A record $84 million was paid out last year for injuries from rear-end crashes - further evidence that inattention and tailgating are growing blights on WA roads.
The Insurance Commission of WA has reported it received 3500 third-party personal injury claims in 2012-13 - and 40 per cent were for accidents with the cause cited as "ran into rear".
And the average claim for each rear-end crash was $59,000, up from $49,000 in 2011-12.
Commission deputy chief executive Lew Watts said the $84 million was just for personal injury claims and did not include vehicle repair costs.
"So the total cost of these crashes is much higher," he said. "Given the cost of these personal injury insurance claim payments is paid from premiums collected from motorists each year, reducing the number and size of insurance claims will reduce pressure on premium rates."
Road Safety Council chairman Murray Lampard said the insurance data was yet another reason road users needed to recognise that driver and rider attention was vital in reducing serious injuries and fatalities on WA roads.
"Traditionally, these crashes get called fender benders but the term underplays the serious and frequent personal injuries that arise from following-vehicle collisions and the dollar cost to our community," Mr Lampard said.
RAC general manager of corporate affairs Will Golsby said the impact of inattention was now comparable to the number of deaths and serious injuries from speed and drink-driving.
"Nationally, it is estimated that inattention was a factor in 46 per cent of fatal crashes in 2012," he said. "And in the five years from 2009 to 2013, 76 per cent of crashes on the Kwinana Freeway, between the Mitchell Freeway and Canning Bridge, were a result of rear-end collisions.
"Rear-end crashes endanger the safety of motorists, contribute to road trauma, and disrupt the efficient flow of traffic."
In its latest mobility bulletin released last week, the RAC said tailgating was a major problem on WA roads that contributed to congestion, irritated and distracted other drivers and, more seriously, increased the chances of rear-end crashes.
Mr Golsby said the RAC would like to see a low-cost trial of carriageway markings to help drivers accurately judge and maintain a safe distance between them and the vehicle in front.