NHTSA's goals in this rulemaking are to enhance the benefits of air bags for all occupants while eliminating or minimizing risks from air bags, and to ensure that the needed improvements in occupant protection are made expeditiously, and in accordance with the recently adopted statutory deadlines. As discussed in the preceding section of this notice, the vehicle manufacturers and their suppliers are already pursuing a wide variety of technological opportunities that can be used to achieve these goals.
The sheer number and variety of available technological opportunities creates special challenges from a regulatory perspective. While the availability of multiple technologies generally makes it easier to solve the current problems with air bags quickly, it also means that the agency must take special care to ensure that the regulatory language it adopts will not be unnecessarily design-restrictive.
Among other things, the agency wishes to avoid:
- inadvertently preventing the use of superior air bag designs;
- favoring one viable technology or design over another, where either would meet the need for safety;
- requiring an expensive solution, where an inexpensive one will work; or
- requiring implementation of a particular technology before it can be appropriately developed.
Moreover, since the ultimate question for regulators, industry, and the public is how the required safety features will work in the real world, NHTSA has sought to specify test procedures that most closely replicate the real world conditions that affect the possibility of traffic deaths and injuries.
As a result, NHTSA is proposing to require manufacturers to meet improved performance criteria in additional tests using a wider array of test dummies. The existing and proposed tests are identified in Figures 1 and 2, below. Figure 1 shows tests for requirements to preserve and improve occupant protection for different size occupants, belted and unbelted. Figure 2 shows tests for requirements to minimize the risk to infants, children, and other occupants from injuries and deaths caused by air bags.
NHTSA notes that, in the future, it expects to propose a higher speed frontal offset test requirement and also is considering proposing one or more tests using 95th percentile adult male dummies. The agency is not proposing a higher speed frontal offset test requirement at this time because it is still conducting research regarding such a requirement.(18) The agency is not proposing tests using 95th percentile adult male dummies at this time because the development of that dummy is not expected to be completed until sometime next year.
Under the proposed performance requirements identified in Figures 1 and 2, vehicle manufacturers would be required to show that the air bags in their vehicles provide protection to small stature occupants as well as to average size males, and to adopt one or more of a number of available design features that will minimize the risk caused by air bags to infants in rear-facing child restraints, out-of-position children, or other out-of-position occupants in low speed crashes.
The test matrix identified in Figures 1 and 2 represents a natural evolution and refinement of Standard No. 208's current requirements. The agency has always sought to include in the standard test procedures that replicate the real world factors that affect the possibility of traffic deaths and injuries. This is the best way to ensure that required safety features will perform well not only in compliance tests, but also in the real world.
Among other things, the agency has long specified full scale vehicle crash tests using instrumented dummies because it is only through such tests that the protection provided by a vehicle and its occupant protection system can be fully measured. Different vehicle models have different crash pulses. The results of crash tests reflect not only the performance of the air bag, but how a particular vehicle model crumples and absorbs energy in a crash, i.e., its individual crash pulse. The use of crash tests necessitates that vehicle manufacturers take into account the crash pulse of their vehicles, the air bag design, occupant compartment design features, seat belt design (for belted tests) and specific attributes of each of their subsystems.
Also, the agency has long included tests for air bag-equipped vehicles using both belted and unbelted dummies, since a large number of occupants in the United States continue to ride unbelted. Even today, nearly half of all occupants in potentially fatal crashes do not wear their seat belts. Teenagers are particularly likely to ride unbelted.
Moreover, the Standard has long included test conditions that replicate a variety of different types of crashes. Of particular note, the standard's longstanding barrier test requirements specify crash tests at any speed up to and including 48 km/h (30 mph), and at a range of impact angles.
NHTSA has also always sought to maximize manufacturer flexibility in providing effective occupant protection. As the agency has stated many times, Standard No. 208 has never specified the design of an air bag. Manufacturers have been free to design their air bags in any manner they like, e.g., any size, any inflation level, etc. so long as the standard's injury criteria limits are not exceeded in specified crash tests.
Today's proposal follows these longstanding practices by proposing to add new tests that replicate additional real world factors that affect the possibility of deaths and injuries which are not directly addressed by the standard's current requirements. Manufacturers would continue to be permitted maximum design freedom in designing their air bags, so long as the standard's injury criteria performance limits are met in specified tests.
Manufacturers can use many different technologies and designs to meet the proposed requirements. One approach is for manufacturers to develop air bags that inflate in a manner that does not cause injuries to out-of-position occupants. Several air bag suppliers have recently demonstrated air bags that incorporate improved folding patterns and internal tethering and venting to reduce the risk of injury to out-of-position occupants. For example, Autoliv has demonstrated an "umbrella" air bag that deploys first radially and then toward the vehicle occupant. It also may be possible to design air bags that use vents or other means of preventing further deployment if the air bag is blocked by the occupant during inflation. Again, under today's proposal, manufacturers would be permitted flexibility in designing their air bags as long as all of the standard's performance requirements are met in specified tests.
A discussion of each of the specific proposed test requirements follows, in the general order presented in Figures 1 and 2.
