The SMART airbag system on the BMW not only knew that both driver and front passenger were wearing their seatbelts, but it also realized what direction the crash was coming from and how severe it would be.

In its 1988 model year, Mercedes-Benz was first to introduce a dual-deployment threshold for its driver front airbag. The following year, a passenger front airbag was introduced with the same dual-deployment feature. Having the airbag deploy at higher or lower crash speeds is now common among automakers.

Besides knowing what speed the crash was occurring at, this early Mercedes system was smart enough to know if there were occupants in the front seats and if they had their seatbelts on at the moment of the crash. If the driver or front passenger were not wearing their seatbelt, for example, the smart airbag system would deploy their frontal airbag during a lower speed impact than if that same occupant were properly buckled up.

This SMART system only deployed the passenger front airbag to supplement the protection for the passenger. The driver’s airbag remained loaded after the crash.

The smart “brain” of the Mercedes system can even figure out who needs an airbag the most or can determine if in fact the crash is minor enough that a belted occupant does not need an airbag to protect them. For example, if the driver of a Mercedes were belted in a low-speed crash and the passenger wasn’t, potentially only the unbelted passenger’s airbag would deploy. This was the beginning of what has now been termed “SMART” airbag technology.

In 1994, the strategy announced by the National Highway Traffic Safety Administration (NHTSA) to address concerns about airbag deaths included a required phase-in of the next generation of SMART technology airbags by the 1999 model year. These systems sense the position or the weight of the passenger and adjust deployment to provide the best protection.

The frontal impact was severe enough to crumple the front engine compartment and dislodge the battery at the passenger side hood hinge.

What this means for responders is that we will encounter any possible combination of deployment of front airbags. With a standard airbag system, if the crash sensors deploy the driver’s airbag, then the passenger’s front airbag will deploy also. Not necessarily so with the SMART technology systems. Let’s look at two recent case studies that vividly demonstrate how SMART airbag technology is changing what we will find when we arrive on-scene.

In our first case study, a brown BMW sedan ran a red light and struck another vehicle broadside. A third vehicle then crashed into the side of the BMW. The BMW was occupied by only the driver and he was wearing his seatbelt.

The secondary collision caused severe impact damage to the passenger’s side, jamming the door.

The SMART airbag system of the BMW knew that no one was in the passenger’s front seat. A weight sensitive grid installed in the cushion of the front seat weighs everyone who sits there. In this case, the seat detected that no one was in that riding position and remembered that at the moment of the crash. Notice that only the steering wheel airbag deployed. The passenger’s front airbag is still loaded. There was no need for the bag to deploy so the SMART system just saved the insurance company some repair cost money.

Rescuers entering the vehicle and placing weight on the passenger seat cushion will not trip the sensor and deploy the airbag. That weight (40 pounds or more) had to be there at the moment of the collision to allow the crash signal to go to the frontal airbag.

The SMART airbag system knew the passenger’s seat was empty and only deployed the airbag for the driver. The passenger front airbag remains loaded.

The second incident involving a red BMW was a little different. This vehicle had two front seat occupants; a driver and front seat passenger. Both were wearing their seatbelts. As the SMART airbag system in this BMW sensed and analyzed the impact that was occurring at the passenger’s front corner, the system determined that the driver would be all right since he was buckled up. His airbag did not deploy.

The passenger however was closer to the point of impact. Vehicle speed was high enough and the energy of the impact was being recorded as potentially sufficient to cause injury to a front seat passenger. The airbag ‘brain’ decided that this occupant should receive the supplemental restraint protection of an airbag. Therefore only the passenger airbag deployed.

Please use these two examples to remind your responders that SMART airbag technology is like a roll of the dice. We won’t know what combination of airbags will deploy until we get to the crash and find out for ourselves. Scan the vehicle. Be alert for loaded airbags and be cautious!