The University’s Centre for Accident Research and Road Safety (CARRS-Q) conducted the study, finding a 20 percent reduction in speed - from an average of 53km/h down to 42 - when drivers could see workers on the job.
More than 400 people took part in the survey, and were asked to estimate their speed during a range of different roadwork site scenarios.
CARRS-Q’s Dr Ross Blackman said the credibility of speed limits was weakened in the eyes of drivers when they could see no present danger to workers.
"It's seen as ‘crying wolf’ - if people are asked to slow down at roadwork sites but find there is no roadwork being undertaken they become de-sensitised to the signage and ignore speed limits," Dr Blackman said.
"In 2013, our research found that at three Queensland rural roadwork sites, the majority of vehicles observed exceeded the posted speed limits by at least 5km/h."
Dr Blackman said collision statistics around roadwork sites measured highly for both frequency and severity, as drivers failed to slow sufficiently and were often not paying attention.
The study’s findings reinforced moves by the Queensland Government to review speed limit signage around roadwork sites, according to Dr Blackman, who cautioned that hazards may remain outside of work hours.
"There are no simple solutions, but multiple measures used in combination may be most effective. With technology, for example, variable speed limit signs can be easily changed without the need for workers to physically move or replace traditional static signage.” Dr Blackman said.
The study found drivers responded well to the ‘display and shame’ signs that showed how fast they were travelling through a roadwork zone, but visible workers had the greatest impact on a driver’s chosen speed.
Results of the study were presented this week at Queensland’s Occupational Safety in Transport Conference (OSIT) on the Gold Coast.