1. Under what circumstances will NHTSA allow air bag deactivation?
If the vehicle manufacturer does not make an ON-OFF switch available for a particular vehicle, NHTSA will authorize deactivation for the following reasons only:
A rear-facing infant restraint must be placed in the front seat of a vehicle because there is no back seat or the back seat is too small for the child restraint. (For the passenger air bag only.)
A child 12 years old or younger must ride in the front seat because the child has a condition that requires frequent medical monitoring in the front seat. (For the passenger air bag only,.)
An individual with a medical condition is safer if the frontal air bag is turned off. A written statement from a physician must accompany each request based on a medical condition unless the request is based on a medical condition for which the National Conference on Medical Indications for Air Bag Deactivation recommends deactivation. (For driver and/or passenger frontal air bag as appropriate.)
Drivers must sit within a few inches of the air bag (typically because they are of extremely small-stature, i.e., four feet, six inches or less). (For the driver frontal air bag only.)
Provided one of the above four conditions are met, the agency will continue to grant deactivation requests even if an aftermarket parts manufacturer makes an ON-OFF switch available for those vehicles. Requests for deactivation will be approved until September 1, 2012.
http://www.safercar.gov/airbags/pages/FAQsABDeactiv.htm