A new car crash test that found an inadequacy in some otherwise five-star crash safety performers in the United States is unlikely to be replicated by the Australian New Car Assessment Program (ANCAP).

Only three of 11 top-end cars tested by the US Insurance Institute for Highway Safety (IIHS) earned a "good" or "acceptable" rating in an overlap test in which 25 per cent of the vehicle's front strikes a solid barrier at 40mph (64km/h).

In one of the tests, the front door of a Volkswagen CC came off, and in another, a Lexus IS crumpled around the legs of the crash test dummy.

Highly rated European cars - the Mercedes C-Class, BMW 3 Series and Audi A4 - that breezed through European NCAP testing were among cars rated marginal or poor in the IIHS test that is designed to replicate a car crashing into an object such as a parked car, tree or pole, striking only a portion of the front of the vehicle, around the headlight.


ANCAP chairman Lauchlan McIntosh told the Australian website GoAuto that a more important priority for his organisation was the adoption of new safety assist anti-collision technology to avoid such crashes.

"I think we have to decide where we put most of our effort, and right now these new collision avoidance technologies are more important than this particular test," he said.

McIntosh said another priority for ANCAP was to get some vehicle manufacturers to comply with current crash tests, including the standard offset deformable barrier test used around the world by other new car assessment programmes.

"Our view is that we still have some problems with cars in the offset tests, so we still have quite a lot of work to do in that space," he said.

"We will watch what happens with the (US) tests that they are doing."

The IIHS says American research shows such crashes account for almost a quarter of frontal crashes involving serious or fatal injury to front-seat occupants. But McIntosh said it was unclear if evidence existed to show that such crashes were a major cause of road trauma in Australia.

The US test would complement the NCAP tests, maintaining the pressure on manufacturers to improve their vehicles.

He said one IIHS crash test on a Ford Lincoln MKZ revealed a particular problem in which the dummy's head missed the airbags deployed from the steering wheel and side roof rail.

"The fact that the head missed the airbag is a concern," he said, and research into the frequency of that problem in Australia was needed.

"We equally have got to get an idea of what sort of numbers of crashes happen in that sort of way."

In the test, the Lincoln jerked sideways on impact, throwing the dummy's head towards the A pillar.

At the same time, the steering wheel moved sideways towards the middle of the car, creating a gap in the airbag cover, and the curtain airbag was too short to cover the A pillar.

The IIHS said most of the cars tested performed poorly because of a structural weakness in their front extremities.

IIHS president Adrian Lund highlighted the structural design of the best-performing car in the tests - the Volvo S60 - which has a rail running from the base of the A pillar towards the front of the car.

Volvo says the deformable steel rail is designed to cope with such impacts.

As well, the S60 has a crossmember running below the instrument panel to further guard against deformation.

The Volvo had only a few centimetres of intrusion into the cabin space.

"The Lexus IS had 10 times as much occupant compartment intrusion as the Volvo," IIHS said.

"The car's A-pillar bent and the footwell collapsed as the front left wheel and tyre were forced rearward."

IIHS said that like the Lexus IS, the Mercedes-Benz C-Class also trapped the dummy's feet.

The Passat-based VW CC took the dubious honour of being the first car tested by the IIHS to lose its door in the test, sheared off at the hinges.

The "after" photo of the CC not only shows the missing door, but also how the main structural chassis rail was largely undamaged by the crash, in which the crash barrier sheared off the front mudguard and front wheel before taking off the door hinges.

Under the standard offset barrier test, which hits 40 per cent of the front of the car, that chassis rail would have taken much of the impact.

Apart from the Volvo S60, the only other test car to manage a "good" rating was the Honda Accord-based Acura TL. The Infiniti G received an "acceptable" rating.

Cars rated "poor" were the Acura TSX, the BMW 3 Series, the Lincoln MKZ, the Volkswagen CC, the Mercedes C-Class, the Lexus IS250/350, the Audi A4 and the Lexus ES350.