As discussed earlier in this notice, NHTSA is proposing to amend Standard No. 208 to improve occupant protection for occupants of different sizes, belted and unbelted, while minimizing the risk to infants, children, and other occupants from injuries and deaths caused by current air bag designs. The current standard provides vehicle manufacturers with the flexibility necessary to introduce advanced air bags, but does not require them to do so.
Partially because Standard No. 208 has always provided the flexibility to address the problem of out-of-position occupants, the agency specified in its depowering rulemaking that the alternative sled test was a temporary measure, instead of a permanent one. NHTSA explained that there is no need to permanently reduce Standard No. 208's performance requirements to enable manufacturers to choose alternatives to the current single inflation level air bags and thus avoid the adverse effects of those air bags. Those requirements permit manufacturers to install air bags that adapt deployment based on one or more factors such as crash severity, belt use, and occupant size, weight or position, or that inflate in a manner that is not seriously harmful to out-of-position occupants.
NHTSA decided to make the alternative sled test available until advanced air bags could be introduced. It specified that the alternative sled test would "sunset" on September 1, 2001, based on its judgment in the Spring of 1997 that vehicle manufacturers could install some types of advanced air bags in their fleets by that date. The agency recognized, however, that there was uncertainty as to how quickly advanced air bags could be incorporated into the entire fleet. Accordingly, the agency indicated that it would revisit the sunset date, to the extent appropriate, in its future rulemaking on advanced air bags. See 62 FR 12968, March 19, 1997.
NHTSA received four petitions requesting that the agency eliminate the sunset date for the alternative unbelted sled test. The petitions were submitted by AAMA, AIAM, Ford, and IIHS.
The agency notes that the sunset date (September 1, 2001) specified in the standard has been superseded by the NHTSA Reauthorization Act of 1998. The Act ensures that the sled test option will remain in place at least until the vehicle manufacturers introduce advanced air bags. As discussed earlier in this notice, the Act provides that the unbelted sled test option "shall remain in effect unless and until changed by [the final rule for advanced air bags]." The Conference Report states that the current sled test certification option remains in effect "unless and until phased out according to the schedule in the final rule."
Since the Act overrides the provision in Standard No. 208 sunsetting the sled test alternative, the Act effectively moots the petitions for reconsideration concerning that provision. Accordingly, there is no need to set out the arguments made in those petitions. Further, those arguments and their underlying premises have themselves been superseded in some respects by the Act, having been submitted long before the air bag provisions of the Act were formulated and enacted. For example, many of those arguments were premised on the continued use of the current, single inflation level air bags, instead of the advanced air bags mandated by Congress in the Act.
Nevertheless, those arguments were generally considered by the agency before deciding to propose terminating the sled test alternative. The following discussion supplements the discussion in the preamble of the reasons for issuing that proposal.
Adoption in 1997 of the Temporary Sled Test Option. AAMA first petitioned the agency to provide a sled test alternative to the unbelted barrier test requirements in August 1996. By the time that organization submitted its petition, it had become clear that while the single inflation level air bag designs then being installed by the industry were highly effective in reducing teenager and adult fatalities from frontal crashes, they also sometimes caused fatalities to out-of-position occupants, especially children, in low speed crashes. NHTSA and the industry were then seeking solutions that could be implemented quickly to reduce the adverse effects of air bags, while also maintaining, to the extent possible, the benefits of air bags.
In analyzing AAMA's rulemaking petition, the agency recognized that there were downsides to the approach recommended by that organization. Unlike a full scale vehicle crash test, a sled test does not, and cannot, measure the actual protection that an occupant will receive in a crash. The test can measure limited performance attributes of the air bag, but not the performance provided by the full air bag system, much less the combination of the vehicle and its occupant crash protection system. It is that combination that determines the amount of protection actually received by occupants in a real world crash.
NHTSA was faced with a difficult decision in evaluating AAMA's rulemaking petition to permit use of the sled test. The agency wanted the industry to quickly mitigate the adverse effects of its then-current air bag designs, which the auto industry said it would do if the agency adopted the sled test, but the agency did not want to reduce the protection being ensured by Standard No. 208.
Faced with this dilemma, NHTSA carefully analyzed whether a reduction in stringency of the Standard was necessary in the short term to address adverse effects of air bags to out-of-position occupants. A review of the record showed that a wide range of technological solutions were, and had been, available to prevent adverse effects of air bags, and still enable vehicles to meet Standard No. 208's barrier crash test requirements.(24) However, these technologies generally could not be implemented as quickly as depowering.
In light of the rulemaking record before it, NHTSA decided to adopt the sled test alternative requested by the auto industry(25) and supported by others to be absolutely sure that, given the air bag designs then being used by the industry, the vehicle manufacturers had the necessary flexibility to address the problem of adverse effects of air bags in the shortest time possible. The agency recognized that there were longer term technological solutions that did not require a reduction in the safety protection afforded by Standard No. 208. It further recognized that many or most vehicles could have their air bags substantially depowered and still meet the standard's longstanding barrier test requirements. Nevertheless, NHTSA wanted to make sure that the standard did not prevent quick action by the manufacturers that would reduce air bag risks while still providing a measure of protection.
The agency took this action because the sled test offered advantages that, in the short run, outweighed the fundamental shortcomings of that test as a representation of potentially fatal real world crashes and thus as a reliable predictor of real world performance. Much of the sled test's short run value lay in the fact that it was simpler and less costly to conduct than a barrier crash test and that, by simplifying compliance testing through removal some of the key elements related to real world performance, it made compliance much easier to achieve, and to demonstrate.
At the same time, the agency made it clear that it viewed the reduction in the standard's safety requirements as a short-term interim measure, while the vehicle manufacturers develop and implement better solutions. 62 FR 12968. The agency considered the sled test to be a short term means of ensuring that the vehicle manufacturers could quickly depower all of their air bags, but not an effective long-term means for measuring a vehicle's occupant protection.
Proposal to Sunset the Sled Test Option. NHTSA has proposed to sunset the unbelted sled test option in part because the agency believes that ensuring continued protection of unbelted occupants is vital to motor vehicle safety. About half of the occupants in potentially fatal crashes are still unbelted. Moreover, youth are overrepresented among unbelted victims in fatal crashes. Young people of both sexes, but particularly males, are disproportionately represented among the unbelted. It is well known that the young are more prone to risky behavior. As drivers grow older, they mature and adopt safer driving and riding habits.(26) By continuing to provide effective air bag protection for the unbelted, the agency and the vehicle manufacturers can help give young drivers and passengers a better chance of safely passing through their risk-prone years. Providing effective air bag protection for the unbelted will also help other disproportionately represented groups, such as rural residents and members of minorities.
The auto industry suggests that unbelted occupants would continue to be provided a level of protection even in the absence of an unbelted barrier test requirement. However, they have not provided any specific information concerning what level of protection would be provided. The agency tentatively concludes that such protection can best be measured, and ensured, in full scale vehicle crash tests.
In order to determine the amount of life-saving and injury-reducing protection that is provided by the combination of a vehicle and its air bags to unbelted occupants, it is necessary to test a vehicle in situations in which an unbelted occupant would, in the absence of an effective air bag, typically face a significant risk of serious injury or death. This need is met by the unbelted 48 km/h (30 mph) barrier test requirement, which is representative of a significant percentage of such real world crashes. A NHTSA paper titled "Review of Potential Test Procedures for FMVSS No. 208," notes that data from the National Automotive Sampling System (NASS) indicate that the barrier crash pulse (full and oblique) represents about three-quarters of real world collisions. A copy of this paper is being placed in the public docket.
NHTSA believes that Standard No. 208 should continue to address the protection of the nearly 50 percent of all occupants in potentially fatal crashes who are still unbelted. Apart from the substantial numbers of lives at stake, the experience with current single inflation level air bags suggests that the agency should amend Standard No. 208 to ensure occupant protection in a wider variety of real world crash scenarios, rather than narrowing its scope.
Nevertheless, some petitioners have argued that NHTSA should drop the unbelted barrier requirement based on an expectation that seat belt use will substantially increase in the future. The agency recognizes that as seat belt use increases, the percentage of real world crashes that is directly represented by the unbelted barrier test decreases. However, there are several reasons why the agency tentatively concludes that dropping that test requirement would not be appropriate, particularly at this time.
First, future projections of increases in seat belt use are uncertain, and seat belt use in potentially fatal crashes is currently little over 50 percent. The agency tentatively concludes that it should not reduce safety performance requirements for nearly one-half the occupants involved in potentially fatal crashes, particularly on the basis of uncertain projections about future seat belt use.
Second, even as seat belt use increases, the persons not using seat belts will tend to be over-involved in potentially fatal crashes. Teenagers are among the persons least likely to use seat belts. They are also much more likely than other groups to be involved in potentially fatal crashes. Moreover, even in countries where seat belt use is 90 percent, unbelted occupants still represent about 33 percent of all fatalities.
The arguments made by the petitioners regarding the effect of the barrier test on air bag performance were typically premised on the continued use of the current, one-size-fits-all, air bag designs. They did not address the range of advanced air bag technologies that may be employed to meet the barrier test requirements. The issue about the compliance tests that should be used in the future should be determined in the context of the air bag technology to be used in the future, and not in the context of the older air bag designs currently in use. When the full range of advanced air bag technologies is considered, the agency believes that it is apparent that the vehicle manufacturers can address the adverse effects of air bags to out-of-position occupants, and provide excellent protection to both belted and unbelted occupants.
The agency believes the appropriate solution to the current air bag problems is to preserve and enhance the life-saving and injury-reducing benefits that air bags are providing to all occupants, belted and unbelted, while dramatically reducing or eliminating fatalities and serious injuries caused by air bags. In the longer run, the agency believes its plan to adopt requirements for advanced air bags and maintain an effective unbelted vehicle test requirement will achieve this goal.
The agency believes that justifying the elimination of the unbelted barrier test based on the shortcomings of current (or pre-depowered) air bag designs has parallels to the rationale for the agency's decision in the early 1980's to rescind the automatic restraint requirements. The agency rescinded those requirements for the stated reason that many vehicle manufacturers had initially chosen to comply with them by detachable automatic seat belts, instead of either nondetachable automatic seat belts or air bags, and that those detachable belts might not significantly improve vehicle safety. The U.S. Supreme Court unanimously concluded that the appropriate regulatory response to ineffective or undesirable design choices by the vehicle manufacturers regarding automatic restraints was not simply to rescind the requirements for those restraints, but first to consider the alternative of amending the requirements to ensure better technological choices in the future. Motor Vehicle Mfrs. Ass'n v. State Farm Mut. Auto. Ins. Co., 403 U.S. 29 (1983). The reasoning underlying that decision suggests that the fact that the air bag designs chosen to date do not meet all safety considerations is not a sufficient reason, by itself, to undercut or negate the broad, longstanding performance requirements for air bags, given that there are other, superior alternative designs from which to choose. Instead, the appropriate long-term solution is to amend the requirements to ensure that the manufacturers select and install better air bag designs in the future.
In arguing for permanent retention of the sled test, the petitioners made a number of arguments about the potential benefits of depowered air bags. However, NHTSA does not believe that it is necessary to retain the sled test to obtain the benefits of depowered air bags. Ultimately, the issue is not whether some vehicles with depowered, single inflation level air bags do not today meet the 48 km/h (30 mph) barrier test requirement. As noted above, the issue about future compliance tests should be determined in the context of future air bag technology, and not in the context of today's less sophisticated air bag designs. Various advanced air bag technologies can be used that will provide full protection in compliance with such substantial test crashes, while not injuring out-of-position occupants.
As discussed above, the primary reason NHTSA decided to adopt the temporary sled test alternative in its depowering rulemaking was because of its desire to ensure that the vehicle manufacturers could depower all of their single inflation level air bags quickly. The certification testing that vehicle manufacturers would have needed to conduct to ensure that their depowered air bags continued to meet the 48 km/h (30 mph) barrier test would have prevented the quick depowering of all air bags. However, the agency did not determine that multi-inflation level or even single inflation level depowered air bags could not, given sufficient time, be produced that would also meet the 48 km/h (30 mph) barrier test.(27)
In this connection, the agency notes that, based on very limited data, it appears that many, perhaps most, vehicles with depowered air bags continue to meet Standard No. 208's unbelted barrier test requirements by wide margins. NHTSA has tested five vehicles with depowered driver air bags in unbelted 48 km/h (30 mph) rigid barrier tests, and all passed Standard No. 208's injury criteria by significant margins.(28) The agency has tested six vehicles with depowered passenger air bags in unbelted 48 km/h (30 mph) rigid barrier tests, and all but one passed the standard's injury criteria performance limits by significant margins.(29)
NHTSA notes that the petitioners suggested that it should evaluate the real world safety impacts of depowering before deciding whether to restore the barrier test. This suggestion does not take into account the limitations of the sled test alternative for measuring the occupant protection provided in a potentially fatal crash, especially as compared to an actual crash test. Further, there is some question whether determining the level of protection provided by the current depowered air bags would enable the agency to assess the level of safety ensured by the sled test. The sled test gives vehicle manufacturers broad flexibility to design and install air bags that are significantly more depowered than the current depowered air bags. In comparing regulatory alternatives, the question for the agency to answer is the level of safety protection actually required by different alternatives instead of the safety protection that is currently provided, or may in the future be provided, voluntarily by the manufacturers.
These concerns are particularly relevant in considering any kind of permanent change to a safety standard. Since the agency analyzed the sled test amendment as a relatively short-term, interim means of ensuring that manufacturers could quickly depower their vehicles' existing air bags, it primarily analyzed the safety impacts of the changes the vehicle manufacturers said they would make. The agency did not analyze the safety implications of replacing the barrier test with a sled test on a long-term basis.
NHTSA does not know what kind of occupant protection the vehicle manufacturers would chose to provide if the sled test alternative were made permanent. As indicated above, based on very limited data, it appears that many vehicles with depowered air bags continue to meet Standard No. 208's unbelted barrier test requirements by wide margins. If the manufacturers continued to voluntarily meet the barrier test requirements for nearly all of their vehicles, the safety impacts of the sled test alternative would obviously be minimal.
However, the agency has no assurance that the vehicle manufacturers would continue to voluntarily meet the barrier test requirements if the sled test alternative were made permanent. The vehicles with depowered air bags being produced in model year 1998 were not primarily designed to meet the sled test. Instead, the vehicles were designed several years ago to meet the barrier test requirements but now have depowered air bags. There is no way of reliably predicting how the vehicle manufacturers would design their vehicles in the context of a permanent sled test alternative.
As to concerns about international harmonization, NHTSA supports international harmonization, when it is consistent with the adoption of best safety practices. For the reasons discussed above, the agency tentatively concludes that permanent retention of the sled test alternative would not be consistent with best safety practices.
Questions for commenters concerning the proposed sunsetting. While the information currently available to the agency on balance supports the proposal to sunset the sled test, the agency wishes to have as much information as possible to aid it in making a sound final decision regarding this proposal. To the end, the agency invites public comment on:
Criteria for assessing tests. What objective criteria should be used to evaluate and compare the available alternative types of compliance test procedures, e.g., the rigid barrier crash test and the sled test. Such criteria might include, but not be limited to:
Impact of a procedure on design flexibility; Extent to which a procedure ensures that good real world performance is provided; Extent to which a procedure creates the potential for degradation of real world performance; Extent to which a procedure is representative of the varied real world crashes in which serious and fatal injuries occur; and Administrative considerations, such as repeatability and costs of test conducted pursuant to a procedure. Comparison and ranking of tests. How do the alternative test procedures rank when compared to each other based on the criteria listed above and any other appropriate objective criteria, and based on advanced air bag technology? The agency emphasizes that any comparisons submitted to the agency should be forward-looking ones in terms of technology. Some past comparisons of the barrier crash test and sled test have been of limited utility and relevance because they have been premised on the continued use of old air bag technology.