CARRS-Q safety study looks at ways to mitigate safety hazards at roadworks

A recently completed study by CARRS-Q looks at the problems and solutions to mitigating hazards at roadworks which affect both roadwork and the public. Gauging the standard of Australia’s roadwork safety has its challenges.

Ashim Debnath from the Queensland University of Technology’s Centre for Accident Research and Road Safety – Queensland (CARRS-Q) explains that statistics on crash incidents through roadwork sites in Australia, for instance, are not very well documented.

If a vehicle speeds through a roadwork site and crashes, police may classify speeding as the primary cause, unless the accident has directly involved the site in some way, such as a worker or roadwork traffic control device being hit.

“If the police officer doesn’t tick the box saying it was involving a roadwork zone, we won’t know that this crash happened in a roadwork zone,” says Dr. Debnath.

Unfortunately, this absence of crash data limits what is known about the frequency of accidents at roadwork sites and, worse yet, hinders any progress towards improving safety and mitigating these potential hazards.

It was this lack of crash data that formed part of the basis for a major CARRS-Q three-year study into safety at Australian roadwork sites.

“Before this project, we didn’t have much insight into the hazards at roadwork sites. The basic idea behind this was to give some background information and the context to what’s happening,” says Dr. Debnath, who managed the study.

The project – Integrating Technological and Organisational Approaches to Enhance the Safety of Roadworkers – was funded by the Australian Research Council, with support from industry partners Leighton Contractors, GHD, Queensland Transport and Main Roads, and the Australian Workers Union.

Dr. Debnath says it is the first major Australian analysis concerning safety at roadwork sites in decades.

The CARRS-Q team conducted the study from February 2012 to June 2015, in collaboration with its industry partners. It covered evaluation of safety treatments, understanding driver and worker views and speeding in relation to roadwork site safety. “We monitored what drivers were doing at real roadwork sites, talked to workers and surveyed drivers to learn their views, and collectively put these things together to get a complete picture, eventually coming up with some solutions that could be used to improve roadwork safety,” he says.

Dr. Debnath and his CARRS-Q colleagues presented their findings at the inaugural Australasian Road Safety Conference at the Gold Coast in October.

One major component of the study, which resulted in some key learnings for industry, was to gauge the perceptions of both drivers and roadwork crews.

Part of the information-gathering process involved an online survey to find out the perceptions and experiences of drivers regarding roadworks, speed choice and related safety concerns. Survey participants viewed 12 roadwork sites from a drivers’ perspective and without the speed signs shown. They were then asked to nominate the speed they thought they should be driving through the work zone.

The survey found that drivers are more likely to slow down when they see workers or police in roadwork sites.

This study also measured drivers’ actual speeds at three real-world roadwork sites and compared these with the speeds nominated by drivers in the online survey. “We found that in real-world sites drivers drive at higher speeds that what they think they should be driving at”, says Dr. Debnath.

“The speed measurement study found that non-compliance with the signposted limits was very high among drivers, which gives the impression that how roadwork signs and speed limits are set up needs to be re-looked at.

“From a driver’s point of view, delay, reduced speed limits and other issues related to driving to and around roadworks could cause frustration among drivers which could even be worse if they don’t see any work going on. There could be a misunderstanding between what drivers think about the reduced speed limit signs at roadworks and why the signs have actually been placed at roadwork sites.”

Dr. Debnath asserts that there needs to be better public understanding that speed restrictions at roadwork sites are for the benefit of both the workers and the road-users. “Ultimately, if drivers do not comply with speed limits, roadwork sites could be unsafe for both the workers and drivers. Roadwork sites are usually not like a standard road section, because of narrower lane width and presence of barriers, bollards, and other traffic control devices.”

If drivers are going at 80 to 100 kilometres per hour, they may not have the necessary time to react and stop, if they have to do so,” he says.

“Public perception is something that is very, very difficult to change, but it is something we need to look at changing.” One solution he suggests is to implement an educational component to the driver licensing process to inform drivers on safety at roadworks.

The CARRS-Q team conducted a similar survey with a selection of road-workers from Queensland. “We interviewed 66 workers, including traffic controllers, machinery operators and project managers, so that we covered people at different levels who are directly exposed, partially exposed or not always exposed to the traffic,” he says. The workers were interviewed on their perceptions and experiences regarding roadwork safety, the common causes of roadwork hazards and the effectiveness of some of the safety treatments currently used on-site.

“The results clearly show that the perception of workers varies based on their level of exposure to traffic,” says Dr. Debnath. Traffic operators were more concerned about oncoming traffic, machinery operators were worried about traffic coming through their workzone and project managers were focused on the impact of safety hazards on the project as a whole.

The survey participants suggested a consideration of more education measures to address driver distraction and aggression issues relating to roadwork sites.

Police presence and enforcement was also seen as the most effective countermeasure to speeding and safety hazards among the participants.

In fact, the study trialled police enforcement as part of three on-road evaluation studies using current and new safety treatments. The intention here was to provide more information on what safety treatments potentially worked well to mitigate the identified roadwork hazards, including speeding.

The CARRS-Q team undertook a trial of variable message signage (VMS) and police enforcement in a roadwork zone on a section of the Pacific Motorway near the Gold Coast. The two safety measures were trialled separately and then together, with the VMS sign warning drivers of police enforcement ahead.

“We found that both treatments reduced driver speed, but when both of these were in place, the reduction in mean speeds was higher than when we had VMS or police alone,” says Dr. Debnath.

The second measure tested was a pilot vehicle at a roadwork zone on a section of the Bruce Highway. “Without it, we found that almost everyone was travelling over the speed limit,” he says.

Under a posted speed limit of 40 kilometres per hour, the mean speeds of vehicles driving through the workzone without the pilot vehicle was 52 kilometres per hour, but it dropped to 46 kilometres per hour when the pilot vehicle was present. Dr. Debnath says the pilot vehicles reduced these average speeds within the work area, but not at a downstream location.

The third safety measure trialled was the use of remote-controlled traffic light devices. The study team employed three variations of traffic light systems on another roadwork zone near Dalby, Queensland. One device used red and amber lights, another used a red light with an amber arrow and the third use a robotic stop/slow sign.

The notable benefit of using such devices is that the traffic controller can operate the system remotely – off the road and out of the danger zone.

Dr. Debnath notes that there was some confusion on the drivers’ front as to what the solid amber light meant. In the conventional traffic light system, the amber light signals ‘prepare to stop’, but this study used the amber light to signal ‘slow’ with an additional sign SLOW ON AMBER displayed below the traffic lights. However, without the traditional green light for ‘go’, he says this wasn’t all that clear for many drivers. The robotic stop/slow sign also resulted in driver confusion due to the absence of a roadworker, who would traditionally control the sign manually.

The red light and amber arrow system produced consistent effects on reducing vehicle speed as drivers approached the work area and showed the potential to remove the traffic controllers away from the road.

The notable confusion around new technology, however, is one major aspect in the study’s findings that Dr. Debnath says needs to be addressed. “With any new safety device that we want to implement, driver education and public campaign is needed,” he says.

Off the back of the survey results and the study’s findings, Dr. Debnath suggests that there are a variety of ways to progress in the realm of roadwork safety, or at least make the next steps count.

Given the fact that the safety treatments trialled are all approved for use on Australian roads, Dr. Debnath asserts that harmonisation of safety technology across the country may be a fruitful next step.

He also states that Australia needs to look at the technology used internationally. Dr. Debnath highlights some of the latest roadwork safety technology being used in the US. “They’re using technology such as remote controlled traffic lights complete with an additional boom gate – that’s one advanced prototype of the device we trialled here.”

The US roads sector is also looking into concepts such as intrusion alarms – sensors attached to cones, bollards and other worksite equipment – that notify workers of where an incident has occurred within the work zone.

“There are a lot of new technologies coming through and we need to start looking at them,” says Dr. Debnath.

“The next step is trialling them in Australian roadwork sites, see how Australian drivers react to them, and then assess whether these technologies should be implemented in the Australian context.

“From CARRS-Q, what we plan to do is use this project as the foundation to learn more about worksite safety and its context, and come up with some solutions best to remedy the situation.”

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