28550 Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules

1 A vehicle stability metric is a measured vehicle

characteristic that is analyzed to determine whether

it is related to a vehicle’s likelihood of rollover

involvement.

2 The tilt table test involves placing the vehicle

on a platform which is then tilted about an axis

parallel to the vehicle’s longitudinal axis. TTA is

the angle at which the last tire on the upper side

of the platform loses contact with the platform and

the vehicle begins to fall off the platform. This

metric is influenced by changes in a vehicle’s mass,

center of gravity height, track width, and

suspension movement, all of which are physically

related to rollover stability.

3 Critical sliding velocity includes the roll

moment of inertia as well as the various static

factors included in tilt table angle. CSV is

calculated from an equation which can be found in

the June 28, 1994 notice, as corrected on July 26,

1994 (59 FR 38038).

that they are under observation. The

FHWA would decide whether to

conduct the road test after analyzing the

results obtained in the simulation and

closed-course tests.

13. Standard Development. The

results of the preceding task would be

analyzed for validity, reliability, and

practicality. If the results of the

validation testing justify specification of

a new standard, a decision framework

for that standard would be constructed.

Specific Questions

The FHWA is specifically interested

in comments addressing the following

issues:

1. Are there any methodological

shortcomings in the research plan

outlined above that need to be

addressed?

2. Is the plan likely to meet the

objective of leading to an improved,

performance-based vision standard?

3. Does the plan reflect an

understanding of the current literature

and consider its implications?

4. Is the plan capable of adequately

addressing practical matters, such as the

cost of any new testing machinery

developed, the level of training required

to conduct new tests, and the time

needed to take tests?

5. Has this type of research been

conducted in other professions? What

were the results?

6. Should the FHWA proceed with the

short-term plan, the long-term plan,

both, or neither?

7. Should the FHWA proceed with an

alternative plan? If so, describe that

plan.

Current Status of the Research Program

The FHWA is currently in the midst

of step 2 of the research plan, which

consists of inventorying existing tests

and evaluating them against a number of

criteria, including their cost, which

visual functions they measure, overlap

between different tests, and the amount

of training required to conduct the tests.

Format of Public Hearing

The FHWA announced in the

November 17th notice (59 FR 59386) its

intention to hold a public hearing to

discuss the research plan. The public

hearing will be held on August 9, 1996,

at the Chicago O’Hare Marriot, 8535

West Higgins Road, Chicago, IL 60631,

(312) 693–4444. The hearing will begin

at 8:30 a.m. and conclude at 4:30 p.m.

Individuals wishing to speak at the

hearing should contact the FHWA at the

address or phone number listed above

under the heading ‘‘For Further

Information Contact.’’ Individuals may

submit written comments in addition to,

or in place of, oral testimony. All

commentors will be limited to ten

minutes of oral remarks.

The hearing will commence with an

explanation of the proposed research

plan, including a brief description of the

background to this effort, the goals of

the proposed research, and the steps of

the proposed plan. The FHWA will then

accept questions from audience

members, with individuals who have

contacted the FHWA given the first

opportunity to speak.

(49 U.S.C. 31136(a)(3), 31502)

Issued on: May 20, 1996.

Rodney E. Slater,

Federal Highway Administrator.

[FR Doc. 96–14041 Filed 6–4–96; 8:45 am]

BILLING CODE 4910–22–P

National Highway Traffic Safety

Administration

49 CFR Part 571

[Docket No. 91–68; Notice 5]

RIN 2127–AC64

Federal Motor Vehicle Safety

Standards; Rollover Prevention

AGENCY: National Highway Traffic

Safety Administration (NHTSA), DOT.

ACTION: Denial of petitions for

reconsideration.

SUMMARY: This notice announces the

denial of petitions for reconsideration of

the agency’s decision to terminate

rulemaking to develop a vehicle rollover

stability standard.

FOR FURTHER INFORMATION CONTACT: The

following persons at the National

Highway Traffic Safety Administration,

400 Seventh Street, S.W., Washington,

D.C. 20590:

For non-legal issues: Gayle

Dalrymple, Office of Crash Avoidance

Standards, telephone (202) 366–5559,

facsimile (202) 366–4329.

For legal issues: Steve Wood, Office of

the Chief Counsel, NCC–20, telephone

(202) 366–2992, facsimile (202) 366–

3820.

SUPPLEMENTARY INFORMATION:

I. 1994 Notice Terminating Rulemaking

on a Vehicle Rollover Stability

Standard

On June 28, 1994, NHTSA published

a notice in the Federal Register

announcing two agency actions: (1) the

termination of rulemaking to develop a

Federal Motor Vehicle Safety Standard

on vehicle rollover stability; and (2) the

proposal of a consumer regulation for

labeling vehicles with rollover stability

information. (59 FR 33254)

In the portion of the 1994 notice

terminating rulemaking, the agency

examined the suitability of using a

variety of vehicle stability metrics 1 as a

basis for a rollover standard. NHTSA

concluded that two such metrics, tilt

table angle (TTA) 2 and critical sliding

velocity (CSV),3 can each separately

account for approximately half of the

variability in rollover risk in single

vehicle accidents remaining after

considering driver, roadway, and

environmental factors. NHTSA stated:

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.

59 FR 33254, at 33258.

While NHTSA concluded that the two

vehicle stability metrics were of some

value in estimating the likelihood that a

single vehicle accident involving a

particular model of vehicle would result
Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules 28551

4The term ‘‘light trucks’’ includes sport utility

vehicles, vans, and pickup trucks with a gross

vehicle weight rating of 4,536 kilograms (10,000

pounds) or less. 5 Id., at 33258.

6The vehicles considered compact SUVs in

NHTSA’s analysis were: Ford Explorer, Chevy S10

Blazer, Jeep Cherokee, Jeep Wrangler, Toyota 4–

Runner, Nissan Pathfinder, Geo Tracker, GMC S–15

Jimmy (essentially a twin of the Blazer), Isuzu

Trooper, Isuzu Rodeo, Suzuki Sidekick (essentially

a twin of the Tracker), Mazda Navaho (essentially

a twin of the 4WD Explorer), Mitsubishi Montero,

Isuzu Amigo, and Suzuki Samurai.

in a rollover, the agency emphasized

that analyses also ‘‘show that other

factors in addition to those analyzed are

affecting rollover risk.’’ (Id., at 33260)

As the agency noted, ‘‘[t]he 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.’’ (Id., at 33258) In other

words, the issue was not simply

whether there is a statistical

relationship, but also whether that

relationship is strong enough,

considering other influences, so that

improvements in the stability metrics,

especially relatively small

improvements, would generate benefits

commensurate with the costs. If the

relationship is not sufficiently strong,

even significant changes in the stability

metrics may be overwhelmed by the

other influences and thus fail to cause

a significant change in rollover

experience.

The agency concluded that while each

of the stability metrics has some causal

relationship to the potential for rollover

and a statistical relationship to realworld rollover frequency, a standard

based on either of the metrics would

yield measurable benefits only if it

required that the metrics be increased to

an extent that would impose excessive

costs and necessitate radically

redesigning one or more types of light

trucks.4 The agency reached this

conclusion after examining the merits of

establishing a single rollover standard

for all light duty vehicles (i.e., passenger

cars and light trucks).

With respect to a single standard, the

agency stated:

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.

Id., at 33258.

To avoid such drastic consequences

for light trucks, the agency considered

whether it would be appropriate to set

one standard for cars and separate

standards for various classes of light

trucks.5 NHTSA concluded that it was

not appropriate. Since its analysis of the

ability of the two vehicle stability

metrics to account for the variability in

rollover risk in single vehicle accidents

was conducted on all light duty vehicles

as a group, the agency examined the

ability of the metrics to account for

variability within individual subgroups

of those vehicles. Regarding the results

of that examination, NHTSA stated:

[I]t 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. * * *

[T]he 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.

Id., at 33528.

II. Petitions for Reconsideration of

Decision To Terminate Rulemaking

In July 1994, the agency received two

petitions for reconsideration of its

decision to terminate rulemaking on a

rollover stability standard. One petition

was submitted by Advocates for

Highway and Auto Safety and the

Insurance Institute for Highway Safety

(Advocates/IIHS) and the other by

Randall and Sandy Vance, Doug White,

and Robert and Glenda Cammack

(Vance, et al.). Both petitions asked

NHTSA to reconsider its decision to

terminate rulemaking to establish a

minimum standard for vehicle rollover

stability. The Vance et al. petition

expressed general disagreement with

that decision, while the Advocates/IIHS

petition identified detailed points of

disagreement. For this reason, unless

otherwise specified, references below to

‘‘the petition’’ or ‘‘the petitioners’’ are

references to the Advocates/IIHS

petition.

While the petitioners made numerous

contentions, they focused on four

general areas: the character of a

reasonable rollover standard, the

agency’s statistical analysis of how a

standard could be selected, the agency’s

benefit calculations, and the agency’s

statements concerning cost burden to

the manufacturing industry. The

following is a summary of the more

important contentions addressed in this

notice and the appendix to this notice:

• NHTSA should have more

thoroughly considered establishing

separate standards for separate classes

of vehicles.

• To achieve a better relationship

between costs and benefits, NHTSA

should have considered the alternative

of setting a standard for the most

rollover-prone vehicles within one or

more of the following groups: sport

utility vehicles (SUVs), vans, and

pickup trucks.

• Compact SUVs 6 are the most

rollover prone group of light duty

vehicles.

• Minor vehicle changes (e.g.,

suspension changes) could be used to

achieve stability improvements at

reasonable cost.

• NHTSA did not provide any factual

support for its assertion that there are

serious safety problems associated with

improving vehicle stability metrics

through suspension changes.

• NHTSA did not explain the nature

and extent of the major design changes

that it said were necessary to meet any

stability metric, nor how much such

changes would cost.

• The level of projected benefits of a

rollover standard was understated by

the agency because it:

• used average class values in lieu of

model specific rollover accident data for

the rollover experience of some vehicle

models;

• used inappropriate statistical

measures; and

• viewed rollover prevention as

accident mitigation instead of accident

prevention.

• Although Congress did not mandate

the issuance of a rollover stability

standard, it expected that such a

standard would be issued.

• Contrary to NHTSA’s position, the

statute governing the agency’s vehicle
28552 Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules

7As noted above, the agency stated in the 1994

notice that a standard limited in its application to

a vehicle subgroup (e.g., sport utility vehicles) is

particularly unlikely to reduce fatalities and

injuries given the weaker statistical relationships

between the stability metrics and the rollover

involvement for vehicle subgroups. (Id., at 33528)

8 In commenting on the ANPRM, Advocates

indicated that it did not share the agency’s

optimism at that time about the desirability of

relying on suspension changes to improve rollover

stability metrics. Advocates commented that the

selection of TTR as the parameter to be regulated

would ‘‘permit a manufacturer to attempt

manipulation of other stability-related elements of

the vehicle’s design, such as its suspension, in

order to secure a barely passing tilt- table score.’’

It also expressed concern that the agency ‘‘may be

already tending towards selection of TTRs [see

footnote 12] that will not move the industry

towards safer overall vehicle designs, particularly

with regard to wheelbase, width, length, and center

of gravity height, but rather will encourage the

perpetuation of the status quo designs especially

with regard to very small cars, small pickups, and

SUVs that will continue to show high rollover

propensities.’’

safety rulemaking readily permits the

elimination of a class of vehicles widely

accepted in the marketplace.

• The agency may not consider the

policy concerns underlying the

Regulatory Flexibility Act without

preparing a regulatory flexibility

analysis.

III. Response To Petitions for

Reconsideration

In response to the petitions, the

agency has reconsidered its decision to

terminate rulemaking on a rollover

stability standard. As explained below,

the agency is, on reconsideration,

reaffirming that decision.

The petitions raise several points that

are not disputed by NHTSA; however,

they do not compel the conclusion that

NHTSA should establish a rollover

standard based on vehicle stability

metrics. For example, the agency agrees

that single vehicle rollover is a

significant safety problem. NHTSA also

agrees that the two vehicle stability

metrics are useful in estimating the

likelihood that a single vehicle accident

involving a particular model of vehicle

will result in a rollover.

Finally, the agency agrees that it is

appropriate in determining the

desirability of a rollover standard to

consider a rollover standard regulating

vehicles in the most rollover-prone

groups. While the 1994 notice focused

primarily on the approach of a single

standard for all light duty vehicles, the

agency did analyze separate standards

for separate classes of vehicles. The

notice explained that the predictive

ability of the vehicle stability metrics

decreased as the vehicle population was

divided into smaller groups. As noted

above, the agency concluded that ‘‘a

standard specifying one minimum

stability value for cars and others for

various classes of light trucks could not

be justified.’’ (Id., at 33257). Since the

petitioners suggest issuing a rollover

standard regulating the most rolloverprone vehicles, NHTSA has focused on

such an approach in responding to the

petitions for reconsideration. The

agency agrees with the petitioners that,

in theory, the comparatively high

rollover rate of compact SUVs makes a

standard regulating that group of

vehicles appear more likely to generate

benefits commensurate with its costs

than would a standard regulating any

other group of vehicles.

These areas of agreement are

insufficient, however, to lead the agency

to the conclusion reached by

petitioners. To the contrary, the

agency’s detailed analysis below of a

rollover stability standard based on TTA

or CSV demonstrates that the costs and

other impacts of such a standard

manifestly outweigh the estimated but

uncertain benefits.

A general response to the petitioners’

arguments appears below. Certain issues

are covered in greater detail in the

Appendix to this notice.

IV. Rationale for Reaffirming Decision

To Terminate

A. Summary

Following its examination of the

arguments raised by the petitioners, the

agency has revisited and, in some

respects expanded, its rationale for

terminating rulemaking on a vehicle

stability standard. The agency again

concludes that it is not appropriate to

establish a vehicle rollover stability

standard based on a vehicle stability

metric.

If a stability standard were set at a

level that would require only minor

vehicle changes in order for the affected

models to achieve compliance, the

standard would not produce any safety

benefits. Minor vehicle changes, which

consist predominately of suspension

changes, would not produce significant

improvements in the vehicle stability

metrics and would not be likely to result

in any reductions in fatalities and

injuries.7 Moreover, there is reason to

conclude that such suspension changes

would, in fact, produce negative safety

side effects.

If a stability standard were set high

enough to require significant

improvements in the vehicle stability

metrics, it would necessitate full vehicle

redesigns and major vehicle changes.

However, the safety benefits of such

changes would nevertheless be

relatively modest. Moreover, the overall

costs and loss of consumer choice

resulting from full vehicle redesigns

involving major vehicle changes would

be substantial and excessive. On

balance, the potential for improved

vehicle safety associated with such

improvements in the vehicle stability

metrics is not sufficiently large to justify

such redesigns.

B. Vehicle Changes To Increase Vehicle

Stability Metrics

There are two general categories of

vehicle changes that would increase the

vehicle stability metrics (TTA and CSV).

One consists of relatively minor vehicle

changes (i.e., suspension changes); the

other, of major vehicle changes (i.e.,

widening the vehicle track and lowering

the center of gravity) that could only be

achieved through full redesign of the

vehicle. The petitioners appear to

believe that a vehicle can be redesigned

so it will be significantly less likely to

roll over, that the means for

accomplishing this will be ‘‘invisible’’

to the consumer, and that the vehicle

will look and function as it did before

the redesign. As discussed below,

redesigning a vehicle to significantly

reduce its likelihood of rolling over

necessarily involves making

fundamental changes in the vehicle’s

dimensions (making it wider, longer,

lower, heavier) and compromising its

utility to consumers (e.g., by reducing

its fuel efficiency, ground clearance,

load-carrying capacity, off-road

capability, or driveability on snowy

roads).

1. Minor Vehicle Changes To Increase

Vehicle Stability Metrics

Minor vehicle changes have very little

effect on the vehicle stability metrics.

Moreover, they do not result in net

safety improvements.

As the petitioners correctly point out,

the Preliminary Regulatory Evaluation

(PRE) for the 1992 Advance Notice of

Proposed Rulemaking (ANPRM)

suggested that there were grounds for

optimism about the ability of minor

vehicle changes, such as suspension

tuning, to affect stability metrics and

improve rollover stability. (57 FR 242;

January 3, 1992) However, after

reviewing the comments on the 1992

ANPRM, the agency concluded in the

1994 notice that minor vehicle changes

could not, in fact, significantly affect the

vehicle stability metrics. Comments

from Advocates itself,8 as well as Ford

and General Motors, on the ANPRM

indicate that suspension changes result

in very little improvement in rollover

stability.

Moreover, vehicle rollover stability is

not the same as vehicle handling and

control. Some measures that improve
Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules 28553

9A ‘‘typical compact SUV’’ and a ‘‘typical fullsize SUV’’ are hypothetical vehicles with the

average TTA and dimensions of all the vehicles in

their class.

10 Advocates/IIHS petition, attachment 2.

11 Advocates/IIHS petition, page 18.

TTA or CSV do not necessarily result in

improved directional control and

stability. Available information suggests

that directional control and stability

would be adversely affected as a result

of relying upon suspension changes to

make small increases in the vehicle

stability metrics. This information was

supplied in comments from Advocates,

Ford, and General Motors on the

ANPRM expressing concern with the

side effects of suspension changes to

improve TTA.

For example, Ford used a computer

simulation of a compact pickup truck to

evaluate the effect of a series of

suspension changes on directional

stability and side-to-side load transfer in

cornering. (Docket 91–68–N01–21) Ford

evaluated substantial suspension

changes, including a 30 percent increase

in spring rates, removal of stabilizer

bars, and a change in the front

suspension roll center by 1.5 inches. It

also examined a ride height change that

would lower the center of gravity by 0.5

inch. Ford noted that, in general, tuning

a suspension system such that both the

front and rear tires lift from the tilt table

simultaneously would maximize the

TTA. However, this optimization

requires either decreasing the front roll

stiffness (by removing the front

stabilizer bar), or increasing the rear roll

stiffness (by using a 30 percent greater

rear spring rate). The simulation showed

that, among the suspension changes

examined by Ford, these two changes

made the greatest improvements in TTA

(an increase of 0.62 and 0.55 degrees,

respectively). However, these changes

were also shown to alter directional

stability toward oversteer (i.e., these

changes tend to make a vehicle turn

more sharply than a driver intends).

Ford’s simulation showed that other

suspension changes, such as an increase

in front spring rate or a decrease in front

roll center height, could increase TTA

(to a lesser degree than those mentioned

above), while altering directional

stability toward understeer (i.e., these

changes tend to make a vehicle turn less

sharply that a driver intends). The only

minor change mentioned by Ford in its

comment which improved TTA without

influencing directional stability was

lowering the vehicle c.g. height by 0.5

inch, resulting in only a 0.17 degree

increase in TTA.

Based on its consideration of such

comments, the agency concludes that

suspension changes would not produce

significant improvements in rollover

stability and would have the potential to

cause undesirable changes in directional

stability and handling, which in turn

could lead to an increase in crashes. In

view of this conclusion, the agency has

not examined whether those changes

could be made at a reasonable cost,

since they are unlikely to yield net

safety benefits.

2. Major Vehicle Changes To Increase

Vehicle Stability Metrics

Thus, significant improvements to the

vehicle stability metrics could be

achieved only through making major

changes to the vehicle chassis and body

to increase the track width and/or lower

the center of gravity. These major

changes would require full vehicle

redesigns that substantially change the

parameters affecting vehicle stability

metrics. The necessary extent of such

redesigns is illustrated in the following

example. Given that the center of gravity

height for a typical compact SUV 9 is 27

inches, to raise its TTA (42.9 degrees) to

that of the typical full- size SUV (46.4

degrees), it would be necessary to

increase the track width (i.e., the

distance between the left and right tires

on an axle) more than 6 inches. Further,

such a track width increase would

require a corresponding wheelbase (i.e.,

the distance between the front and rear

axles) lengthening of 10 inches to retain

the braking stability of the smaller SUV.

As noted later in the sections regarding

cost and impact on consumer choice,

such modifications would eliminate

most of the compact SUVs as they

currently exist, converting the typical

compact SUV into a full-size SUV.

Citing the example of the GMC

Jimmy, which was redesigned for 1995,

petitioners argued that vehicle

manufacturers can gradually redesign

their compact SUVs so as to increase

their vehicle stability. The petitioners

presented an article from Automotive

News stating that the new Jimmy is

longer, lower, and wider than its

predecessor.10 The petitioners further

attributed to the new Jimmy ‘‘a chassis

modification that can result in better

stability metrics and in lower rollover

crash rates.’’ 11

NHTSA draws a very different lesson

than do petitioners from the example of

the Jimmy. In the agency’s view, the

petitioners underestimate the extent to

which the parameters affecting a

vehicle’s stability metrics must be

changed to significantly improve those

metrics. As explained below, the overall

lessons of the new Jimmy are that even

a significant partial redesign of a vehicle

will change its vehicle stability metrics

little in the absence of major changes to

the vehicle’s c.g. height and track width,

and that even minor changes in those

parameters may come at the cost of

adversely affecting other attributes

desired by consumers. For example, the

new Jimmy is heavier and more costly

than the prior model.

The agency agrees that the vehicle

stability metrics of the new Jimmy are

likely to be somewhat better than those

of the old Jimmy. Although the agency

has no TTA or CSV data on the new

design, its lower body height and wider

track suggest that it has a slightly better

TTA than its predecessor and its longer,

wider, and heavier body suggests that it

may have a greater roll moment of

inertia and, therefore, a slightly greater

CSV.

However, the increases in the Jimmy’s

vehicle stability metrics are likely to be

very small. The reason is that the

changes made to the parameters

affecting those metrics were relatively

minor. Although the changes increased

the size and weight of the Jimmy, the

magnitude of those changes fell short of

the levels needed to make a significant

improvement in its TTA or CSV. The

body height of the 2WD model was

reduced by 1.6 inches, but the

associated reduction in center of gravity

height is likely to be much less, since

the location of the engine, drive train,

suspension, and passenger

accommodation component masses

remained unchanged. The height

reduction of the 4WD model was only

0.8 inches. Likewise, the body width

was increased by 2.4 inches, but the

front and rear track widths of the 4WD

model were increased less: 1.6 and 1.0

inches, respectively. The 2WD model

track width increases were even less: 0.9

inch at the front and 0.5 inch at the rear.

Taken together, these changes to the

Jimmy’s parameters affecting the

rollover stability metrics are very minor

compared to the ones described above

as being necessary for a typical compact

SUV to achieve a TTA of 46.4 degrees.

Thus, these changes predict at best a

very small improvement in TTA or CSV.

The impact of such small

improvements in vehicle stability

metrics on rollover risk is unknown.

Since this is a new model for 1995,

neither NHTSA nor the petitioners have

data on the rollover experience of the

new Jimmy. There is no way to know at

this time if the changes will actually

lead to a reduced risk of rollover.

C. Benefits of Improvements in Vehicle

Stability Metrics

NHTSA’s 1994 notice estimated that

the benefits of a rollover standard

requiring a TTA of 46.4 degrees for all

light duty vehicles included a modest
28554 Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules

12 TTR is the tangent of TTA. In its analysis prior

to the 1994 notice, the agency used TTR. Because

TTA is an easier concept to depict on labels for the

general public, the agency proposed the use of TTA

rather than TTR for the vehicle label under a

consumer information regulation that was proposed

in the 1994 notice. NHTSA used TTA throughout

the 1994 notice for that reason. However, NHTSA

has not converted the TTR values to TTA values

when discussing its statistical and benefits analyses

in this document.

13 A TTR of 1.05 is the equivalent of a TTA of

46.4 degrees. On page 33261 of the 1994 notice, the

agency explained that, if the agency were to adopt

a rollover stability standard applicable to all

vehicles, a TTA of 46.4 degrees was the highest

practicable standard. The agency explained that a

TTA of 46.4 degrees is representative of the average

full-size SUV. Since the design changes to increase

TTA to that level would cause a compact SUV to

approach the size of full-size SUVs, establishing

any higher standard, whether for all vehicles or for

compact SUVs alone, would lead to the virtual

elimination of compact SUVs as that class currently

exists.

14 The recomputation was performed using the

same procedures used for the 1994 estimates and

explained in detail in the document ‘‘Potential

Reductions in Fatalities and Injuries in Single

Vehicle Rollover Crashes as a Result of a Minimum

Rollover Stability Standard.’’ That document is in

Docket 91–68; Notice 3. However, while the

procedures were the same, an expanded set of data

(the number of rollover accidents and single vehicle

accidents) were used in the recomputation to

increase its accuracy. The use of the new data

adequately addresses the petitioners’ concerns

about the agency’s use in the 1994 notice of

weighted averages for models for which there was

insufficient data to determine the actual rollover

rate.

amount of benefits for compact SUVs.

The agency’s estimate that 63 fatalities

and 61 serious injuries might be

prevented for all light duty vehicles

included the prevention of 31 fatalities

and 22 serious injuries for compact

SUVs. The potential compact SUV

benefits were predominately attributable

to those particular compact SUV models

that would require significant changes

in track width and/or center of gravity

height to achieve the required TTA.

As part of its review of the petitions,

the agency recomputed its estimate of

the benefits of making significant design

changes in order to raise the TTR12 of

compact SUVs to 1.05,13 using data that

were not available for some makes and

models when the analysis was done for

the 1994 notice.14 The agency estimates

that, using the more current data and

certain optimistic assumptions

(discussed below), 22 serious injuries

and 32 fatalities might be prevented

annually if all new compact SUVs were

redesigned to the extent necessary so

that each vehicle in that class had a TTR

of 1.05 and if all existing compact SUVs

with a lower TTR were retired from the

vehicles-in-use fleet. The potential

benefits for a rollover stability standard

are computed by considering:

(1) The reduction of rollovers per

single vehicle accident (RO/SVA)

predicted for increases in TTR;

(2) The number of single vehicle

accidents experienced by vehicles that

would need to be altered in order to

comply with the standard; and

(3) The degree of harm mitigation (in

the number of fatalities and serious

injuries) as a result of rollover

prevention given that a single vehicle

accident has occurred.

The following table, corresponding to

Table 1 of the document ‘‘Potential

Reductions in Fatalities and Injuries in

Single Vehicle Rollover Crashes as a

Result of a Minimum Rollover Stability

Standard,’’ contains the results of this

latest computation. For an explanation

of the headings and entries in the table,

see that document.

Compact SUV make

model Drive

MY 1991

productionTTR

1986–88 5

state SVA/

RV

1986–90

Michigan

RO/SVA

Est %

of

compact

SUV

ROs

Est

AIS3 +

injuries

Est fatalities

Projected

RO/SVA @

min TTR

1.05

AIS3 +

reduction

@ min

TTR 1.05

Fatality

reduction

@ min

TTR 1.05

Vehicle A ....................... 2 WD*15 65,515 0.88 **160.0068 **0.359 6 39 28 0.270 9.6 6.9

4 WD 184,554 0.88 **0.0068 **0.359 16 110 79 0.270 27.2 19.5

Vehicle B ....................... 2 WD 29,480 0.95 0.0103 0.342 4 25 18 0.280 4.6 3.3

4 WD 93,866 0.99 **0.0102 0.27 9 63 45 0.244 6.1 4.4

Vehicle C ....................... 2 WD* 19,920 1.08 0.0091 0.317 2 14 10 .................... ................ ................

4 WD 101,541 1.08 0.0091 0.317 11 71 51 .................... ................ ................

Vehicle D ....................... 2 WD 0 .................... ...................... ................ ............ ............ ............ .................... ................ ................

4 WD 46,478 1.03 0.0163 0.273 8 50 36 0.263 1.8 1.3

Vehicle E ....................... 2 WD* 4,892 1.01 0.0211 0.362 1 9 7 0.338 0.6 0.4

4 WD 39,989 1.01 0.0211 0.362 11 74 53 0.338 4.9 3.5

Vehicle F ........................ 2 WD* 3,555 0.93 **0.0215 **0.315 1 6 4 0.258 1.1 0.8

4 WD 35,945 0.93 **0.0215 **0.315 9 59 42 0.258 10.8 7.7

Vehicle G ....................... 2 WD 0 .................... ...................... ................ ............ ............ ............ .................... ................ ................

4 WD 30,702 0.978 ...................... 0.394 5 31 22 0.348 3.6 2.6

Vehicle H ....................... 2 WD 6,479 0.95 0.0114 0.259 1 5 3 0.219 0.7 0.5

4 WD 23,515 0.99 **0.0123 0.252 3 18 13 0.228 1.7 1.2

Vehicle I ......................... 2 WD 0 .................... ...................... ................ ............ ............ ............ .................... ................ ................

4 WD 26,776 0.98 ...................... **0.481 5 33 24 0.427 3.7 2.7

Vehicle J ........................ 2 WD* 740 0.947 ...................... ................ 0 1 0 0.281 0.1 0.1

4 WD 23,870 0.947 ...................... ................ 3 20 15 0.281 3.3 2.1

Vehicle K ....................... 2 WD* 1,257 0.978 ...................... 0.407 0 2 1 0.360 0.2 0.1

4 WD 10,492 0.978 ...................... 0.407 2 13 10 0.360 1.6 1.1

Vehicle L ........................ 2 WD 0 .................... ...................... ................ ............ ............ ............ .................... ................ ................

4 WD 11,404 0.88 **0.0068 **0.359 1 7 5 0.270 1.7 1.2

Vehicle M ....................... 2 WD 0 .................... ...................... ................ ............ ............ ............ .................... ................ ................

4 WD 10,616 0.93 ...................... ................ 1 9 7 0.274 1.7 1.2

Vehicle N ....................... 2 WD* 5,011 1.016 ...................... ................ 1 4 3 0.315 0.2 0.2

4 WD 2,818 1.016 ...................... ................ 0 2 2 0.315 0.1 0.1

Vehicle O ....................... 2 WD* 832 1.04 ...................... ................ 0 1 1 0.329 0.0 0.0

4 WD 3,546 1.04 ...................... ................ 0 3 2 0.329 0.1 0.0
Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules 28555

19The agency made these assumptions because

limitations in available data made it impossible to

use more precise values. When making these

assumptions, the agency took an optimistic

approach so as to present the prospects of a vehicle

stability standard in the best possible light.

20As explained in the Appendix, NHTSA made

two cost estimates. The first was based on the

assumption that compact SUVs needing a TTR

increase of more than 0.06 would require a full

vehicle redesign. The second was based on the

assumption that only compact SUVs needing a TTR

increase of more than 0.04 would require such a

redesign.

21Model year 1994 sales data from Automotive

News 1995 Market Data Book, Crain

Communications, Detroit, Michigan, May 24, 1995.

All light trucks—6,097,787 vehicles.

Compact SUVs—21.9% of light trucks, or

1,335,415 vehicles.

Full-size SUVs—3.6% of light trucks, or 219,520

vehicles.

Compact SUV make

model Drive

MY 1991

productionTTR

1986–88 5

state SVA/

RV

1986–90

Michigan

RO/SVA

Est %

of

compact

SUV

ROs

Est

AIS3 +

injuries

Est fatalities

Projected

RO/SVA @

min TTR

1.05

AIS3 +

reduction

@ min

TTR 1.05

Fatality

reduction

@ min

TTR 1.05

Weighted Averge ........... ................ .................... 0.01049 0.335 ............ ............ ............ .................... ................ ................

Total 17 ................ 783,783 .................... ...................... ................ 100 669 480 .................... 85.0 61.0

Total 18 ................ ................ .................... ...................... ................ ............ ............ ............ .................... 22.0 32

15An ‘‘*’’ in this column indicates that the agency lacked sufficient data for the 2WD version of the model. For these models, the agency assumed that the 2WD version had the same TTR and the same rollover rate as the 4WD version. 16An ‘‘**’’ in this column and in the next one indicates that 1988–91 Michigan accident data were used instead of the data indicated by the column heading. 17The serious injury and fatality reduction figures in this row are the benefits that might result if the standard prevented not only a rollover, but

also an accident of any type. 18The serious injury and fatality reduction figures in this row are the benefits that might result if the standard prevented a rollover, but still allowed an injury-causing accident of some type to occur after the vehicle left the road. The injury and fatality figures in this row were derived by

multiplying the figures in the row immediately above by a mitigation factor of 26 percent for injuries and 52 percent for fatalities. For further details on these factors, see section 3 of the Appendix to this notice.

There are two optimistic assumptions

incorporated in the computation process

for both the original and new

estimates: 19

• The number of rollover injuries and

fatalities prevented will be proportional

to the number of rollovers prevented;

and

• The fatality and injury rates of the

late 1980’s will be representative of

future rates.

The effect of these optimistic

assumptions is that these new estimates,

like the 1994 estimates based on the

same assumptions, may in fact overstate

the actual benefits, i.e., the number of

fatalities and injuries likely to be

prevented by improving the TTR of

compact SUVs to 1.05.

The first assumption assumes that the

rollover accidents that would be

prevented as a result of requiring an

increase in TTR would have the same

fatality and injury rates as rollover

accidents in general. There is reason to

believe that this would not be the case.

The likelihood of fatalities and serious

injuries in rollover accidents is heavily

skewed toward crashes involving more

than one quarter turn. Data show that

light truck rollover crashes involving

only a single quarter turn have about

one-third the fatality rate of the average

rollover. This difference in likelihood of

harm is significant if moderately

improving TTR would not be equally

likely to prevent a multiple quarter-turn

rollover as a single quarter-turn rollover.

NHTSA believes that it is more likely

that the prevented rollovers would tend

to be the lowest energy rollovers, i.e.,

the single quarter-turn rollovers. At best,

improving TTR would only slightly

mitigate the more severe rollovers.

Thus, by assuming that rollovers

prevented by an improvement in TTR

would be average rollovers instead of

the least severe rollovers, the agency is

overstating the benefits obtainable from

such an improvement. Had the agency

based its benefit estimates on the fatality

rate of rollovers involving a single

quarter turn, the estimated number of

prevented fatalities would have been

about 11 instead of 32.

The second assumption, that the

fatality and injury rate in rollovers will

remain constant, is likely to overstate

the benefits of a vehicle stability

standard since, if recent trends

continue, future increases in safety belt

use, as a result of Federal, state, and

local efforts, can reasonably be expected

to reduce the overall harm from rollover

accidents. As belt use increases, rollover

casualties decrease, even if the number

of rollover crashes remains constant.

Consequently, even with liberal

assumptions and using the most current

and complete database available,

NHTSA estimates that a rollover

stability standard requiring compact

SUVs to achieve the same TTR (1.05) as

the typical full-size SUV would prevent

22 serious injuries and 32 fatalities

annually. While precise quantification

is impossible, the agency believes, for

the reasons stated above, that the actual

level of safety benefits would be

significantly lower.

D. Costs of Improvements in Vehicle

Stability Metrics

The substantial vehicle redesigns

necessary to enable many existing

compact SUVs to achieve a TTR of 1.05

and produce the estimated reductions in

fatalities and injuries discussed above

would have substantial negative

impacts, both in terms of reduced

consumer choice and unmet preferences

and in terms of increases in

manufacturer and consumer costs.20 As

noted above, the only way to achieve

significant increases in TTR is to

increase the track width and/or lower

the center of gravity. Increasing track

width or lowering the center of gravity,

using conventional, commonly used

designs and production methods, would

necessarily, and significantly, increase

vehicle size and weight. For NHTSA, in

effect, to require compact SUVs to

approach the size and weight of full-size

SUVs would run counter to consumer

preferences that have led to the existing

fleet of compact SUVs. The strength of

those preferences is demonstrated by

the fact that compact SUVs outsold fullsize SUVs by a margin of six to one in

1994, the latest year for which the

agency has sales data.21 The Ford

Explorer, the compact SUV model with

the lowest TTR and therefore the

compact SUV which would be most

affected by any minimum standard, is

the best-selling SUV and is the ninth

most popular make/model of all car and

truck models combined.

Upsizing compact SUVs so as to

eliminate much of the size and weight

difference between those vehicles and

full-size SUVs also might have a

significant adverse affect on the
28556 Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules

22As demonstrated by Table 1, the vast majority

of the measurable benefits from such a standard

would come from improvements to these fully

redesigned vehicles, instead of those vehicles that

would need only lesser changes to comply with the

standard.

23 Advocates/IIHS petition, page 12.

1 A detailed discussion of the method can be

found in ‘‘Potential Reductions in Fatalities and

Injuries in Single Vehicle Rollover Crashes as a

Result of a Minimum Rollover Stability Standard’’

in Docket 91–68, Notice 3.

production and sales of SUVs. The body

of the average full-size SUV is currently

about 10 inches wider than that of the

average compact SUV, and the track

width is about 9 inches greater. The 6-

inch increase in track width necessary

to bring the TTR of compact SUVs up

to that of full-size SUVs (assuming no

increase in c.g. height) would remove

much of those differences between

compact SUVs and full-size SUVs.

Given the admonition in the legislative

history of the National Traffic and

Motor Vehicle Safety Act against

eliminating vehicle types (see the

discussion in section D of the Appendix

to this notice), such a dramatic potential

impact on the design of compact SUVs

and on the market for those vehicles

must be carefully weighed.

In addition to impacts on consumer

choice and sales, there are substantial

monetary costs associated with

redesigning those compact SUVs that

would need significant increases in TTR

to meet a standard of 1.05.22 The agency

estimated those costs using confidential

cost data submitted by domestic

automobile manufacturers during the

course of several agency rulemaking

proceedings to establish light truck

Corporate Average Fuel Economy

(CAFE) standards. The estimated

consumer cost of bringing all such new

compact SUVs into compliance with

such a standard is between $310 million

and $335 million, depending on which

of two assumptions is made about the

vehicles that would require a full

vehicle redesign. A detailed discussion

of the method used to estimate these

costs is included in the Appendix to

this notice.

The agency believes that the foregoing

estimate of the costs of a rollover

standard requiring compact SUVs to

achieve a minimum TTR of 1.05 is

understated. Those estimates do not

include the incremental costs of

material and labor involved in the

manufacture of a larger vehicle. In

addition, the estimates do not include

any costs for vehicles that would only

need minor changes, instead of a full

vehicle redesign, to comply with the

standard. NHTSA has not attempted to

calculate those costs because the

benefits of the standard are already

outweighed by the initial cost estimate.

The agency recognizes that providing

a lengthy leadtime period would reduce

the costs of compliance to the extent

that manufacturers were able to make

their compliance efforts coincide with

their normal model changeover

timetable. However, providing

additional leadtime would do nothing to

reduce the adverse impacts on

consumer preferences. Further, an

extended lead time would not affect the

costs of additional labor or materials.

VI. Conclusion

The discussion above and in the

Appendix demonstrates that even a

standard applicable only to compact

SUVs, the vehicle type that the

petitioners characterize as one of the

two ‘‘most rollover-prone vehicle

types,’’ 23 would generate substantial

adverse impacts on manufacturers and

consumers, both in terms of monetary

costs and in loss of consumer choice,

that would outweigh the benefits of

such a standard. There is no reason to

believe that a standard that would

mandate significant increases in TTR/

TTA or CSV for any other vehicle type

or group of vehicle types would be any

more cost beneficial.

Accordingly, NHTSA reaffirms its

decision to terminate this rulemaking

without proposing a rollover stability

performance standard.

Issued on May 31, 1996.

Barry Felrice,

Associate Administrator for Safety

Performance Standards.

Appendix

The Advocates/IIHS petition contained

many detailed technical arguments.

Responses to the more significant ones are

provided in this appendix.

A. The Benefits Estimate

1. Replacing Weighted Averages With Actual

Rollover Data Now Available Makes No

Appreciable Change in the Estimate

The petitioners criticized the benefit

estimates made by the agency in connection

with the 1994 notice because, for those

vehicle models for which the agency lacked

sufficient rollover accident data, it used the

average of the rollover per single vehicle

accident rate (RO/SVA) of the class of

vehicles to which that make and model

belonged, weighted by the 1991 production

of each make and model for which the

agency had RO/SVA. The benefits were

calculated using the TTRs of 1991 makes and

models and the accident records of 1991

makes and models (and identical vehicles

from prior model years) to represent a

hypothetical future fleet.1

The petitioners pointed out that the

average TTR for vehicles for which the

agency did not have adequate RO/SVA data

was lower than the average TTR of vehicles

for which it had RO/SVA data, and therefore

claimed that use of weighted averages was

inappropriate. The petitioners’ criticism

concerning the use of weighted averages as

substitutes for missing data was focused

particularly on the use of those averages for

the large number of vehicles in the

hypothetical future fleet that were

represented by the Ford Explorer. The agency

had no RO/SVA or single vehicle accident

involvement rate (SVA/RV) data for the Ford

Explorer and certain other vehicles at the

time of the notice because they were either

recently introduced or comparatively low

production volume models. The petitioners

argued that a higher rollover rate should have

been used for vehicles like the Explorer

which have a lower TTA than the vehicles

from which the weighted average was

derived.

It is not appropriate to assume that a higher

than average rollover rate is appropriate for

the Explorer or the other vehicles simply

based on their having a lower than average

TTA. The data demonstrate that the order of

vehicle models ranked according to TTA is

not the same as the order of models ranked

according to rollover rate. See Table 1 in the

accompanying notice of denial of petitions

for reconsideration. Thus, although two

different vehicle models may have the same

TTA, they may not necessarily have the same

rollover rate. Likewise, a vehicle model with

a TTA lower than that of another model may

nevertheless have a lower rollover rate, and

vice versa.

Accordingly, the agency has not assumed

a higher rollover rate for those models for

which sufficient rollover data are lacking.

However, the agency has responded to the

petitioners’ concern about the use of

weighted averages in connection with the

1994 notice by replacing those averages,

where possible, with rates based on actual

rollover accident data that became available

after that notice was prepared.

Where sufficient, the 1988—1991 Michigan

accident data were used to calculate the

rollover rate figures for models for which

data were previously missing. Following the

practice of previous analyses, the agency

used the accident data to calculate rollover

rates only for makes and models which had

at least 25 single vehicle accidents. Actual

rollover rates (RO/SVA) from Michigan were

added for the 4WD Ford Explorer, Nissan

Pathfinder, and Isuzu Trooper, and actual

single vehicle accident rates (SVA/RV) were

added for the 4WD Ford Explorer, the 4WD

S10 Blazer, the Nissan Pathfinder, and the

4WD GMC S15 Jimmy. The 4WD Explorer

data were used for the nearly identical, but

low production volume, Mazda Navajo.

There were still some models for which the

agency lacked sufficient actual make and

model accident data. For most of these

models, while the agency lacked sufficient

data for the 2WD versions of those models,

it had sufficient data for the more numerous

4WD versions. In these instances, the agency

assumed that the rates for the 2WD versions

were identical to the rates for the 4WD

versions of the same make and model,

instead of calculating rates based on

weighted averages. New weighted averages
Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules 28557

2As explained below, the agency did not

calculate all costs of a standard because it

determined that one category of those costs, the

investment costs for vehicles requiring major

changes, would by itself exceed the benefits of a

standard.

were computed on the basis of the expanded

data and were used only where sufficient

specific data remained unavailable for a

particular model. The instances in which the

agency computed new weighted averages

were limited. Weighted averages of RO/SVA

and SVA/RV were used for less than 10

percent and 19 percent, respectively, of the

example population of compact SUVs. See

Table 1.

Using actual rollover data wherever

available, the agency recomputed the benefit

estimates for compact SUVs. Substitution of

the new rollover rates produced very little

change in the estimate of the numbers of

fatalities and serious injuries that might be

prevented if a rollover stability standard were

adopted for compact SUVs. Replacing the

weighted averages used in the 1994 notice

with rates based on accident data for

particular makes and models changed the

result of the analysis very little, i.e., by less

than four percent. This may be seen by

comparing the estimates of the benefits that

would be obtained if preventing a rollover

meant preventing an accident altogether.

Those benefits were estimated to be 83

serious injuries and 59 fatalities in the 1994

notice. They have been recomputed to be 85

serious injuries and 61 fatalities, based on the

new accident data and less reliance on

weighted averages. See Table 1.

2. Accident Mitigation, Not Accident

Prevention, Is the Proper Measure of Benefits

Since an accident would still occur in the

vast majority of instances in which a rollover

is prevented, the agency reduced those

figures accordingly using an accident

mitigation factor. The resulting new benefit

estimate is 22 serious injuries and 32

fatalities.

The petitioners criticized the agency for

making the same adjustment to the benefits

in the 1994 notice. Then, as now, NHTSA

assumed that the benefits would come from

accident mitigation instead of accident

prevention. It was appropriate for the agency

to assume that the benefits would be in terms

of accident mitigation since over 90 percent

of all single vehicle rollovers are off-road,

tripped rollovers, i.e., rollovers that occur

when a vehicle leaves the roadway sideways,

encounters a tripping mechanism, and rolls.

Since a vehicle is running off the road in a

tripped rollover situation, such a vehicle will

still likely crash into some off-road object

even if the vehicle is prevented from rolling

over after it leaves the road. If a rollover can

be prevented in that situation, then the

resulting accident will most likely be one of

lower severity than if a rollover had occurred

because rollovers tend to be more severe than

non-rollover accidents. The primary benefits

from a rollover stability standard would

result from preventing the more severe form

of off-road accident.

3. A Single Accident Mitigation Factor, Not

Separate Factors for Individual Vehicle

Types, Is the Proper Basis for Measuring

Benefits

The petitioners also criticized the agency

for using a single accident mitigation factor

(52 percent) for fatalities across the board

instead of computing separate factors for

different types of vehicles. In support of their

argument for the use of different factors, they

noted that rollover accidents account for 80

percent of the fatalities of the occupants of

compact SUVs in single vehicle accidents.

Based on this, the petitioners concluded that

rollovers in compact SUVs are four times as

deadly as non-rollover accidents, and

therefore the agency should have used a

mitigation factor of 75 percent for compact

SUVs.

The agency rejects the petitioners’

argument. A mitigation factor based on ratios

of absolute numbers of fatalities, instead of

on fatality rates, is incorrect unless the same

number of occupants were exposed to

rollover accidents and non-rollover

accidents. If the exposure is not the same,

then it is impossible to determine the extent

to which the ratio reflects the difference in

accident exposure versus a difference in

accident severity. Further, the issue of a

difference in accident severity is not just a

matter of the difference in severity of a

rollover accident and a non-rollover accident

at the same speed. It is also a matter of

possible differences in speed. For example, it

is necessary to determine whether the

consequences of 60 mph rollovers are being

compared to those of 30 mph non-rollover

accidents. Finally, it is also necessary to

examine whether apparent differences

between vehicle groups are a result of

differences in crashworthiness, or just a

consequence of smaller sample sizes.

The agency’s use of a single mitigation

factor for fatalities takes these considerations

into account. NHTSA considered the number

of occupants exposed to rollover and nonrollover single vehicle accidents as well as

the number of fatalities for each accident

type. It also considered the speed limit of the

road as a rough indication of the severity of

the accident.

As a first step in determining the

mitigation factor, NHTSA compared the

overall fatality rate of rollover accidents to

the overall fatality rate of non-rollover

accidents, based on single vehicle accidents

of all cars and light trucks without

consideration of accident severity. The

fatality rate of rollover accidents was slightly

more than twice that of non-rollovers,

suggesting a 52 percent mitigation factor.

Next, the agency computed a series of

relative fatality rates (with and without

rollover), comparing only accidents occurring

on roads with the same range of posted speed

limits (25 mph or less; 30–35 mph; 40–50

mph; 55–65 mph). While the accident data

do not indicate the actual accident speed,

grouping by speed limit acts as a rough

control on accident severity, because it

restricts accident groups to the same kinds of

roads, even though the actual range of crash

speeds may significantly exceed the range of

posted speed limits for a particular group of

accidents. The relative fatality rate for each

road speed limit group were added and then

averaged. The result was the same 52 percent

mitigation factor for fatalities. Using the same

process led to a mitigation factor of 26

percent for serious injuries.

In addition, even if the agency were to use

different mitigation factors for different

vehicle types, their use would not result in

dramatic changes in benefit estimates. For

compact SUVs, the 75 percent mitigation

factor suggested by the petitioners would

result in a fatality reduction of 46 rather than

the 32 calculated by the agency. This

difference is 0.15 percent of the 9,000 annual

rollover fatalities. Using the estimates

prepared for the 1994 notice, for the entire

light duty vehicle fleet, the use of different

mitigation factors resulted in predicting 71,

instead of the agency’s 63, lives saved from

requiring a TTR of 1.05. This is a difference

of 0.089 percent.

B. The Cost Estimate

The petitioners criticized the agency for

failing to provide any costs for the vehicle

changes that would be necessary to meet a

minimum rollover stability standard. The

agency concluded in the 1994 notice that a

large number of vehicles would require

fundamental full redesigns to meet a

minimum stability standard. Because the

agency was aware of the magnitude of costs

involved in vehicle redesigns, it was

apparent that the costs and other impacts

would substantially exceed the benefits.

NHTSA did not, however, provide a

quantification of those costs and other

impacts.

To demonstrate the validity of its

conclusion about the costs and other impacts,

the agency has conducted a rough cost

analysis for this notice as set forth below.2 To

estimate the compliance costs for those

vehicles which would have to be fully

redesigned to make the substantial changes

necessary to comply with a minimum

stability standard, the agency used

confidential cost data submitted by domestic

automobile manufacturers during the course

of several agency rulemaking proceedings for

light truck Corporate Average Fuel Economy

(CAFE) standards. These data are

manufacturer estimates of the costs of full

redesigns of compact SUVs that would have

been necessary if the CAFE standards had

been set at certain levels. These submissions

include estimates of investment costs for a

redesigned vehicle model, but do not include

material and labor costs for the manufacture

of the vehicle. NHTSA believes a full vehicle

redesign for rollover stability purposes would

necessitate similar investment costs.

Accordingly, it is appropriate to use the

investment cost figures from the CAFE

program to estimate the investment costs for

vehicles which would require a full redesign

to comply with a rollover stability standard.

The CAFE submissions include investment

cost data for five models of compact SUVs.

Since the specific raw data are confidential,

they cannot be set forth here or otherwise

publicly released. To convert those data into

a form in which the original data can not be

determined, the agency divided the per

model data by the applicable manufacturer’s

estimated average annual production

capacity and then divided by the number of
28558 Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules

3 Since the submissions were made in 1986,

1989, 1993, and 1994, submissions for years prior

to 1994 were adjusted to 1994 dollars using the

implicit gross domestic product deflator as

calculated by the Bureau of Economic Analysis.

4 Variability is the difference between what the

statistical model predicts and actual accident

records.

5 D.W. Hosmer and S. Lemeshow, Applied

Logistic Regression, Wiley Interscience, New York,

1989.

6 After the publication of the termination notice,

the Safety Act was codified in volume 49 of the

United States Code. Any cites to provisions of the

Safety Act have been updated to reflect the

codification.

7 The agency agrees with the petitioners that this

termination is ‘‘final agency action’’ for the

purposes of judicial review.

years of the vehicle’s design cycle life.3 The

per-vehicle cost estimates for these five

vehicle design cycle lives were then averaged

to arrive at the estimate used in this analysis.

The individual per-vehicle cost estimates

range from $317.37 to $532.37 and the

average is $416.77. Since these costs are costs

to the manufacturer, they were adjusted to

represent costs to the consumer by dividing

them by 0.75, a standard factor used by the

agency in its vehicle rulemaking in

estimating consumer costs from

manufacturer’s wholesale costs. The resulting

estimated average consumer cost per vehicle

resulting from the redesign of a compact SUV

is $555.69.

The agency then determined the number of

vehicles that would need vehicle redesigns to

comply with a vehicle rollover stability

standard requiring a minimum TTR of 1.05.

Based on available data, the agency believes

at least some models would have to be fully

redesigned to achieve TTR increases of more

than 0.04, and that almost all models would

have to be fully redesigned to achieve at TTR

increase of 0.06. The agency determined next

that 558,756 vehicles would need to be fully

redesigned if the threshold for having to

make a full redesign were 0.06 and 603,637

vehicles would need to be fully redesigned

if the threshold were 0.04. Multiplying these

numbers of vehicles by the $555.69 per

vehicle investment cost estimate, the agency

estimated that the total investment costs of a

standard requiring a TTR of 1.05 would be

$310,495,121 to $335,435,044.

The agency believes that this range of

estimated costs of a rollover standard

requiring compact SUVs to achieve a

minimum TTR of 1.05 is understated. As

noted earlier, these cost estimates do not

include estimates of the incremental costs of

material and labor involved in the

manufacture of the vehicle. Since vehicles

would need significant increases in track

width, and attendant increases in wheelbase,

they would be generally larger and heavier.

As a result, the agency concludes that there

would be significant increases in the costs of

material and labor involved in the

manufacture of such vehicles. In addition,

these cost estimates do not include any costs

for vehicles which could comply with the

standard by changes that are less than a full

vehicle redesign.

C. Objections to the Statistical Tools Used by

the Agency in Reaching Its Decision

The petitioners asserted that the agency

did not use the ‘‘typical’’ statistical measure,

the deviance statistic, to judge the adequacy

of the logistic regression models used by the

agency in its analyses of the relationship of

TTA to RO/SVA, and the importance of the

vehicle stability metrics. The petitioners also

objected to the agency’s use of two statistical

measures, R2 and the C-statistic. Finally, the

petitioners questioned the agency’s reliance

on data from the State of Michigan.

Although the agency did not use the

deviance statistic to judge the adequacy of

the logistic regression models, the agency did

use a mathematically equivalent measure, the

likelihood statistic (-2*ln(likelihood)). Using

that measure permitted the agency to

compare the effect of adding variables

(specifically the vehicle stability metrics) to

the hypothesized models. Detailed

discussions of the agency’s analyses are

found in the Technical Assessment Paper

(TAP) (Docket 91–68–N01–03) and the

Addendum to the Technical Assessment

Paper (Docket 91–68–N03–02) which were

placed in NHTSA’s docket. The TAP and the

Addendum present analyses using five

measures: the C-statistic, R2, the percentage

change in R2, the likelihood statistic, and the

variables’ chi-square. It is true that the

deviance statistic was not reported because

the computer software the agency used to

conduct this analysis, SAS Institute’s PROC

LOGIST, does not include the deviance

statistic as one of the model diagnostics.

However, the agency does not believe that

this affects the general conclusions regarding

the importance of the vehicle stability

metrics.

NHTSA believes that it may help to

explain this issue in non-statistical terms.

The petitioners’ argument amounts to a

complaint that the agency described various

glasses of water in terms of how much water

is in the glass, instead of in terms of how

much water could be added to the glass. In

either case, the capacity of the glass is the

same. If the capacity is known, and if either

the amount of water or the amount of unused

capacity is known, the other amount can be

derived.

Similarly, the deviance statistic preferred

by the petitioners describes how much of the

variability 4 in the regression model is left to

be explained. The likelihood statistic, which

the agency used, describes how much of the

variability in the model is explained. In

either case, the total variability to be

explained is the same. If, as the agency’s

analysis showed, the addition of TTR to the

model decreased the value of the likelihood

statistic, the deviance statistic would have

increased by the same amount. Using either

measure would lead to the same conclusion

about the value of TTR.

The petitioners also assert that the use of

R2 was inappropriate because it is not

weighted, i.e., it does not reflect the number

of single vehicle accidents for each vehicle

make and model. The petitioners also state

that R2 is sensitive to extreme values. The

agency’s use of R2 was described fully on

page 5–66 of the TAP. The agency agrees, as

explained in the TAP, that there are

limitations to the use of R2. As also explained

in the TAP, R2 was used as an approach to

providing the types of descriptive statistics of

model fit with which more people are

familiar, and not to provide a mathematically

rigorous assessment of model fit. The

agency’s use of R2 was an attempt to make

the explanation of the analysis

understandable to a wider audience, and was

not the sole basis of the agency’s decision.

The petitioners’ assertions of problems

with the use of the C-statistic are not

applicable to the C-statistic as used by the

agency. In an attempt to support their

assertions, the petitioners pointed to an

example of how the C-statistic can

‘‘misbehave’’ presented on page 146 of

Hosmer and Lemeshow.5 The agency’s use of

the C-statistic is not the same as that in

Hosmer and Lemeshow’s example. That

example simply uses a classification table

with an arbitrary cut point to determine, e.g.,

whether an actual rollover was predicted to

be a rollover. The C-statistic employed by

NHTSA measured the concordance between

all possible pairs of observations, taking one

from the actual rollover population and one

from the actual non-rollover population. The

C-statistic represents the percentage of those

pairs (which number literally in the millions)

for which the actual rollover had a higher

predicted probability than the actual nonrollover’s predicted probability (of rolling

over), minus one-half the number of ties.

There is no arbitrary cutoff point. In addition,

the agency’s decision was not based on a

single statistical measure. The agency

analyzed the data with a number of statistical

measures, all of which pointed to the same

conclusions. Accordingly, the agency

remains confident in its results.

Finally, the petitioners’ objection to the

agency’s reliance on Michigan data for

performing the statistical regressions instead

of using the data from the other four states

was based on their concern that the agency

did not examine the extent to which the state

is anomalous because of its generally flat

topography. The petitioners stated that this

could lead to a lower proportion of rollovers

per single vehicle accident than the other

states in the data base. The agency relied on

Michigan data because they included a large

number of available observations, and were

based on a low reporting threshold and more

refined accident reporting variables. The

agency did examine whether the rollover rate

in this state was anomalous, and as stated on

page 13 of the Addendum, discovered that

‘‘(t)he rollover rate in Michigan is near the

midpoint of the range for all five states

studied.’’ The examination of the relative

rollover rates of the five different states was

fully explained in the TAP on pages 59–65.

D. Legal Arguments

The petitioners also addressed the

implications of the Intermodal Surface

Transportation Efficiency Act of 1991

(ISTEA) (P.L. 102–240), the National Traffic

and Motor Vehicle Safety Act of 1966 (the

Safety Act) (P.L. 89–563),6 and the Regulatory

Flexibility Act (P.L. 96–354) for rulemaking

concerning a vehicle stability standard. The

petitioners also argue that the decision not to

issue a rollover standard is judicially

reviewable.7
Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules 28559

8Advocates/IIHS petition, page 41.

The petitioners begin by citing the

provision in ISTEA that required NHTSA to

initiate rulemaking concerning a rollover

standard. The petitioners acknowledge that

Congress did not mandate the issuance of a

final rule in this area.

Although the petitioners make this

concession, it bears emphasizing how clearly

ISTEA and its legislative history demonstrate

that in each instance in which Congress

mandated that the agency initiate vehicle

safety rulemaking, it clearly specified

whether the agency had the discretion to

decide not to issue a final rule. In sections

2502–3 of ISTEA, Congress specified that the

agency was to initiate rulemaking regarding

five different areas of vehicle safety

performance. With respect to one area, upper

interior head impact protection, Congress

specified that rulemaking would be

considered completed only when a final rule

was issued. However, with respect to the

other four areas, including rollover, Congress

did not mandate the issuance of a final rule.

It expressly provided that rulemaking on

rollover and the other three areas would be

considered completed either when the

agency issued a final rule or when the agency

decided, after considering public comments,

not to issue a final rule. The Conference

Report on ISTEA emphasized the discretion

which it had reserved to the agency. The

conferees said, with reference to the

mandated rulemaking on rollover, ‘‘the

conferees do not predetermine the outcome

of [this rulemaking]. The [NHTSA] is free to

conclude the rulemaking in any manner

consistent with the APA and the 1966 Act’’

(H. Conf. Rep. 404, 102d Cong., 1st Sess., at

397 (1991)). Thus, Congress made no

judgment in ISTEA about the ultimate merits

of issuing a final rule on rollover. Instead,

Congress provided NHTSA with the latitude

to decide that a rollover standard should not

be issued if, in the agency’s judgment, the

facts did not warrant such issuance. The

agency’s conclusion that such a regulation

would not have sufficient benefits to justify

its cost is an ample and proper basis for a

decision not to issue a final rule.

Although the petitioners concede that

Congress did not require the agency to issue

a final rule on rollover, they assert that

Congress ‘‘expected the agency to set some

form of stability-enhancing regulation.’’ 8 As

authority for that assertion, they cite the

legislative history of the Department of

Transportation and Related Agencies

Appropriations Act of 1995. (P.L. 104–59)

The Senate committee report on that Act

contended that NHTSA had ‘‘effectively

abandoned efforts at developing a

performance standard for improved rollover

protection.’’

The 1995 Appropriation Act legislative

history is inapposite here and lacks any

possible binding effect. Since that history

pertains to a different statute, it carries no

weight in the interpretation of NHTSA’s

duties under ISTEA. NHTSA notes further

that the language cited by the petitioners is

part of a discussion expressing concern about

the agency’s delay in publishing some of the

ISTEA rulemakings. The discussion does not

express any expectation about the

substantive outcome of agency rulemaking on

rollover, but does express an expectation that

NHTSA will complete the remaining ISTEA

rulemakings expeditiously. Finally, even if

the Senate committee had specifically

expressed an expectation concerning the

outcome of the rollover rulemaking, that

expectation would not impose a binding

obligation on NHTSA unless Congress

coupled that expectation with a mandate to

issue a final rule on rollover and enacted that

mandate into law. See Center for Auto Safety

v. Peck, 751 F.2d 1336, at 1351 (D.C. Cir.

1985). Congress did not do so. Instead, it

expressly decided not to mandate the

issuance of a final rule on that subject.

The petitioners argued that neither the

Safety Act nor the Regulatory Flexibility Act

provide any legal grounds for terminating

rulemaking on a vehicle stability standard.

The petitioners quoted statements in the

1994 notice that 49 U.S.C. § 30111(b)(3)

would preclude NHTSA from mandating any

stability requirement that is ‘‘incompatible

with certain types of vehicles,’’ and that a

stability requirement ‘‘could raise concerns’’

under the Regulatory Flexibility Act. (59 FR

33254, 33263) They interpreted these

statements as implying that the agency

believed it was prohibited from issuing any

standard that might require ‘‘the radical

redesign of the characteristics [of] many, and

in some cases all, vehicles of certain classes

* * * and possibly even the elimination of

certain classes of vehicles as they are known

today.’’ The petitioners countered with

alternative propositions, arguing that NHTSA

has authority to eliminate whole classes of

vehicles, and that, even if NHTSA does not

have such authority, it failed to consider a

less demanding regulatory approach such as

setting different standards for separate

vehicle types which would not require all

vehicles in a class to be altered. The

petitioners argued also that NHTSA cannot

rely on the Regulatory Flexibility Act when

the agency did not prepare any analysis of

the impacts of a standard on small entities.

The primary bases for the agency’s

decision to terminate rulemaking on a

vehicle stability standard are the limited

safety benefits, and the excessive costs and

market disruption of such a standard,

regardless of whether that standard applies to

all light duty vehicles or to particular class

such as compact SUVs. The 1994 notice

discussed the high costs of a standard that

specifies a single performance level which

was applicable to all light duty vehicles and

was high enough to require the full redesign

of at least some passenger cars. As explained

previously, the agency concluded that such

a standard would have costs and other

impacts which outweighed its benefits.

NHTSA similarly concludes that the costs

and other impacts of a standard applicable to

compact SUVs would far outweigh its

benefits. Logically, if a standard for the most

rollover-prone light duty vehicles would fail

this basis test, it follows that a standard for

other groups of light duty vehicles would not

be justified.

It should be noted that neither 49 U.S.C.

30111(b)(3) nor the Regulatory Flexibility Act

impose an absolute legal bar to a minimum

stability standard. The agency is not

foreclosing any possibility of further

rulemaking. As stated above, NHTSA might

reinitiate rulemaking in this area if

information becomes available demonstrating

the cost effectiveness of a minimum stability

standard.

However, the Safety Act does place limits

on the agency’s rulemaking authority. The

agency lacks authority to eliminate entire

classes of vehicles. This interpretation

reflects the language of 49 U.S.C. 30111(b)(3)

and its legislative history. 49 U.S.C.

30111(b)(3) states:

When prescribing a motor vehicle safety

standard under this chapter, the Secretary

shall * * * consider whether a proposed

standard is reasonable, practicable, and

appropriate for the particular type of motor

vehicle or item of motor vehicle equipment

for which it is prescribed.

The Senate Report accompanying the 1966

Safety Act explained this provision as

follows:

In determining whether any proposed

standard is ‘‘appropriate’’ for the particular

type of motor vehicle or item of motor

vehicle equipment for which it is prescribed,

the committee intends that the [NHTSA] will

consider the desirability of affording

consumers continued wide range of choices

in the selection of motor vehicles. Thus it is

not intended that standards will be set which

will eliminate or necessarily be the same for

small cars or such widely accepted models as

convertibles and sports cars, so long as all

motor vehicles meet basic minimum

standards.

(S. Rep. 1301, 89th Cong., 2d Sess., at 6

(1966))

Given this legislative history, NHTSA

cannot mandate a stability requirement so

incompatible with the most fundamental

characteristics which define a class of

vehicles that implementing the requirement

would cause the elimination of that class. As

an example, the agency noted in the 1994

notice that sport utility vehicles have features

(high ground clearance and narrow track

width) to facilitate off-road use and use on

snowy roads. The agency would not have the

authority to set a performance level so

stringent that no vehicles could have these

features. This is neither a radical, nor a new

interpretation of the agency’s authority.

NHTSA is not suggesting, as the petitioners

suggest, that the agency lacks any authority

to issue a standard that requires significant

change to all vehicles in a class. In fact, there

are many examples of the agency using its

authority to require changes to all vehicles in

a particular class. Those changes did not,

however, eliminate as a practical matter any

recognized classes of vehicles.

Petitioners incorrectly suggested that the

agency had a duty under the Regulatory

Flexibility Act to prepare a regulatory

flexibility analysis in connection with either

the 1994 notice or the ANPRM which

preceded it. NHTSA did not ‘‘fail’’ to prepare

any required report. That Act mandates the

preparation of analyses in connection with

notices of proposed rulemaking and final

rules only.

NHTSA believes that the Regulatory

Flexibility Act was a relevant concern in
28560 Federal Register / Vol. 61, No. 109 / Wednesday, June 5, 1996 / Proposed Rules

considering the possibility of proposing a

stability standard applicable to all light duty

vehicles because multistage manufacturers,

especially van converters, which are often

small business entities, could be affected by

such a standard. NHTSA is not suggesting

that that Act would prevent the issuance of

such a standard or that the concerns about

impacts on small manufacturers were

insurmountable regardless of what approach

is taken by the agency in setting the standard.

In fact, a standard limited to compact SUVs

would essentially eliminate those impacts

because few, if any, of those vehicles are

produced by multistage or other small

manufacturers.

F. NHTSA’s Alleged Lack of a

Comprehensive Rollover Program

The petitioners characterized NHTSA’s

identification of seven separate measures as

part of a comprehensive agency plan to

address rollovers as simply ‘‘a chronicle of

ongoing or prospective crash reduction

programs that are not aimed uniquely at

mitigating rollover losses.’’ The petition went

on to complain that some of the measures

‘‘may never come to fruition,’’ and that others

have not been specifically tailored by the

agency to address the rollover problem. The

petitioners concluded by stating their belief

that NHTSA’s comprehensive program for

rollover is really an attempt to try to

persuade the public that the agency is taking

action on rollover safety, notwithstanding the

termination of the vehicle stability

rulemaking.

The agency believes that the question of

whether the activities comprising its

comprehensive rollover program uniquely

address rollover safety is irrelevant if those

activities effectively address that issue. If

NHTSA can take actions, such as issuing a

standard, that significantly reduces the

deaths and injuries that occur in rollover

crashes, it should make no difference

whether that reduction is achieved by means

that also reduce deaths and injuries in other

types of crashes. The agency agrees that there

is a possibility that some of the regulatory

initiatives announced by the agency as part

of its rollover program involve proposals that

may never become final rules. However, this

possibility exists with any regulatory

initiative. The agency cannot foretell the

nature of the public comments that it will

receive or prejudge the outcome of its

analyses of comments and other information

obtained during the rulemaking process.

NHTSA included those initiatives in its

rollover program because preliminary

evaluations of those initiatives indicate that

they are promising avenues for addressing

rollovers. The agency will pursue these

initiatives expeditiously and conscientiously.

For example, since the 1994 notice was

published, NHTSA has published a final rule

to extend the current requirements for side

door latches to rear door latches. (60 FR

50124) This rule is an attempt to reduce the

number of ejections from the rear door of

vehicles, thus reducing injuries and fatalities.

Based on data for years 1988–1992, NHTSA

estimates that 147 occupants were fatally

ejected from the rear door of vehicles. Forty

two percent of those fatalities occurred in

rollover accidents.

One of the specific initiatives singled out

for criticism by petitioners was the upgrade

of Standard 201 to reduce head impact

injuries. The petitioners objected to its

inclusion in NHTSA’s comprehensive

rollover plan because the proposed

compliance impact speeds ‘‘are often less

than those [speeds] responsible for the very

high rate of severe head trauma that is

suffered by occupants in rollover crashes.’’

The final rule upgrading Standard No. 201

was published on August 16, 1995. (60 FR

43031) Even if the petitioners were correct,

the essential fact remains that the final rule

will make substantial reductions in rollover

fatalities and injuries. The agency estimated

that 244–334 fatalities and 189–273 serious

injuries would be averted in rollovers as a

result of that rule.

Authority: 49 U.S.C. 322, 30111, 30115,

30117 and 30166; delegation of authority at

49 CFR 1.50 and 501.8.

[FR Doc. 96–14145 Filed 5–31–96; 4:38 pm]

BILLING CODE 4910–59–P

National Highway Traffic Safety

Administration

49 CFR Part 571

[Docket No. 91–68; Notice 06]

RIN 2127–AC54

Consumer Information Regulations;

Vehicle Rollover Stability Label

AGENCY: National Highway Traffic

Safety Administration (NHTSA), DOT.

ACTION: Notice of proposed rulemaking;

reopening of comment period.

SUMMARY: This notice reopens the

comment period for a notice of

proposed rulemaking published June 28,

1994, regarding a rollover stability label

for light vehicles. The comment period

for this proposed rulemaking action

closed on October 21, 1994. Since that

time, the National Academy of Sciences

(NAS) has published a study of

consumer needs for automotive safety

information. NHTSA would like public

comments on the NAS study and how

that study should be reflected in

NHTSA’s rulemaking decisions on

requirements for rollover stability

labeling. Accordingly, the agency is

reopening the comment period for an

additional 60 days.

DATES: Comments must be received by

August 5, 1996.

ADDRESSES: Comments should refer to

Docket No. 91–68; Notice 5 and be

submitted to: Docket Section, Room

5109, National Highway Traffic Safety

Administration, 400 Seventh Street,

SW., Washington, DC 20590. (Docket

hours are 9:30 a.m. to 4 p.m., Monday

through Friday.)

FOR FURTHER INFORMATION CONTACT: For

labeling issues: Stephen R. Kratzke,

Office of Safety Performance Standards,

NPS–31, NHTSA, 400 Seventh Street,

SW., Washington, DC 20590. Mr.

Kratzke can be reached by telephone at

(202) 366–5203 or by fax at (202) 366–

4329.

For general rollover issues: Gayle

Dalrymple, Office of Safety Performance

Standards, NPS–20, NHTSA, 400

Seventh Street, SW., Washington, DC

20590. Ms. Dalrymple can be reached by

telephone at (202) 366–5559 or by fax at

(202) 366–4329.

For legal issues: Stephen P. Wood,

Assistant Chief Counsel for Rulemaking,

NCC–20, NHTSA, 400 Seventh Street,

SW., Washington, DC 20590. Mr. Wood

can be reached by telephone at (202)

366–2992 or by fax at (202) 366–3820.

SUPPLEMENTARY INFORMATION: NHTSA

currently requires that sport utility

vehicles with a wheelbase of 110 inches

or less have a prominent label advising

drivers that these vehicles are less stable

than passenger cars and more likely to

roll over during abrupt maneuvers. 49

CFR 575.105. On June 28, 1994 (59 FR

33254), NHTSA published a notice

proposing to supplement the existing

requirement for a rollover label with

another label. This proposed additional

rollover stability label would be

required on all passenger cars, trucks,

and multipurpose passenger vehicles

with a Gross Vehicle Weight Rating of

10,000 pounds or less. The comment

period for this proposal was scheduled

to close on August 29, 1994. However,

NHTSA extended the comment period

so that it closed October 21, 1994; 59 FR

44121, August 26, 1994. NHTSA

received 70 comments to its docket for

the proposed additional labeling

requirements.

During this comment period, Congress

enacted the Department of

Transportation and Related Agencies

Appropriations Act, 1995 (P.L. 103–331;

September 30, 1994). In that Act,

Congress gave NHTSA funds ‘‘for a

study to be conducted by the National

Academy of Sciences (NAS) of motor

vehicle safety consumer information

needs and the most cost effective

methods of communicating this

information.’’ The Act directed NAS to

complete its study by March 31, 1996.

The Act also included the following

language: ‘‘In order to ensure that the

results of the study are considered in

the rulemaking process, the conferees

agree that NHTSA shall not issue a final

regulation concerning motor vehicle

safety labeling requirements until after

the NAS study is completed.’’ As a

result of this language, NHTSA deferred