SUPPLEMENTARY INFORMATION:

On Thursday, June 1, 2000, NHTSA published a request for comment on the agency's intent to include a vehicle measure of rollover resistance, its Static Stability Factor (SSF), as an addition to the New Car Assessment Program (NCAP).

The agency believes that consumer information on the rollover risk of passenger cars and light multipurpose passenger vehicles and trucks, based on the vehicle's SSF, would reduce the number of injuries and fatalities from rollover crashes. This information would enable prospective purchasers to make informed choices about new vehicles based on differences in real-world rollover risk and serve as a market incentive to manufacturers in striving to design their vehicles with greater rollover resistance.

Included in the notice was a new statistical study undertaken to demonstrate a relationship between SSF and rollover rate representative of the whole country. A relationship between rollover rate and SSF normalized to the national rollover rate and to a nationally representative set of driver and road use variables was developed as a basis for a comparative rating system for rollover risk in the event of a single-vehicle crash. We had available crash reports of 185,000 single-vehicle crashes from six states from 1994 to 1997 in which it was possible to determine the make/model of the vehicles and whether rollover occurred in the course of a single-vehicle crash, and for which SSF data were also available. We also had the NASS GES data sampling system, with far fewer but nationally representative crash reports, to determine the national average rollover rate for the population of vehicles investigated in the state reports.

The notice specified a comment closing date of July 31, 2000 (60 days after date of publication). However, on July 10, 2000 we received a request for an extension of the comment closing date from the Alliance of Automobile Manufacturers (AAM). The AAM stated that it would need an additional 30 days to allow for replication and analysis of the statistical study presented in the appendix to the notice.

NHTSA wants the public to have adequate time to analyze the statistical study and other facts that are the basis for our proposed rollover rating system. The request for an additional 30 days ( printed page 46885) does not seem excessive. Thus, in order to provide the AAM and other interested parties ample time and opportunity to analyze the study presented in the notice and to express their views on the proposal, NHTSA believes that there is good cause for the extension of the comment period and that such extension in consistent with the public interest. Accordingly, the AAM request to extend the comment period for an additional 30 days is granted. The comment period will now close August 30, 2000.

Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166; delegation of authority is at 49 CFR 1.50.