Rookie MILKA DUNO crashed hard into the wall exiting turn one during IndyCar practice for the 91st Indianapolis 500 at Indianapolis Motor Speedway on Friday. She was uninjured, but her car sustained severe damage which kept her off the track the remainder of the weekend, missing the first two days of qualifying.

The crash impacted the SAFER Barrier with a predictable response. "The SAFER Barrier is a passive system," explained KEVIN FORBES, director of engineering and construction at IMS, "It doesn't do anything - it's just there. So when there is an impact, the wall gets crushed and the car crushes - which is the what they're supposed to do. That's energy attenuation.

"The barrier moves backwards during the impact. It is designed to come apart, like the nosecone on a car. After an impact, entire sections can be removed and replaced. If the damage is less severe, the barrier can be 'taped up' like the fender of a stock car."

Duno's crash was in an 'expected' area of the track. Each corner at the Speedway has SAFER Barriers in 80 per cent of the outside geometric configuration. The barriers are also on the inside of the backstretch wall, for capturing rebounding cars.

The SAFER Barriers are found at virtually all major speedways in the United States, and also at Motegi where Indy Racing League runs each spring. The SAFER Barrier is recommended for areas where there is the likelihood of a low angle impact. For head-on impacts, tyre walls make a better barrier.

The Speedway now has a second generation - 'universal' - SAFER Barrier system, which means it can be used year-round for all kinds of racing including NASCAR, Formula One and IRL. Formerly, there was a different system of the Styrofoam blocks behind the wall - three blocks for the lighter IndyCars and five blocks for the heavier stock cars, and they had to be swapped out after each type of race at the Brickyard.

Each type of car hits the wall differently, based on how big the car and how hard the hit. The barrier has to respond accordingly. With a little amount of Styrofoam behind the wall, there is a quicker response. With more of an impact, there is a slower but stronger response.

The new second generation SAFER Barrier has tapered Styrofoam bundles rather than the square bundles formerly used. The narrower end of the cone is closest to the wall, for the lighter cars, and the larger end of the cone is at the other end, for the larger, heavier NASCAR impacts.

The new version also has a fifth tube on the exterior of the barrier, which gives strength to the area where the gearbox of a rear-ending IndyCar impacts - a la Duno's crash.

The second generation Barrier has been used since March 2005, as the result of the research done at the University of Nebraska-Lincoln Midwest Roadside Safety Facility. The original barrier was installed in 2002.