Many South Africans are all too familiar with the scene: highway traffic reduced to walking pace as cars filter through the one or two lanes open next to a wreckage.
At least 37 people died each day on the country’s roads in 2015, a report for the Road Traffic Management Corporation shows. The RTMC is an agency of the department of transport aimed at the planning, regulation and facilitation of matters concerned with public roads.
How to reduce traffic deaths vexes politicians, road safety organisations and the public alike.
When the City of Johannesburg booted out speed camera service providers earlier this year, the Justice Project – a nonprofit aimed at reforming law enforcement – said it’s a good thing. (Note: The Johannesburg Metropolitan Police Department are using mobile cameras to enforce speed limits, spokesman Wayne Minnaar confirmed to Africa Check.)
“The proponents of camera-based ‘speed enforcement’ make claims of it enhancing road safety, whilst simultaneously failing to provide any empirical evidence to support their claims that hidden speed cameras reduce crashes,” it read.
As it turns out, there is empirical evidence – backing up some common-place ideas about speed cameras, while contradicting others.
‘Dummy’ camera halted crashes
In theory, anything which reduces speed could have an effect on the number of crashes that occur in a given area.
The effect of speed on crashes may be well documented, but what does the data say about the efficacy of speed cameras?
Deon Roux is the head of research at the Road Traffic Management Corporation. In 2011, he installed a “dummy camera” fitted only with a flasher on a section of road outside Bloemfontein that was notorious for serious crashes.
“In the month after the flasher was installed, no accidents were recorded at the intersection. Even though it was only a small investigation performed over a limited time, dramatic reductions in speed were observed,” Roux told Africa Check.
Reviews show fewer collisions & casualties
What happens when you scale this effect up to a larger area?
In 2005, the British Medical Journal published a review incorporating 14 studies, featuring both visible and hidden cameras from high-income countries in America, Europe, Asia and Australia. It focused on road traffic collisions, injuries and deaths. Follow-up periods varied from one to up to four years after a camera was added to a site and remained operational.
All the studies reported a reduction in road traffic collisions and casualties – but with sizable variability. Collisions were reduced between 5% to 69%, injuries were down between 12% and 65% and the number of deaths decreased between 17% and 71%.
A more recent review of visible and hidden cameras across similar high-income countries was published by the Cochrane organisation in 2010. For this analysis, 35 studies made the cut. Their conclusions were that in the vicinity of camera sites, the reduction in the number of crashes at most locations ranged from 14% to 25%, while injuries were reduced by between 8% and 50% and deaths by 11% to 44%.
Surprisingly, these results weren’t limited to the immediate vicinity of the cameras. The reviewers also identified a reduction in the total number of crashes in a wider area of between 11% and 27%, with deaths decreasing by between 30% and 40%. The studies which followed up on the continued efficacy of the cameras for a number of years found that the trends were maintained as time went by.
Although these studies consistently reported a reduction in speed and number of crashes, the reviewers urged caution when interpreting these results given the wide variety in the size of the effects. They recommended higher quality studies where data is collected both before and after speed cameras were introduced and for longer periods.
Are these studies relevant to SA?
The keen observer may readily point out that these are all developed countries, with very different cultures and access to more resources. Is any of it relevant to South Africa?
“When attempting to extrapolate data between different contexts we must keep in mind the fact that road conditions, level of driver training, condition of vehicles [and] regard for the rules of road all vary between countries, making exact comparison difficult,” Karien Venter, senior researcher from the CSIR’s Department of Built Environment, explained to Africa Check.
Furthermore, South Africa “may lack the human resources to enforce speed rules and hence have less accountability for our behaviour as drivers”, Tamara Kredo, senior specialist scientist at the Cochrane Centre in South Africa, told Africa Check. “What that might mean in our context and with respect to this kind of evidence, is that although there may be a reduction, it may be relatively less effective.”
Despite these limitations, local research conducted by Traffic Management Technologies on high-risk roads in Johannesburg in 2009 showed that reducing car speeds (as encouraged by the presence of traffic cameras) also reduced crashes.
‘Catching individuals not familiar with region’
But surely drivers just slow down for a camera once they know it’s there and then speed up again afterwards?
Research conducted at Imperial College London and supported by internal findings of the University of Stellenbosch attest that people tend to slow down for fixed cameras and then speed up again once past the camera.
“Many cameras in use today are placed in areas where the environment favours higher speeds than what laws may mandate,” Louis Roodt, a senior engineer and lecturer in the field of transport engineering at Stellenbosch University, explained.
“Drivers tend to assess the road conditions against their own judgment and act accordingly. Cameras placed in such areas only favour catching individuals not familiar with the region who didn’t know about the need to slow down.”
Roodt added that “it becomes difficult to argue that cameras placed in such a manner aren’t simply done to provide an additional revenue stream for municipalities. If we want to minimise road accidents, traffic cameras need to be placed in regions known to carry a significant accident burden.”
The take-home message is, that traffic cameras, whether hidden or visible, are able to reduce the number of road crashes and deaths – but more research is needed, especially in South Africa.
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