Might is right, despite crash ratings

BUYING a safe small car still leaves you at a very high risk of death in a collision with a big soft-roader, research from the US shows.

A research paper published by the University of Buffalo and authored by Erie County Medical Center professor of emergency medicine Dietrich Jehle says small-car owners are 10 times as likely to die in a head-on collision with an SUV if the bigger vehicle had a better safety rating than the small car.

Even if the small car has a better crash rating than the SUV, Prof Jehle concluded that the small car’s occupants were still four times as likely to die in a head-on crash.

“When two vehicles are involved in a crash, the overwhelming majority of fatalities occur in the smaller and lighter of the two vehicles,” says Dietrich Jehle, MD, UB professor of emergency medicine at Erie County Medical Center and first author.

He said this was because in a front-on collision, SUVs tended to “ride over shorter passenger vehicles, due to bumper mismatch, crushing the occupant of the passenger car”.

“But even when the two vehicles are of similar weights, outcomes are still better in the SUVs,” he says.

Prof Jehle said the strong crash safety ratings of small cars “may provide a false degree of confidence” to buyers.

“Consumers should take into consideration the increased safety of SUVs in head-on crashes with passenger vehicles when purchasing a car,” he said.

The study was based on the assessment of 83,521 vehicles involved in head-on crashes.

Australasian New Car Assessment Program (ANCAP) communications manager Rhianne Robson said testing for crash performance ratings was “conducted to provide consumers with comparative safety ratings across vehicles of similar mass, within the same vehicle category”.

“It is not appropriate to compare ANCAP safety ratings across vehicle categories, particularly if there is a large weight difference,” Ms Robson said.

“The reason is that in car-to-car crashes, the heavier vehicle has a theoretical advantage (due to the physics of the crash).

“Similarly, a higher ride height might be an advantage in a car-to-car crash. However in single vehicle crashes, such as with solid fixed objects like a tree or a pole, the weight might no longer be an advantage.

“Approximately 45 per cent of all fatal crashes involve a single vehicle.”Ms Robson said some smaller cars performed remarkably well in crashes with larger vehicles as they had very strong passenger compartments and advanced occupant restraint systems that made up for the mass disadvantage.

She said crashes happened in “a range of circumstances”, with ANCAP tests covering crashes where the risk of death or serious injury was the greatest.

“The University of Buffalo report is interesting but there are many other reports which illustrate that there is no definite view about how well small cars might perform against larger cars,” Ms Robson said.

“For example, given the age of the Australian fleet you are most likely safer in a modern small car compared to an old large car.”