Her family didn't know until this year that a defect with the
"We thought it was air bag-related, but we had no information to connect the dots,"
Weaver's family and others are part of a deep investigation into defective air bag systems and a massive recall involving 17 million older model vehicles and 10 automakers, including the Detroit Three.
But after months of testing by air bag maker
"This may not be something as simple as just one root cause," said former National Highway Traffic Safety Administration Administrator
It's a painful, open question for families of victims and a big concern for anyone driving a car or shopping for a new or used vehicle.
It's also unclear whether the replacement air bag systems are safer. That's because they use the same volatile chemical to inflate the bags, ammonium nitrate, that some suspect is at the heart of the problem. Other air bag manufacturers use less-volatile chemicals, but they cost more.
Chemicals are key to how an air bag operates. When the car's sensors detect an imminent crash, the inflator -- like a rocket booster -- sets off a chemical charge to produce nitrogen gas that fills the air bag like a pillow. After the crash, vents in the pillow allow for a slow deflation.
NHTSA Deputy Administrator
Still, no one has been willing to pin the problem on the chemical, or on any other specific cause, yet.
All modern vehicles have air bags and
The 10 automakers that have recalled vehicles with
They also hired Kelly, the former NHTSA administrator, as a consultant to manage and coordinate the testing. Kelly told the
"We didn't jump in with any preconceived notions," Kelly said. "We very clearly took a position that we were going to look at everything. We are going to test all of the preliminary conclusions that have been made so far."
Looking at multiple past investigations could yield many different reasons for the defect, he said.
The automakers involved are having regular conversations with NHTSA and have agreed to provide the safety agency with the data they collect, said NHTSA spokesman
NHTSA and the automakers also continue to encourage consumers to take their recalled cars to dealers to be fixed.
Despite the high-profile names and resources devoted to tracking down the source of the defect, the cause remains elusive.
To be sure, air bags save far more lives than those killed or injured by them. And they reduce the severity of injuries sustained in most crashes. But the realization that defective air bags could be killing some drivers and passengers has exposed an ironic reality that some systems are proving too complex for their creators and regulators to fully understand.
The complexity of air bag systems -- which rely on a network of algorithms, sensors and chemically complex propellants -- has confounded automakers, suppliers and federal regulators for years. Air bags are unlike most other parts and components in a car. They go unused for years but must deploy flawlessly in a fraction of a second when an accident occurs.
NHTSA has been unhappy with
And on Tuesday, NHTSA is to hold a workshop in
Weaver's family wants answers.
The young woman, 24, was in
Her boyfriend was driving the car, but the family doesn't blame him or hold him responsible.
And it didn't occur to anyone at the time that the car's air bag was to blame.
The 2004 Impreza wasn't part of a
Even so, that's when it dawned on Kopf, Weaver's older sister, that an air bag defect might be responsible.
The family met with the Beattie Law Firm in
In the mid-1990s,
"The other consideration was the performance of the chemical itself," he said, because with tetrazole there's an eruption of solid particles, as well as gases.
Ammonium nitrate doesn't emit much other than carbon dioxide gas. But it is also very volatile and used to implode abandoned buildings.
The risk is higher in regions where hot humid weather lasts from late spring through early fall: That's because ammonium nitrate tends to become unstable when cars are exposed to temperatures about 100 degrees, then cool to 65 or 70 degrees with air-conditioning before heating up again when parked in the sunlight.
Guanidine nitrate is "easier to handle" and "would improve the safety of manufacture and transport and lessen the environmental concerns of disposal," according to a patent application filed in 1994 by
But guanidine nitrate is more expensive.
Years to fix
Fixing all the vehicles with
Of 17 million vehicles under recall for at least one faulty air bag, about 2 million were repaired by the end of 2014, according to NHTSA. First-quarter reports with updated figures are due at the end of the month.
Despite the political fallout, nobody disputes air bags have worked properly more often than not.
In 2012 alone, NHTSA estimates that 2,213 lives were saved by front air bags. Between 1986 and 2012, front air bags are estimated to have saved almost 37,000 lives.
"It's something we take for granted, because we have been doing it for so long," said
The technology has come a long way since
Even then, there were challenges. NHTSA estimates from 1990-2008 more than 290 deaths were caused by front air bags going off in low-speed crashes. About 90% of the deaths occurred in vehicles manufactured before 1998, which had first-generation bags that inflated with too much force.
Women and young children were especially susceptible to injuries. Revised regulations and technological advances have made them safer.
Industry leaders including
"All of us in the industry are constantly fine-tuning the systems," said
Crash sensors in today's vehicles are "contact-based," Boran said. The new frontier is radar-based or camera-based sensors that anticipate an accident, giving the air bag system more time to deploy.
"Is that going to bring us to perfection? Unfortunately not," Boran said. "But these types of sensors can certainly enhance the system."
A history of air bags
1984: Mercedes-Benz begins to offer an air bag safety system as an option in the U.S. and
1990: Ford becomes the first automaker to make driver and passenger air bags standard on all models.
1998-99: Front driver and passenger air bags become standard equipment in all passenger model year 1998 cars and in all 1999 model year SUVs, pickups and vans.
2012: Ford introduces an inflatable safety belt for back seat passengers aimed at reducing rear-seat injuries. In a crash, the seat belt inflates, distributing crash forces across the torso and chest. Toyota's Scion brand introduces a rear window curtain air bag as a standard feature on the Scion iQ.
What are air bags and how do they work?
--Air bags are cushions built into a vehicle that protect occupants from hitting the vehicle interior or objects outside the vehicle, such as other vehicles or trees, during a collision.
--The instant a crash begins, sensors start to measure impact severity. If the crash is severe enough, the sensors signal inflators to fill the bags with gas in a fraction of a second.
--Front air bags deploy in crashes that equal the force of a car hitting a wall at 10-15 m.p.h.
--The speed of a deploying air bag can reach up to 200 m.p.h. Air bags are designed to offer the most protection when occupants are buckled up and sitting properly in the seat.
NHTSA meeting Tuesday
(c)2015 the Detroit Free Press
Visit the Detroit Free Press at www.freep.com
Distributed by Tribune Content Agency, LLC.