October 2004 - Accident Reconstruction Newsletter

Air Bags - Frequently Asked Questions (FAQ)

• General Questions
• Side Impact Air Bags
• Advanced Frontal Air Bags
• Air Bag ON-OFF Switches
• Air Bag Deactivation

Advanced Air Bags

What are advanced frontal air bags?
Advanced frontal air bags are designed to meet the needs of the occupant in a variety of specific crash situations. Depending on design, advanced frontal air bag systems automatically determine if and with what level of power the driver frontal air bag and the passenger frontal air bag will inflate. The appropriate level of power is based upon sensor inputs that can typically detect: 1) occupant size, 2) seat position, 3) seat belt use of the occupant, and 4) crash severity.

Why do we need advanced frontal air bags?
Advanced frontal air bag systems are designed to be even more effective than current—or "depowered"—air bags in saving lives, while at the same time reducing the potential of causing an air bag-induced serious injury or death (see Are advanced frontal air bags the same as "depowered" airbags?).

Some earlier generation air bags have been known to injure or kill adults and children who were seated too close to the driver or right front passenger air bag when it deployed. "Too close" can occur when an occupant, typically unbelted or leaning out of position, slides forward just before the crash impact (the period known as pre-crash braking) to within a few inches of or directly on top of the rapidly accelerating air bag. NHTSA estimates as of June, 2003, 231 people (144 children and 87 adults) have lost their lives in such incidents.

Advanced frontal air bags were designed primarily to minimize the risk of an air bag-related injury or death to children and small-stature adults. In crashes where a higher-powered air bag deployment would not be necessary and/or could cause injury, such as in a low-speed crash or in a crash where the occupant is leaning out of position, the system reduces the risk of an air bag injury by either: 1) shutting off (suppressing) the frontal air bag, or 2) deploying the frontal air bag with less inflation force.

I just bought a vehicle with advanced frontal air bags. Does this mean I can start putting my kids in the front seat again?
No. NHTSA continues to recommend that children 12 and under be transported in the rear seat in an appropriate child restraint system. Children are safer in the rear seat.

This applies to all children 12 and under: an infant riding in a rear-facing infant seat, a child riding in a forward-facing child restraint, an older child riding in a booster seat and children large enough to wear a safety belt.

NHTSA also recognizes that there are occasions when a parent or caregiver has no other option than to place a child other than an infant in a rear-facing child safety seat in the right front seat (for example, in a pickup truck with insufficient or no available rear seat, or when a parent is transporting more children than available rear seating positions).

In the event there is no available rear seat and parents have no other option than to place a child other than an infant in a rear-facing child safety seat in a front passenger seating position, take these steps:

• Ensure the child* is properly restrained,
• Move the seat as far back as possible,
• Make sure the child is not leaning out of position, and
• Set the air bag ON-OFF switch, if available, to the OFF position.

This applies to all children 12 and under: an infant riding in a rear-facing infant seat, a child riding in a forward-facing child restraint, an older child riding in a booster seat and children large enough to wear a safety belt.

Please keep in mind that placing a child in the front seat, no matter what the circumstances, comes with increased risk. Frontal impact crashes represent 49 percent of all vehicle crashes and result in 39 percent of all occupant fatalities (1997-2001 NASS-CDS, 2001 FARS data). Children should always ride in the back seat in an appropriate child restraint system when rear seat space is available.

*When faced with having to choose which child to place in front of an air bag in the front seat, select the child that can be relied upon to remain in a proper seating position. This may not necessarily be the oldest child, but the child who is held back (restrained) at all times.

Do all new 2004 Model Year vehicles come with advanced frontal air bags?
No. Vehicle models equipped with advanced frontal air bags will be phased into the marketplace over the next few years. Beginning September 1, 2003, 20 percent of each manufacturer's vehicles intended for sale in the United States must meet NHTSA's advanced frontal air bag requirements. The percentage will increase to 65 percent by September 1, 2004 for 2005 Model Year vehicles and to 100 percent by September 1, 2005 for 2006 Model Year vehicles. All passenger cars and light trucks produced after September 1, 2006 will have advanced frontal air bags.

The advanced air bag rule (as part of Federal Motor Vehicle Safety Standard No. 208) applies to all classes of vehicles—passenger cars and light trucks, such as pickups, SUVs and vans—that have a gross vehicle weight rating (GVWR) of 8,500 pounds or less and an unloaded vehicle weight of 5,500 pounds or less. The GVWR is the weight of the empty vehicle plus the maximum weight of cargo and passengers that can be safely loaded in the vehicle, as specified by the manufacturer.

How do I know if my vehicle has advanced frontal air bags?
There are several ways to tell:

• Vehicles with advanced frontal air bags are required to have warning labels with the phrase "EVEN WITH ADVANCED AIR BAGS" on the sun visors for both the driver and passenger seating positions.
• Vehicles with advanced frontal air bags that are designed to suppress the air bags (not allow them to deploy) are also required to have an indicator light with the phrase "PASSENGER AIR BAG OFF" or "PASS AIR BAG OFF". When illuminated, the purpose of this indicator light is to inform you that the passenger frontal air bag has been automatically turned off (suppressed) by the advanced frontal air bag system and therefore will not deploy. This can happen if sensors detect a small-statured passenger such as an infant or toddler in the right front passenger seating position.
  
  The exact location of the "PASS AIR BAG OFF" indicator light will vary depending on the design of the individual vehicle. Manufacturers are required to place this indicator light in a position that is both visible and recognizable to the driver and right front passenger under all driving conditions, typically on the dashboard center or on the rearview mirror.
  
  The "PASS AIR BAG OFF" indicator light is different than air bag readiness indicator light located in the driver's side instrumental panel. The air bag readiness indicator light illuminates or flashes when the air bag diagnostic system detects a fault in your vehicle's air bag system, such as a system or component failure, informing you that service is immediately required.
• Vehicle manufacturers are also required to provide detailed information in your owner's manual about the features of the advanced frontal air bag system and how it operates.

What should I do when the "PASS AIR BAG OFF" indicator light does not give me the expected result?
It is important for consumers to know that the proper operation of some advanced frontal air bag systems is highly dependent on the pressure (also known as "loading") placed on the seat bottom by the occupant. Situations that add ("onload") or subtract ("offload") sensed weight (see How does sensor technology classify the type of occupant?) can result in an occupant misclassification. Advanced frontal air bag systems that are designed to suppress the air bag will have a "PASS AIR BAG OFF" indicator light (see How do I know if my vehicle has advanced frontal air bags?). If "onload" or "offload" conditions occur, an unexpected "PASS AIR BAG OFF" indicator light status may result. If you do not get the expected result from your "PASS AIR BAG OFF" indicator light according to your owner's manual, please follow your manual's instructions to correct the problem. Your manual may recommend you do the following:

• Check seating posture. Occupants should be seated upright with their back against the seat back and feet on the floor.
• Check loading conditions of the seat. Extra weight from items such as bags of groceries and children's toys hanging on the seat back can add to the sensed weight of the occupant in the seat.
• Check the air bag readiness indicator light. The air bag readiness indicator light illuminates or flashes when the air bag diagnostic system detects a fault in your vehicle's air bag system, such as a system or component failure, informing you that service is immediately required.

Are advanced frontal air bags the same as "depowered" air bags?
No. In 1997, NHTSA allowed manufacturers the option to reduce the inflation power, or aggressiveness, of 1st generation air bags to lessen the likelihood of an air bag-related injury. These less powerful air bags are known as "depowered" air bags and have been in most vehicles since 1997. Advanced frontal air bag systems are a next-generation air bag system designed to be even more effective than the current depowered air bags in saving lives, while at the same time minimizing the likelihood of an air bag-related serious injury or death.

Are side-impact air bags or rollover curtain/canopy air bags part of my advanced frontal air bag system?
No. Side-impact air bags and rollover curtain/canopy air bags are not part of the advanced frontal air bag system. At this time, the government's advanced frontal air bag requirement applies to the driver frontal air bag and the passenger frontal air bag only.

Do I need to input any information, like my height and weight, to make my advanced frontal air bag system work?
No. Advanced frontal air bags, just like earlier generation air bags, work automatically with no input required from the driver or passenger. During normal operation of your vehicle, the advanced frontal air bag system is continually self-monitoring and verifying its readiness to deploy in a crash.

Why might only one, or neither, of my frontal advanced air bags deploy in a crash?
The driver and passenger frontal air bags operate independently of one another. It is possible for the driver or passenger frontal air bag to deploy, neither to deploy or both to deploy, depending on the crash severity and the characteristics of the occupants (such as presence, size, seat position and seat belt use). For example, if the right front seat is empty, the passenger frontal air bag may not inflate.

What is meant by dual-stage, multi-stage or variable output?
Dual-stage, multi-stage or variable output are terms used to describe the operation of the air bag inflators in your air bag system that cause the air bag to fill. For dual stage or multi-stage inflators, the inflators may go off in two or more stages (steps) to tailor the amount of pressure in the frontal air bag during a crash. For a variable output inflator, the inflator can tailor the output across a range of inflation pressures.

In general, for less severe crashes requiring less inflation force, only one stage of a dual-stage/multi-stage inflator may go off, or there may be less output pressure from a variable output inflator. Both result in a lower-pressure air bag deployment. For more severe crashes, all stages of a dual-stage/multi-stage inflator may go off at the same time or there may be full output from a variable output inflator. In these cases, both result in a higher-pressure air bag deployment.

After an advanced frontal air bag deploys, can it be re-used?
No. Once deployed, an air bag cannot be re-used and must be replaced by an authorized service technician.

How does sensor technology classify the type of occupant?
Most occupant classification systems in use today classify the occupant based upon weight. Occupant weight (sensed weight) is determined using pressure sensors in the seat cushion, weight sensors between the seat and the floor and/or by measuring seat belt tension.

As an additional way of classifying an occupant, other technologies are becoming available that can help the advanced frontal air bag system recognize the pressure profile on the seat bottom, such as pattern recognition technologies. Still more sophisticated systems utilize optical, infrared, ultrasonic or electric field sensors to classify the occupant type. Check your owner's manual or contact your vehicle's manufacturer to determine what type of occupant classification technology you may have in your vehicle.

Have advanced air bag systems been tested on child-sized dummies?
Yes. Federal Motor Vehicle Safety Standard (FMVSS) No. 208 (Advanced Air Bag) rule requires that all light vehicles (passenger cars and light duty trucks) must meet specific safety performance criteria for dummies representing 12-month-old infants, 3-year-old toddlers, 6-year-old children and small-stature women.

For those manufacturers electing to provide a lower-powered air bag deployment to a child or small female occupant in certain low-speed crashes, the advanced frontal air bag must meet specific safety criteria as set in FMVSS No. 208.

For those manufacturers electing to suppress (not deploy) an air bag for an infant or child occupant in all crashes, the occupant-sensing devices in their advanced frontal air bag systems have been tested with child-sized dummies, representing an infant in a child safety seat and small children in and out of child safety seats, to ensure that the air bag will turn itself off.

Are air bag ON-OFF switches still available for vehicles with advanced frontal air bags?
Yes. Manufacturers may install, as original equipment, passenger-side air bag ON-OFF switches in advanced frontal air bag-equipped vehicles with no rear seat or where there is insufficient room for a rear-facing child safety seat to be properly installed.

NHTSA will also still allow aftermarket ON-OFF switches to be installed in vehicles with advanced frontal air bags after they are sold to their owners based on the following circumstances:

• A shorter driver who must sit too close to the steering wheel,
• A driver or passenger with a special medical condition,
• A child age one to 12 who can only be seated in the front passenger seat, or
• An infant in a rear-facing infant seat who can only be seated in the front passenger seat.

If you have both advanced frontal air bags and an ON-OFF switch as original equipment, carefully review your owner's manual to understand how they interact. In vehicles with or without advanced frontal air bags, when the switch is in the OFF position, the passenger frontal air bag is disabled and will not deploy. In vehicles with advanced frontal air bags, when the switch is in the ON position, the full range of automatic operation of the advanced frontal air bag system is allowed.

Having the switch in the ON position does not necessarily mean that the passenger frontal air bag will deploy. For example, in an advanced air bag-equipped vehicle with an ON-OFF switch, if the passenger frontal air bag is designed to suppress (turn off) for child occupants, then it should still suppress even when the switch is in the ON position. Some manufacturers may label the ON position of the switch as AUTO to indicate this automatic operation.

Do I still need to maintain 10 inches between the air bag cover and my breastbone?
Yes. To minimize the potential of any air bag-related injury, NHTSA still recommends maintaining a 10-inch minimum between the air bag cover and the driver's breastbone by maintaining a proper seating position and by moving the seat as far back as possible.

Is it safe for small-stature and elderly adults to be seated in front of an advanced frontal air bag?
Yes. It has generally been found to be safe, and will continue to be safe, for smaller adults and elderly people to be seated in front of an air bag as long as they are properly belted, maintain a proper seating position and move the seat as far back as possible.

Are advanced frontal air bags safe for pregnant women?
Yes. The combination of safety belts and air bags offer the best level of protection to pregnant women as long as they follow the same advice as other adults: ensure they are properly belted, maintain a proper seating position and move the seat as far back as possible.

The lap belt should be positioned low on the abdomen, below the fetus, with the shoulder belt worn normally. When crashes occur, the fetus can be injured by striking the lower rim of the steering wheel or from crash forces concentrated in the area where a seat belt crosses the mother's abdomen. The seat belt will keep a pregnant woman as far as possible from the steering wheel. The air bag will help spread out the crash forces that would otherwise be concentrated by the seat belt.

Which 2004 vehicles have advanced frontal air bags?
The following are vehicle models that are currently certified to the advanced frontal air bag requirements or NHTSA has reason to believe will be certified to the advanced frontal air bag requirements sometime by September 1, 2004.

Again, to know if your vehicle has advanced frontal air bags, check sun visors for the warning labels with the phrase "EVEN WITH ADVANCED AIR BAGS" (see How do I know if my vehicle has advanced frontal air bags?).

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