduction in serious casualty crashes observed after their introduction in the state of Victoria, Australia between 2001 and 2004.7 Importantly, covert operations are more likely to increase drivers' perceived risk of detection and are therefore more likely to achieve the urgently needed reductions in speed across the entire road network and not just on the isolated road on which a fixed camera operates.

There is still considerable opportunity for tangible reductions in speed-related road trauma in Australia and other highly motorised countries as long as effective speed management schemes are comprehensively and consistently adopted. Like other successful road safety strategies, such as seat belt restraint legislation and associated enforcement in the 1970s,8 the use of speed cameras to mitigate excess speed across the road network will only achieve its goal as long as jurisdictions initiate expansive overt and covert speed camera programmes. A significant concern recently is the fact that a number of jurisdictions are challenging the need for such programmes. For example, in Australia, the Roads Minister in the State of New South Wales turned off over 25% of the state's cameras, citing that they were ineffective. While in the northern hemisphere, budget constraints have been cited as a reason for jurisdictions across the UK turning off their cameras.9

In the absence of research evidence, one might excuse politically driven decisions such as the recent one in the State of New South Wales, which was linked, in part, to an electoral pledge. However, two systematic reviews10 11 have both concurred that considerable road safety benefits are achieved with speed camera programmes, albeit with varying estimates of effectiveness. For example, the most recent review11 found a reduction in serious injuries and deaths ranging from 11% to 44% associated with speed camera programmes, while an earlier review reported reductions in fatalities in the range 17–71%.10 Although both reviews reported that much of the selected research is of varying quality, there is an overwhelming consistency in the findings of the evaluations supporting the use of overt and covert cameras for the prevention of road injury. On this basis, it is a significant concern that there is an increasing reticence to embrace one of the most successful road safety interventions: speed (or should that be safety?) cameras.

On 11 May 2011, the United Nations Decade of Action for Road Safety 2011–2020 was launched in which global efforts are being garnered to reduce the burden of road traffic injury. In all motorised countries, whether high-income, middle-income or low-income, considerable activity at the national level is being supported to ensure that ambitious targets are being set to reduce road fatalities by 2020. In order to achieve such targets, countries will need to make a commitment to the implementation (or enhancement) of speed enforcement practices such that overt and covert/anytime, anywhere enforcement with increased penalties is adopted. Importantly, if revenue from cameras and other speed enforcement practices can be hypothecated to support the implementation of national road safety interventions and not be transferred to general revenue (as is the case in a number of jurisdictions), it will not only contribute to changing the public's perception of speed management as safety (and not revenue) driven, it will also provide the necessary fiscal foundation from which the implementation of other comprehensive road safety programmes can be undertaken and thereby support the goal of the Decade of Action for Road Safety.



  • Competing interests None.

  • Provenance and peer review Commissioned; internally peer reviewed.