[Federal Register Volume 61, Number 235 (Thursday, December 5, 1996)]
[Notices]
[Pages 64563-64567]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-30773]
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DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
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 requesting that the
agency commence a
[[Page 64564]]
proceeding to determine the existence of a defect related to motor
vehicle safety.
Ms. Joan Claybrook of Public Citizen submitted a petition dated
June 4, 1996, requesting the agency to investigate more than 40 million
model year (MY) 1978 through 1988 GM vehicles, equipped with the
General Motors Corporation (GM) Type III door latch, to remedy an
alleged safety-related defect in the door latch which reportedly fails
to hold the door closed during a crash. Specifically, the petitioner
alleges that during a collision, the Type III door latch allows the
detent lever to be out of alignment with respect to the fork bolt.
According to the petitioner, when this occurs, the fork bolt may be
free to rotate and may disengage from the striker, allowing the door to
inadvertently open and the occupants to be ejected.
The petition was based on information from an Alabama product
liability case Hardy v. General Motors Corporation, et al. (Circuit
Court, Lowndes County, Alabama, Civil Action File No. CV9356), in which
the plaintiff alleged that Mr. Hardy was ejected through an opened side
door from a MY 1987 Chevrolet S-10 Blazer, equipped with the GM Type
III door latch, and injured because the door latch failed to hold the
door closed during a rollover accident.
After reviewing the petition and its supporting materials, as well
as information both furnished by GM and within the agency's possession
from previous rulemakings and other actions, NHTSA has concluded that
further investigation of the GM Type III side door latch is unlikely to
result in a determination that the latch contains a safety-related
defect and that a further commitment of agency resources in this effort
is not warranted. The agency has accordingly denied the petition.
NHTSA's Office of Defects Investigation (ODI) has prepared a report
that describes in detail the agency's analysis of the allegation
presented in the petition. Interested persons may obtain copies of that
report by contacting the Technical Reference Division, NAD-52, Room
5108B, 400 7th Street, SW, Washington, DC 20590, (202) 366-2768. A
summary of this report is presented below.
System Description
Front Door Latch and Lock Assembly. The side door latch assembly in
these GM vehicles provides three major functions as described below.
a. It provides a means of keeping the door closed.
When closing the door, the latch fork bolt contacts the striker pin
body. This causes the fork bolt to rotate in the latch and the
``throat'' to wrap around the striker pin. A cam surface of the fork
bolt causes the detent lever to ride on the cam until it drops into
engagement with the secondary latch tooth of the fork bolt. Further
inboard movement of the door causes the detent lever to ride on a
second cam surface until it drops into engagement with the primary
latch tooth of the fork bolt. A spring on the detent lever keeps the
detent lever engaged with the fork bolt, keeping the door latched.
b. It provides a means to unlatch the door from inside and outside
the vehicle.
To open the door, a release lever actuated by the door handle
operates an intermittent lever that disengages the detent from the
teeth of the fork bolt. When the outside handle is operated, a rod
attached to the handle pushes the release lever in the latch, thereby
disengaging the detent. When the inside handle is operated, a rod
attached to the handle pulls a remote lever in the latch. This lever
moves the release lever and also disengages the detent. When the detent
is disengaged from the fork bolt, continuous outboard movement of the
door causes the fork bolt to rotate until it clears the striker bolt.
c. It provides a means to lock and unlock the door.
To lock the door, a rod attached to the key cylinder mechanism or a
rod attached to the inside locking button drives the locking lever in
the latch to a locked position. The intermittent lever is thereby moved
out of engagement with the detent lever and renders the door handles
inoperative.
Modification
The GM Type III door latch has two basic versions: one is the
original design and the other is a modification of the same. The
petitioner alleges that the original Type III side door latch is
defective.
The modification of the original latch involved the addition of a
metal plate (support plate) within the latch assembly. This support
plate was riveted in front of the fork bolt and detent lever and welded
on the latch inboard edge. According to GM, the purpose of adding the
support plate was to increase resistance to ``bypass,'' i.e., release
of the latch due to mis-alignment of the fork bolt from the detent
lever. The modification was first introduced as a running change on
GM's K body passenger vehicles during MY 1986.
Vehicles Involved
GM produced approximately 46 million MY 1978 through 1988 vehicles
equipped with GM's ``original'' Type III and ``modified'' Type III door
latches. Approximately 40 million of these vehicles were equipped with
the GM's original Type III door latch that was built without a support
plate. Beginning in MY 1986, the modified Type III door latch, which
was built with a support plate, was used in certain models.
Owner Reports
Analysis of the Office of Defects Investigation (ODI) computerized
database for the subject vehicles revealed only one (1) complaint
concerning side door opening during a collision accident. The vehicle
involved was a MY 1984 Chevrolet Camaro that was built with the
original Type III door latch. The report mentions that during the March
13, 1996 accident, the side door was opened and the driver was injured
but not ejected.
Testing
1. Static Test--Performed by NHTSA
NHTSA's Office of Vehicle Safety Compliance (OVSC) has tested
thirty-nine MY 1978-88 GM vehicles according to Federal Motor Vehicle
Safety Standard (FMVSS) No. 206, ``Door locks and door retention
components'' and all passed the requirements of the standard. The test
vehicles were equipped with three different latches: twelve with the
original Type III latch, eight with the modified Type III latch, and
the remaining nineteen with a different (non-Type III) latch.
Beginning with model year 1978, certain door latches that passed
compliance testing to FMVSS 206 were further tested until failure to
determine the ultimate load for each latch. The purpose was to gather
additional information on the strength of the latches. Of the twenty
compliance tests involving MY 1978-88 vehicles equipped with the Type
III latches, ten were further tested until failure. The test-to-failure
results showed that: (1) there was insignificant difference in strength
between the original and modified Type III latches, and (2) both the
original and modified Type III latches exceeded NHTSA's safety standard
requirements, in many cases by a factor of two or more.
In an effort to reduce the accident ejection rates on the nation's
roadways, NHTSA has considered the possible benefits of upgrading FMVSS
No. 206. In 1986, NHTSA initiated a pilot study and contracted with Chi
Associates Inc. to correlate the ultimate strength (test-to-failure) of
side door latches with the overall occupant ejection rates. In this
[[Page 64565]]
study, the ejection rate was determined, using the number of ejections
in the Fatal Accident Reporting System (FARS) data divided by the
number of vehicle registrations obtained from the POLK database for 173
vehicles of various make and models. These vehicles were then divided
and ranked into three groups with high, average, and low ejection
rates. Eight vehicles from each of the high, average and low categories
were selected for ultimate strength testing, with priority given to the
major automobile manufacturers. All 24 vehicles tested were MY 1983
models. The test results showed that GM's original Type III latch
performed far better than many other latches. In fact, three of the
four strongest tested latches in both longitudinal strength tests and
transverse strength tests were original GM Type III latches.
In 1988, as a follow-up study, NHTSA conducted its own door latch
testing program at the Vehicle Research and Test Center (VRTC) to
validate the findings of Chi Associates' study. A total of 25 latches
were tested: two GM models with the original latch, two GM models with
non-Type III Latches, and 21 non-GM latches. Each specimen was tested
until failure, using a procedure similar to FMVSS No. 206, in order to
determine its ultimate latch strength. The test results showed that in
both the longitudinal and transverse loading directions, GM's original
Type III latch was among the top six in terms of strength for the 25
latches tested.
In the mid-1980's, GM developed the Horizontal Rotation Test (HRT)
as a way of simulating (and ultimately reducing the incidence of )
latch ``bypass,'' which can occur on all vehicles. In this test, the
door latch and striker are allowed to rotate relative to one another to
simulate rotation of the surrounding vehicle structure. GM provided
NHTSA with information on the test fixture and some early test results.
In 1991, NHTSA conducted an evaluation of GM's HRT on door latch
integrity to determine if that test is a suitable replacement of or
supplement to the FMVSS No. 206 test requirements. NHTSA analyzed the
National Accident Sampling System (NASS) data and found that a GM's HRT
would represent approximately 16 percent of the door opening cases that
involve B pillar twisting.
To further evaluate the HRT fixture, NHTSA conducted tests on door
latches from thirteen MY 1981 and 1983 non-GM vehicles and from the MY
1983 Buick Regal using GM's original Type III latch. For each latch-
type, two latches were tested to failure. To evaluate repeatability,
five additional latches were selected from each previously tested
vehicle group; a total of 25 additional latches were tested. The
failure loads were correlated with ejection rates for the vehicles
under consideration. The test results showed that the GM Type III latch
was the strongest tested; the average strength of the seven tests of
the original GM Type III latch was well above the breaking load of all
non-GM latches.
In January 1994, NHTSA conducted an additional follow-up study of
the potential for different door latch failure modes. The following
test-to-failure tests were conducted:
a. Five MY 1989 non-GM vehicles and one MY 1993 non-GM vehicle were
tested to failure, using a procedure similar to one specified in FMVSS
No. 206. The test results were compared with those for the MY 1983 GM
vehicles with the original Type III latch. Even against the newer non-
GM models, the original GM Type III latch compared favorably, at or
above the median of all tests.
b. Full-door longitudinal strength tests (latch strength tests with
each latch mounted on a full door instead of on a test fixture) were
conducted on 21 non-GM doors and two doors from GM models having the
original Type III door latch. The full-door transverse strength test
was performed on 15 non-GM doors and one door from a GM model using the
original Type III door latch. In the full-door longitudinal strength
test, the 1983 Buick Regal's original Type III latch outperformed all
but two of the non-GM designs. In the full-door transverse strength
test, the Buick Regal's original Type III latch outperformed all but
one non-GM latch.
c. The HRT was performed on six non-GM vehicles. The test results
were compared with the average of the seven tests previously reported
for the original Type III latch. Once again, the GM Type III latch from
a 1983 model car compared favorably to all the newer vehicles tested by
NHTSA.
Static Test--Conducted by GM:
GM's September 5, 1996 response to ODI's DP96-008 information
request indicated that GM had tested twenty-four original Type III
latches to the requirements of FMVSS No. 206--all passed.
2. Dynamic Tests--Performed by NHTSA:
FMVSS No. 208, ``Occupant crash protection''. NHTSA's OVSC tested
two subject vehicles equipped with the original Type III latches and
one subject vehicle equipped with a modified Type III latch. A review
of the photographs in the three test reports revealed that no side door
was opened on any of the test vehicles as a result of the 30 mph rigid
barrier frontal crash.
FMVSS No. 301, ``Fuel system integrity'' (Rear impact): NHTSA
tested 20 vehicles equipped with the GM original Type III latch, and
one subject vehicle equipped with the modified latch. A review of the
photographs in the 21 test reports revealed that no side door opened on
any of the test vehicles as a result of the 30 mph rear impact by a
4,000 moving barrier.
New Car Assessment Program. NHTSA tested 31 subject vehicles
equipped with the original Type III latch, four subject vehicles
equipped with the modified Type III latch, and five subject vehicles
equipped with either the original or modified Type III latch (in
certain model and model year vehicles both the original and modified
Type III latches were used). Despite the severity of the 35 mph rigid
barrier crash, a review of the photographs in the test reports revealed
that no side door opened as a result of the crash.
2. Dynamic Tests--Performed by GM
In its September 5, 1996 response to ODI, GM provided 42 crash test
reports on vehicles equipped with Type III latches. These crash tests
involved both developmental (non-production) vehicles and production
vehicles, and were performed for a variety of evaluation purposes. Of
the 38 developmental test vehicles, 28 were equipped with the original
Type III latch, seven were equipped with the modified Type III latch,
and three were equipped with unspecified Type III latches. Of the four
production vehicles tested, three were equipped with the original Type
III latch and one was equipped with the modified Type III latch.
A total of 28 developmental vehicles equipped with the Type III
door latch reportedly experienced side door openings during crash
testing; 22 were equipped with the original Type III latch, four were
equipped with the modified Type III latch, and two were equipped with
either the original or the modified Type III latch. There was only one
production vehicle which reportedly experienced side door opening--a MY
86 Oldsmobile `H' body vehicle equipped with the original Type III
latch. During the 50 mph high speed impact, the passenger side rear
door latch separated from the striker, allowing the door to open.
The rear door on a second production vehicle, a MY 1978 Chevrolet
`T' body vehicle equipped with the original Type III latch, came
partially unlatched during a 31 mph rear impact test.
[[Page 64566]]
It is important to note that many of these crash tests involved
prototype or altered Type III latches and vehicles and thus cannot be
considered equivalent to tests involving standard Type III latches and
production vehicles. Prototype or altered latches involved
significantly different weld patterns, bolt structures, materials, and
varying striker and detent sizes. These developmental modifications may
significantly change the Type III latch's strength, and there is no
record that any of these developmental modifications (with the
exception of the support plate) survived into the final design.
Similarly, the vehicles used in developmental tests were often two or
more years ahead of their production date. These differences mean that
the prototype Type III door latches or vehicles used in developmental
crashes are not necessarily representative of production versions, and
thus doors opening in developmental crashes do not necessarily indicate
that doors will open in production vehicles under the same crash
conditions.
Accident Data
In response to DP96-008 Information Request concerning reports of
inadvertent side door openings on the subject vehicles involved in a
collision or rollover, GM's September 5, 1996 response did not limit
the reports to those involving a ``bypass'' although the petition
focused on that type of door latch failure. According to GM, it has
provided reports involving all door openings regardless of the causes,
which include side door openings caused by something other than door
latch failure. Further, GM indicated that door openings can and do
result from many causes including intentional or accidental actuation
of the door handle, or vehicle crash damage to the actuating rods
inside the door, the door hinges, the door pillar or other parts of the
door system.
Analysis of GM's September 5, 1996 response indicates that: (a) the
majority of door-opening cases occurred from high speed collisions, and
(b) under high speed collisions, both the original and modified latches
cannot always prevent side door opening.
1. Accident Reports and Lawsuits
GM reported 19 accident reports and 105 lawsuits involving side
door openings in the subject vehicles. In the 45 cases where the posted
speed limits were reported, all of the accidents occurred in areas
where the posted speed limits were 35 mph or higher, and eighty percent
of the accidents occurred on roadways where the posted speed limits
were 50 mph or higher. In the 38 cases where the estimated impact
speeds were reported, all of the accidents occurred at an estimated
impact speed of 36 mph or higher. In cases where neither the posted
speed limits nor the estimated impact speeds were reported, almost all
the vehicles were declared a total loss.
Of the 45 cases where the posted speed limits were reported, 29
involved the original Type III latch and 16 involved the modified Type
III latch. Similarly, of the 38 cases where the estimated impact speeds
were reported, 25 involved the original Type III latch and 13 involved
the modified latch. One would expect to have more accident cases
involving the subject vehicles with the original Type III latch than
those with the modified Type III latch because there were 40 million
vehicles equipped with the original Type III latch and only 6 million
vehicles equipped with the modified latch.
2. Survey
Unlike other manufacturers, GM owns an insurance company that
provides it with collision performance and injury reports (CPIR) on the
crashworthiness of certain new model GM vehicles. GM provided NHTSA
with 322 CPIRs involving side door openings during a collision and 265
of which involved Type III latches.
Analysis of the 265 CPIRs involving Type III latches showed that
243 cases included the posted speed limits in the reports. Eighty-six
(86) percent of the accidents occurred on roadways where the posted
speed limits were 35 mph or higher, and 50 percent of the accidents
occurred on roadways where the posted speed limits were 50 mph or
higher. Eighty-one (81) cases included the estimated impact speeds in
the reports. Among those cases, 83 percent of the accidents occurred at
an estimated impact speed of 35 mph or higher, and 48 percent of the
accidents occurred at an estimated impact speed of 50 mph or higher.
Based on the accident reports, lawsuits, and CPIR cases provided,
the difference between the number of door opening cases for vehicles
equipped with the GM's original Type III latch and that with the
modified Type III latch is not statistically significant.
3. Analysis of FARS and NASS Data--Performed by ODI
Accident data were analyzed to determine the ``real world''
performance of the subject vehicles and peer vehicles.
ODI's analysis was based on a peer vehicle comparison, i.e., GM
vehicles with the original Type III latch compared to vehicles
manufactured by other companies that are similar in size and/or use.
Data analyses were conducted, using these two vehicle sets, using both
NHTSA's Fatal Accident Reporting System (FARS) and National Accident
Sampling System (NASS) Crashworthiness Data System (CDS) data.
Vehicle Selection and Peer Sets. The GM vehicles which used the
original Type III latch were organized according to type and size. A
peer vehicle group was selected according to size and type to be
similar to those of the GM vehicle group.
Results of the analysis showed that:
a. Analysis of the NASS-CDS database indicated that the GM vehicles
equipped with the original Type III latch without the support plate
performed in a similar manner as the peer vehicle group, i.e., the
rates of ejections, door openings, or latch failures for the GM
vehicles equipped with the original Type III latch were about the same
as those of the peer vehicles.
b. Analysis of the FARS data base indicated that the GM vehicle
group performed no worse than the peer vehicle group, i.e., the
ejection rates for the GM vehicle group equipped with the original Type
III latch, involving fatally injured occupants and ejected occupants,
were about the same as those of the peer vehicle group.
c. Analysis using both FARS and NASS data indicated that during
rollover crashes, the vehicle group equipped with the original GM Type
III latch performed the same as the peer vehicle group, i.e., the
ejection rates for the GM vehicle group equipped with the original Type
III latch were about the same as those of the peer vehicle group.
d. Analysis using both FARS and NASS data indicated that unbelted
occupants in crashes in the vehicle group equipped with the original GM
Type III latch performed the same as the peer vehicle group.
4. Analysis of FARS and NASS Data--Performed by GM
GM submitted to NHTSA a report dated September 25, 1996, including
accident data analyses of the ``real world'' performance of the subject
vehicles equipped with the original Type III latch. These analyses were
developed from NHTSA's FARS and NASS-CDS data systems. GM's summary
stated that ``GM vehicles equipped with Type III door latches have no
higher rate of door opening than vehicles made by other manufacturers
at the same time. Even
[[Page 64567]]
more importantly, GM vehicles with Type III door latches have no higher
rate of ejection--either overall or through side-door openings--than
contemporaneous vehicles of other manufacturers. * * * ''
Using 1984-94 NASS data, GM's detailed analysis indicates that the
GM and non-GM vehicles have similar door opening rates.
GM conducted several analyses using NHTSA's FARS data. Details of
these analyses are summarized below.
Overall ejection rate: In an analysis using 28 different car lines
of unbelted front seat outboard occupants in model year 1978 through
1987 passenger cars that were involved in fatal collisions in FARS
years 1975-1994, GM determined the number of ejected occupants per 100
unbelted occupants. The results showed that GM vehicles had the second
to lowest ejection rate, i.e., approximately 17 ejections per 100
unbelted occupants in fatal crashes.
Side door ejection rate: In a similar analysis using the number of
ejections through side door openings in 1978 through 1987 passenger
cars in the 1991 through 1994 FARS files, GM found a median ejection
rate of about 1.8 unbelted front seat outboard occupants per 100
unbelted occupants in fatal crashes. The GM vehicles had a side door
opening ejection rate of about 1.6 front seat outboard occupants per
100 unbelted occupants in fatal crashes.
Rollover ejection rates: GM presented an analysis of rollover and
non-rollover crashes, comparing its vehicles that used the original
Type III latch with other manufacturer's vehicles. The analysis shows
that the overall ejection rate for GM cars equipped with the Type III
latch was lower than that for five other manufacturers' cars, and the
side door ejection rate for GM cars equipped with the Type III latch
was lower than that for four other manufacturers' cars.
Make/Model analysis: GM analyzed FARS data concerning the ejection
rate of front seat occupants in vehicles at the make-model level for
four different vehicles: GM's S-10 pickup, GM's A body cars (Chevrolet
Chevelle/Malibu, Pontiac Lemans/6000, Oldsmobile Cutlas/Ciera, and
Buick Century), Ford Ranger and Ford Taurus. The results showed that
the ejection rate of the S-10 pickups was lower than that of the
Rangers for both overall and side door ejections, and the overall
ejection rate of the A body cars was lower than that of the Taurus. For
side doors, the ejection rate was the same for the A body cars and the
Taurus.
Summary
1. The GM original Type III door latch has performed better than
many other side door latches used in GM and non-GM vehicles, in both
static and dynamic tests, in the laboratory and in the field.
2. Test and accident data indicate that vehicle side door openings
did occur under certain crash conditions for all vehicles, regardless
of vehicle make or model, including GM vehicles equipped with the
modified Type III door latch as well as GM vehicles equipped with the
original Type III door latches. Most crashes in which the side door
opened were high speed crashes.
3. ``Real-world'' accident data indicate that GM vehicles equipped
with the original Type III door latch have ejection rates or side door
opening rates similar to or lower than those of vehicles made by other
manufacturers.
4. There was only one complaint in the ODI database concerning an
alleged side door opening during a collision accident involving a
subject vehicle.
Based on the information available at the present time, no defect
trend has been identified for the GM Type III door latch in 1978
through 1988 GM vehicles.
For the foregoing reasons and for the reasons stated in the ODI
report, further expenditure of the agency's investigative resources on
the allegation in the petition does not appear to be warranted.
Therefore, the petition is denied.
Authority: 49 U.S.C. 30162(d); delegations of authority at CFR
1.50 and 501.8.
Issued on November 27, 1996.
Michael B. Brownlee,
Associate Administrator for Safety Assurance.
[FR Doc. 96-30773 Filed 12-4-96; 8:45 am]
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