Head Impact Isn’t Necessary in Fatal Crashes

About the Project

This is the result of six months of research and reporting by Tribune Auto Race Writer Ed Hinton, with help from staffers at other Tribune papers, among them Darin Esper of the Los Angeles Times. It sheds new light on the decline of traditional fatalism among race drivers and the need for more research and action to prevent the violent deaths the sport has come to accept. In this two-part series, Hinton explores new head-securing apparatus, softer walls and the wide divergence of opinion on some of these safety issues among the leading racing groups: CART, IRL, Formula One and NASCAR.

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At least 12 of the 15 drivers killed in major auto racing since 1991 died of injuries caused by violent motion of their inadequately restrained heads in crashes.

At least nine, and four of the last five, suffered a syndrome called basal skull fracture.

At least eight died specifically of it: NASCAR’s J.D. McDuffie in 1991, the U.S. Auto Club’s Jovy Marcello and NASCAR’s Clifford Allison in ‘92, Formula One’s Roland Ratzenberger in ‘94, the Indy Racing League’s Scott Brayton in ‘96, CART’s Gonzalo Rodriguez in ’99 and NASCAR’s Adam Petty and Kenny Irwin in 2000.

The ninth, CART’s Greg Moore in ‘99, probably would have died of basal skull fracture had he not suffered other lethal injuries to his head and neck.

Yet basal skull fractures and related intense, whiplash-like injuries to race drivers remain widely misunderstood. Many physicians, including some pathologists, still believe basal skull fracture must involve impact of the head against something solid, such as a roll bar.

Indeed, in the New Hampshire state medical examiner’s death certificates on Petty and Irwin, the descriptions of the causes of both deaths began, “Blunt impact of the head . . . “

“That’s a classic view of it,” says John Melvin, a Detroit biomechanical engineer and one of the world’s leading authorities on racing injuries.

But, he adds, “The head doesn’t have to hit anything. We’re very convinced that this basal skull fracture [the type race drivers suffer] occurs very early [during the accident], due to the violent whipping motion of the head, before the head can hit anything.”

Melvin’s research with computerized crash dummies in racing simulations began in 1992. But he has studied basal skull fracture for nearly 30 years--first as a professor at the University of Michigan for the federal Occupational Health and Safety Administration (OSHA), then for 13 years at General Motors, and now at Wayne State University’s Detroit center for the study of racing injuries.

Here is a layman’s synopsis of what occurs, based on the studies of Melvin and Robert Hubbard, a professor of biomechanical engineering at Michigan State. Hubbard, who has taught in MSU’s engineering and medical schools, has developed a head-restraint device--the HANS--scientifically proven to prevent basal skull fracture and related head-whip injuries.

When a car crashes, usually against an immovable concrete retaining wall, the “rapid deceleration”--i.e., the sudden stop--creates surges of energy, many times the force of gravity, called “G-spikes.”

Inertia, which is the physical tendency of mass to continue in motion at a sustained rate, tries to keep the human body moving forward inside the car. But the driver’s safety harness--a system of lap and shoulder belts--stops the pelvis first, then the torso. That leaves the head in motion--and in violent velocity relative to the car.

“The neck is now acting as the restraint, or the tether, for the head,” Melvin says. And when the head reaches the end of its tether but strains to continue moving, the fatal damage occurs “right then and there,” Melvin says.

The forces are trying to pull everything in the head and neck straight through the top of the skull. But the top is strong enough that when, literally, something has to give, the base--the weakest part of the skull--usually cracks. If it doesn’t, then the neck usually breaks and/or severe brain stem stretching occurs.

Basal skull fracture is “a structural failure of the base of the skull,” Melvin says. “In and of itself, [it] shouldn’t matter much from the standpoint of threat to life.”

But at the base of the skull, major blood vessels are grouped near the hole where the spinal cord begins to extend down from the brain stem.

“The fracturing process itself, that crack going through the bone, can cause the blood vessels to rupture,” Melvin says.

So drivers bleed to death, often within seconds.

“It’s not a brain injury at all,” Melvin says.

Many pathologists still think the head recoils violently, but Melvin’s studies show it doesn’t. And even if it did, it wouldn’t matter. After the instant of greatest hyper-extension of the head, and the accompanying whipping motion, the damage has been done.

Severity of the injury varies. One driver, NASCAR’s Ernie Irvan, survived basal skull fracture in a 1994 crash. Irvan, who remembers nothing of the crash, has long considered his survival a miracle. But Melvin sees scientific reasons.

“In Ernie’s case, luckily, the cuts to his arteries weren’t as bad, and so he didn’t bleed to death immediately,” Melvin says. “I suspect Kenny Irwin did.”

In the worst extreme, Rodriguez “bled out before [his car] even hit the ground,” says Stephen Olvey, CART’s medical director, who was at the crash site. “Most of his blood volume was on the wall and the sign [over which the car flipped after impact].”

Melvin offers Irvan as proof that basal skull fracture doesn’t necessarily include brain injury “because Ernie returned to be a functional race driver,” even winning, before he decided to retire in 1999 after suffering further head injuries.

High-tech Indy and Formula One cars carry on-board computer chips that measure and record the level of G-spike the cars themselves undergo during crashes. There is not yet a precise measure for the force exerted on drivers’ bodies, but scientists believe it to be as much as 50% greater than the G-spike on the car itself.

Because NASCAR doesn’t use crash recorders on its cars, the energy level of the Petty and Irwin crashes isn’t known. The severity of G-spike that can be fatal varies with the type of car and its built-in protection. Drivers of Indy cars, which offer the most sophisticated protection against G-spikes, have survived car-wall impacts as high as 190 G. But in cars with less protection, such as in NASCAR, a 90-G impact by the car can be the threshold between life and death.

If, for example, the Petty and Irwin cars hit the concrete wall at New Hampshire International Speedway with 100-G impact, then the forces pulling on their heads could have been 150 times the force of gravity.

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The HANS device

The HANS (head and neck support) device is worn like a harness over the driver’s shoulders. Made of carbon fiber and Kevlar -- the same material used in bulletproof vests -- it is designed to prevent the whipping movement of a driver’s head during a crash.

How the HANS reduces driver injuries:

When a speeding car crashes into a concrete wall, the sudden stop puts the body through tremendous strain -- more than 100 times the force of gravity. A standard racing harness stops the driver’s body, but the head continues forward, puting deadly stress on the neck and skull.

The HANS device is strapped to the helmet to precent head movement. Harness straps run through grooves holding driver and device to seat.

With HANS: Helmet strapped to device keeps head from moving forward. Raised sides of device prevent side movement.

Wthough HANS: Head whips forward, which can lead to fatal injury. Base of skull cracks, causing blood vessels to rupture. Head snaps forward, neck may break. Harness stops body, but not head. Head jerks to the side, which can lead to fatal injury. Head snaps to the side. Neck may break.

Source: HANS

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Safety device could have prevented fatal injuries

Since 1991, 15 drivers have been killed in major league auto racing. At least 12 of them died of injuries caused by precisely what the HANS is designed to prevent -- violent head movement -- including seven of the eight drivers killed in NASCAR in that time span.

Developing the HANS

1970s: NASCAR founder Bill France Sr. draws a sketch on paper of a similar device with straps attached to a helmet.

1980: Atlanta sports car racer Jim Downing asks his brother-in-law, Robert Hubbard, a biochemical engineer, to help him develop a better restraint device for drivers.

1987: After testing by General Motors and Wayne State University, Hubbard obtains a patent on his original HANS.

1989: Downing wears the HANS during International Motor Sports Assoc. races.

1991: Hubbard and Downing offer the HANS to drivers in all types of racing, for $600 a unit. But because of its bulkiness, they find only a few takers.

1994-95: Kyle Petty wears the HANS but has to stop using it after a NASCAR rule shrinks the size of side windows, making the device impossible to fit in a race car.

1996: Mercedes-Benz safety engineer Hubert Gramling contacts Hubbard to inquire about the HANS, noticing its enormous potential.

1997: Hubbard and Mercedes-Benz enter a joint agreement to further develop the HANS to make it smaller and more practical for Formula One and Indy cars.

1999: GM safety engineer Tom Gideon and Wayne State expert John Melvin begin testing Mercedes’ refined version of the HANS on a NASCAR simulation sled. The device does what it claims - prevent head and neck injuries.

2000: Three models of the HANS -- ranging in price from $875 to $2,000 -- are offered. Although interest in the device increases among drivers, there is still no consensus. NASCAR driver Brett Bodine advocates the device and begins wearing it in Winston Cup practice and races.

CART votes to make the HANS mandatory for its oval-track races in 2001.

Formula One requires its drivers to use the HANS device in all of its races.

To date, NASCAR still does not require nor recommend the use of the HANS device.

Racing deaths since 1991

Aug. 11, 1991: NASCAR driver J.D. McDuffie. Crash site: Watkins Glen, N.Y. Cause of death: Basal skull fracture after hitting a tire barrier and guard rail.

May 15, 1992: USAC driver Jovy Marcello. Crash site: Indianapolis Motor Speedway. Cause of death: Basal skull fracture after hitting wall.

Aug. 13, 1992: NASCAR driver Clifford Allison (son of NASCAR’s Bobby Allison). Crash site: Daytona International Speedway. Cause of death: Basal skull fracture after crashing into a concrete wall during practice.

Feb. 11, 1994: NASCAR veteran Neil Bonnett. Crash site: Daytona International Speedway. Cause of death: Head injuries suffered after crashing into a wall during practice. (Previously suffered head-whip injury in 1990.)

Feb. 14, 1994: NASCAR driver Rodney Orr. Crash site: Daytona International Speedway. Cause of death: Head trauma after hitting caution-light stand.

April 30, 1994: Rookie Formula One driver Roland Ratzenberger. Crash site: Imola, Italy. Cause of death: Basal skull fracture suffered after slamming into wall.

May 1, 1994: Formula One superstar Ayrton Senna. Crash site: Imola, Italy. Cause of death: Massive head injuries after crashing into wall at almost 200 mph.

May 17, 1996: Scott Brayton, Indy Racing League. Crash site: Indianapolis Motor Speedway.Cause of death: Basal skull fracture after hitting wall in Turn 2.

July 14, 1996: CART driver Jeff Krosnoff. Crash site: Exhibition Place, Toronto. Cause of death: Head and chest injuries after his car tumbled into a fence.

March 21, 1997: NASCAR Craftsman Truck driver John Nemechek. Crash site: Homestead-Miami Speedway. Cause of death: Massive head injuries after his head struck a wall March 16.

Sept. 11, 1999: CART rookie Gonzalo Rodriguez. Crash site: Laguna Seca Raceway near Monterey. Cause of death: Basal skull fracture after his car smashed into a concrete wall. (A computer re-enactment of the crash showed the HANS would have saved his life.)

Oct. 31, 1999: CART driver Greg Moore. Crash site: California Speedway. Cause of death: Massive head injuries after his car hit a wall and slammed into the ground several times.

May 12, 2000: NASCAR driver Adam Petty. Crash site: New Hampshire International Speedway. Cause of death: Basal skull fracture after crashing into wall on Turn 3.

July 7, 2000: NASCAR driver Kenny Irwin: Crash site: New Hampshire International Speedway.Cause of death: Basal skull fracture. (Died on the same turn as Adam Petty.)

Oct. 14, 2000: NASCAR Craftsman Truck driver Rony Roper. Crash site: Texas Motor Speedway. Cause of death: Head injuries suffered after crashing into a wall the night before.