[Federal Register Volume 64, Number 96 (Wednesday, May 19, 1999)]
[Notices]
[Pages 27343-27353]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-12579]



[[Page 27343]]

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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration


Denial of Motor Vehicle Defect Petition, DP97-006

AGENCY: National Highway Traffic Safety Administration (NHTSA), 
Department of Transportation.

ACTION: Denial of petition for a defect investigation.

-----------------------------------------------------------------------

SUMMARY: This notice sets forth the reasons for the denial of a 
petition submitted to NHTSA under 49 U.S.C. 30162, requesting that the 
agency commence a proceeding to determine the existence of a defect 
related to motor vehicle safety. The petition is hereinafter identified 
as DP97-006.

FOR FURTHER INFORMATION CONTACT: Dr. George Chiang, Office of Defects 
Investigation (ODI), NHTSA, 400 Seventh Street, SW, Washington, DC 
20590. Telephone: (202) 366-5206.

SUPPLEMENTARY INFORMATION: Edgar F. Heiskell, III (petitioner), 
Attorney at Law, 400 Bank One Center, P.O. Box 3761, Charleston, West 
Virginia 25337-3761, submitted a petition to the National Highway 
Traffic Safety Administration (NHTSA) by letter dated December 3, 1997, 
requesting that an investigation be initiated to determine whether to 
issue an order concerning the notification and remedy of a defect in 
model year 1983 through 1990 Bronco II sport utility vehicles (subject 
vehicles) manufactured by Ford Motor Company (Ford) because of concerns 
related to their rollover propensity.

    The petitioner alleges that the subject vehicles were ``designed 
with handling and stability defects which have caused an extraordinary 
number of rollover accidents resulting in thousands of deaths and 
severe injuries.''

    NHTSA has reviewed all information brought to its attention and 
reviewed crash databases and Office of Defects Investigation's consumer 
complaint database. The results of this review and analysis are set 
forth in a Petition Analysis Report for DP97-006, which is published in 
its entirety as an appendix to this notice.

    For the reasons presented in the petition analysis report, there is 
no reasonable possibility that an order concerning the notification and 
remedy of a safety-related defect in the subject vehicles would be 
issued at the conclusion of an investigation. Therefore, in view of the 
need to allocate and prioritize NHTSA's limited resources to best 
accomplish the agency's safety mission, the petition is denied.

    Authority: 49 U.S.C. 30162(d); delegations of authority at CFR 
1.50 and 501.8.

    Issued on: May 14, 1999.
Kenneth N. Weinstein,
Associate Administrator for Safety Assurance.

Appendix--Petition Analysis--DP97-006

1.0  Introduction

    Edgar F. Heiskell, III (petitioner), Attorney at Law, 400 Bank 
One Center, P.O. Box 3761, Charleston, West Virginia 25337-3761, 
submitted a petition to the National Highway Traffic Safety 
Administration (NHTSA) by letter dated December 3, 1997, requesting 
that an investigation be initiated to determine whether to issue an 
order concerning the notification and remedy of a defect in model 
year 1983 through 1990 Bronco II sport utility vehicles (subject 
vehicles) manufactured by Ford Motor Company (Ford) because of 
concerns related to their rollover propensity.

2.0  Previous Inquiries and Investigations by NHTSA Into Alleged 
Rollover Defects

    In October 1979 and July 1981, NHTSA's Office of Defects 
Investigation (ODI) received two petitions (DP80-002 and DP81-018) 
for defect investigations into the alleged instability of Jeep CJ 
vehicles. Both these petitions were denied due to the lack of 
specific information indicating that there was a defect that caused 
the vehicles to roll over.
    In 1988, ODI received two petitions for defect investigations 
into the alleged rollover propensity of 1986 through 1988 Suzuki 
Samurai vehicles, including the convertible, the Samurai, and the 
SJ410 and LJ80 models (DP88-011 and DP88-019). NHTSA also denied 
these petitions, primarily because the available information did not 
show that the alleged rollovers were caused by a defect in the 
vehicle rather than by the driver and/or environmental factors.
    In 1989, ODI conducted investigation EA89-013 concerning 1984-
1989 Ford Bronco II sport utility vehicles. This investigation was 
opened in response to a defect petition, DP88-020. A peer analysis 
of rollover rates showed the Bronco II to be similar to other sport 
utility vehicles, as measured using the metric of first-event 
single-vehicle rollovers per single-vehicle crash. ODI closed this 
investigation in October 1990, because ``there appears no reasonable 
expectation that further investigation would lead to a determination 
of the existence of a safety-related defect with respect to any of 
the allegations regarding the propensity of the Bronco II to roll 
over.'' Also during this same time period, ODI was petitioned again 
to investigate Jeep CJ models (DP90-012). This petition was also 
denied for the same reasons as the Bronco II petition.
    In 1996, ODI was petitioned to open a defect investigation into 
the rollover propensity of the 1986-1995 Suzuki Samurai convertible 
(DP96-004). The petitioner alleged that Samurai convertibles have 
high rollover propensity, as reflected by their low static stability 
factor (the track width to center of gravity ratio), and, when 
loaded with occupants, the vehicle is even less stable. After 
reviewing the materials presented in that petition and other 
available data and information, the agency concluded that it was 
unlikely that further investigation of alleged Samurai convertible 
rollover propensity would enable NHTSA to identify a safety-related 
defect. The petition was therefore denied.
    In August 1996, ODI received a petition (DP96-011) from 
Consumers Union of the United States (CU) to investigate 1995 and 
1996 Isuzu Trooper and Acura SLX sport utility vehicles because of 
their alleged propensity to roll over in a reverse steer maneuver. 
CU alleged that these vehicles were prone to tip-up during a double 
lane maneuver known as the CU ``short course.'' CU's testing of peer 
vehicles indicated different performance for the peer vehicles 
compared to the Trooper and SLX. NHTSA conducted crash data 
analysis, a computer simulation, and a comprehensive test program 
comparing these vehicles and a peer vehicle during its analysis of 
the petition. NHTSA testing showed that the results of tests on the 
CU short course were not repeatable and were affected by driver 
performance. When these driver performance inconsistencies were 
accounted for, the Trooper and SLX performed similarly to the peer 
vehicles during testing using the CU short course. This petition was 
denied.

3.0  Vehicle Inforamtion

3.1  Subject Vehicle Description

    The Ford Bronco II is a light utility vehicle, i.e., a 
multipurpose passenger vehicle having a wheelbase of 110 inches or 
less and special features for occasional off-road use, and was 
originally introduced for sale in the United States in late 1983 as 
a 1984 model year vehicle. It continued in production through the 
1990 model year. It is a two-door, four-passenger vehicle with body-
on-frame construction, a 94 inch wheelbase and a 56.9 inch track 
width (front and rear). The vehicle was equipped with front coil and 
rear leaf springs and a front-mounted engine throughout its 
production. All 1984-1986 model year Bronco II vehicles were 
equipped with four-wheel drive. Beginning with the 1987 model year 
and through the remainder of its production, the Bronco II was also 
available in a two-wheel drive configuration.

3.2  Vehicles Involved

    Table 1 presents the number of subject vehicles sold in the 
United States.

[[Page 27344]]



                            Table 1.--Sales of Subject Vehicles in the United States
----------------------------------------------------------------------------------------------------------------
                           Model year                                   4X4             4X2            Total
----------------------------------------------------------------------------------------------------------------
1984............................................................         144,061               0         144,061
1985............................................................          98,153               0          98,153
1986............................................................         109,846               0         109,846
1987............................................................          88,818          22,286         111,104
1988............................................................         109,524          38,201         147,725
1989............................................................          67,356          29,835          97,191
1990............................................................          38,451          16,445          54,896
                                                                 -----------------------------------------------
    Grand Total.................................................  ..............  ..............         762,976
----------------------------------------------------------------------------------------------------------------

4.0  Alleged Defect

    The petitioner alleges that the subject vehicles were ``designed 
with handling and stability defects which have caused an 
extraordinary number of rollover accidents resulting in thousands of 
deaths and severe injuries.''

5.0  Complaints

5.1  Complaints to ODI Concerning the Subject Vehicles' Rollover 
Propensity

    ODI has reviewed all owner complaints in the ODI database that 
may be related to the alleged defect in the subject vehicles.
    Each complaint in the ODI database is given ``Fault'' codes for 
``cause'' and ``result.'' Each complaint that had a ``cause fault'' 
or ``result fault'' of ``rollover'' was individually reviewed to 
eliminate duplications and non-rollovers.
    Figure 1 shows the number of rollover-related complaints 
regarding the subject vehicles received by ODI during each calendar 
year from 1989 through 1998. It indicates that after EA89-013 was 
closed on October 31, 1990, the number of such complaints to ODI 
decreased sharply.

BILLING CODE 4910-59-P


    Figure 1. Number of Bronco II Rollover Complaints Received by ODI: 
1989 through 1998.
[GRAPHIC] [TIFF OMITTED] TN19MY99.022


BILLING CODE 4910-59-C

5.2  Complaints to ODI Concerning the Rollover Propensity of Peer 
Vehicles

    ODI has also reviewed rollover-related owner complaints in the 
ODI database regarding certain peer vehicles. Figure 2 shows the 
complaint rate (the number of complaints per 100,000 vehicles sold) 
based on the complaints received by ODI since January 1, 1994. The 
rollover complaint rate of the Bronco II is much lower than those of 
many of the peer vehicles, including some for which ODI has recently 
denied petitions to open defect investigations.

    Figure 2. Complaint Rate of Bronco II and Peers Based on ODI 
Complaints Received Since 1/1/94.

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[GRAPHIC] [TIFF OMITTED] TN19MY99.023



BILLING CODE 4910-59-C

6.0  Additional Documents Submitted to Petition File

    Prior to submitting his petition, Mr. Heiskell submitted three 
letters with attachments, concerning the rollover propensity of the 
subject vehicles. In his letters (dated March 13, April 16, and 
April 24, 1997), Mr. Heiskell presented arguments and provided 
copies of various documents that he claimed set out new information 
that would justify reopening EA89-013. Mr. Heiskell's letters and 
attachments have been placed in the DP97-006 petition file.
    In addition, W. Randolph Barnhart, Esq., submitted documents on 
September 10, 1997, which he alleged demonstrated the rollover 
susceptibility of the Bronco II. By letter of September 16, 1997, 
Mr. Barnhart provided the agency with an index to the previously-
submitted documents. Both of Mr. Barnhart's submissions have been 
placed in the DP97-006 petition file.
    In their submissions, Mr. Heiskell and Mr. Barnhart focused on 
vehicle handling tests conducted by Ford in March/April 1982, during 
its development of the Bronco II, in which the test vehicles rolled 
over at speeds equal to or greater than 25 mph. They also noted that 
Ford had not provided reports of those tests in response to ODI's 
information requests in EA89-013. NHTSA has addressed Ford's failure 
to provide those test reports during EA89-013 in a May 29, 1998, 
letter from John Womack, the agency's Senior Assistant Chief 
Counsel. A copy of that letter has been placed in the DP97-006 
public file.
    ODI has reviewed the reports of the pre-production tests that 
were submitted by Mr. Heiskell. While they are clearly relevant to 
the issues raised by this petition, they do not in themselves 
warrant granting the petition, for the following reasons. The 
development of a complex motor vehicle from a concept into a 
marketable consumer product involves a process of design, testing, 
and an evaluation of test results. Generally, this leads to a cycle 
of re-design, re-testing, and re-evaluation, which is repeated until 
the product meets its performance objectives. When tests conducted 
during product development disclose a potential problem of any type, 
a manufacturer generally will take steps to resolve the problem.
    When viewed from a defect investigation perspective, the fact 
that the test reports suggest a relatively high rollover propensity 
in pre-production Bronco II vehicles illustrates the extent of the 
problem at the pre-production stage. A variety of modifications were 
made to the Bronco II after those tests that were likely to affect 
its rollover propensity to some degree. Thus, the in-service history 
of the Bronco II with respect to rollover incidents is far more 
significant than developmental and pre-production testing.

7.0  Crash Data Analysis

    ODI and the National Center for Statistics and Analysis (NCSA) 
have evaluated the rollover performance of a number of light sport 
utility vehicles by reviewing and analyzing the crash data obtained 
from several databases, including State data, the Fatality Analysis 
Reporting System (FARS) data, and the National Automotive Sampling 
System (NASS) Crashworthiness Data System (CDS) data. ODI also 
reviewed data provided by Ford on January 29, 1998 in connection 
with this petition, and data supplied by American Suzuki Motor 
Corporation (Suzuki)

[[Page 27346]]

in response to Defect Petition DP96-011, specifically those data 
related to fatal on-road rollover crashes.
    The subject vehicles were manufactured from the mid 1980s 
through 1990, and these vehicles have been in operation and exposed 
to the crash environment for many years; therefore, the crash data 
is considered to be mature, representative, and reliable.

7.1  Previous NHTSA Analysis of Bronco II Rollover Propensity

    As noted above, EA89-013 was an investigation into the rollover 
propensity of Bronco II vehicles. In that investigation, NHTSA 
applied logistic regression to the state data covering 11 groups of 
vehicles in order to obtain the ratio of first-event single-vehicle 
rollovers to all single-vehicle crashes of each group. The 
analytical procedure accounted for environmental factors, such as 
the location of the incident (e.g., rural vs. urban; straight vs. 
curved road), and driver characteristics, such as age and sex. By 
considering these variables, the rollover rate data were controlled 
to normalize the vehicles to a common set of outside-the-vehicle 
factors that can influence crash outcome. The results of that 
analysis, taken from the EA89-013 Closing Report, are depicted in 
Figure 3 and give the best estimate of the controlled first-event 
single-vehicle rollover rate for single-vehicle crashes for each 
vehicle group, along with the upper and lower 95 percent confidence 
intervals for crash years 1986 through 1988. For this analysis, 
Maryland, Michigan, New Mexico, and Utah data were combined.
    Figure 3 shows that the Bronco II has a first-event single-
vehicle rollover rate similar to several other vehicles, notably 
CJ5/6/7 (71-80), Toyota 4Runner, CJ5/7/8 (81-86), Suzuki Samurai, 
Isuzu Trooper II, and GM S-10/S-15.

BILLING CODE 4910-59-P
[GRAPHIC] [TIFF OMITTED] TN19MY99.024


BILLING CODE 4910-59-C

7.2  1993 Analysis of Michigan Data

    In November 1993, an analysis of Michigan state rollover data 
was conducted by NHTSA in connection with a proposed rulemaking 
effort (Docket 91-68, No. 2, Item 018). In this analysis, rollover 
data was computed for crash years 1986 through 1990. Table 2 
presents the first-event single-vehicle rollover rates for selected 
sport utility vehicles.1 When more than one variation of 
a make/model is included, a range of rates is presented. Table 2 
shows that the Bronco II has a first-event single-vehicle rollover 
rate similar to several other vehicles.
---------------------------------------------------------------------------

    \1\ The vehicles were selected to match the vehicles considered 
in EA89-013, except the GM S and T vehicles were combined together.

[[Page 27347]]



   Table 2.--Michigan First-Event Single-Vehicle Rollover Percentages,
                         Crash Years: 1986-1990
------------------------------------------------------------------------
                                                       Percent of first-
                                                         event single-
                   Make and model*                     vehicle rollovers
                                                          per single-
                                                        vehicle crash **
------------------------------------------------------------------------
Ford Bronco II.......................................           39-49
GM S & T series......................................           24-34
Isuzu Trooper II.....................................              31
Jeep Cherokee........................................              30
Jeep CJ-5............................................           49-51
Jeep CJ-7............................................           46-48
Jeep Wrangler........................................              28
Suzuki Samurai.......................................              29
Toyota 4Runner.......................................             *36
------------------------------------------------------------------------
* Listed Alphabetically; No data for Jeep Wagoneer.
** Make/models with a range represent the upper and lower rates reported
  in the Finalized Database of Michigan Data for different variations of
  the same make/model. This could include variations with different
  badges, e.g., Chevy and GMC; different drive configurations, e.g., 4x4
  and 4x2, or different brake systems, e.g., ABS and non-ABS.

    The vehicles compared in this table are of similar age and were 
fairly new during the time period that the crash data were 
collected. Vehicle age can affect performance due to change of 
components, such as new tires, wheels, and shocks absorbers, which 
may not be the same size or quality as the original ones. 
Additionally, as a vehicle ages, components on the vehicle wear, 
which can change the performance characteristics of the vehicle and 
its susceptibility to rollover.

7.3  1998 Analysis of NASS/CDS Data

    Following receipt of Mr. Heiskell's petition, NHTSA analyzed the 
NASS/CDS data files for NASS years 1988 through 1996. The vehicles 
analyzed were similar to those considered in the EA89-013 analysis, 
except the GM S and T vehicles were combined to compare them with 
the Bronco II data.
    Again first-event single-vehicle rollovers and all single-
vehicle crashes were considered, which exclude not only crashes with 
other vehicles, but also with moving objects such as animals, 
pedestrians, and bicycles. The data are presented in Table 3. The 
range of model years included in the analysis was 1984 through 1990, 
except for the Suzuki Samurai, which began production in MY 1986, 
and the Jeep CJ vehicles. The model year ranges are noted in the 
table. The sample size (listed in the table as ``Number of NASS 
Single Vehicle Cases'') is small for all vehicles except the Bronco 
II and the GM S&T series. Based on comparison of the T-values, the 
Bronco II rollover rate is not statistically significantly greater 
than that of any other make/model listed in Table 3, except the Jeep 
Cherokee. Furthermore, the Bronco II rollover rate is statistically 
significantly lower than that of the Suzuki Samurai. Finally, the 
Bronco II's rollover rate is not statistically significantly 
different from that of all light trucks and vans considered as a 
whole.
    Table 3 also provides an estimate of the total number of first-
event single-vehicle rollovers for the time interval analyzed (1988-
1996). For example, the total number of Bronco II first-event 
single-vehicle rollovers is estimated to be about 14,000. During 
this same time, the total number of first-event single-vehicle 
rollovers for the Blazer/Jimmy (GM S&T models) was about 19,000.

[[Page 27348]]



                                        Table 3.--NASS/CDS First-Event Single-Vehicle Rollover Percent, 1988-1996
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                                     Percent
                                                                             Number of    Number of                first-event
                                                   Number of    Number of   NASS first-  first-event  First-event       SV        Percent
            Make*/model**/year range              NASS single-   crashes,     event SV        SV      SV rollover   rollovers      sample    T-value****
                                                    vehicle      weighted     rollover    rollovers,     sample    per single-     error
                                                   (SV) cases                  cases       weighted      error       vehicle      (SE)***
                                                                                                                      crash
--------------------------------------------------------------------------------------------------------------------------------------------------------
Ford Bronco II, 84-90...........................          108       38,078           47       13,620        3,697           36          8.6            0
GM S&T series, 84-90............................          167       77,557           30       18,935        8,875           24          7.2       -1.014
Isuzu Trooper, 84-90............................           14        4,049            6        2,453        1,877           61         22.0        1.052
Jeep Cherokee, 84-90............................           32        7,074            6        1,061          523           15          5.6       -2.020
Jeep CJ-5, 71-80................................           47       19,375           23       12,476        9,840           64         22.9        1.169
Jeep CJ-7, 81-86................................           30       15,270           10        8,086        4,690           53         16.8        0.910
Jeep Wagoneer, 84-90............................            6        1,431            1          296          296           21         20.2       -0.687
Suzuki Samurai, 86-90...........................           25       12,829           13       10,712        7,659           84         12.3        3.170
Toyota 4Runner, 84-90...........................           30        9,102           13        4,005        2,605           44         12.4        0.544
Passenger cars, 84-90...........................        5,494    2,260,883          596      256,910       45,658           11          1.0       -2.810
Light trucks and vans, 84-90....................        1,855      773,115          431      203,131       42,125           26          3.1       -1.036
--------------------------------------------------------------------------------------------------------------------------------------------------------
* Makes listed alphabetically.
** Data for Jeep Wrangler was too small to analyze and is not presented in this table.
*** NASS estimates have a sampling error because NASS is a survey rather than a complete census of all crashes. Rollover rates for two vehicles can be
  compared to each other for significant differences using the sample error at the 95 percent confidence interval as follows: If |Ra-Rb| >1.96
  multiplied by SQRT [SEa2+SEb2], then they are different; where R=rate, SE=sample error, SQRT=square root, and a & b are different vehicles.
**** The T-value for a vehicle in the table is obtained by: (1) computing the difference between its percentage of first-event SV rollovers and that of
  Bronco II, (2) computing the standard error of that difference as the square root of the sum of the squares of the two standard errors involved, and
  (3) dividing the difference by its standard error. If the statistic is greater than 1.96, the compared vehicle is statistically different from the
  Bronco II at the 95% confidence interval. Positive values of T indicate that the compared vehicle has a greater rollover rate than the Bronco II.
  Conversely, negative values of T indicate that the compared vehicle has a lower rollover rate than the Bronco II.


[[Page 27349]]

7.4 Analysis of FARS Data

    FARS data were analyzed for first-event single-vehicle rollovers 
in all single-vehicle crashes where at least one occupant in the 
vehicle was fatally injured. This excluded non-occupant fatal 
single-vehicle crashes, such as pedestrian fatalities. FARS years 
1984-1996 were included to maximize the size of the sample. The Jeep 
CJ-5 and CJ-7 vehicles were not included in the FARS analysis 
because they were not produced during the same range of years (1984-
90) as the Bronco II. The model year range for each make/model was 
selected to be as similar as possible to that of the subject 
vehicle. Unlike the State data described in Section 7.1, these FARS 
data are not adjusted and have not been controlled for 
environmental, roadway, or driver differences. Table 4 gives the 
results of this analysis by number of vehicles involved in fatal 
crashes, while Table 5 considers the total number of fatalities 
within each fatal vehicle.

                     Table 4.--Fatal Vehicles in First-Event Single-Vehicle Rollover Crashes
----------------------------------------------------------------------------------------------------------------
                                                                                   Percentage of
                                                   Fatal vehicle   Fatal vehicle   the rollovers      Percent
        Make and model *            Model year    single-vehicle  first-event SV     in fatal     standard error
                                                    crashes **       rollover     single vehicle   [SQRT(P * Q/
                                                                      crashes         crashes           N)]
----------------------------------------------------------------------------------------------------------------
Chevy/Blazer GMC/Jimmy..........           84-90             385             168              44            2.53
Ford Bronco II..................           84-90            1259             762              61            1.38
Isuzu Trooper...................           84-90              99              39              39            4.91
Jeep Cherokee...................           84-90             296             111              38            2.81
Suzuki Samurai..................           84-90             203              81              40            3.44
Toyota 4Runner..................           84-90             326             175              54            2.76
----------------------------------------------------------------------------------------------------------------
* Makes listed alphabetically.
** FARS years 1984-1996.


              Table 5.--Fatalities in Fatal Vehicles in First-Event Single-Vehicle Rollover Crashes
----------------------------------------------------------------------------------------------------------------
                                                                                   Percentage of
                                                   Fatalities in   Fatalities in  single vehicle      Percent
        Make and model *            Model year    single-vehicle  first-event SV       crash      standard error
                                                    crashes **       rollover      fatalities in   [SQRT(P * Q/
                                                                      crashes      the rollovers        N)]
----------------------------------------------------------------------------------------------------------------
Chevy/Blazer GMC/Jimmy..........           84-90             423             183              43            2.41
Ford Bronco II..................           84-90            1364             823              60            1.32
Isuzu Trooper...................           84-90             109              43              39            4.68
Jeep Cherokee...................           84-90             316             115              36            2.71
Suzuki Samurai..................           84-90             214              85              40            3.34
Toyota 4Runner..................           84-90             361             194              54            2.6
----------------------------------------------------------------------------------------------------------------
* Makes listed alphabetically.
** FARS years 1984-1996.

    The fifth column of Tables 4 and 5 shows that the Ford Bronco II 
has a higher percentage of fatal vehicles and fatalities in first-
event single-vehicle rollovers than that of the other five peer 
vehicles, although it is somewhat similar to the Toyota 4Runner. 
While the Bronco II rollover rate is not statistically significantly 
different from that of its peers, these FARS analyses indicate that 
there could be an issue regarding the relative crashworthiness of 
Bronco II vehicles in rollovers. In an effort to cast additional 
light on the crashworthiness issue, several analyses were performed, 
as documented in section 7.5.

7.5  Crashworthiness Analyses

7.5.1.  Crashworthiness Aspects

    NCSA analyzed the NASS/CDS and FARS data using the same vehicles 
listed in the above FARS tables to compute the ratio of the number 
of fatally injured occupants in first-event single-vehicle rollover 
crashes (from FARS) to the number of involved occupants in such 
crashes (from NASS/CDS). Table 6 presents these data.

              Table 6.--Crashworthiness Analysis of First-Event Single-Vehicle Rollover Crashes ***
----------------------------------------------------------------------------------------------------------------
                                                                   Percentage of
                                     Number of                        fatally
Make/model for model years 1984-     involved        Number of        injured     Standard error   T difference
             1990 *                  occupants      fatalities     occupants to    of percentage   in percentage
                                  (weighted NASS    (FARS data)      involved                           **
                                       data)                         occupants
----------------------------------------------------------------------------------------------------------------
Chevy/Blazer GMC/Jimmy..........          27,935             183            0.65            0.27          -2.979
Ford Bronco II..................          17,721             823            4.44            1.24           0
Isuzu Trooper...................           5,334              43            0.80            0.33          -2.831
Jeep Cherokee...................           2,772             115            3.98            1.46          -0.238
Suzuki Samurai..................          22,199              85            0.38            0.26          -3.195
Toyota 4Runner..................           9,886             194            1.93            1.10          -1.517
----------------------------------------------------------------------------------------------------------------
* Makes listed alphabetically
** The T-value gives the difference in the percentage of fatalities divided by the standard error of the
  difference between the Bronco II and each vehicle. If the absolute value of the statistic is greater than
  1.96, the compared vehicle is statistically different from the Bronco II at the 0.05 confidence level.
  Negative values indicated that the compared vehicle has a lower percentage of fatalities per involved occupant
  than the Bronco II.
*** Involved occupants were from NASS years 1988-1996, and fatally injured occupants were from FARS years 1984-
  1996.


[[Page 27350]]

    These data indicate that the Bronco II has a significantly 
higher percentage of fatally injured occupants per the total number 
of involved occupants in first-event single-vehicle rollover crashes 
than three of the peer vehicles. However, it has a similar 
percentage when compared to the Jeep Cherokee and possibly to the 
Toyota 4Runner. This would suggest that if a first-event single-
vehicle rollover occurs, there is more likely to be a fatality in a 
Bronco II than in some, but not all, of its peers.

7.5.2  FARS Ejection Path Analysis

    To attempt to determine whether the unique design of the rear 
side windows in the Bronco II may have affected rollover 
crashworthiness, ODI reviewed available data on ejection path, 
including 1991-1996 FARS data on ejection path. FARS data prior to 
1991 do not include such information.
    Since FARS uses police reports to generate the data entered in 
the FARS system, it is generally limited to the data contained in 
the Police Accident Report (PAR). Most of the time, the ejection 
path is not reported on the PAR. In fact, for the 1991-1996 FARS, 
the data for first-event single-vehicle rollover crashes indicate 
that there were 16,124 unknown ejection paths out of the 21,325 
ejected persons, whether or not they were fatalities.
    Distribution of the ejection paths identified in FARS for each 
vehicle analyzed in section 7.4 is shown in Table 7. In these 
analyses, the parameter of ``side door'' includes all side doors; 
``side window'' includes all side glass; ``through roof opening'' is 
through a convertible top which is down or a sunroof; and ``through 
roof'' is through a convertible roof which is up.

                                Table 7.--Distribution of Ejections by Path in Fatal First-Event Single-Vehicle Rollovers
--------------------------------------------------------------------------------------------------------------------------------------------------------
                                                                                                               Through
                                                      Side door     Side    Windshield     Back    Back door     roof     Through     Other     Unknown
          Make/model, model years 1984-1990                        window    (percent)    window               opening      roof       path       path
                                                      (percent)  (percent)              (percent)  (percent)  (percent)  (percent)  (percent)  (percent)
--------------------------------------------------------------------------------------------------------------------------------------------------------
Chevy/Blazer, GMC/Jimmy.............................        2.1       11.0         0.7        0.0        0.0        0.7        0.0        1.4       84.2
Ford Bronco II......................................        2.3        7.4         1.7        1.3        0.2        0.0        0.0        0.2       87.0
Isuzu Trooper.......................................        0.0       11.9         2.4        4.8        0.0        0.0        0.0        0.0       81.0
Jeep Cherokee.......................................        5.3        9.7         4.4        0.9        0.0        0.0        0.0        0.0       79.6
Suzuki Samurai......................................        1.3        2.6         0.0        0.0        0.0        3.9        5.3        0.0       86.8
Toyota 4Runner......................................        2.9        6.2         1.1        2.2        0.0       10.5        1.5        1.8       73.8
--------------------------------------------------------------------------------------------------------------------------------------------------------
FARS data: 1991-1996.

    The results shown in Table 7 do not indicate a difference 
between the Bronco II and its peers in the ejection path for these 
fatal crashes. For ejection through the side windows including the 
rear side windows, the Bronco II rate is lower than that of three of 
its peers. When all glazing is considered as a single ejection path 
(Side Windows + Windshield + Back Window), the Bronco II still 
remains in the middle of the peer vehicles. It is noted that these 
results are based on a small sample of the crashes because most of 
the ejection paths are coded ``unknown'' in FARS.

7.5.3  NASS Case Analysis

    To further study the ejection path issue, a hard copy review of 
all Bronco II rollover crashes in the NASS Crashworthiness Data 
System was conducted. Both totally and partially ejected occupants 
were included in this review.
    As shown in Table 3, there were 47 NASS cases in which there was 
a Bronco II first-event single-vehicle rollover. ODI reviewed each 
of these cases and found that out of the 47 cases (each case 
contains one rollover incident), 23 cases had ejections involving 33 
occupants (27 totally ejected and 6 partially ejected), 22 cases had 
no occupant ejections, and in 2 cases occupant ejections were 
unknown.
    Table 8 shows recorded ejection paths for the 33 ejected 
occupants.

                                Table 8.--Ejection Paths for 33 Ejected Occupants
----------------------------------------------------------------------------------------------------------------
                                                                                                     Weighted
                                                                     Number of       Weighted      percentage of
                          Ejection path                              ejections       number of     ejections by
                                                                                    ejections *    ejection path
----------------------------------------------------------------------------------------------------------------
Unknown.........................................................              11             667              19
Left Front (Driver Window)......................................               7             822              24
Left Door Opened................................................               2             344              10
Right Front (Passenger Window)..................................               5             924              27
Windshield......................................................               3             447              13
Left Rear Window (Fixed)........................................               2              67               2
Right Rear Window (Fixed).......................................               1              62               2
Rear Backlight..................................................               1              30               1
Sunroof.........................................................               1              86               3
----------------------------------------------------------------------------------------------------------------
* The total for all ejection paths does not equal to that shown in Item 4 of section 7.5.2. because the partial
  ejections are included in this analysis.

    ODI's review of the 47 cases indicate the following:
    1. In a majority of the cases, the crash scenario involved 
running off the road at highway speed and driver overcorrection, 
resulting in vehicle yaw, followed by rollover.
    2. There was a wide variation in crash dynamics in the incidents 
reviewed.
    3. Distortion of the vehicle body during rollover typically 
created several potential occupant ejection paths when glazing 
disintegrated at several locations.
    4. The data reviewed are inconclusive with respect to 
identification of a ``most probable'' occupant ejection path during 
rollover.

7.6  Other Data Reviewed

7.6.1  Ford Data Review

    Ford supplied analyses of rollover propensity in its January 29, 
1998, submission in response to this petition. (A copy is in the 
public file.) These included an overall rollover rate analysis and a 
logistic regression analysis similar to the NHTSA analysis used in 
EA89-013.
    In the Ford overall rollover rate analysis, rollover crash data 
were collected from five states and combined to obtain an overall 
rollover rate. The following states and crash years were used: 
Alabama, 1990-95; Arkansas, 1987-94; Michigan, 1985-91; Maryland, 
1986-94; and Pennsylvania, 1988-

[[Page 27351]]

95. For exposure, Ford used registered vehicle years (RVY) for these 
same states and periods. Ford analyzed all types of vehicles, and 
included about 700 make/model/model year combinations.
    For illustration purposes, Table 9 presents Ford's data for the 
first 11 sport utility vehicles in Ford's table as shown in Exhibit 
B of Ford's January 29, 1998, submission. In addition to the 11 
sport utility vehicles in Ford's table, there were 4 other vehicles, 
including 3 pickup trucks (83-94 Ford Ranger--Rollover Rate--76; 81-
83 Toyota pickups--75; and 84-94 Toyota pickups--67) and one 
passenger car (87-94 Mitsubishi Precis--68.)
    The NASS/CDS analysis reported in Section 7.3 included four 
additional vehicle groups not in Table 9, which are the GM-S&T 
series, Isuzu Trooper, Jeep Cherokee, and Jeep Wagoneer. Their 
rollover rates ranged from about 20 rollovers per 10,000 Registered 
Vehicles Years (RVY) to about 36 rollovers per 10,000 RVY, with the 
remainder in the low to high twenties.

                                Table 9.--Ford State Data Analysis Rollover Rates
----------------------------------------------------------------------------------------------------------------
                                                                                                   Rollover rate
        Make and model           Model years          Type             RVY *         Rollover       (rollovers/
                                                                                      crashes      10,000 RVY *)
----------------------------------------------------------------------------------------------------------------
Toyota J4 Land Cruiser.......           81-83  4 x 4 SUV........             762               8             105
Geo Tracker..................           89-94  4 x 4 SUV........          46,966             370              79
Jeep CJ-7....................           81-86  4 x 4 SUV........         137,670           1,032              75
Honda Passport...............              94  4 x 4 SUV........           1,243               9              72
Ford Bronco II...............           84-90  4 x 4 SUV........         605,297           4,132              68
Geo Tracker..................           91-94  4 x 2 SUV........           8,255              56              68
Ford Bronco II...............           86-90  4 x 2 SUV........          50,217             321              64
Dodge Raider.................           87-89  4 x 4 SUV........          31,263             188              60
Toyota 4Runner...............           84-94  4 x 4 SUV........         121,813             728              60
Jeep CJ-5....................           81-83  4 x 4 SUV........          12,852              74              58
Suzuki Samurai...............           86-94  4 x 4 SUV........          81,780             451              55
----------------------------------------------------------------------------------------------------------------
* RVY: registered vehicle years.

    For the occupant injury analysis, Ford looked at injury rate 
data in four states for several crash years, Arkansas, 1987-94; 
Michigan, 1985-91; Maryland, 1986-94; and Pennsylvania, 1988-95. The 
total number of rollover crashes, total number of occupants involved 
in those crashes, and number of severe and fatal injuries were 
reported for about 700 make/model/model year combinations of 
vehicles. For illustration purpose, Table 10 presents selected data 
from Ford's analysis for vehicles similar to the Bronco II.

                            Table 10.--Ford Occupant Injury Rates in Rollover Crashes
----------------------------------------------------------------------------------------------------------------
                                                                                                  Percent severe
                                                                                                     and fatal
                                     Number of       Number of       Number of       Number of        injured
 Make,* model, model year range       crashes        occupants    severe injured   fatal injured   occupants in
                                                                     occupants       occupants       rollover
                                                                                                      crashes
----------------------------------------------------------------------------------------------------------------
Ford, Bronco II, 84-90..........           4,074           6,453             492              55             8.5
GM, S&T series, 83-94...........           3,261           5,130             415              68             9.4
Isuzu, Trooper II, 84-91........             446             718              53               4             7.9
Jeep, Cherokee, 81-94...........           1,301           2,078              98              15             5.4
Jeep, CJ-5, 81-83...............              72             106              12               3            14.2
Jeep, CJ-7, 81-86...............             989           1,492             122              12             9.0
Jeep, Wagoneer, 81-90...........             205             330              20               1             6.4
Jeep, Wrangler, 87-94...........             378             577              46               4             8.7
Suzuki, Samurai, 86-94..........             418             601              73               6            13.1
Toyota, 4Runner, 84-94..........             675           1,067              98              14            10.5
----------------------------------------------------------------------------------------------------------------
* Makes listed alphabetically.

    Ford also conducted a logistic regression analysis similar to 
the analysis conducted by NHTSA during EA89-013. In this analysis, 
the rollover rates for several sport utility vehicles were compared. 
The data were normalized for driver and environmental factors, which 
included age, sex, location, and roadway alignment, and included 
crash data from Michigan (85-91), Arkansas (87-94), Florida (89-94), 
Maryland (86-88), and Pennsylvania (88-95). Figure 4 presents these 
data. The upper and lower 95 percent confidence intervals are 
presented along with each vehicle's average adjusted rollover rate. 
This analysis indicates that while the rollover propensity of the 
Bronco II is relatively high (in fact, the two-wheel drive model has 
the highest rate), it is not statistically significantly different 
from that of most of its peers.

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7.6.2  Suzuki Data Review

    On March 19, 1997, Suzuki submitted a FARS data analysis related 
to certain 4X4 SUV rollovers. This analysis only considered those 
vehicles where the rollover occurred ``on road,'' hence no off-road 
rollovers were considered. Suzuki stated that comparison of on-road 
rollovers tends to normalize the rollover rate for some 
environmental and roadway conditions where the crash occurred. FARS 
years 1982 through 1995 were used in the analysis. Table 11 presents 
data for these vehicles.
    Table 11 indicates that the rate of on-road first-event single-
vehicle rollovers in fatal single-vehicle crashes per 100 vehicles 
with at least one occupant fatality for the Bronco II is slightly 
lower than the Toyota 4Runner, and is higher than that of the other 
five peer vehicles.

             Table 11.--Suzuki FARS Analysis Regarding On-Road First-Event Single-Vehicle Rollovers
----------------------------------------------------------------------------------------------------------------
                                                                                                  On road first-
                                                                                                   event single-
                                                                  On road first-   SVC involved       vehicle
                                                                   event single-   vehicles with    rollover in
                 Make and model                     Model years       vehicle        occupant     fatal SVCs per
                                                                   rollovers in      fatality      100 vehicles
                                                                   fatal SVCs**                    with occupant
                                                                                                     fatality
----------------------------------------------------------------------------------------------------------------
Toyota 4Runner..................................           90-94              40             188            23.8
Ford Bronco II..................................           84-90             291           1,372            21.2
Nissan Pathfinder...............................           87-94              22             185            11.9
Jeep Grand Cherokee.............................           93-94               9              76            11.8
Chevrolet T10 Blazer............................           83-90             108           1,057            10.2
Ford Explorer...................................           91-94              22             227             9.7
Isuzu Trooper...................................           84-89              14             146             9.6
----------------------------------------------------------------------------------------------------------------
** SVCs: Single Vehicle Crashes.

8.0  PETITIONER'S DATA ANALYSIS

    In support of his petition, the petitioner stated that sworn 
deposition testimony of Dr. Michelle Vogler, a statistical expert 
retained by Ford in Bronco II product liability litigation, shows, 
by actual count, that there have been 5,672 rollovers of Bronco II 
vehicles in six states during a six-year time period. The petitioner 
extrapolated this figure to assert that ``there have been 50,000 
Bronco II rollovers nationally since the subject vehicles were first 
placed in the hands of American consumers.'' By his estimation, ``as 
many as 300,000 Bronco II owners are going to suffer the same fate 
[rollover].''
    After reviewing NASS/CDS data, the agency believes that Mr. 
Heiskell's extrapolation overstates the number of Bronco II 
rollovers that would be expected in a 14-year period. Regardless, 
the absolute number of rollovers is an inappropriate measure for an 
analysis of rollover propensity. The petitioner's extrapolation 
focuses on the number of rollovers of any type (as opposed to first-
event rollovers) and represents the raw number of rollovers expected 
(as opposed to the rollover rate) over a 14-year period, without 
adjusting for attrition of the Bronco II fleet over time. In 
contrast, NHTSA's analysis uses the percentage of single-vehicle 
crashes in which a first-event single-vehicle rollover occurred.

[[Page 27353]]

    First, the total number of rollovers is, to a large degree, 
related directly to the number of vehicles on the road. Thus, 
everything else being equal, two make/models with equivalent 
rollover propensity could have vastly different numbers of rollovers 
based solely on variations in the on-road fleet of each make/model. 
Therefore, the total number of rollovers is insufficient on its own 
to assess risk. Risk assessment is based on normalized populations 
and expected outcomes, and can be best accomplished using the 
agency's long-accepted metric, ``first-event single-vehicle 
rollovers per single-vehicle crash.''
    Secondly, the agency used first-event single-vehicle rollovers 
as its measure because these crashes focus more on the handling and 
stability aspects of vehicle performance than do all rollovers 
combined. Subsequent event rollovers, which were included in the 
petitioner's extrapolation, generally result from multiple-vehicle 
collisions and collisions with objects such as utility poles, 
guardrails, etc., where the inherent handling and stability of each 
vehicle plays a lesser role due to the presence of forces exerted 
upon the vehicle by its collision partner.
    The use of first-event single-vehicle rollovers per single-
vehicle crash has been the focus of most serious efforts to relate 
vehicle roll stability measures to real-world vehicle rollover 
propensity. The agency subscribes to this approach, and believes 
that this measure is an effective way to focus on the contribution 
of vehicle stability to rollover propensity, while the total number 
of rollovers experienced by a particular make/model is not.

9.0  Findings

    1. An analysis of rollover complaints in the ODI consumer 
database reveals a sharp decrease in Bronco II rollover complaints 
since EA89-013 was closed. Additionally, an analysis of ODI rollover 
complaints received since 1994 on peer vehicles does not suggest 
that the subject vehicles have an abnormally high rollover 
propensity compared to other sport utility vehicles.
    2. Earlier analyses of rollover propensity demonstrated that the 
Bronco II first-event single-vehicle rollover rate was consistent 
with that of its peers, and the recently updated analyses, using 
both state and NASS data, confirm this finding.
    3. FARS data indicate that the subject vehicles have a 
percentage of first-event single-vehicle rollover fatal crashes (out 
of all fatal single vehicle crashes) and a percentage of first-event 
single vehicle rollover fatalities (out of all fatalities in single 
vehicle crashes) that are substantially higher than that of five 
peer vehicles, although the results for the Bronco II are somewhat 
similar to those for the Toyota 4Runner.
    4. The Bronco II had a similar number of fatalities per involved 
occupant in first-event single-vehicle rollover crashes when 
compared to the Jeep Cherokee and possibly to the Toyota 4Runner, 
and had more fatalities per involved occupant in first-event single-
vehicle rollover crashes when compared to three other peer vehicles. 
This suggests that if a first-event single-vehicle rollover occurs, 
there is more likely to be a fatality in a Bronco II than in some, 
but not all, of its peers.
    5. A review of FARS data between 1991 and 1996 describing 
occupant ejection path did not indicate a difference between the 
Bronco II and its peers, in part because most ejection paths were 
coded ``unknown'' in FARS.
    6. A detailed review of the 47 NASS cases in which there was a 
Bronco II first-event single-vehicle rollover did not permit an 
identification of a ``most probable'' occupant ejection path.
    7. In analyses conducted by Ford, the Bronco II's first-event 
single-vehicle rollover rate, measured as a proportion of the number 
of registered vehicles, is similar to that of several of its sport 
utility vehicle peers, pickups and a passenger car. In a logistic 
regression analysis which controlled for driver and roadway 
variables, a duplication of NHTSA's EA89-013 analysis using newer 
data, the Bronco II rollover rate was relatively high, but was not 
statistically significantly different from that of most of its 
peers.
    8. Suzuki's FARS analysis indicates that the Bronco II and one 
of its peers have a similar rate of ``on-road'' first-event single-
vehicle rollovers as a percentage of all single vehicle fatal 
crashes.
    9. The petitioner's estimate of the number of rollover crashes 
involving the Bronco II appears to overestimate the number. In any 
event, the total number of rollover occurrences involving a 
particular vehicle is not an appropriate analytical tool to assess 
rollover risk.

10.0  Conclusion

    The focus of this defect petition was on the allegedly high 
rollover propensity of the Bronco II. Consistent with its findings 
several years ago at the time it closed EA89-013, ODI's analysis of 
more recent data indicates that the rollover propensity of the 
Bronco II does not stand out from that of other peer SUVs. Although 
it was not directly raised by the petitioner, ODI conducted an 
extensive analysis of the crashworthiness of the Bronco II in 
rollover crashes. These analyses indicated a cause for concern, 
since the Bronco II vehicles have a percentage of first-event single 
vehicle rollover fatal crashes and a percentage of first-event 
single vehicle rollover fatalities that are substantially higher 
than that of most of the peer vehicles. However, ODI was unable to 
identify a most probable ejection path or to identify a specific 
aspect of the vehicle that appeared to adversely affect the 
vehicle's rollover crashworthiness.
    Based on the information presented above, as well as the age of 
the subject vehicles, it is unlikely that NHTSA would issue an order 
for the notification and remedy of a safety-related defect in the 
subject vehicles at the conclusion of the investigation requested in 
the petition. Therefore, in view of the need to allocate and 
prioritize NHTSA's limited resources to best accomplish the agency's 
safety mission, the petition is denied.

[FR Doc. 99-12579 Filed 5-14-99; 3:29 pm]
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