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Consumer Information Regulations; Federal Motor Vehicle Safety Standards; Rollover Prevention

American Government Special Collections Reference Desk

American Government Topics:  National Highway Traffic Safety Administration

Consumer Information Regulations; Federal Motor Vehicle Safety Standards; Rollover Prevention

Barry Felrice
Federal Register
June 28, 1994

[Federal Register: June 28, 1994]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Part 575

[Docket No. 91-68; Notice 03]
RIN 2127-AC64

 
Consumer Information Regulations; Federal Motor Vehicle Safety 
Standards; Rollover Prevention

AGENCY: National Highway Traffic Safety Administration (NHTSA), DOT.

ACTION: Notice of proposed rulemaking (Consumer Information 
Regulation); Termination of rulemaking (Federal Motor Vehicle Safety 
Standard).

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SUMMARY: As part of its comprehensive efforts to address the problem of 
light vehicle rollover, this agency is proposing a new consumer 
information regulation that would require that passenger cars and light 
multipurpose passenger vehicles and trucks be labeled with information 
about their resistance to rollover. This information would enable 
prospective purchasers to make choices about new vehicles based on 
differences in rollover risk; motivate manufacturers to give more 
priority to rollover stability in designing their vehicles; and inform 
motorists that they can reduce the risk of injury in a rollover by 
wearing their safety belts. NHTSA believes that this would reduce the 
number of injuries and fatalities from rollover accidents.

DATES: Comment Date: Comments must be received by August 29, 1994.

ADDRESSES: Comments should refer to the docket and notice number of 
this notice and be submitted to: Docket Section, Room 5109, National 
Highway Traffic Safety Administration, 400 Seventh Street, SW., 
Washington, DC 20590. (Docket Room hours are 9:30 a.m.-4 p.m., Monday 
through Friday.)

FOR FURTHER INFORMATION CONTACT: Gayle Dalrymple, Office of Vehicle 
Safety Standards, NRM-11, National Highway Traffic Safety 
Administration, 400 Seventh Street, SW., Washington, DC 20590. 
Telephone: (202) 366-5559.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. The Rollover Crash Problem
II. Relationship to Other Agency Activities
    A. Agency Efforts to Address the Rollover Crash Problem
    B. Consumer Information Activities
III. Background
    A. Statutory Requirement for Rulemaking
    B. ANPRM and the Planning Document
    C. Comments on the ANPRM and the Planning Document
IV. Summary
    A. Summary of Agency Decision Not to Propose a Vehicle Standard
    B. Summary of Proposed Consumer Information Regulation
V. Agency Analysis of the Vehicle Stability Metrics
    A. Identification of Vehicle Stability Metrics
    B. Analysis of Importance of Factors
    1. Additional Analyses since the ANPRM
    2. Predictive Power of the Metrics
VI. Decision Not to Propose a Vehicle Stability Standard
    A. Estimates of the Benefits of a Standard
    1. Rollover Risk Reduction
    2. Predicted Single Vehicle Accident Rate
    3. Injury/Fatality Rate Reduction
    B. Estimates of the Costs of a Standard
    C. Conclusions
VII. Proposed Consumer Information Regulation
    A. Rationale
    B. Proposed Label
    C. Stability Metrics
    1. Critical Sliding Velocity
    2. Tilt Table Angle
    D. Timing of Information Provided by the Manufacturers and NHTSA
    E. Benefits
    F. Costs
VIII. Final Stage Manufacturers and Alterers
IX. Rulemaking Analyses and Notices
    A. Executive Order 12866 and DOT Regulatory Policies and 
Procedures
    B. Regulatory Flexibility Act
    C. Paperwork Reduction Act
    D. National Environmental Policy Act
    E. Executive Order 12612 (Federalism)
    F. Civil Justice Reform
X. Effective Date of Final Rule
XI. Submission of Comments

I. The Rollover Crash Problem

    Rollover crashes occur for many reasons, and involve the 
interaction of a variety of factors including the driver, the roadway, 
the vehicle, and environmental conditions. The relationship of these 
various factors to rollover crashes can be examined by analyzing data 
from various sources.
    The agency estimates that there were 220,000 rollover crashes 
involving passenger cars, and multipurpose passenger vehicles and 
trucks under 4,536 kilograms (10,000 pounds) gross vehicle weight 
rating (collectively, ``light trucks'') in 1991. These resulted in 
9,186 fatalities; 56,000 occupants of these vehicles received serious, 
incapacitating injuries. These numbers have remained relatively 
constant over the past six years. Ejections are responsible for 63 
percent of the fatalities. Safety belts are used by only 13 percent of 
the fatally injured occupants.
    Of the 220,000 rollover crashes, 207,000, or 94 percent, were 
single vehicle crashes and 192,000 of these, or 93 percent, occurred 
off the road. Various accident studies have indicated that loss of 
vehicle directional control is a prelude to rollover in 50 percent to 
80 percent of all rollover crashes.
    For the years 1985-1991, small cars had the greatest number of 
rollover fatalities, followed by standard-size pickup trucks. However, 
pickup trucks and sport utility vehicles have fatality rates per 
million registered vehicles between two and three times as great as 
that of passenger cars. The difference between the numbers of rollover 
fatalities and the rollover fatality rates for particular vehicle types 
is a result of the relative proportions of various types of vehicles in 
the fleet. There are currently many more small cars than pickup trucks 
and sport utility vehicles on the road today.
    (A more extensive discussion of rollover statistics, and the 
sources for this information, can be found in the ``Addendum to 
Technical Assessment Paper,'' NHTSA 1994, which is in Docket No. 91-68, 
Notice 03.)

II. Relationship to Other Agency Activities

A. Agency Efforts To Address the Rollover Crash Problem

    The agency believes that no single type of rulemaking or other 
agency action could solve all, or even a majority of, the problems 
associated with rollover. Accordingly, it is pursuing a broad range of 
actions to address those problems.
    First, NHTSA has published an NPRM to reduce the potential for 
injuries to the head from contact with upper interior components (58 FR 
7506, February 8, 1993). The comment period was reopened to December 1, 
1993 (58 FR 54099, October 20, 1993) and a public hearing was held on 
November 15, 1993. As explained in the Addendum to Technical Assessment 
Paper, NHTSA's research indicates that head injuries are the most 
prevalent type of injury associated with rollovers. The agency expects 
to issue a final rule on this subject in late 1994.
    Second, with respect to anti-lock brake systems, the agency has 
published an advance notice of proposed rulemaking (ANPRM) for light 
duty vehicles (January 4, 1994, 59 FR 281). (``Light duty vehicles'' 
include cars, vans, pickup trucks and sport utility vehicles with a 
gross vehicle weight rating of 4,536 kilograms (10,000 pounds) or 
less.) Since most vehicles involved in rollovers lose their 
longitudinal stability before leaving the roadway, where they then trip 
and roll over, and since anti-lock brake systems are designed to 
enhance the longitudinal stability of a vehicle, a requirement for 
anti- lock brakes could reduce the number of rollovers. NHTSA's 
preliminary evaluation of rear-wheel anti-lock brake systems, the type 
of anti-lock brakes most often found on light trucks, indicates that 
anti-lock brakes on light trucks are effective in reducing the number 
of nonfatal single vehicle accident rollovers for almost every type of 
truck, under any type of road condition. Reductions of single vehicle 
accident rollovers were typically in the range of 30 percent to 40 
percent. NHTSA is continuing to analyze the data and a comprehensive 
report of the findings will be published at a later date. (The 
preliminary evaluation is available in Docket No. 70-27-GR-026.)
    Third, as noted above, ejections are a frequent occurrence in fatal 
rollover crashes. To attempt to reduce the frequency of ejections, the 
agency is conducting research on glass/plastic side windows and 
improved door latches. Preliminary research results should be available 
within the next year to enable NHTSA to determine if rulemaking should 
be pursued in these areas.
    Fourth, the agency is conducting research on improvements to 
vehicles' roof strength that could reduce head and neck injuries. A 
decision whether to begin rulemaking on this subject is expected in 
1994.
    Fifth, as noted above, safety belt use is very low among persons 
fatally or seriously injured in rollover crashes. NHTSA promotes 
increased use of safety belts through public awareness and education 
efforts and by supporting the implementation and enforcement of state 
safety belt use laws. Agency occupant protection awareness and 
education activities include national media campaigns; outreach through 
national health, medical, civic, and intergovernmental organizations; 
and, administration of Section 402 state highway safety program funds. 
The agency promotes effective state safety belt usage laws by 
conducting evaluation studies and demonstration projects, training law 
enforcement personnel, and by administering the Section 153 state 
incentive grant program.
    In addition, NHTSA has contracted with the Advertising Council to 
prepare two ``Vince and LarrySM'' (the agency's safety belt 
``spokespersons'') public service announcements (PSAs) for television, 
and one ``Vince and LarrySM'' PSA for radio, on the specific 
benefits of safety belts in rollover crashes. One of the television 
PSAs and the radio PSA were available at the end of March, 1994. The 
other television PSA will be available approximately six months later. 
These safety belt initiatives will supplement the other actions to 
address the rollover problem.
    Sixth, it is well known that rollover crashes have a high incidence 
of alcohol involvement. The agency has numerous programs and activities 
aimed at reducing alcohol-related crashes, injuries, and fatalities, 
which follow two fundamental strategies: information-education (such as 
Advertising Council PSAs on television) and laws-enforcement-sanctions 
(such as .08 BAC, sobriety checkpoints, and increasingly severe 
sanctions for repeat offenders). Section 410 grants to states provide 
incentives to states to use these strategies. These combined strategies 
have been effective as alcohol-related fatalities have decreased 30 
percent over the past 10 years.
    Seventh, and finally, the agency is issuing this notice regarding 
vehicle stability requirements and consumer information.

B. Consumer Information Activities

    NHTSA believes that consumer and manufacturer behavior can be 
affected through the provision of consumer information regarding 
vehicle safety. The agency's experience with the New Car Assessment 
Program (NCAP) demonstrates the power of consumer information. Under 
the NCAP Program, the agency tests the ability of vehicles to protect 
their front seat occupants in frontal crash tests. The tests are 
similar to those conducted under Standard No. 208, Occupant Protection, 
to determine whether vehicles meet the Standard's injury criteria, 
except that the Standard's tests are conducted at 30 mph, while NCAP 
tests are conducted at 35 mph. Several manufacturers have informed the 
agency that they view it as important to perform well in the NCAP 
tests, even though there is no regulatory requirement to do so. The 
decline in the injury scores in NCAP tests over time for all 
manufacturers, as reported in ``Report on the Historical Performance of 
Different Auto Manufacturers in the New Car Assessment Program Tests,'' 
NHTSA, August 1993, can also be attributed partially to NCAP.
    The agency believes that further safety improvements could be 
gained through providing consumers with information about additional 
aspects of new vehicle safety performance. NHTSA recently conducted a 
series of 15 focus groups, comprised of members of the public, to 
examine the type and format of desired consumer information about 
vehicle safety. (See ``Focus Groups on Traffic Safety Issues: Public 
Response to NCAP,'' S.W. Morris & Company, Inc., August 1993, which can 
be found in Docket No. 79-17, Notice 01, or ``New Car Assessment 
Program--Response to the NCAP FY 1992 Congressional Requirements,'' 
Report to the Congress, December 1993, which can be found in Docket No. 
97-17, Notice 39). One of the topics examined was the current NCAP and 
how it could be improved. In response to the results of the focus group 
work, the agency has changed the format for NCAP test results. The new 
format responds to consumer demand for reporting results in a way that 
is less technical and easier to understand.
    The focus groups also indicated that the agency's consumer safety 
information activities should be expanded to include additional kinds 
of crashes, including side impacts and rollovers. The potential 
importance of providing broader safety information about new light duty 
vehicle performance can be seen from figures regarding the proportion 
of fatalities in each of the three most important types of crashes. In 
1991, frontal crashes accounted for 39 percent of all fatalities 
involving light duty vehicle occupants, rollover crashes for 30 
percent, and side impact crashes for 25 percent. Together, these three 
types of crashes account for 94 percent of all fatalities. Information 
on performance in all three types of crashes could provide consumers 
with a comprehensive, balanced picture of the safety of new vehicles.
    As part of its efforts to expand its consumer safety information 
programs, NHTSA has sought participation and guidance from the general 
public on the types and format of safety information to be provided to 
consumers. On January 3, 1994, the agency published a request for 
comments on whether to supplement the agency's efforts by holding a 
public meeting to discuss, among other items, the expansion of the NCAP 
program to other crash modes (59 FR 104).
    Based on the foregoing, the agency plans to supplement this 
rollover proposal with a future proposal for requiring that each new 
vehicle have a window sticker providing information not only on vehicle 
rollover resistance, but also on frontal and side impact crash 
performance.

III. Background

A. Statutory Requirement for Rulemaking

    The NHTSA Authorization Act of 1991 (the Act) (part of the 
Intermodel Surface Transportation Efficiency Act) requires the agency 
to address several vehicle safety subjects through rulemaking. One of 
the subjects, set forth in section 2503(1), is protection against 
unreasonable risk of rollovers of passenger cars, multipurpose 
passenger vehicles, and trucks with a gross vehicle weight rating of 
8,500 pounds or less and an unloaded vehicle weight of 5,500 pounds or 
less.
    Section 2502(b)(2)(A) of the Act required that NHTSA publish, no 
later than May 31, 1992, an ANPRM or a notice of proposed rulemaking 
(NPRM) on this subject. The January 3, 1992, ANPRM fulfilled this 
mandate.
    Section 2502(b)(2)(B)(i) of the Act provides that the agency must 
complete a rulemaking action on rollover within 26 months of publishing 
the ANPRM. The ANPRM was published on January 3, 1992; thus, this 
rulemaking action was to have been completed by March 3, 1994. Section 
2502(b)(2)(B)(ii) of the Act provides that this rulemaking will be 
considered completed when NHTSA either publishes a final rule or 
decides and announces that it is not promulgating a rule.

B. ANPRM and Planning Document

    NHTSA announced in its January 3, 1992 ANPRM on the rollover 
problem that it was considering various regulatory actions to reduce 
the frequency of vehicle rollovers and/or the number and severity of 
injuries resulting from vehicle rollovers (57 FR 242). The agency 
requested comments on potential regulatory actions in the areas of: (1) 
Improved stability; (2) improved crashworthiness; and (3) consumer 
information. NHTSA said that it might issue a rule or rules in any one 
of these three categories, or in any combination of them.
    The ANPRM discussed the agency's statistical analyses of the 
interaction of driver characteristics, vehicle stability metrics, 
roadway and environmental conditions. The notice described the 
following vehicle stability metrics as having a potentially significant 
role in vehicle rollover: center of gravity height; static stability 
factor; tilt table ratio; side pull ratio; wheelbase; critical sliding 
velocity; rollover prevention metric; braking stability metric; and 
percent of total vehicle weight on the rear axle. A vehicle stability 
metric is a measured vehicle parameter that presumably is related to 
the vehicle's likelihood of rollover involvement. To supplement the 
ANPRM, a Technical Assessment Paper that discussed testing activities, 
testing results, accident data collection, and analysis of the data was 
placed in the docket on January 6, 1992. A description of the 
individual metrics can be found in the Technical Assessment Paper.

    (Note: For the remainder of this notice, ``tilt table angle'' is 
used in place of ``tilt table ratio,'' regardless of the term used 
in any other document. NHTSA is using ``tilt table angle'' because 
the agency is proposing tilt table angle as one of the possible 
measurements to be used in the proposed consumer information 
regulation. Tilt table angle is the angle at which the last uphill 
tire of a vehicle lifts off a tilting platform. Tilt table ratio is 
the tangent of the tilt table angle and is believed to be harder for 
the average consumer to understand.)

    During the development of the ANPRM and subsequent to receiving and 
analyzing comments to the ANPRM, it became obvious that no single type 
of rulemaking could solve all, or even a majority of, the problems 
associated with rollover. This view was strengthened by the agency's 
review and analysis of the comments on the ANPRM. To emphasize this 
conclusion and inform the public further about the complicated nature 
of the light duty vehicle rollover problem, the agency released a 
document titled ``Planning Document for Rollover Prevention and Injury 
Mitigation'' at a Society of Automotive Engineers meeting on rollover 
on September 23, 1992. The Planning Document gave an overview of the 
rollover problem and a list of alternative actions that NHTSA was 
examining to address the problem. Alternatives for regulatory action 
and a schedule for decisions on each were included. The current status 
of the presented alternative actions was discussed earlier in this 
notice. The document was placed in Docket No. 91-68; Notice 02, on the 
same day. NHTSA published a notice in the Federal Register announcing 
the availability of the Planning Document and requesting comment 
(September 29, 1992; 57 FR 44721).

C. Comments on the ANPRM and the Planning Document

    Forty-two comments concerning the ANPRM and the Planning Document 
were received. A Summary of Comments was placed in the docket on 
September 15, 1993. Ten commenters addressed the Planning Document, 
eight of whom had also commented on the ANPRM. Responses to the 
Planning Document, for the most part, were abridged forms of the 
commenters' responses to the ANPRM.
    All the commenting vehicle manufacturers asserted that, while 
stability metrics are statistically related to the rates with which 
single vehicle accidents result in rollovers, they are not causally 
related to rollover. Therefore, the manufacturers asserted, the agency 
cannot issue a regulation based on any one of these metrics solely 
because of its statistical correlation with accident data. Automotive 
Testing, BMW, Ford, GM, the American Automobile Manufacturers 
Association (AAMA, then known as the Motor Vehicle Manufacturers 
Association), and VW claimed that stability metrics are insufficient by 
themselves to explain a vehicle's degree of involvement in rollover 
crashes. These commenters stated that driver and environmental factors 
outweigh the contributions of vehicle factors to the likelihood of a 
single vehicle accident becoming a rollover. Nevertheless, most 
commenters addressed the relevancy of several of the individual metrics 
the agency considered for a vehicle stability rulemaking.
    Tilt table angle, one of the metrics being proposed in this notice, 
appeared to be more acceptable to the commenters than the other 
stability metrics. While side pull ratio was favored by Automotive 
Testing, Chrysler, GM, and Nissan, all these commenters also commented 
favorably on aspects of tilt table angle. Static stability factor was 
favored by only Perrone Forensic Consulting, who also commented 
favorably on tilt table angle. All other commenters who indicated a 
preference among the metrics discussed in the ANPRM favored tilt table 
angle. However, Chrysler, Ford, GM, Isuzu, and VW claim vehicle changes 
made to improve a vehicle's tilt table performance may degrade a 
vehicle's control and handling attributes. Chrysler said that the 
repeatability of results from the tilt table procedure was unknown. On 
the other hand, Advocates for Highway and Auto Safety, the 
International Organization of Motor Vehicle Manufacturers, and GM 
stated they believe that the procedure is repeatable. Chrysler and AAMA 
also commented that the tilt table test is not a standard practice and 
its measurement error has not been established.
    Commenters did not respond directly to the idea of using critical 
sliding velocity, which is also being proposed for use in this notice. 
However, most manufacturers commented that center of gravity height (a 
measurement necessary to calculate critical sliding velocity) is 
difficult to measure and that the measurement is not repeatable. 
Therefore, according to these commenters, any metric which uses center 
of gravity height would be impracticable.
    The commenters also focussed on crashworthiness improvements. By 
far the most favorable crashworthiness countermeasure cited by the 
commenters was increased seat belt use to prevent ejections. In 
general, commenters believe that more benefits could be gained through 
increased seat belt use than through any vehicle related 
crashworthiness or crash avoidance countermeasure. Some commenters also 
favored improved roof structures including roll bars or cages, but 
Ford, GM, Nissan, and VW believe the installation of a roll bar or cage 
raises the vehicle's center of gravity and decreases rollover 
stability. Other suggestions were for improved glazing, improved latch/
lock/hinge systems for doors, anti-lock brakes, bumper height 
regulations, removal of drunk and otherwise impaired drivers from the 
road, stricter enforcement of speed limits, and improved public 
awareness of the causes of rollover crashes as ways to reduce rollover 
casualties.
    Finally, Chrysler, GM, AAMA, and Toyota claimed that labeling 
vehicles with a stability metric would be simplistic and could mislead 
consumers, giving them a false sense of security in a vehicle labeled 
with a high stability metric (i.e., a metric indicating comparatively 
high resistance to rollover). These commenters believe that consumers 
could consider the metric to be an absolute measure of rollover 
likelihood, regardless of driver behavior or roadway conditions.

IV. Summary

A. Summary of Agency Decision Not To Propose a Vehicle Standard

    In analyzing whether to proceed with a vehicle stability 
rulemaking, the agency identified several criteria that had to be met 
before proposing a safety standard. First, the identified vehicle 
metrics had to have a causal relationship to the likelihood of 
rollover. For example, center of gravity height affects rollover 
likelihood; the color of the vehicle does not. Second, the metric had 
to have a statistical relationship to rollover frequency. Third, 
improvement in the metric should result in significant safety benefits 
at a reasonable cost without having the effect of necessitating the 
radical redesigning of one or more types of vehicles. As discussed 
below, the agency identified two metrics that met the first two 
criteria, but not the third.
    To determine whether it was appropriate to propose a new vehicle 
safety standard, NHTSA examined the complex interactions between driver 
behavior, vehicle properties, and roadway characteristics which result 
in rollovers. The suitability of a vehicle safety standard based on 
rollover stability depends on the importance of rollover stability, as 
represented by a vehicle metric, relative to other rollover influences, 
such as vehicle handling properties, vehicle condition, the nature of 
the roadway and shoulder terrain, and driver behavior. The agency 
sought to determine whether vehicle stability metrics are significant 
variables in a statistical model of the risk of rollover. If they are, 
then a standard regulating stability might be justified, depending on 
the results of a comparison of benefits and costs for such a standard.
    After analyzing a number of static and dynamic rollover metrics, 
the agency concluded that two vehicle metrics, tilt table angle and 
critical sliding velocity, can account for about 50 percent of the 
variability in rollover risk in single vehicle accidents, after 
considering driver, roadway, and environmental factors. (Rollover risk 
is the number of single vehicle rollovers involving a particular make/
model divided by the number of single vehicle crashes of all types 
involving the same make/model.) This statistical analysis was conducted 
on all light duty vehicles treated as a group. However, analysis of 
accident data indicated that certain subgroups of light duty vehicles 
are more likely to roll over than other subgroups. For example, sport 
utility vehicles and compact pickup trucks tend to be the most likely 
vehicles to roll over. Large passenger cars tend to be the least likely 
to roll over. The importance of this difference is that if significant 
benefits are to be achieved, then changes in the metric should be made 
that affect passenger cars since nearly 60 percent of rollover 
fatalities occur in those vehicles.
    The agency's analysis showed that setting a performance level high 
enough to affect passenger cars, would require redesign of nearly all 
sport utility vehicles, vans, and pickup trucks. Using a single value 
of one of these metrics as the performance standard for all light duty 
vehicles would have resulted in the radical redesign of the 
characteristics many, and in some cases all, vehicles of certain 
classes. That degree of redesign would have raised issues of public 
acceptance and possibly even the elimination of certain classes of 
vehicles as they are known today.
    To avoid this consequence, the agency then examined whether several 
values for these metrics, each applying to a different class of 
vehicles (e.g., one value for passenger cars and a different value for 
light trucks) would be feasible. Since the statistical analyses 
discussed above were conducted on all light duty vehicles treated as a 
group, it was necessary to determine whether either of the stability 
metrics exhibited sufficiently high levels of correlation to assure the 
agency that a requirement applying to only one class of vehicle would 
be expected to reduce the incidence of rollovers for vehicles in that 
class. As explained later in this notice, the agency found that the 
statistical correlations of the metrics with rollover accident data 
within a class of vehicles was not so consistent as for all vehicles 
grouped together. This weakening of the predictive ability of the 
metric is, to some extent, the result of the smaller range of the 
metric within any class of vehicles together with the inherent 
variability in the data. Based on this analysis, and the general 
analysis of costs and benefits discussed later, the agency determined 
that proposing a standard specifying one minimum stability value for 
cars and others for various classes of light trucks could not be 
justified.
    The agency also determined that, considering the costs and benefits 
involved, proposing a safety standard specifying a single minimum 
stability value for both cars and light trucks could not be justified. 
While light trucks have lower stability measurements than cars do, the 
greatest number of rollover-related deaths and injuries occur in 
passenger cars because of their larger population size. Therefore, if 
the agency wished to set a stability minimum high enough to realize 
significant reductions in the number of fatalities in all light duty 
vehicles, it would have to set the minimum above the stability number 
of most light trucks. The costs of such a standard, in terms of the 
cost of vehicle redesign and the loss of consumer-desired attributes, 
were determined to be very high, as entire classes of light trucks 
would probably need to be substantially redesigned to meet such a 
standard. This redesign could result in the elimination of some vehicle 
types, e.g., sport utility vehicles, as they are known today.
    Based on this analysis, NHTSA has decided not to propose a vehicle 
stability rule, and is deferring any further action on this subject 
until such time as information becomes available demonstrating the cost 
effectiveness of such a rule. The agency may reinitiate such a 
rulemaking upon receipt of such information. This termination of 
rulemaking on vehicle stability fulfills the statutory mandate of 
section 2502(b)(2)(B)(i). However, through the consumer information 
proposal being published today, and the other actions mentioned above, 
NHTSA is continuing to take a comprehensive approach to reducing 
rollover casualties.

B. Summary of Proposed Consumer Information Regulation

    While NHTSA is terminating rulemaking on a vehicle stability 
standard, NHTSA believes that the correlation between stability and 
rollover risk is significant enough to justify proposing a consumer 
information regulation to relieve the possibility of uninformed risk. 
The agency believes that informing consumers of the relative resistance 
of different vehicles to rollover will influence consumers to purchase 
more stable vehicles and encourage manufacturers to improve the 
stability of their vehicles. The agency believes that these results are 
possible based on its assessment of how consumers and manufacturers 
reacted to the provision of frontal crashworthiness information through 
the New Car Assessment Program.
    The consumer information regulation being proposed by the agency 
would require manufacturers of passenger cars and light trucks to label 
their vehicles with information relating to rollover stability. To that 
end, manufacturers would be required to report a stability metric for 
each vehicle make/model to NHTSA by January 1 of each year. 
Manufacturers would decide how to group vehicle make/models for the 
purpose of reporting stability metrics for those groups. To ensure that 
the information is neither understated nor overstated, the reported 
stability metric would be measured with a specified procedure and an 
accuracy tolerance on reported data would be required. NHTSA would use 
the information reported by manufacturers to provide the manufacturers 
with the ranges of metrics for both passenger cars and light trucks by 
April 1 of each year. For comparison purposes, these ranges would be 
included on vehicle labels.
    New vehicles manufactured after September 1, 1996 would be required 
to have a prescribed window label listing the metric of the labeled 
vehicle, the range of that metric for cars and the range for light 
trucks. In addition, prescribed language on the label would explain the 
significance of the metric, warn consumers that all vehicles can and do 
roll over, and remind consumers to always wear seat belts. The proposed 
regulation would also require manufacturers to include the information 
on the vehicle label in the vehicle's owner's manual.
    The agency requests comment on whether or not the proposed vehicle 
label should be a permanent sticker, in addition to the window label 
which would be removed after first sale. If a commenter believes the 
label should be permanent, NHTSA requests comment on whether the 
permanent sticker should be required on all vehicles, or only some 
subset of vehicles with lower rollover stability. Finally, NHTSA 
requests suggestions on placement and size of a permanent sticker. A 
permanent sticker would be useful to purchasers of used vehicles and 
drivers of rental vehicles.
    NHTSA is considering two metrics for providing information 
regarding rollover stability: critical sliding velocity and tilt table 
angle. Critical sliding velocity is a measure of the minimum lateral 
(sideways) vehicle velocity required to initiate rollover when the 
vehicle is tripped by something in the roadway environment, e.g., a 
curb. Tilt table angle is the angle at which the last uphill tire of 
the vehicle lifts off a platform as the platform is increasingly 
tilted.
    NHTSA is proposing two different options for specifying stability 
information using these metrics. First, NHTSA may select one of the two 
metrics to appear on the label. For example, if the agency selected 
tilt table angle, it would require that the specific angle for each 
vehicle be shown on its label. Second, NHTSA may require the label to 
include a nonquantitative statement concerning the vehicle's rollover 
resistance based on one or both of the metrics. For example, instead of 
stating a specific angle, the label might use symbols such as one, two, 
or three stars.

V. Agency Analysis of the Vehicle Stability Metrics

A. Identification of Vehicle Stability Metrics

    The agency has concluded that the two metrics with the best 
correlation to accident statistics are tilt table angle, a static 
measurement, and critical sliding velocity, a metric calculated from 
static and dynamic vehicle measurements and expressed as velocity, 
i.e., units of feet per second, miles per hour, or kilometers per hour.
    Tilt table angle includes the influences of the vehicle's mass, 
center of gravity height, track width, and suspension movement, all of 
which are physically related to rollover stability. Because it does not 
require an independent measurement of center of gravity height, it is 
more practicable, less costly, and more repeatable than most static 
rollover metrics.
    Critical sliding velocity includes the roll moment of inertia as 
well as the various static factors mentioned above in its calculation. 
The Technical Assessment Paper found critical sliding velocity alone to 
have less correlation with rollover accident statistics than tilt table 
angle, but found it to be a statistically significant addition to a 
model already containing tilt table angle. However, an error in the 
computation of critical sliding velocity was made in the Technical 
Assessment Paper. When the logistic regression was repeated with the 
correct critical sliding velocity values and data for more vehicle 
make/models and additional accident years, NHTSA found the correlation 
of critical sliding velocity to accident statistics for all light duty 
vehicles grouped together and for the light truck and passenger car 
categories to be better than that for tilt table angle. The Addendum to 
Technical Assessment Paper contains the corrected analysis.

B. Analysis of Importance of Factors

1. Additional Analyses Since the ANPRM
    Since the ANPRM, new vehicles have been added to the data base and 
their metrics measured. Several make/models have been tested in 
different configurations to determine the range of metrics within a 
make/model, given the different available original equipment options. 
Also included are several make/models of trucks and vans with anti-lock 
brakes as standard equipment and several make/models of high sales 
volume passenger cars equipped with anti-lock brakes. A complete list 
of all vehicles measured to date, their tilt table angles and critical 
sliding velocities, and the ratio of the number of rollovers involving 
a particular vehicle model to the number of single vehicle accidents 
involving the same model (RO/SVA) in Michigan from 1986 through 1990 
can be found in Docket 91-68, Notice 2.
2. Predictive Power of the Metrics
    The agency performed two types of analyses attempting to separate 
the influence of driver characteristics, road, and environmental 
variables in the accident data so that the effect of vehicle rollover 
stability could be isolated. A logistic regression analysis 
individually considered every accident in a very large data base. Make/
models represented in a great number of accidents influenced the 
results more than make/models with fewer accidents. A linear regression 
analysis was also done on the rollover risk of make/models, adjusted 
for differences in driver and road characteristics within their 
individual accident data bases, but not weighted by differences in 
accident numbers. The two analyses are discussed in detail in the 
Addendum to Technical Assessment Paper.
    These analyses were conducted using three statistical models: (a) A 
model containing only driver, roadway, and environmental 
characteristics; (b) a model containing driver, roadway, and 
environmental characteristics, and critical sliding velocity; and (c) a 
model containing driver, roadway, and environmental characteristics, 
and tilt table angle. For the purposes of comparison, the analyses were 
limited to accidents involving those make/models for which the agency 
had both tilt table angle and critical sliding velocity data. This 
results in an equal number of accidents, or observations (88,397), in 
each statistical model.
    The logistic regression predicts whether a single vehicle accident 
will be a rollover based on the factors in a particular model. Then the 
predicted outcomes of the individual accidents are compiled to predict 
a rollover risk (rollovers per single vehicle accident) for each of the 
128 make/models for which the agency has data on both metrics. This 
predicted risk is then compared to the actual risk known from accident 
data on these make/models. Two numbers are presented in the table below 
for each of the statistical models. The first is the percent 
variability explained by the comparison of the rollover risk predicted 
by the logistic regression model and the actual rollover risk. The 
second number is the percentage of the variability unexplained by the 
model containing only driver, roadway, and environmental 
characteristics which is explained by the addition of either tilt table 
angle or critical sliding velocity. For example, the driver/road/
environmental model leaves 77 percent of the variability in the data 
unexplained; 23 percent is explained. When tilt table angle was added 
to the model to represent vehicle stability, 65 percent of the 
variability in rollover risk was explained. The difference between the 
77 percent unexplained variability in the driver/road variable model 
and the 35 percent unexplained variability of the driver/road variable 
plus tilt table angle model is 42 percent, which is 55 percent of the 
unexplained variability in the driver/road variable model (42 percent/
77 percent). Slightly more than half of the variability unaccounted for 
by driver and road characteristics was explained by the addition of 
tilt table angle. Thus, the logistic regression analysis indicates that 
stability, as measured by tilt table angle, is an important predictor 
of the likelihood of a single vehicle accident becoming a rollover. 
Substitution of critical sliding velocity produced similar results. A 
complete discussion of the results of these analyses can be found in 
the Addendum to Technical Assessment Paper in the docket.

 Table 1.--Results of Logistic Regression Analysis for All Vehicles for 
  Which Tilt Table Angle (TTA) and Critical Sliding Velocity (CSV) Are  
                                 Known                                  
------------------------------------------------------------------------
                                                              Percent   
                                                            variability 
                                              Percent       explained,  
                  Model                     variability    which is not 
                                             explained    explained by D/
                                                          R/E only model
------------------------------------------------------------------------
D/R/E only..............................              23              NA
D/R/E & TTA.............................              65              55
D/R/E & CSV.............................              75              68
------------------------------------------------------------------------

    The linear regression analysis also demonstrates the predictive 
power of tilt table angle and critical sliding velocity. This analysis 
showed that tilt table angle accounts for about 53 percent of the 
variability in rollover risk remaining after adjustment for differences 
in driver and road characteristics. The analysis showed that critical 
sliding velocity accounts for about 66 percent of the variability in 
rollover risk remaining after adjustments for driver and road 
characteristics. These compare to the 55 percent and 68 percent values 
found by logistic regression. These figures demonstrate that the two 
analytic methods are essentially in agreement regarding the statistical 
significance of stability metrics to the prediction of rollover.
    The results of both the logistic and linear regression analyses 
performed by the agency suggest that a vehicle stability metric alone 
can account for approximately 50 percent of the variability in rollover 
risk in single vehicle accidents, for the population of make/models 
studied. While ideally it would be desirable to have these variables 
explain 100 percent of the remaining variability, such statistical 
correlations are almost never achieved. The agency views these analyses 
as demonstrating sound statistical and causal relationships between 
these variables and the likelihood of rollover. At the same time, the 
analyses show that other factors in addition to those analyzed are 
affecting rollover risk, as 35 percent to 25 percent of the variability 
in rollover risk is still unexplained after accounting for the driver, 
roadway, and tilt table angle or critical sliding velocity, 
respectively.
    The above analyses used a Michigan accident data base combining 
passenger cars, pickup trucks, vans, and sport utility vehicles. As 
explained in section I, the rate of rollover fatalities and injuries 
per million registered vehicles is higher for sport utility vehicles 
and compact pickup trucks, but the absolute majority of harm occurs in 
passenger cars, because of their large numbers in use. In the current 
vehicle fleet, passenger cars generally have higher measured stability 
than light trucks. Thus, a safety standard requiring a minimum level of 
stability appropriate for all light duty vehicles would not be expected 
to affect many present or future small cars and therefore would not 
result in significant safety benefits. (For a further discussion of the 
problems associated with a minimum standard, see the section below 
entitled, ``Estimate of the Costs of a Standard.'')
    Hence, the agency also examined the relative predictive capability 
of the stability metrics to rollover risk for passenger cars and light 
trucks separately, to investigate the possibility of setting a higher 
minimum level of stability for passenger cars. The results are shown in 
the table below, including a comparison to the results for all vehicles 
considered as a single group (see Table 1). As with the analysis of all 
vehicles considered as a single group, these analyses were limited to 
make/models for which both tilt table angle and critical sliding 
velocity were known.

                    Table 2.--Results of Logistic Regression Analysis for Vehicles by Class                     
----------------------------------------------------------------------------------------------------------------
                                                         TTA as metric                    CSV as metric         
                                               -----------------------------------------------------------------
                                                Percent variability              Percent variability            
                Vehicle class                  ----------------------  Percent  ----------------------  Percent 
                                                  D/R/E                explain     D/R/E                explain 
                                                  only     + metric                only     + metric            
----------------------------------------------------------------------------------------------------------------
All vehicle...................................         23         65         55         23         75         68
Lt. Truck only................................         21         52         39         21         70         62
Car only......................................         39         56         28         39         63         39
----------------------------------------------------------------------------------------------------------------

    These results show that, while a good proportion of the variability 
remaining in the driver/road/environmental model is explained by either 
metric for the group containing all vehicles, when the vehicles are 
divided into classes, the results are not consistent. The inconsistency 
seen in the model results by vehicle class is, to some extent, the 
result of the smaller range of the metric within any subgroup of 
vehicles together with the inherent variability in the data. These 
analyses and the analyses of benefits and costs discussed later, 
indicate that different minimum standards for passenger cars and light 
trucks cannot be supported using either tilt table angle or critical 
sliding velocity.

VI. Decision Not To Propose a Vehicle Stability Standard

    As discussed previously, NHTSA concluded that both of the vehicle 
metrics, tilt table angle and critical sliding velocity, were 
statistically and causally related to the likelihood of rollover in a 
single vehicle crash. To determine whether to propose a vehicle 
stability standard, NHTSA next compared the benefits and costs of such 
a standard. A detailed discussion of the benefits analysis can be found 
in ``Potential Reductions in Fatalities and Injuries in Single Vehicle 
Rollover Crashes as a Result of a Minimum Rollover Stability 
Standard,'' which has been placed in Docket No. 91-68, Notice 03. A 
detailed discussion of the cost estimates can be found in the 
Preliminary Regulatory Evaluation, which has also been placed in Docket 
No. 91-68, Notice 03.

A. Estimate of the Benefits of a Standard

    The agency made two basic estimates of benefits of a minimum 
standard for rollover stability. One was based on the reductions in RO/
SVA predicted by the logistic regression model for increases in 
critical sliding velocity. The other was based on reductions in RO/SVA 
predicted for increases in tilt table angle. All other factors being 
equal, it is reasonable to expect an inverse relationship between 
rollover risk and either critical sliding velocity or tilt table angle. 
Thus, the higher the lateral sliding velocity necessary to trip a 
vehicle, the less likely it is to roll over, and vice versa. Similarly, 
the greater the angle necessary to tip a vehicle from the tilt table, 
the less likely it is to roll over, and vice versa.
    To quantify the benefits of potential minimum standards for 
rollover stability, NHTSA examined the net prevention of fatalities and 
serious injuries associated with various minimum levels of critical 
sliding velocity and tilt table angle. Fatality and injury levels were 
estimated by using:
    1. The reduction of the rollover risk predicted for increases in 
critical sliding velocity or tilt table angle;
    2. The number of single vehicle accidents per registered vehicle 
expected to occur; and
    3. The reduction in fatalities and/or injuries if a single vehicle 
accident does not result in a rollover.
    The estimate of the benefits of a minimum stability safety standard 
incorporated several simplifying assumptions. First, the agency assumed 
that the severity of the accidents would be reduced but that the 
accidents would not be prevented. Because single vehicle rollover 
accidents are more severe than single vehicle non-rollover accidents, 
prevention of rollover reduces the number of serious injuries and 
fatalities. However, under this scenario, the total number of single 
vehicle accidents is assumed to remain constant. This assumption is 
somewhat pessimistic, because an unknown number of crashes would most 
likely be avoided. But the remaining assumptions used may tend to 
overestimate the benefits since NHTSA also assumed:
    1. The numbers of rollover injuries and fatalities prevented would 
be proportional to the number of rollovers prevented, and
    2. The fatality and injury rates of the late 1980s for the make/
models which would be affected by a minimum standard will remain 
representative in the future.
    The second assumption may overstate the benefits if increased 
safety belt use in the 1990s, as is the goal of NHTSA, reduces the 
overall harm from rollover accidents. That is, as belt use increases, 
rollover casualties decrease, even though the number of rollover 
crashes remains constant.
1. Rollover Risk Reduction
    To estimate the reduction in the rollover risk that would be 
obtained by changing a vehicle metric, the agency used logistic 
regression to determine the sensitivity of rollover risk to changes in 
critical sliding velocity or tilt table angle. The outcome of each 
accident of the subject make/model in the data base was re-evaluated 
individually changing the stability metric but retaining the other 
vehicle, driver, and road characteristics present in the actual crash. 
A new RO/SVA ratio was determined on the basis of the predicted outcome 
of each accident.
    To examine the sensitivity of the model to a change in critical 
sliding velocity, the agency divided the range of critical sliding 
velocities from 14.26 to 16.73 kilometers per hour (kph). The low end 
of this range is representative of vehicles in NHTSA's database with 
the lowest critical sliding velocity. The high end of this range is 
representative of a critical sliding velocity equivalent to the 1.20 
value for static stability factor recommended in the Wirth petition 
(also equivalent to a tilt table angle of 46.4 degrees). (A discussion 
of the Wirth petition can be found in the ANPRM, 57 FR 242, 244-45.) 
The highest value in the range is greater than the proposed European 
tilt table angle limit of 44.3 degrees, and in the agency's judgement 
represents the highest practicable standard. A standard at the upper 
limit of the range would affect 1,648,000 vehicles manufactured in 
1991, including 87 percent of compact sport utility vehicles, 100 
percent of standard vans, and 31 percent of compact pickups.
    The agency then divided this range into six even increments and 
calculated the RO/SVA for each increment for various classes of 
vehicles. Each successively higher increment represents an increase in 
critical sliding velocity of 0.41 kph. The agency then predicted the 
decrease in single vehicle accident rollovers for each incremental 
increase in critical sliding velocity. (See Table 3.)

 Table 3.--Sensitivity of RO/SVA to Changes in CSV in kph Simulated by Logistic Regression Model for Vehicles of
                                                 CSV <16.73 kph                                                 
----------------------------------------------------------------------------------------------------------------
                                                                           CSV range kph                        
                    Make/model                    --------------------------------------------------------------
                                                    14.26    14.68    15.09    15.50    15.91    16.32    16.73 
----------------------------------------------------------------------------------------------------------------
Compact SUVs.....................................    0.434    0.420    0.406    0.391    0.378    0.364    0.350
Standard SUVs....................................    0.347    0.334    0.320    0.307    0.294    0.282    0.269
Compact Pickup...................................    0.355    0.341    0.328    0.314    0.301    0.288    0.276
Minivan..........................................    0.275    0.263    0.252    0.241    0.230    0.219    0.209
Standard Van.....................................    0.229    0.219    0.209    0.199    0.190    0.180   0.171 
----------------------------------------------------------------------------------------------------------------

    As an example, for vehicles with a critical sliding velocity 
between 14.26 and 16.73 kph, an increase of 12 percent in critical 
sliding velocity was predicted to decrease single vehicle accident 
rollovers of compact sport utility vehicles by about 13 percent, 
standard sport utility vehicles by about 15 percent, compact pickups by 
about 15 percent, and minivans by about 16 percent. There is only one 
standard van with a critical sliding velocity below 16.73 kph. Its 
rollover risk is predicted to decrease 17 percent if its critical 
sliding velocity were to increase 12 percent. A 12 percent increase in 
critical sliding velocity represents a change of 1.65 kph, or four 
increments. A complete discussion of these analyses can be found in the 
paper ``Potential Reductions in Fatalities and Injuries in Single 
Vehicle Crashes as a Result of a Minimum Stability Standard'' in the 
docket.
    A similar analysis was done using tilt table angle. For tilt table 
angle, each increment was approximately equivalent to 0.75 degrees. For 
vehicles with a tilt table angle between 42 and 46.4 degrees (the 
equivalent of the critical sliding velocity range), an increase of 11 
percent (also four increments, or 3.00 degrees) in tilt table angle was 
predicted to decrease single vehicle accident rollovers among compact 
sport utility vehicles by about 15 percent, standard sport utility 
vehicles by about 19 percent, compact pickups by about 17 percent, 
minivans by about 20 percent, and standard vans by about 22 percent. 
(See Table 4.)

  Table 4.--Sensitivity of RO/SVA to Changes in TTA Simulated by Logistic Regression Model for Vehicles of TTA  
                                                   <46.4 deg.                                                   
----------------------------------------------------------------------------------------------------------------
                                                                      TTA range                                 
             Make/model             ----------------------------------------------------------------------------
                                     42.0 deg.  42.8 deg.  43.5 deg.  44.3 deg.  45.0 deg.  45.7 deg.  46.4 deg.
----------------------------------------------------------------------------------------------------------------
Compact SUVs.......................     0.465      0.448      0.430      0.413      0.396      0.380      0.363 
Standard SUVs......................     0.293      0.278      0.264      0.249      0.236      0.223      0.210 
Compact Pickup.....................     0.406      0.388      0.370      0.353      0.336      0.319      0.302 
Standard Van.......................     0.178      0.168      0.158      0.148      0.139      0.130      0.122 
Minivan............................     0.265      0.251      0.238      0.225      0.212      0.200     0.189  
----------------------------------------------------------------------------------------------------------------

2. Predicted Single Vehicle Accident Rate
    To estimate the number of single vehicle accidents in a 
hypothetical future vehicle population, NHTSA assumed that the future 
population would have the same proportion of vans, pickups, and sport 
utility vehicles as the 1991 production, and that the population would 
have the same proportion of high and low critical sliding velocity and 
tilt table angle vehicles within these categories.
    NHTSA then distributed the numbers of serious injuries by vehicle 
category (as tabulated by Data Link Inc., under contract to NHTSA) 
among the 1991 example vehicles on the basis of relative production 
volume, relative single vehicle accident involvement rate, and relative 
rollover risk per single vehicle accident. (The Data Link reports are 
available in Docket 91-68, Notice 2.) Data Link reported injuries and 
fatalities by vehicle types: pickup truck, van, sport utility vehicle 
(called MPV in Data Link reports), and car. NHTSA further divided the 
vehicle types into subcategories of compact and standard to make 
average accident rate and rollover risk more meaningful.
    NHTSA also divided injuries and fatalities between compact and 
standard versions of each vehicle type. To do this, NHTSA assumed that 
rollover harm was proportional to the number of rollover accidents 
within a vehicle type. The numbers of rollover accidents among compact 
vehicles relative to those among their standard counterparts were 
estimated by multiplying their 1991 production ratios by their single 
vehicle accident per registered vehicle ratios and their RO/SVA ratios. 
The total number of injuries and fatalities was then divided 
proportionally.
    The reduction in rollover harm for each type/size category is a 
summary of the reductions in injuries and fatalities for each example 
vehicle within the category if the tilt table angle for the category 
were increased a specified level. The reduction in harm associated with 
each affected vehicle is assumed to be proportional to its projected 
reduction in rollover risk. A minimum tilt table angle standard of 42.8 
degrees, an increase of one increment explained above, would be 
expected to reduce serious rollover injuries by 13 and rollover 
fatalities by 8. A minimum tilt table angle standard of 46.4 degrees, 
the highest measurement in the range studied, would be expected to 
reduce serious rollover injuries by 233 and rollover fatalities by 121, 
if rollover avoidance were viewed as crash avoidance. A parallel 
exercise was done using the rollover risk predicted using critical 
sliding velocity as the stability metric in the logistic regression 
model.
3. Injury/Fatality Rate Reduction
    Because the agency assumed that a single vehicle accident would 
still occur even though a rollover was prevented, it reduced these 
estimates of benefits based on a comparison of the relative harm of 
single vehicle accidents with rollover to that of similar accidents 
without rollover. The comparison indicated that the overall fatality 
rate for single vehicle rollover accidents was 2.07 times the fatality 
rate for single vehicle accidents without rollover. When only accidents 
occurring on roads with speed limits of 40-50 mph are considered, the 
rollover accidents are 2.3 times as likely to result in fatality. When 
accidents on 55-65 mph roads are considered, the fatality rate of 
rollover accidents is 1.6 times that for other accidents. These 
statistics suggest that rollover prevention is equivalent to about a 50 
percent reduction in fatalities for the number of accidents in which 
rollovers would be prevented.
    Likewise, the injury data indicate an overall relative rate of 
serious injuries (AIS 3+) 1.36 times greater for single vehicle 
accidents with rollover than without rollover. The ratio of AIS 3+ 
injuries in non-rollover to AIS 3+ injuries in rollovers was 1.38 for 
accidents occurring on roads with speed limits of 40-50 mph and 1.47 
for accidents occurring on 55-65 mph roads. These statistics suggest 
that rollover prevention is roughly equivalent to a 25 percent 
reduction in serious injuries for the number of accidents in which 
rollovers would be prevented.
    Viewing rollover prevention as roughly a 50 percent mitigation of 
fatalities and a 25 percent mitigation of serious injuries leads to an 
estimate of net benefits resulting from the reduction in harm from 
rollover accidents. Net reductions of 3 to 61 serious injuries and 4 to 
63 fatalities would be expected for a minimum tilt table angle standard 
in the range of 42.8 to 46.4 degrees. Net reductions of 3 to 68 serious 
injuries and 2 to 68 fatalities would be expected for a minimum 
critical sliding velocity standard in the range studied, i.e., 14.68 to 
16.73 kph.
    Minimum rollover stability requirements at the levels examined 
would have minimal impact on the annual single vehicle accident 
rollover fatality toll, because the vehicles affected would be less 
than 20 percent of the total light duty vehicle fleet and the vehicles' 
stability would only be improved by a marginal amount.
    The great majority of rollover fatalities would be unaffected by a 
minimum stability standard set at any of these levels, because they 
occur in cars, which greatly outnumber light trucks in use, and which, 
with few exceptions, have significantly higher rollover stability than 
sport utility vehicles, pickup trucks, and vans.

B. Estimate of the Costs of a Standard

    As explained above, the agency's analyses predicted a saving of 63 
lives for a minimum tilt table angle of 46.4 degrees. This level would 
necessitate the modification of an estimated 87 percent of present 
compact sport utility vehicles and virtually all present standard vans. 
A minimum tilt table angle of 45 degrees, which is higher than the tilt 
table angle of 69 percent of present compact sport utility vehicles, 
could save 23 lives. Similarly, a minimum critical sliding velocity 
standard of 16.73 kph would affect 89 percent of present compact sport 
utility vehicles, 38 percent of standard sport utility vehicles, and 38 
percent of compact pickups, while saving 68 lives. A critical sliding 
velocity minimum standard of 15.91 kph would affect 71 percent of 
compact sport utility vehicles and 31 percent of compact pickups, while 
saving 34 lives.
    Unfortunately, inexpensive vehicle changes, such as offset wheels 
or modified tire and rim width combinations, cannot be counted on to 
improve stability without producing handling or steering problems. An 
increase in track width, derived from frame or suspension alterations, 
or a decrease in center of gravity height are the only methods of 
improving stability without potential safety liabilities. Such changes 
would require large initial costs related to the design and development 
of major vehicle components, if not the entire vehicle.
    These costs do not take into account the cost of the tests 
necessary to determine the tilt table angle or critical sliding 
velocity. Because these costs will also be associated with the proposed 
consumer information regulation, the testing costs are discussed later 
in this notice.
    Some of the changes necessary to comply with a minimum standard may 
also be incompatible with some of the vehicle characteristics many 
consumers seek in vehicles such as sport utility vehicles, vans, motor 
homes, and campers. For example, in the case of sport utility vehicles, 
the capability to operate in off-road conditions may require both high 
ground clearance (necessitating a relatively high center of gravity) 
and narrow width to maneuver in wooded or rocky areas (necessitating a 
relatively narrow track width). Section 103(f)(3) of the National 
Traffic and Motor Vehicle Safety Act provides that a Federal motor 
vehicle safety standard must be reasonable and appropriate for each 
vehicle type to which it applies, and therefore NHTSA could not mandate 
a stability requirement incompatible with certain types of vehicles. In 
addition, the manufacturers of many of these types of vehicles would be 
considered small businesses, and a standard could raise concerns under 
the Regulatory Flexibility Act.
    Another possible cost of a minimum rollover standard is decreased 
fuel economy. Compact sport utility vehicles have become popular, in 
part, because the original sport utility vehicles, which were larger, 
heavier, and more stable against rollover, were also more difficult to 
park and maneuver and had very poor fuel mileage. The compact sport 
utility vehicles with higher stability tend to be the larger vehicles 
in the class, or open vehicles with less mass in the top. A stability 
standard would be expected to cause a growth in size and weight of 
compact sport utility vehicles and a reduction in fuel mileage.

C. Conclusions

    Based on these estimates of the benefits and costs of a minimum 
stability standard, NHTSA believes that the benefits would not be 
sufficient to justify the expected costs. Therefore, as noted above, 
NHTSA has decided to defer any further action on this subject until 
information becomes available demonstrating the cost effectiveness of 
such a rule. The agency may reinitiate such a rulemaking upon receipt 
of such information. This termination of rulemaking on vehicle 
stability fulfills the statutory mandate of Section 2502(b)(2)(B)(i).
    While the agency is terminating rulemaking on a vehicle stability 
standard, NHTSA believes that the correlation between stability and 
rollover risk is significant enough to justify proposing a consumer 
information regulation to relieve the possibility of uninformed risk. 
The agency's decision to propose such a regulation is explained below.

VII. Proposed Consumer Information Regulation

A. Rationale

    NHTSA is proposing a new consumer information regulation requiring 
manufacturers to report the stability metric of cars and light trucks 
to enable consumers to make more informed choices concerning the trade-
offs of vehicle attributes and rollover stability. NHTSA believes that 
a consumer information regulation would inform drivers of general 
differences in stability between light trucks and cars, and among 
vehicles in those classes so that consumers can make an informed choice 
concerning relative rollover risk. This regulation would inform drivers 
who still chose a less stable vehicle that they may wish to drive more 
cautiously in certain circumstances and that the higher risk of driving 
low stability vehicles can be greatly reduced by using safety belts. In 
addition, NHTSA believes that a consumer information regulation would 
motivate manufacturers to give more priority to rollover stability in 
the design of new vehicles. NHTSA believes these goals can be 
accomplished with a minimum burden on industry and consumers.
    NHTSA believes that consumer and manufacturer behavior can be 
affected through the provision of consumer information. The agency's 
experience with the New Car Assessment Program (NCAP) demonstrates the 
power of consumer information. Several manufacturers have informed the 
agency that they have internal goals of performing well in these 35 mph 
frontal crash tests, even though there is no regulatory requirement to 
do so. The lowering of the injury scores over time for all 
manufacturers, as reported in ``Report on the Historical Performance of 
Different Auto Manufacturers in the New Car Assessment Program Tests'', 
NHTSA, August 1993, can also be attributed partially to NCAP. The 
attention of the media to the program and the more than 20,000 calls 
annually to NHTSA's Hotline, the most for any NHTSA consumer 
information activity, speak to the consumer's interest in relevant 
consumer safety information. As to whether consumers want information 
on rollover, recent agency focus groups indicate they would (``Focus 
Groups on Traffic Safety Issues: Public Response to NCAP,'' S.W. Morris 
& Company, Inc., August 1993, which can be found in Docket No. 79-17, 
Notice 01). The consensus of the focus groups was that the agency's 
consumer safety information activities should be expanded to include 
additional kinds of crashes, including rollover. Consumers also desired 
point of sale information, which would be satisfied with the proposed 
vehicle sticker requirement.
    NHTSA does not agree with those manufacturers who believe that 
labeling vehicles with stability information will mislead consumers or 
that consumers would consider the metric an absolute measure of the 
likelihood of rollover, regardless of driver behavior or roadway 
conditions. It has never been shown that improvements in safety or 
availability of information regarding safety increase risk-taking. In 
addition, the proposed label not only contains the stability 
information, it contains the statements: ``All vehicles roll over! 
Always wear seat belts! In a rollover crash, an unbelted person is 6 to 
9 times more likely to die than a person wearing a seat belt.'' These 
statements emphasize to the consumer that a vehicle with a higher 
stability rating can still roll over.
    NHTSA is considering two possible options for specifying the 
stability metric. Under option one, NHTSA would select one of two 
metrics, critical sliding velocity or tilt table angle, and require the 
metric to be stated for each vehicle. NHTSA requests comments on which 
metric is preferable if NHTSA selects only one metric. (Note: The 
proposed regulatory text in this notice illustrates this option first 
for critical sliding velocity, and then for tilt table angle.) Under 
option two, NHTSA would not require a metric to be stated. Instead, the 
agency would require vehicles to be labeled with a statement concerning 
the rollover stability (e.g., one, two, or three stars) based on 
vehicle performance when tested for one or both of the metrics.

B. Proposed Label

    NHTSA is proposing to require three types of information on the 
label and in owner's manuals. First, manufacturers would be required to 
include the stability metric for that vehicle. This information would 
either be the same as that reported by the manufacturer to NHTSA (for 
option one) or the ``rating'' provided by NHTSA (for option two). This 
metric would be required to be reported ``accurate to the nearest 
kilometer per hour'' for critical sliding velocity and ``accurate to 
the nearest degree'' for tilt table angle. As explained in the 
discussion of the two metrics in this notice, NHTSA believes that the 
test procedure for both metrics produces results repeatable to this 
degree of accuracy. Manufacturers would be allowed to choose which 
models and configurations could be grouped together, because they have 
the same metric, for the purpose of reporting metrics. However, for 
each metric reported by a manufacturer, the manufacturer would have to 
fully describe the vehicles to which the metric applies.
    Second, the label would be required to contain the metric or rating 
ranges provided by NHTSA for both passenger cars and light trucks. The 
purpose of this requirement is to emphasize to consumers that there are 
significant differences between the stability of the average passenger 
car and that of the average truck-based vehicle. This information would 
allow consumers to make an informed choice in purchasing a passenger 
car or a truck-based vehicle and to compare a vehicle they are 
considering to other vehicles in its class.
    Third, NHTSA is proposing to require a warning to inform consumers 
that all vehicles can, and do, roll over and that the best protection 
against injury or fatality, should a rollover occur, is wearing seat 
belts.

C. Stability Metrics

    As noted above, NHTSA's analyses indicate that there are two 
metrics, critical sliding velocity and tilt table angle, which 
correlate well with rollover accident data. Either of these metrics 
could be used in a stability labeling regulation. Each has its 
advantages and disadvantages.
    Critical sliding velocity, a dynamic metric, includes the influence 
of roll moment of inertia as well as the various static factors 
included by the static metrics such as tilt table angle. The advantage 
of critical sliding velocity is that it more consistently predicts 
rollover risk for light trucks. The disadvantage is that calculation of 
critical sliding velocity requires knowledge of the vehicle's center of 
gravity height and roll mass moment of inertia. These two parameters 
are difficult to measure on complete vehicles and require specialized 
equipment to obtain accurate results. However, these parameters can be 
measured on vehicle components and manufacturers of complete vehicles 
could calculate center of gravity height and roll mass moment of 
inertia of complete vehicles from data they have on component 
parameters. However, the agency is unsure whether final stage 
manufacturers and alterers of specialty vehicles are provided enough 
information from incomplete vehicle manufacturers to do this.
    Tilt table angle, a static metric, is simple and inexpensive to 
measure. The nature of the test is easy for the consumer to understand. 
The disadvantage of this metric stems from the statistical relationship 
between tilt table angle and accident data. The correlation between 
tilt table angle and accident data breaks down if passenger cars are 
analyzed separately from light trucks. Further, statistical models 
containing tilt table angle data consistently overestimate the rollover 
risk for standard vans.
1. Critical Sliding Velocity
    Critical sliding velocity, in kilometers per hour, is determined 
from the equation:



where,



and
Ixx = roll mass moment of inertia of the vehicle, in kilogram-
kilometers\2\
g = gravitational constant, in kilometers/hour\2\
M = mass of the vehicle, loaded, in kilograms
hcg = center of gravity height of the vehicle, in kilometers
TW = the average of the front and rear track width of the vehicle, in 
kilometers.

    Calculation of critical sliding velocity requires knowledge of the 
vehicle's mass, track width, center of gravity height, and roll moment 
of inertia. NHTSA agrees with commenters that the center of gravity 
height and roll moment of inertia are complicated measurements. To 
address comments on the repeatability of center of gravity height 
measurement, NHTSA reviewed two reports.
    The study ``Center of Gravity Height: A Round-Robin Measurement 
Program,'' sponsored by the Motor Vehicle Manufacturers Association and 
conducted by the University of Michigan Transportation Research 
Institute (UMTRI-91-4) compared the test facilities, procedures, and 
results of center of gravity height measurements at four laboratories. 
Each of the four laboratories used different test equipment and 
procedures. The study concluded that different measurement procedures 
can produce significantly different results. However, the study also 
concluded that for each laboratory and test procedure, repeatability 
was very good.
    Another study, ``Vehicle Inertial Parameters--Measured Values and 
Approximations,'' by Garrott et al. (Society of Automotive Engineers 
#881767) shows the coefficient of variation of center of gravity height 
at the Vehicle Research and Test Center (VRTC) facility to be 0.8 
percent. The measurements used in the analyses of the relationship of 
critical sliding velocity and single vehicle rollover accidents came 
from the VRTC facility.
    Based on these studies, NHTSA believes that measurements of center 
of gravity height and roll moment of inertia are repeatable within an 
individual laboratory using a specified procedure. NHTSA also believes 
that these measurements would be repeatable among different 
laboratories if all were using the same test procedure. The agency has 
data on a group of six make/models of light trucks and one make/model 
of car for which tests were run on identical vehicles, or repeated 
tests were run on the same vehicle. The results for all of these tests 
show the repeatability of critical sliding velocity to be well within 
the required accuracy of one kilometer per hour. Therefore, NHTSA 
tentatively concludes that the test procedure proposed in this notice 
would produce repeatable results. The proposed regulatory text does not 
include language for either the test equipment or the test procedure. 
The test equipment to be used in the procedure is VTRC's Inertial 
Parameter Measuring Device (IPMD). The equipment is described in United 
States Patent No. 5,177,998. VRTC is in the process of refining the 
test procedure for use with the IPMD, which is described in the report, 
``Vehicle Inertial Parameters--Measured Values and Approximations,'' by 
Garrott et al. of NHTSA's VRTC. Copies of both the patent and the 
report have been placed in Docket No. 91-68, Notice 03.
2. Tilt Table Angle
    Some commenters to the ANPRM stated that the tilt table procedure 
is not standard practice and its repeatability is not known. Other 
commenters stated that the procedure was repeatable.
    NHTSA examined two studies which concluded that the tilt table test 
is a simple, repeatable method of estimating the static roll stability 
of a vehicle. ``Sensitivity Analysis of the Tilt Table Test 
Methodology'' is a study sponsored by the Motor Vehicle Manufacturers 
Association and conducted by the University of Michigan Transportation 
Research Institute (UMTRI-91-48 December 1991). UMTRI found the tilt 
table test to be repeatable in their laboratory and found nothing to 
prevent site-to-site reproducibility. The other study is a NHTSA study 
which found the following parameters to be critical to achieving an 
accurate tilt table angle: slow, steady lift rate, minimal platform 
deflection, platform angle measurement accurate to 0.1 degree, and 
accuracy of measurement of the point at which the last tire leaves the 
table (DOT HS 807 747 May 1991).
    Based on these studies, NHTSA believes that the tilt table test 
would result in repeatable measurements if conducted under specified 
conditions. The agency's results for either tests on identical vehicles 
or multiple tests on the same vehicle show the repeatability of tilt 
table angle to be within the required accuracy of one degree. To ensure 
repeatability, NHTSA has included specific test conditions in the tilt 
table angle test procedure.

D. Timing of Information Provided by the Manufacturers and NHTSA

    By each January 1st, each manufacturer would be required to report 
to NHTSA the stability metric for each vehicle to be manufactured on or 
after the next September 1 and on or before the first August 31 
following that September 1st. Thus, the information for ``1997 model 
year'' vehicles (vehicles manufactured between September 1, 1996 and 
August 31, 1997) would have to be reported by January 1, 1996. NHTSA 
recognizes that not all manufacturers change to production of a new 
model year on the same date. If a manufacturer changes production on a 
date after September 1, and the difference between model years affects 
the stability metric, the manufacturer would have to report a metric 
for two ``vehicles'' for a single make/model. NHTSA requests comments 
on these proposed dates. NHTSA would consider changing the beginning 
and ending date of the annual production period specified in this 
regulation if there was a different date that coincides with a majority 
of manufacturers' ``model year.''
    If option one, which is a quantitative measure based on vehicle 
metric calculations, were chosen for a final rule, NHTSA would use the 
information provided by the manufacturers to supply manufacturers with 
ranges for all passenger cars and light trucks for the upcoming model 
year by April 1 of that year (i.e., in the above example, NHTSA would 
provide manufacturers ranges for 1997 model year vehicles by April 1, 
1996.) If option two were chosen, NHTSA would use the information 
provided to provide manufacturers with the ``rating'' which must be 
labeled on the vehicle. Since there is a possibility that this 
information could not be provided by April 1, the agency requests 
comments on how much leadtime manufacturers would need to place the 
information on labels and in owner's manuals on all vehicles 
manufactured on or after September 1.
    NHTSA is proposing to make this new regulation effective on January 
1, 1996, based on the presumption that this would give manufacturers at 
least one year to complete testing necessary to report the tilt table 
angle and/or critical sliding velocity for all vehicles following 
publication of a final rule.

E. Benefits

    As stated previously, NHTSA anticipates that this consumer 
information regulation will result in a more informed public which, 
through purchasing and/or driving decisions, could improve motor 
vehicle safety. Similarly, consumer purchasing behavior could affect 
manufacturers' design and/or marketing of vehicles. The agency is 
unable to quantify at this time the benefits of this rulemaking. A more 
detailed discussion of the possible benefits of this rulemaking can be 
found in the Preliminary Regulatory Evaluation.

F. Costs

    The costs associated with the proposed consumer information 
regulation would arise from three different activities: generating the 
stability metric for the label, printing the labels, and affixing 
labels to the vehicles. This rule would not require manufacturers to 
make vehicle changes. While such modifications are desirable, they are 
not mandated, and if they occurred, would be the indirect result of 
market forces and not a direct result of this rulemaking.
    As explained in detail in the Preliminary Regulatory Evaluation, 
NHTSA estimates that the total testing and labeling costs of a 
regulation based on critical sliding velocity would range from $4.71 to 
$6.35 million and the total cost of a regulation based on tilt table 
angle would range from $3.93 to $5.57 million.

VIII. Final Stage Manufacturers and Alterers

    NHTSA requests comments on how final stage manufacturers and 
alterers would comply with the proposed consumer information 
regulation. Would final stage manufacturers and alterers have 
sufficient information on upcoming model year vehicles to report the 
tilt table angle and/or critical sliding velocity of the vehicles they 
will be producing by January 1 as required? How much information can 
incomplete vehicle manufacturers pass on to final stage manufacturers 
to assist them in predicting the tilt table angle or critical sliding 
velocity of the final vehicle, and when?
    NHTSA also asks for comment on how many vehicles in this category 
would have a GVWR of 4,536 kilograms or less.
    Given that many of these vehicles are manufactured for special 
uses, NHTSA requests comments on whether certain types of vehicles 
(e.g., walk-in van-type vehicles, campers, and motor homes) should be 
excluded from the consumer information requirement. Would consumer 
choice for these special-use vehicles be affected by the information 
provided by this proposed regulation?

IX. Rulemaking Analyses and Notices

A. Executive Order 12866 and DOT Regulatory Policies and Procedures

    NHTSA has examined the impact of this rulemaking action and 
determined that it is ``significant'' within the meaning of E.O. 12866 
and the Department of Transportation's regulatory policies and 
procedures. This rulemaking was reviewed under E.O. 12866. The agency's 
detailed analysis of the economic effects can be found in the 
Preliminary Regulatory Evaluation available in the docket for this 
rulemaking. The agency estimates that the proposed regulation would 
cost $3.93 to $6.35 million annually.

B. Regulatory Flexibility Act

    NHTSA has also considered the impacts of this notice under the 
Regulatory Flexibility Act. I hereby certify that this proposed rule 
would not have a significant economic impact on a substantial number of 
small entities. As explained above, NHTSA does not expect any 
significant economic impacts from this proposed rule. While the agency 
has asked questions regarding the availability of data to certain 
manufacturers who could be small businesses (final stage manufacturers 
and alterers), NHTSA believes that these manufacturers will be able to 
obtain sufficient information on the vehicles they complete or alter 
that this proposed regulation will not impose a significantly different 
burden on these manufacturers.

C. Paperwork Reduction Act

    The reporting requirements associated with this proposed rule will 
be submitted to the Office of Management and Budget for approval in 
accordance with 44 U.S.C. chapter 35. Administration: National Highway 
Traffic Safety Administration; Title: Vehicle Rollover Stability 
Consumer Information Regulation; Need for Information: To determine 
vehicle metric ranges for each model year; Proposed Use of Information: 
Metric ranges will be provided to manufacturers for inclusion on 
vehicle label; Frequency: Annual; Burden Estimate: 192 hours; 
Respondents: 24; Form(s): None; Average Burden Hours for Respondent: 8.

D. National Environmental Policy Act

    NHTSA has also analyzed this proposed rule under the National 
Environmental Policy Act and determined that it would not have a 
significant impact on the human environment.

E. Executive Order 12612 (Federalism)

    NHTSA has analyzed this proposal in accordance with the principles 
and criteria contained in E.O. 12612, and has determined that this 
proposed rule would not have significant federalism implications to 
warrant the preparation of a Federalism Assessment.

F. Civil Justice Reform

    This proposed rule would not have any retroactive effect. There is 
no express statutory intent to preempt any State law. Section 105 of 
the Safety Act (15 U.S.C. 1394) sets forth a procedure for judicial 
review of final rules. That section does not require submission of a 
petition for reconsideration or other administrative proceedings before 
parties may file suit in court.

X. Effective Date of Final Rule

    If adopted, the proposed amendments would become effective on 
January 1, 1996.

XI. Submission of Comments

    Interested persons are invited to submit comments on the proposal. 
It is requested but not required that 10 copies be submitted.
    All comments must not exceed 15 pages in length. (49 CFR 553.21). 
Necessary attachments may be appended to these submissions without 
regard to the 15-page limit. This limitation is intended to encourage 
commenters to detail their primary arguments in a concise fashion.
    If a commenter wishes to submit certain information under a claim 
of confidentiality, three copies of the complete submission, including 
purportedly confidential business information, should be submitted to 
the Chief Counsel, NHTSA, at the street address given above, and seven 
copies from which the purportedly confidential information has been 
deleted should be submitted to the Docket Section. A request for 
confidentiality should be accompanied by a cover letter setting forth 
the information specified in the agency's confidential business 
information regulation. 49 CFR part 512.
    All comments received before the close of business on the comment 
closing date indicated above for the proposal will be considered, and 
will be available for examination in the docket at the above address 
both before and after that date. To the extent possible, comments filed 
after the closing date will also be considered. Comments received too 
late for consideration in regard to the final rule will be considered 
as suggestions for further rulemaking action. Comments on the proposal 
will be available for inspection in the docket. The NHTSA will continue 
to file relevant information as it becomes available in the docket 
after the closing date, and it is recommended that interested persons 
continue to examine the docket for new material.
    Those persons desiring to be notified upon receipt of their 
comments in the rules docket should enclose a self-addressed, stamped 
postcard in the envelope with their comments. Upon receiving the 
comments, the docket supervisor will return the postcard by mail.

List of Subjects in 49 CFR Part 575

    Consumer protection, Incorporation by reference, Labeling, Motor 
vehicle safety, Motor vehicles.

    In consideration of the foregoing, it is proposed that 49 CFR part 
575 be amended as follows:

PART 575--CONSUMER INFORMATION REGULATIONS

    1. The authority citation for part 575 of title 49 would continue 
to read as follows:

    Authority: 15 U.S.C. 1392, 1401, 1407, 1421, and 1423; 
delegation of authority at 49 CFR 1.50.

    2. Part 575 would be amended by adding a new Sec. 575.102 to read 
as follows:


Sec. 575.102   Vehicle Rollover Stability.

    (a) Purpose and Scope. This section requires motor vehicle 
manufacturers to provide information on the resistance of vehicles to 
rollover to aid consumers in making an informed choice in the purchase 
of new motor vehicles.
    (b) Application. This section applies to passenger cars, and to 
multipurpose passenger vehicles and trucks with a GVWR of 4,536 
kilograms or less, and to manufacturers and dealers of such vehicles.

Alternative One

    (c) Definition.--Nearest kilometer per hour means the next lower 
whole kilometer per hour, in the case of a calculated critical sliding 
velocity value (expressed in kilometers per hour) that falls above a 
whole number by 0.00 to 0.49 kilometers per hour, and the next higher 
whole kilometer per hour, in the case of a calculated critical sliding 
velocity value (expressed in kilometers per hour) that falls above a 
whole number by 0.50 to 0.99 kilometers per hour.
    Critical Sliding Velocity (CSV) for a vehicle is the value 
determined, in kilometers per hour, from the equation:



where,



and

Ixx=roll mass moment of inertia of the vehicle, in kilogram-
kilometers2
g=gravitational constant, in kilometers/hour2
M=mass of the vehicle, loaded, in kilograms
hcg=center of gravity height of the vehicle, in kilometers
TW=the average of the front and rear track width of the vehicle, in 
kilometers.

    Production year means the period from September 1 of a calendar 
year to August 31 of the next calendar year, inclusive.
    Vehicle means a group of vehicles within a make, model, or car 
division which have a degree of commonality in construction (e.g., 
body, chassis). It does not consider any level of decor, opulence, or 
other characteristics that do not affect CSV.
    (d) Reporting Requirements--(1) Reporting. On or before January 1 
of each calendar year, beginning with the 1996 calendar year, each 
manufacturer shall report to the Administrator a CSV for each vehicle 
to be manufactured in the production year beginning on September 1 of 
that calendar year. The CSV shall be accurate to the nearest kilometer 
per hour. In reporting a CSV, the manufacturer shall list the 
vehicle(s) to which it applies.
    (2) Information. On or before April 1 of each calendar year, 
beginning with the 1996 calendar year, the Administrator, based on the 
information provided by all manufacturers under paragraph (d)(1) of 
this section, provides manufacturers with the passenger car and 
multipurpose passenger vehicle/truck CSV ranges to appear on the 
vehicle label and in the owner's manual under paragraphs (e)(1)(i) 
through (e)(1)(iii) of this section.
    (e) Label--(1) Attachment and Maintenance of Label. (i) Each 
vehicle manufactured on or after September 1, 1996 shall have affixed 
to it a vehicle rollover stability label as described in paragraph 
(e)(3) of this section. Each manufacturer shall affix or cause to be 
affixed the labels required by this paragraph at the final assembly 
point.
    (ii) Each dealer shall maintain or cause to be maintained, any 
vehicle rollover stability label on the vehicles it receives until the 
vehicles are sold to consumers for purposes other than resale. If a 
label becomes damaged so that any of the information on it is not 
legible, the dealer shall replace it by affixing an identical, 
undamaged label.
    (iii) Each vehicle required by paragraph (e)(1)(i) of this section 
to have a vehicle rollover stability label shall have in the vehicle 
owner's manual the same information required to be on the label under 
paragraphs (e)(3)(i) through (e)(3)(vii) of this section.
    (2) Location of Label. (i) The label required by paragraph 
(e)(1)(i) of this section shall be affixed on a side window of the 
vehicle in a manner so that it can be read from outside the vehicle.
    (ii) The label shall be either a separate label, a part of the 
price information label required by 15 U.S.C. Sec. 1232, or a part of 
the fuel economy label required by 15 U.S.C. Sec. 2006. If the rollover 
stability label is separate and the window is not large enough to 
contain both the price information label and the rollover stability 
label, it shall be affixed on a side window, as close as possible to 
the price information label.
    (3) Label Requirements. (i) Each rollover stability label shall be 
rectangular, not less than 114 mm high by 178 mm wide, and shall be in 
the exact format shown in Figure 1. Each label shall bear the exact 
wording shown in Figure 1. The CSV in the circle shall be the CSV 
reported to the Administrator pursuant to paragraph (d)(1) of this 
section for the labeled vehicle and the square brackets shall be 
replaced by CSV range data given to the vehicle manufacturer by the 
Administrator pursuant to paragraph (d)(2) of this section for the 
production year of the labeled vehicle.

BILLING CODE 4910-59-P




BILLING CODE 4910-59-C
    (ii) The color of the label picture and text shall contrast with 
the background of the label.
    (iii) All rollover stability information on the label shall be 
completely surrounded by a border at least 3 mm wide which contrasts 
with the background of the label.
    (iv) The title, ``Vehicle Rollover Stability,'' shall be centered 
over the label and shall be printed in bold caps no smaller than 12 
points.
    (v) The remainder of the label text shall be 10 points.
    (vi) The illustration of the vehicle in Figure 1 shall be centered 
in a square not less than 50 mm on each side. The inside diameter of 
the circle in which the CSV appears shall be no smaller than 16 mm. The 
CSV figure shall be centered in the circle and no smaller than 10 mm in 
height.
    (f) Test Conditions--(1) Test Device. Measurement of center of 
gravity height and roll moment of inertia are done on the Inertial 
Parameter Measuring Device (IPMD). The IPMD is described in United 
States Patent No. 5,177,998. A copy of the patent is available in 
Docket No. 91-68, Notice 03.
    (2) Vehicle--(i) The test vehicle has all fluids, other than fuel, 
at the full level. The fuel tank and the fuel system are filled as 
specified in S7.1.1 and S7.1.2 of Sec. 571.301 of this title.
    (ii) The vehicle's seat is positioned according to S8.1.2 and 
S8.1.3 of Sec. 571.208 of this title.
    (iii) Tires used during the test are of the same size and 
construction recommended by the manufacturer for the vehicle. The tires 
have accumulated not less than 80 and not more than 1620 kilometers. 
Not less than 80 of those kilometers are accumulated at a speed of not 
less than 80 kilometers per hour. All tires are clean and dry. All 
tires are inflated to the vehicle manufacturer's recommended inflation 
pressure for maximum vehicle loading and measured when the tire is 
cold.
    (iv) All vehicle openings (doors, windows, hood, trunk, convertible 
top, etc) are in the closed position.
    (3) Load. A Hybrid III Test Dummy, as defined in Subpart E of 
Sec. 572 of this title, is placed in the left front seating position, 
positioned according to S11 of Sec. 571.208 of this title, and secured 
with the vehicle's safety belt system, whether manual or automatic. The 
dummy may be placed in the test vehicle before or after moving the 
vehicle onto the test device. The test vehicle carries no load other 
than the test dummy.
    (4) Ambient conditions. The measurements of the center of gravity 
height and roll mass moment of inertia are made with both the vehicle 
and the test device at a temperature not less than 4 and not more than 
39 degrees Celsius. Air motion around the vehicle and device is less 
than 6 kilometers per hour.
    (g) Test Procedures. The test procedure for use with the IPMD is 
described in the report, ``Vehicle Inertial Parameters--Measured Values 
and Approximations,'' by Garrott et al. of NHTSA's VRTC. A copy of the 
report is available in Docket No. 91-68, Notice 03.

Alternative Two

    (c) Definitions--Nearest degree means the next lower whole degree, 
in the case of a measurement that falls above a whole number by 0.00 to 
0.49 degrees, and the next higher whole degree, in the case of a 
measurement that falls above a whole number by 0.50 to 0.99.
    Production year means the period from September 1 of a calendar 
year to August 31 of the next calendar year, inclusive.
    Tilt table angle (TTA) means, with respect to a motor vehicle 
placed on a tilt table, the angle between the horizontal and the 
platform of the tilt table when the last uphill tire of the vehicle 
ceases contact with the platform surface.
    Vehicle means a group of vehicles within a make, model, or car 
division which have a degree of commonality in construction (e.g., 
body, chassis). It does not consider any level of decor, opulence, or 
other characteristics that do not affect TTA.
    (d) Reporting Requirements--(1) Reporting. On or before January 1 
of each calendar year, beginning with the 1996 calendar year, each 
manufacturer shall report to the Administrator a TTA for each vehicle 
to be manufactured in the production year beginning on September 1 of 
that calendar year. The TTA shall be accurate to the nearest degree. In 
reporting a TTA, the manufacturer shall list the vehicle(s) to which it 
applies.
    (2) Information. On or before April 1 of each calendar year, 
beginning with the 1996 calendar year, the Administrator, based on the 
information provided by all manufacturers under paragraph (d)(1) of 
this section, provides manufacturers with the passenger car and 
multipurpose passenger vehicle/truck TTA ranges to appear on the 
vehicle label and in the owner's manual under paragraphs (e)(1)(i) 
through (e)(1)(iii) of this section.
    (e) Label--(1) Attachment and Maintenance of Label. (i) Each 
vehicle manufactured on or after September 1, 1996 shall have affixed 
to it a vehicle rollover stability label as described in paragraph 
(e)(3) of this section. Each manufacturer shall affix or cause to be 
affixed the labels required by this paragraph at the final assembly 
point.
    (ii) Each dealer shall maintain or cause to be maintained, any 
vehicle rollover stability label on the vehicles it receives until the 
vehicles are sold to consumers for purposes other than resale. If a 
label becomes damaged so that any of the information on it is not 
legible, the dealer shall replace it by affixing an identical, 
undamaged label.
    (iii) Each vehicle required by paragraph (e)(1)(i) of this section 
to have a vehicle rollover stability label shall have in the vehicle 
owner's manual the same information required to be on the label under 
paragraphs (e)(3)(i) through (e)(3)(vii) of this section.
    (2) Location of Label. (i) The label required by paragraph 
(e)(1)(i) of this section shall be affixed on a side window of the 
vehicle in a manner so that it can be read from outside the vehicle.
    (ii) The label shall be either a separate label, a part of the 
price information label required by 15 U.S.C. Sec. 1232, or a part of 
the fuel economy label required by 15 U.S.C. Sec. 2006. If the rollover 
stability label is separate and the window is not large enough to 
contain both the price information label and the rollover stability 
label, it shall be affixed on a side window, as close as possible to 
the price information label.
    (3) Label Requirements. (i) Each rollover stability label shall be 
rectangular, not less than 114 mm high by 178 mm wide, and shall be in 
the exact format shown in Figure 2. Each label shall bear the exact 
wording shown in Figure 2. The TTA in the circle shall be the TTA 
reported to the Administrator pursuant to paragraph (d)(1) of this 
section for the labeled vehicle and the square brackets shall be 
replaced by TTA range data given to the vehicle manufacturer by the 
Administrator pursuant to paragraph (d)(2) of this section for the 
production year of the labeled vehicle.
    (ii) The color of the label picture and text shall contrast with 
the background of the label.
    (iii) All rollover stability information on the label shall be 
completely surrounded by a border at least 3 mm wide which contrasts 
with the background of the label.
    (iv) The title, ``Vehicle Rollover Stability,'' shall be centered 
over the label and shall be printed in bold caps no smaller than 12 
points.
    (v) The remainder of the label text shall be 10 points.
    (vi) The illustration of the vehicle in Figure 2 shall be centered 
in a square not less than 50 mm on each side. The inside diameter of 
the circle in which the TTA appears shall be no smaller than 16 mm. The 
TTA figure shall be centered in the circle and no smaller than 10 mm in 
height.
    (f) Test Conditions--(1) Tilt table. (i) The tilt table has a rigid 
platform or platforms onto which a test vehicle can be rolled.

BILLING CODE 4910-59-P




BILLING CODE 4910-59-C
    (ii) The surfaces of the areas on the platform(s) where the tires 
of the test vehicle rest are in the same plane at all times during the 
test.
    (iii) The surface of each tire contact area is smooth, cold rolled 
finished, unpainted steel. The surface of the platform(s) is dry and 
free of corrosion.
    (iv) The table is able to rotate about a longitudinal axis not less 
than 50 degrees from the horizontal position.
    (v) The axes of rotation are horizontal and parallel to one of the 
sides of the tilt table platform(s). If rotation is accomplished via 
hinges, all of the hinge axes of rotation are collinear.
    (vi) The rate of rotation is constant and does not exceed 0.25 
degree per second.
    (vii) The tilt table platform has a 2.5 centimeter high trip rail 
for each of the vehicle's axles. Each trip rail is parallel to the axis 
of rotation of the table and is able to move perpendicular to the axis 
of rotation. The length of each trip rail is equal to or greater than 
the diameter of the tire on the vehicle to be tested. The trip rail 
surface facing the tire is parallel to the axis of rotation of the 
table and perpendicular to the table surface. The trip rail does not 
move during a test.
    (viii) If the tilt table has a vehicle restraint system to prevent 
the test vehicle from falling off the platform during a test, the 
restraint system shall allow all tires on the uphill side of the test 
vehicle to lift at least 0.33 meter off the platform(s). The portion of 
the restraint system supported by the test vehicle when the uphill 
tires have lifted off the platform(s) shall weigh no more than 6.75 
kilograms.
    (ix) The tilt table instrumentation consists of means to measure 
the angle of the platform(s) from the horizontal and one contact switch 
under each of the uphill side tires to indicate when each tire has 
lifted off its platform surface contact area.
    (2) Vehicle. (i) The test vehicle has all fluids, other than fuel, 
at the full level. The fuel tank and the fuel system are filled as 
specified in S7.1.1 and S7.1.2 of Sec. 571.301 of this title.
    (ii) The vehicle's seat is positioned according to S8.1.2 and 
S8.1.3 of Sec. 571.208 of this title.
    (iii) Tires used during the test are of the same size and 
construction recommended by the manufacturer for the vehicle. The tires 
have accumulated not less than 80 and not more than 1620 kilometers. 
Not less than 80 of those kilometers are accumulated at a speed of not 
less than 80 kilometers per hour. All tires are clean and dry. All 
tires are inflated to the vehicle tire manufacturer's recommended 
inflation pressure for maximum vehicle loading and measured when the 
tire is cold.
    (iv) All vehicle openings (doors, windows, hood, trunk, convertible 
top, etc) are in the closed position.
    (3) Load. A Hybrid III Test Dummy, as defined in Subpart E of 
Sec. 572 of this title, is placed in the left front seating position, 
positioned according to S11 of Sec. 571.208 of this title, and secured 
with the vehicle's safety belt system, whether manual or automatic. The 
dummy may be placed in the test vehicle before or after moving the 
vehicle on to the tilt table. The test vehicle carries no load other 
than the test dummy.
    (4) Ambient conditions. The tilt table test is conducted with both 
the vehicle and the tilt table at a temperature not less than 4 and not 
more than 39 degrees Celsius. Air motion around the vehicle and tilt 
table is less than 6 kilometers per hour.
    (g) Test Procedure--(1) Vehicle Positioning. (i) The test vehicle 
is positioned on the tilt table such that the vehicle's longitudinal 
axis is parallel to the axis of rotation of the table and the left side 
of the vehicle is positioned such that the driver's side of the vehicle 
will be on the low side when the table is tilted. The wheels are 
parallel to the vehicle's longitudinal axis.
    (ii) After the vehicle has been positioned in accordance with 
paragraph (g)(1)(i) of this section, the engine is turned off. For 
automatic transmission vehicles, the transmission is in Park or, if the 
vehicle does not have a Park position, the transmission is placed in 
the Neutral position and the parking brake applied such that the 
vehicle does not roll during the test. For manual transmission 
vehicles, the transmission is in first gear and the parking brake is 
applied such that the vehicle does not roll during the test.
    (iii) The front trip rail is moved until it is just touching the 
driver's side front tire of the test vehicle, then locked in place. The 
rear trip rail is moved until it is just touching the driver's side 
rear tire of the test vehicle, then locked in place.
    (2) Testing. (i) Each tilt table test consists of six tilts. The 
positioning of the test vehicle on the tilt table and the contents of 
the vehicle are not adjusted between tilts.
    (ii) For each tilt, the platform is rotated from the horizontal 
until all of the uphill tires on the test vehicle have lifted off the 
platform, as indicated by the contact switches under the uphill tires.
    (iii) The platform angle at which the last tire lifts off the 
platform is the TTA of the vehicle for that tilt. The vehicle shall 
then be returned to the horizontal position at a rate not to exceed 
0.25 degrees per second.
    (iv) The lowest TTA of the last three tilts in the six-tilt series 
is the TTA for the tested vehicle.

    Issued on June 23, 1994.
Barry Felrice,
Associate Administrator for Rulemaking.
[FR Doc. 94-15598 Filed 6-23-94; 11:51 am]
BILLING CODE 4910-59-P






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