Confusion over what is considered a “safe following distance” has led Queensland researchers to call for a standardized definition to prevent tailgating.

Queensland University of Technology (QUT)’s Centre for Accident Research & Road Safety – Queensland (CARRS-Q) has released the results of a study which found 50% of drivers tailgate, and that drivers are confused about the size of the gap they should leave between them and the vehicle in front.

“This study, for the first time conclusively linked tailgating with rear-end crashes, but we also identified confusion among drivers over what is deemed to be a safe following distance,” said Dr Sebastien Demmel, CARRS-Q. “Despite drivers perceiving they are following at a safe distance, our on-road data showed that in reality most don’t leave the recommended two to three second gap. At some locations 55% of drivers were found to leave less than a two second gap between them and the vehicle in front, and 44% less than a one second.”

The study, presented at the recent 2017 Australasian Road Safety Conference in Perth, used Queensland state road crash data to pinpoint rear-end crash blackspots, and on-road monitoring to determine driving conditions, speed and tailgating. More than 500 drivers were also surveyed on their perceptions of driving behaviour and their knowledge of safe following distances.

Dr Demmel said most drivers reported keeping the same gap regardless of traffic flow or road type.

“One of the reasons drivers may not be leaving a safe following distance is because 60% used metres or another unit of distance rather than the recommended seconds to assess a safe following distance,” he said. “When using metres compared to seconds, the gap between vehicles changes, however most drivers said they kept the same gap length regardless of traffic flow or travelling speed.”

According to Dr Demmel, rear-end collisions account for around one in five crashes on Queensland roads.