Building a Safer Airbag

The 2004s are the first vehicles required by the National Highway Traffic Safety Administration to begin phasing in new, smarter, gentler airbags designed to minimize the risk of injury and death to front-seat riders during a crash.

While some automakers already have been adding the so-called advanced airbags in recent years to their cars, the 2004 model year marks the start of an industry-wide ramp-up of the airbags required by NHTSA.

Indeed, by the 2007 model year, all passenger vehicles are mandated to have the advanced bags that are expected to be safer for children and small-statured adults such as petite women.

Technology Comes to the Fore
Note there is no one single kind of advanced airbag.

NHTSA gave automakers leeway to decide for themselves what technology they wanted to use to meet the NHTSA regulation.

Primarily, the automaker's efforts focus on two alternatives:

• Turning off the frontal airbag entirely for the front passenger if a weight sensor or other type of sensor detects a child or child-sized person is in the outboard front seat.
• Deploying the frontal airbag in a way that's less likely to cause harm to an occupant who's sitting out of position in a seat. An example is to install dual-stage inflators in the front-passenger frontal airbag that provide for a lower-level airbag deployment when needed.

Reasons for the New Airbags
Frontal airbags began appearing in a small number of new cars in the 1970s and by the mid-1980s were a growing feature. They were not required by NHTSA until the 1997 model year, following years of debate.

NHTSA noted frontal airbags' life-saving potential, saying that the lives of more than 5,300 people had been saved by airbags in the 14 years between 1986 and March 2000. The federal agency estimated at least 2,400 people annually would be saved in car crashes once all vehicles on the road had frontal airbags.

The real-world data also showed a troubling problem. More than 150 people, most of them children, were killed by airbags, often in low-speed crashes, according to NHTSA statistics.

The reason: Frontal airbags had been designed to meet government requirements to provide protection for a 50th-percentile male who is unbelted in a car crash. Therefore, automakers had to make sure their airbags deployed quickly enough and with enough pressure to give the requisite protection for a sizable male body not held in its seat by a safety belt.

What researchers discovered was this kind of airbag could be lethal to smaller-sized people, including children, small women and the elderly in some circumstances, particularly if they are sitting too close to the airbag.

More Tests Now
Not wanting to repeat the problem with the original airbag mandate, NHTSA requires a battery of tests by the automakers for the advanced airbags. And the tests are done using a "family" of crash test dummies representing one-, three- and six-year-old children, a small, 5th percentile female as well as the average, 50th percentile male.

NHTSA's regulation requires a test that puts child dummies in child seats that are then placed on the vehicle's outboard passenger seat, for example.

It also requires tests that place unrestrained child dummies in a variety of positions in the seat —kneeling, standing, lying down and sitting, even though the government does not encourage or condone children kneeling, standing or lying down in front of a frontal airbag.

Indeed, even with the arrival of advanced airbags, government officials continue to tell parents and caregivers that children under age 12 should ride in the back seats of vehicles, where they will be safest.

Major Gains Expected
Obviously, NHTSA officials expect the new mandate to reduce fatalities caused by airbags.

"We estimate that if advanced airbag technologies (suppression and low risk deployment) are 100 percent reliable, they could have eliminated 95 percent of the known airbag fatalities that have occurred to date in low-speed crashes." NHTSA wrote in its docket on the new mandate.

Further, the safety agency went on to explain the nature of the danger from the frontal airbags:

"The one fact that is common to all persons who died is not their height, weight, gender, or age," NHTSA wrote in its regulations docket. "Instead, it is the fact that they were very close to an airbag when it started to deploy. For some people, e.g., infants in rear-facing infant seats, this occurred because they were initially sitting very close to the airbag. For the other occupants, this typically occurred because they were not restrained by seat belts or child safety seats and moved forward during pre-crash braking."

Being close to a deploying airbag is ill advised because in order to provide the proper protection in a crash, an airbag must deploy quickly—and with sufficient force. The idea is to prevent a person from striking the steering wheel, dashboard or windshield.

In the process, anyone close to the airbag as it deploys is at risk for injury, even fatal injury. Children, in particular, face the risk of head and neck injury if they are close to a deploying airbag.

Many Advanced Airbags Already Here
Automakers haven't been waiting for the NHTSA mandate to make changes in their frontal airbags.

As word spread about the airbag fatalities, many automakers reduced the deployment pressures of the airbags in their 1998 model year vehicles.

"Comparison of the data for model year 1997 and model year 1998 vehicles shows that, on average, the pressure rise rate in model year 1998 vehicles decreased about 22 percent for the driver airbag and 14 percent for the passenger airbags," NHTSA reported.

Airbag design also has changed. "One change is the recessing of driver airbags so that the module is located farther away from the plane of the steering wheel, and thus farther from the driver," NHTSA reported. "Similarly, the airbag mounting location on the passenger side has also shown significant changes. Other features, such as cover tear patterns, tear pressure, fold patterns and the number and type of tethers, have changed in recent years, all of which may have collectively contributed to the reduced aggressiveness of airbags."

Many automakers have put advanced airbags - primarily those with dual-stage inflators—already in their vehicles, ahead of the 2004 model year requirement.

Ann Job is a writer for T&A Ink.

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