Safety Test Ignores Real-Life Conditions

Automakers argue decades-old test is fair and easy to repeat

By Jeff Plungis, and Bill Vlasic / The Detroit News

 

WASHINGTON – In an age of computer-aided design, high-tech crash tests and multimillion-dollar dummies, the test the federal government uses to assess roof strength is a relic of an earlier era.

The newly created National Highway Traffic Safety Administration finalized the rule, known as Federal Motor Vehicle Safety Standard 216, on Dec. 8, 1971. It took effect in 1973 and has not been changed significantly since.

In stark contrast to modern government tests that ensure a minimum level of protection in frontal- or side-impact collisions, the roof-strength test involves no crashes, no test dummies and no measurement of crash forces inside the vehicle’s cabin.

"The (roof) test really does not reflect what happens in the real world," Dr. Ricardo Martinez, who headed the NHTSA from 1994-99, told The Detroit News. “It comes nowhere near the forces experienced in a real rollover crash."

Under rule 216, a 30-inch by 72-inch steel plate is pressed against one side of a vehicle roof with a force equal to 1.5 times the weight of the car or truck.

The plate is angled at 25 degrees on one axis and 5 degrees in another in an attempt to replicate a rollover crash angle. If the roof crushes less than 5 inches, the car or truck passes the test and can be sold in the United States.

In contrast to its reliance on a 33-year-old roof-strength test, NHTSA has aggressively tackled other auto safety issues. NHTSA has revised regulations that protect people in head-on collisions, producing standard driver-side and passenger air bags. The agency also came up with a tough side-impact collision test in the 1980s.

Despite growing concerns about rollovers, NHTSA only now is taking a serious look at roof strength. The agency hopes to finalize a new regulation by 2006.

Rating the test

Critics of 216 say the test fails in several ways to emulate real-world rollover accidents. They contend:

* The force in real-world rollovers easily exceeds the 1.5 strength-to-weight ratio used in the test.

* Accident data show the damage in fatal crashes occurs at the steel A-pillars, which frame the front windshield. The government test spreads force across the whole side of the roof.

* The test fails to simulate the likely additional damage done when the roof hits the ground for a second time, after the first impact has weakened the roof structure.

* In real-world rollovers, side and back windows typically shatter and the windshield cracks, weakening the roof structure. NHTSA conducts the 216 test with the glass in place.

* The largest SUVs and trucks, those weighing 6,000 pounds or more, aren’t subject to any roof strength regulations.

Critics say weak roofs are especially dangerous for popular SUVs and pickups, which experience fatal rollover crashes twice as frequently as cars and vans due to their top-heavy designs.

"Rollover is not a figment of anybody’s imagination,” said R. David Pittle, senior vice president for technical policy and advocacy at Consumers Union, which publishes Consumer Reports magazine. “It’s a very real problem with these vehicles. It’s surprising how that gets discounted.”

Automakers say the government and safety advocates have failed to make a convincing argument, backed by a thorough analysis of real-world crashes, that stronger roofs would save lives. They contend the current test is fair and “repeatable.”

A repeatable test results in the same kind of damage every time it is conducted, allowing engineers to measure whether subsequent design changes result in improvements. By law, NHTSA tests must be repeatable.

In formal comments filed with the government in December 2001, General Motors Corp., Ford Motor Co., and other auto companies argued that that there is no other test more reflective of real-world forces that can be consistently repeated.

Some safety officials outside the United States have challenged the contention that 216 is the best available roof-strength test.

An official evaluation of safety standard 216 commissioned by the Australian government in 1995 concluded roof strength at the level set by the U.S. standard would yield practically no benefit.

The study also found improved roof strength and better seat restraints would reduce rollover injuries.

More than three decades ago, before 216 was enacted, the government devised a tougher roof-strength test. on Jan. 6, 1971, NHTSA’s predecessor, the National Highway Safety Bureau, proposed a test that would have used a 12-inch-square plate to apply force to a vehicle’s A-pillars — first on one side then the other. The A-pillars, which frame the windshield, often bear the brunt of a rollover crash.

On Jan. 11 that year, GM began a testing program to determine how its vehicles would hold up under the government’s proposal, according to company documents used as exhibits in court cases. Of six models tested in January, only one could meet the government’s proposed test. In April 1971, GM weighed in with public comments on the government’s proposal. The company suggested a different roof test — one its vehicles could pass. A wider, longer steel plate was suggested. GM also recommended a flatter test angle. Both changes spread the force across the entire side of the vehicle instead of concentrating it at the A-pillar, making it easier to pass.

GM also said it was pointless to test both sides of the roof, because the roof structure was the same on either side. This discounts the fact a vehicle’s first contact with the ground during a rollover often shatters windows and weakens roof integrity, making the second or trailing impact more dangerous.

At the same time, the auto industry’s main lobbying group in 1971, the Automobile Manufacturers Association, was challenging the government’s assertion that stronger roofs would save lives in rollover crashes.

Weaker test approved

In December 1971, the government adopted the less stringent test proposed by GM and the AMA — the rule 216 that still applies today.

Internal company documents that have surfaced in recent lawsuits, however, show that automakers’ public statement in 1971 didn’t always match internal discussions.

In an April 1966 meeting of its general technical committee, GM engineers outlined safety goals for the 1969 model year. one goal was to protect an occupant during a 70-mph rollover. The rollover would be simulated by a 45-degree, 5 1/2-foot drop test.

The auto companies did not share information about their internal goals or testing programs with the government.

While NHTSA agreed to the weaker 216 roof-strength test, it said the test would be used temporarily while it ironed out problems with a test that would better simulate real-world rollovers.

NHTSA eventually hoped to employ a dolly test, which consists of loading a vehicle on a slanted cart, accelerating it to 30 mph, and then bringing it to a sudden stop to trip the vehicle into a rollover.

From 1971 until today, automakers have had the option of conducting the dolly test instead of safety standard 216 to meet government requirements. But no automakers use the option. Both automakers and safety advocates say the dolly test is difficult to repeat. NHTSA conducted research on improvements off and on during the 1970s and 1990s, but it could never devise a test that was also repeatable.

In Europe, some manufacturers use dolly tests as part of their internal efforts to improve safety. Volvo and Mercedes-Benz both use dolly tests and another dynamic test, known as a drop test, in addition to the government’s 216 roof-crush test. Toyota, Volkswagen and BMW also conduct dolly tests, according to company safety brochures.

Detroit’s automakers conduct the tests only in connection with litigation.

Steve Forrest is senior engineer with Safety Analysis and Forensic Engineering, an independent research firm in Goleta, Calif. Forrest is often hired by lawyers of crash victims to estimate the roof strength of specific vehicles. He was trained at General Motors Institute in Flint.

Forrest uses a drop test, developed by the Society of Automotive Engineers in 1967. A vehicle is suspended upside-down with steel cables at a specified angle. The cables are released, and the vehicle crashes onto its roof.

Forrest said he can replicate the damage done to a roof by standard 216 with a 3-inch drop. To replicate the damage done in real-world crashes, he usually has to drop the vehicles from between 12 inches and 18 inches.

In one test, a medium-size SUV suspended from 18 inches suffered 14 inches of roof crush. An identical model, strengthened with structural foam and steel rods, crushes less than 3 inches. Forrest estimates the materials would cost an automaker as little as $20 per unit in mass production.

The test results, Forrest says, show rule 216 is dangerously inadequate. “It’s like trying to predict occupant protection in a 30 mph crash by doing a 5-mph bumper test,” he said, “without any crash-test dummies.”

You can reach Jeff Plungis at (202) 906-8204 or [email protected].