The driver’s face is boiling red, their window starts to slide down. The rider—just a metre away—prepares for a spray, or a swerve, and their fight or flight reflex prepares to kick in.
It is a scenario that just about every bike rider would have encountered.
The unpleasant memory stays with us for years, perhaps making us more alert, but also dimming our faith in human nature.
The key questions though are: Is an angry driver a bad driver? Does road rage aggression towards others on the road translate into increased possibility of harm?
Thanks to new research from the University of Warwick in the UK, the answer is yes: aggressive drivers drive faster (5.32 km/h, and take more risks, e.g., changing lanes without indicating).
The report, The relationship between aggressive driving and driver performance: A systematic review with meta-analysis, looked at 34 studies and compared aggressive drivers to a control group.
The researchers were interested in discovering how best to identify, describe and measure aggression on the road.
Aggressive driving was defined as “any driving behaviour that intentionally (whether fuelled by anger or frustration or as a calculated means to an end) endangers others psychologically, physically, or both”.
Previous research established that human factors contributed to 90–95% of road crashes, while road and environment contributed to 28–35% of crashes, and vehicle issues 8–10% of crashes. And sometimes a combination of these elements is at play.
The review identified that angry drivers had wider impacts than just increased safety risks.
They also had a negative influence on energy consumption and emissions, unstable traffic flow, and induced aggressive driving behaviour in others.
The study also raised the issue of how the algorithms that drive autonomous vehicles could be programmed to deal with the unpredictability of road rage.
It concluded that while speed was an accurate and reliable measure of the level of aggression in drivers, there were other behavioural factors such as frequent acceleration/deceleration that needed better understanding.
This research was published in Accident Analysis & Prevention.