Turning off the air bags

General Motors is claiming to be the first automaker to implement a passenger-side frontal air bag sensing system that will automatically turn off the air bag under certain conditions.

The passenger sensing system is designed to prevent the passenger frontal air bag from deploying when a rear-facing infant seat, a forward-facing child restraint or a booster seat is detected. It also is designed to turn off the air bag if no occupant is detected.

GM’s passenger sensing system is standard on most 2003 full-size pickups and sport-utility vehicles, including the Chevrolet Silverado and GMC Sierra pickups (except commercial models or chassis-cabs) and Chevrolet Suburban, Tahoeand Avalanche; GMC Yukon XL, Yukon and Denali; and Cadillac Escalade and Escalade EXT. The company says that the system meets newly modified US Federal advanced air bag specifications one year early.

GM’s passenger sensing system uses sensors in the seat to collect information that helps the vehicle’s air bag computer determine whether the right front passenger air bag should inflate in a frontal crash. The sensors gather information on the occupant’s weight and the type of pressure placed on the seat to help determine whether there may be a smaller occupant present who may be at greater risk of injury from a deploying air bag.

The system also uses a sensor in the passenger-side seat belt to measure how much tension is exerted by the seat belt when it is being cinched down, another means of determining what may be on the seat.

An important feature of this safety system is an indicator on the rear-view mirror that alerts vehicle occupants to the status of the system at all times. If the light reads ‘Passenger Air Bag ON,’ the air bag is programmed to deploy in a frontal crash of sufficient severity. If it reads ‘Passenger Air Bag OFF,’ the system has turned off the air bag because it determined either that there is no occupant on the front passenger seat, or that a rear-facing infant seat, a forward-facing child restraint, a booster seat or a smaller person, such as a child who has outgrown child restraints, is present.

GM engineers subjected the passenger sensing system to more than 3,000 tests that included various child seats, test dummies and human volunteers, according to Bob Lange, GM executive director of vehicle safety.

Despite this new technology, Lange urged families to continue transporting their children in the rear seat. Crash statistics show that children are safer if they are restrained in the rear.

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