[Federal Register Volume 61, Number 187 (Wednesday, September 25, 1996)]
[Notices]
[Page 50372]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-24574]
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DEPARTMENT OF TRANSPORTATION
Denial of Motor Vehicle Defect Petition
This notice sets forth the reasons for the denial of a petition
submitted to NHTSA under 49 U.S.C. Sec. 30162 for the agency to
commence a proceeding to determine the existence of a defect related to
motor vehicle safety.
On February 28, 1996, Mr. R.A. Whitfield of Crownsville, Maryland,
submitted a petition asking NHTSA to determine whether the Suzuki
Samurai 4x4 convertible sport utility vehicle contains a safety-related
defect. The petition describes the alleged defect in this vehicle as a
particular vulnerability to untripped or ``friction'' rollovers that do
not require tripping of the vehicle (e.g. from an impact between the
wheels and a curb) to initiate the roll, but instead occur in tight
turns or crash avoidance maneuvers and result from the lateral drag of
friction generated by the tires and the roadway surface. The petitioner
attributed this untripped rollover vulnerability to what he
characterized as the vehicle's very low roll stability and light
weight, as well as to the high ratio of the occupants' mass to the
vehicle mass, especially when the Samurai is loaded with passengers.
Additionally, the petitioner asked NHTSA to determine whether the
vehicle can safely carry passengers up to its claimed gross vehicle
weight rating.
In 1988, the agency investigated the alleged rollover propensity of
the Suzuki Samurai and two variants of this vehicle, the SJ410 and
LJ80, in response to two petitions (DP88-011 and DP88-019). In the
course of this investigation, NHTSA conducted its own vehicle testing
and analyzed a large body of data, including accident and test data of
these and other vehicles. However, NHTSA did not decide that the
Samurai vehicles contained a safety-related defect, largely because the
information available did not show that the rollover accidents were
caused by a defect in the vehicle rather than by driver and/or
environmental factors.
This petition did not provide any significant new evidence that
bears on the issue of whether a safety-related defect exists in the
Samurai. The only ``new'' information presented in the petition was the
allegation that the Samurai 4x4 convertible sport utility vehicles
cannot safely carry the number of occupants for which it has seats
without affecting its propensity to roll over in a fatal crash.
The petitioner asserted that the cause of the subject vehicle's
apparent disproportionate involvement in single-vehicle rollover-
initiated fatal crashes is the very low roll stability and the high
ratio of the occupants' mass to the vehicle mass, especially when the
Samurai is loaded with passengers. This conclusion relies heavily on a
statistical regression analysis which shows that the Suzuki Samurai 4x4
convertible has a higher percentage of identified friction rollovers in
fatal, single-vehicle crashes as the number of its occupants increases.
The petitioner further concluded that additional control variables such
as roadway speed limit, driver age, and pavement condition are not
statistically significant.
Contrary to the petitioner's analysis, the Samurai has a track
width to center of gravity ratio higher than that of most other light
sports utility vehicles. This ratio has been demonstrated to have a
fundamental effect on the rollover propensity of vehicles.
Those vehicles with higher ratios tend to have lower rollover
propensity. There is also evidence that the subject vehicle has a lower
sensitivity to mass ratio than many other sport utility vehicles.
Vehicles with a higher sensitivity to mass ratio demonstrate an
increased propensity for rollover with the addition of mass that raises
their center of gravity.
Based on a statistical analysis, the petitioner stated that more
than 5,000 persons were occupants in Suzuki Samurai light utility
vehicles that rolled over in single-vehicle crashes during 1988-1993
and more than 1,700 of these occupants were injured. He also stated
that 46 percent of all Suzuki Samurai crashes in 1992-1993 were
untripped rollover crashes. These are not actual numbers but estimates
based on a very small sample size, which neglect many unknown
variables, especially the driver and environmental factors. Moreover,
one must always exercise great caution in the use of public reported
accident statistics in evaluating alleged defects, such as that
addressed in this petition. These statistics are heavily influenced by
driver and environmental causes that tend to obscure vehicle causes.
The petitioner's regression analysis does not overcome this difficulty.
In fact, previous investigations demonstrate that many of the rollovers
which have occurred appear to have involved adverse driver and
environmental factors such as high risk driving maneuvers, drinking,
ambient light, vehicle/road familiarity, etc.
Although the rollover crash involvement rate of the Samurai is no
worse than that of most other light utility vehicles, it is
significantly higher than most passenger vehicles. In a notice of the
denial of a petition for rulemaking (52 FR 49037, December 29, 1987),
NHTSA stated that while the agency recognized the existence of a higher
rollover rate in light utility vehicles, there was no basis for
proceeding with rulemaking based on stability factors alone because of
the importance of other vehicle factors, the lack of predictiveness of
the stability factor for vehicle rollover involvement, and statutory
limitations that may preclude standards that have the effect of
eliminating classes of motor vehicles. Similarly, the stability factor
distinction does not appear to be an appropriate basis on which to
conduct a defect investigation analysis.
After reviewing the petition and its supporting materials, as well
as information furnished by Suzuki and within the agencys possession
from previous rulemaking proceedings and other actions, NHTSA has
concluded that further investigation of the Suzuki Samurais rollover
propensity is not likely to lead to a decision that the vehicle
contains a safety-related defect and that a further commitment of
agency resources on this matter is not warranted. The agency has
accordingly denied the petition.
Authority: 49 U.S.C. 30162 (d); delegations of authority at CFR
1.50 and 501.8.
Issued on: September 19, 1996.
Michael B. Brownlee,
Associate Administrator for Safety Assurance.
[FR Doc. 96-24574 Filed 9-24-96; 8:45 am]
BILLING CODE 4910-59-P
