[Federal Register Volume 70, Number 162 (Tuesday, August 23, 2005)]
[Proposed Rules]
[Pages 49248-49254]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-16721]


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DEPARTMENT OF TRANSPORTATION

National Highway Traffic Safety Administration

49 CFR Parts 571 and 572

[Docket No. NHTSA-2005-21698]
RIN 2127-AH73 and 2127-AI39


Federal Motor Vehicle Safety Standards; Occupant Crash 
Protection; Anthropomorphic Test Devices; Instrumented Lower Legs for 
50th Percentile Male and 5th Percentile Female Hybrid III Dummies

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

ACTION: Withdrawal of rulemakings.

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SUMMARY: On February 3, 2004, NHTSA published a notice in the Federal 
Register requesting comments on whether to propose adding a high speed 
frontal offset crash test to Federal Motor Vehicle Safety Standard 
(FMVSS) No. 208, ``Occupant crash protection.'' The notice informed the 
public about recent testing the agency conducted to assess the benefits 
and/or disbenefits of such an approach. Based on our analysis of those 
comments, and other information gathered by the agency, we have decided 
to withdraw the rulemaking proceeding to amend FMVSS No. 208 to include 
a high speed frontal offset crash test requirement. Additional research 
and data analyses are needed to make an informed decision on rulemaking 
in this area. Additionally, we have decided to withdraw the related 
rulemaking proceeding to amend part 572 to include lower leg 
instrumentation until further testing necessary for federalization is 
completed.

FOR FURTHER INFORMATION CONTACT: For non-legal issues: Lori Summers, 
Office of Crashworthiness Standards, NVS-112, National Highway Traffic 
Safety Administration, 400 Seventh Street, SW., Washington, DC 20590. 
Telephone (202) 366-1740. Fax: (202) 366-7002.
    For legal issues: Dorothy Nakama, Office of the Chief Counsel, NCC-
112, National Highway Traffic Safety Administration, 400 Seventh 
Street, SW., Washington, DC 20590. Telephone: (202) 366-2992. Fax: 
(202) 366-3820.

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Background
II. Summary of Request for Comments
III. Analysis of Comments
IV. Rationale for Withdrawal
V. Conclusion

I. Background

    Improving occupant protection in frontal crashes is a major goal of 
the National Highway Traffic Safety Administration (NHTSA). Frontal 
crashes are the most frequent cause of motor vehicle fatalities. In 
1972, NHTSA promulgated FMVSS No. 208 to improve the frontal crash 
protection provided to motor vehicle occupants. The dynamic performance 
requirements of the standard include frontal rigid barrier crash tests, 
at angles between perpendicular and <plus-minus>30 degrees with belted 
and unbelted dummies.\1\ Occupant protection is evaluated based on data 
acquired from anthropomorphic test dummies positioned in the driver and 
right front passenger seats. Data collection instrumentation is mounted 
in the head, neck, chest, and femurs of the test dummies.
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    \1\ In March of 1997, NHTSA temporarily amended FMVSS No. 208 so 
that passenger cars and light trucks had the option of using a sled 
test for meeting the unrestrained dummy requirements. This option 
will be phased out in accordance with the advanced air bag 
rulemaking schedule.
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    NHTSA initiated research in the early 1990s to develop performance 
tests not currently included in FMVSS No. 208, such as high severity 
frontal offset crashes that involve only partial engagement of a 
vehicle's front structure. Such performance tests result in large 
amounts of occupant compartment intrusion and increased potential for 
intrusion-related injury. The agency also instrumented the dummies in 
these tests with advanced lower leg instrumentation, not currently 
required in FMVSS No. 208, to assess the potential for lower extremity 
injury, specifically, to the knee, tibia, and ankle.
    During the same time period, considerable international research 
focused on the development of a fixed offset deformable barrier crash 
test procedure. In December 1996, the European Union (EU) adopted the 
EU Directive 96/79 EC for frontal crash protection. This directive 
required vehicle compliance with a 56 km/h, 40 percent offset, fixed 
deformable barrier crash test. In 1998, Australia introduced a similar 
regulation for new passenger car model approvals. In addition to these 
regulations, several consumer information programs also began to 
utilize the EU Directive 96/79 EC crash test procedure, but raised the 
impact speed to 64 km/h. These programs included the European New Car 
Assessment Program (EuroNCAP), Australia NCAP (ANCAP), Japan NCAP and 
the Insurance Institute for Highway Safety (IIHS) Crashworthiness 
Evaluation program in the U.S.
    Given the world-wide focus on the fixed offset deformable barrier 
crash test procedure, the conferees on the appropriations legislation 
for the Department of Transportation for FY 1997 directed NHTSA to work 
``toward establishing a Federal motor vehicle safety standard for 
frontal offset crash testing'' in fiscal year 1997.\2\ NHTSA was 
further directed to consider the harmonization potential with other 
countries and to work with interested parties, including the automotive 
industry, under standard rulemaking procedures. In 1997, NHTSA 
submitted a Report to Congress \3\ on the status of the agency's 
efforts toward establishing a high speed frontal offset crash test 
requirement. The agency made a preliminary assessment that the adoption 
of the EU 96/79 EC frontal offset test procedure, in addition to the 
current requirements of FMVSS No. 208, could result in substantial 
benefits, since lower leg injuries were typically associated with long-
term recovery and significant economic cost. However, the Report to 
Congress also made note of NHTSA's concerns relative to the potential 
for exacerbating small and large car incompatibility, as a result of 
adopting a frontal offset crash test procedure.
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    \2\ Conference Report 104-785, September 16, 1996. This report 
accompanied H.R. 3675.
    \3\ Report to Congress, ``Status Report on Establishing a 
Federal Motor Vehicle Safety Standard for Frontal Offset Crash 
Testing,'' April 1997.
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    During 1998-2002, NHTSA completed over 25 frontal offset crash 
tests in an attempt to answer a number of research questions. 
Specifically, what are the merits of a fixed offset deformable barrier 
crash test procedure and what is the most appropriate dummy size, lower 
leg instrumentation and impact speed? Dummy injury measures from the 
fixed offset deformable barrier crash tests demonstrated the potential 
for injury reductions over and above the full frontal rigid barrier 
test configuration.\4\

[[Page 49249]]

The results demonstrated that the 5th percentile female dummy generally 
produced higher normalized lower leg injury measurements than the 50th 
percentile male dummy under comparable frontal offset crash test 
conditions.\5\ Crash tests comparing lower leg instrumentation showed 
that the Thor-Lx/HIIIr lower leg instrumentation predicted a higher 
incidence of foot and ankle injury than the Denton/Hybrid III lower 
leg.\6\ Finally, fixed offset deformable barrier crash tests conducted 
at a range of impact speeds, including 56 km/h, 60 km/h, and 64 km/h, 
demonstrated notable differences in the pass/fail rates, with the 56 
km/h impact speed being the most benign.
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    \4\ Docket No. NHTSA-1998-3332.
    \5\ Park, Morgan, Hackney, Lee, Stucki, ``Frontal Offset Crash 
Test Study Using 50th Percentile Male and 5th Percentile Female 
Dummies,'' Proceedings of the 16th International Technical 
Conference on the Enhanced Safety of Vehicles, Paper No. 98-S1-O-01, 
1998.
    \6\ Kuppa, Haffner, Eppinger, Saunders, ``Lower Extremity 
Response and Trauma Assessment Using the Thor-Lx/HIIIr and the 
Denton Leg in Frontal Offset Vehicle Crashes,'' Proceedings of the 
17th International Technical Conference on the Enhanced Safety of 
Vehicles, Paper No. 456, 2001.
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    In the 2000 and 2001 Regulatory Plans published in the Federal 
Register, NHTSA indicated that it was considering a rulemaking to 
establish a high speed frontal offset test. In response, the 
Administrator of the Office of Information and Regulatory Affairs of 
the Office of Management and Budget, wrote a letter dated December 7, 
2001, asking the U.S. Department of Transportation and NHTSA to 
consider giving greater priority to modifying its frontal occupant 
protection standard by establishing a high speed, frontal offset crash 
test requirement. The letter suggested that if the agency were to give 
this matter greater priority, the agency would need to refine its 
estimates of the specific safety benefits that a new offset test would 
generate. It said that this assessment would also need to include 
potential losses in existing safety benefits due to possible changes in 
vehicle structure and design. This reinforced the agency's intent to 
look at both the benefits and disbenefits from adoption of a high speed 
frontal offset crash test requirement.
    In 2002, the agency initiated a vehicle-to-vehicle crash test 
program to assess the potential disbenefits of adopting a high speed 
frontal offset requirement.\7\ NHTSA used the vehicle-to-vehicle crash 
test configuration from the agency's vehicle compatibility program \8\ 
and test vehicles selected from vehicle models that had improved 
ratings in the IIHS frontal crashworthiness evaluation program.\9\ The 
tests were configured to simulate both vehicles moving at 56.3 km/h, 
such that the subject vehicle impacted the left front corner of its 
collision partner at an offset of 50 percent and an impact angle of 30 
degrees. Two vehicle-to-vehicle crash tests were conducted for each 
vehicle model under study, one using an older model and the other using 
a later redesign. Both vehicles struck a model year 1997 Honda Accord. 
The two sets of injury measurements for the driver dummy of the Honda 
Accord were compared to determine which version of the subject vehicle 
(i.e., the older model or the redesign) imparted higher injury numbers.
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    \7\ See 69 FR 5110.
    \8\ Summers, Prasad, Hollowell, ``NHTSA's Vehicle Compatibility 
Research Program,'' Society of Automotive Engineers Paper No. 1999-
01-0071, March 1999.
    \9\ In this program, vehicles are rated based on their 
performance in a 64 km/h fixed offset deformable barrier crash test.
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    The results of the testing suggested that, for some sport utility 
vehicles (SUVs), design changes that improved their performance in high 
speed frontal offset crash tests may also result in adverse effects to 
occupants of their collision partners. The results raised questions 
about whether or not these results are representative of the effects on 
collision partner protection in the current fleet, and the extent to 
which disbenefits to crash partners are associated with design changes 
made to improve performance in a high speed frontal offset crash test.
    Because of our concern, the agency published a request for comments 
in the Federal Register (February 3, 2004, 69 FR 5108).\10,\ \11\ The 
notice informed the public about the crash tests conducted to date, and 
sought comments on its findings and on alternative strategies that 
could be coupled with a frontal offset crash test requirement. The 
agency also planned to study the performance of four additional vehicle 
models, from different vehicle classes, that improved IIHS 
crashworthiness ratings as the result of a vehicle redesign.
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    \10\ Docket No. NHTSA-2003-15715.
    \11\ Comment period subsequently extended to July 5, 2004 (69 FR 
18015).
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    Shortly after publication of the Request for Comments, the agency 
completed the four additional pairs of vehicle-to-vehicle crash 
tests.\12\ The combined results showed that in five of the six vehicle 
pairs, the head injury criteria of the Honda Accord driver dummy 
increased when struck by the redesigned vehicle compared to when struck 
by the older model. Similarly, in four of the six vehicle pairs, the 
chest acceleration of the Honda Accord driver dummy increased when 
struck by the redesigned vehicle compared to when struck by the older 
model. Overall, the earlier trends observed in the SUV vehicle model 
testing were generally exhibited in the other vehicle classes tested, 
but to a lesser extent for passenger cars.
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    \12\ Docket No. NHTSA-1998-3332.
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II. Summary of Request for Comments

    A total of seventeen organizations and private individuals 
submitted comments in response to the February 3, 2004, request for 
comments notice on frontal offset crash testing. Comments were 
submitted by the Alliance of Automobile Manufacturers (Alliance), the 
Association of International Automobile Manufacturers, Inc. (AIAM), 
American Honda Motor Co., Inc. (Honda), General Motors Corporation 
(GM), DaimlerChrysler and Mercedes-Benz USA, LLC (DaimlerChrysler), 
Ford Motor Company (Ford), the Insurance Institute for Highway Safety 
(IIHS), the Property Casualty Insurers Association of America (PIA), 
the Advocates for Highway and Auto Safety (Advocates), and eight 
comments from private individuals.
    Vehicle manufacturers and vehicle manufacturer associations 
supported the overall goal of reducing lower extremity injuries in 
frontal crashes, but did not support the agency's pursuing a rulemaking 
at this time. They recommended that NHTSA conduct additional research 
on the sources of lower extremity injury, as well as determine the 
appropriate anthropomorphic test device and injury criteria. Vehicle 
manufacturers also generally shared NHTSA's concern that some design 
changes that improve a vehicle's performance in a high speed frontal 
offset crash test may also result in adverse effects on their collision 
partner occupants. Consequently, some strongly advocated linking a 
vehicle compatibility strategy to any frontal offset crash test.
    Conversely, the IIHS, PIA, the Advocates, and the majority of the 
private citizen comments supported the immediate adoption of a frontal 
offset crash test requirement. The IIHS stated that such a requirement 
would ensure all vehicle types are designed with state-of-the-art 
frontal crash protection; however, it believes that NHTSA should not 
delay the implementation of an offset crash test requirement because of 
unsubstantiated fears of compatibility disbenefits. The IIHS also 
stated that such a requirement could not be effective without 
specifically addressing

[[Page 49250]]

occupant compartment integrity. PIA generally supported the IIHS's 
position and noted that frontal offset crash testing simulates a crash 
scenario that current Federal testing does not address. The Advocates 
further stated that it represents a majority of real world crashes and 
its adoption would complement full frontal crash tests.

III. Analysis of Comments

    The main comments raised in response to the Request for Comments 
involved the projected benefits and potential disbenefits of a fixed 
offset deformable barrier crash test, the effect of industry's 
voluntary compatibility commitments, and consideration of alternative 
approaches. The following sections briefly analyze each issue.
    A. Underestimated the benefits of improved frontal offset crash 
protection: The IIHS suggested that NHTSA greatly underestimated the 
benefits of improved frontal offset crash protection. It stated that 
NHTSA's analysis is inconsistent with real-world crash experience, 
which it said increasingly shows the benefits of improved frontal 
offset crash test performance for reducing serious and fatal injuries. 
The IIHS cited a study \13\ indicating that drivers of vehicles with 
good frontal offset crash test ratings involved in fatal head-on 
crashes with poor-rated vehicles were 74 percent less likely to be the 
fatally injured driver. The IIHS also cited a Scandinavian study \14\ 
that found that cars with better performance in EuroNCAP had much lower 
rates of serious injury than cars with worse performance.
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    \13\ Farmer, ``Relationship of Frontal Offset Crash Test Results 
to Real-World Driver Fatality Rates,'' Traffic Injury Prevention, 
2004.
    \14\ Lie and Tingvall, ``How do EuroNCAP Results Correlate with 
Real-Life Injury Risks? A Paired-Comparison Study of Car-to-Car 
Crashes,'' Traffic Injury Prevention, 2002.
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    The agency reviewed the two publications cited by the IIHS. The 
IIHS publication showed that drivers of good-rated vehicles involved in 
fatal head-on crashes with poor-rated vehicles were significantly less 
likely to be the fatally injured driver. However, since the inter-
dependent relationship between frontal offset ratings and important 
factors such as vehicle age, vehicle weight, driver age, and driver 
gender were not examined, we question whether the fatality risk for 
better-rated vehicles might be overstated compared to the poor-rated 
vehicles. For example, the poor-rated vehicles might be consistently 
older than the good-rated vehicles, or the good-rated vehicles might 
tend to be heavier vehicles within a particular rating class. These 
inter-dependencies could decrease the fatality risk reduction estimated 
in the study.
    We also note that the fatality reductions were only significant for 
head-on crashes of similar vehicles rated good and poor. Other 
estimated fatality risk reductions for acceptably and marginally-rated 
vehicles were inconclusive. In addition, we found that certain 
statistics were counter-intuitive. For example, for cars (the largest 
data set in the study), it showed that good-rated cars had higher 
frontal fatality rates than acceptably- and marginally-rated cars. 
Finally, the paper did not address the benefits of the frontal offset 
rating when two potentially incompatible vehicles collided (i.e., car-
to-SUV, car-to-pickup, etc.) Therefore, the magnitude of the overall 
benefit is not clear.
    With respect to the Scandinavian field study cited by the IIHS, we 
are concerned that the comparison of EuroNCAP performance to real-world 
experience may not apply to the U.S., due to differences in mass 
distribution between the fleets and greater percentage of unbelted 
occupants in the U.S. We also observed a number of limitations in the 
study that raise questions as to whether it is appropriate to attribute 
life-saving benefits to a fixed offset deformable barrier test. First, 
the study stated there were insufficient data to separate the frontal 
impact rating from the side impact rating, so the analysis included 
both frontal and side impacts together. Consequently, it is unclear to 
what extent the front or side impact ratings were contributing to the 
correlation. Second, the paper used the Swedish injury classification 
of ``severe'' (or ``typically admitted to the hospital''). The 
resulting correlation to ``severe'' injury may have been driven by 
lower limb injuries (maximum AIS 3 injuries), rather than life-
threatening head or chest injuries. Also, due to insufficient data, the 
study combined all vehicle categories with similar EuroNCAP ratings 
together, regardless of mass. This may be problematic in providing 
meaningful real world results since frontal NCAP ratings (both full and 
offset) are only comparable within a given weight class. Finally, we 
found it noteworthy that the paper itself suggested that the results 
should not be seen as proof that there is a predictive value in the 
EuroNCAP system, especially not for individual car model scores. Thus, 
based on our concerns regarding these two studies, we believe more 
definitive analyses are needed to attribute lifesaving benefits to a 
fixed frontal offset deformable barrier crash test procedure.
    In response to the Request for Comments, the IIHS also stated that 
NHTSA inappropriately relied solely on injury measures recorded by test 
dummies and discounted important information about occupant compartment 
integrity in the agency's tests. The IIHS stated that if the 
compartment is significantly damaged, good dummy injury measures offer 
no assurance of effective protection for the range of occupants who sit 
in different positions and may have different crash kinematics. It also 
stated that NHTSA's analysis is inconsistent with real-world crash 
experience, which increasingly shows that improved frontal offset crash 
test performance reduces serious and fatal injuries.\15\
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    \15\ The IIHS cited a Scandinavian study that found that cars 
with better performance in EuroNCAP had much lower rates of serious 
injury than cars with worse performance. The IIHS also cited their 
own study that showed that drivers of vehicles with good frontal 
offset crash test ratings involved in fatal head-on crashes with 
poor-rated vehicles were 74 percent less likely to be the fatally 
injured driver.
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    NHTSA has monitored toe pan and other intrusion measurements in its 
frontal offset crash tests. While the IIHS strongly advocated that 
intrusion measurement be included in a future requirement, we have not 
seen how to express this measurement as a performance requirement that 
could provide objective results and be used to compute benefits. 
Ideally, dummy instrumentation should provide an objective and direct 
assessment of injury risk to a human occupant. However, the IIHS noted 
that good dummy injury measures, from a test with a single-sized dummy 
in a single seating position, offer no assurance of effective 
protection for the range of occupants who sit in different positions 
and may have different crash kinematics. While we acknowledge that a 
minimum performance requirement cannot account for every intrusion 
scenario that occurs in the real world, there needs to be an objective 
method for converting post-crash intrusion measurements in a particular 
location, of a particular vehicle, to the number of injuries it might 
cause for the range of occupants who sit in different positions and 
have different crash kinematics. Until further analysis can provide 
guidance on an intrusion-based approach, the agency will continue to 
consider using two regulated dummy sizes in its frontal offset crash 
tests to capture the injury spectrum associated with the most 
vulnerable and average-sized occupants. However, we are exploring 
development of a performance requirement approach to compartment 
intrusion, and plan to

[[Page 49251]]

revisit its potential during the course of future research.
    B. Increased vehicle aggressivity from improved frontal offset 
crash protection: Some commenters shared the agency's concern that 
vehicle design changes that improve performance in high speed frontal 
offset crash tests may also result in increased aggressivity toward the 
occupants of their collision partners. As previously discussed, the 
agency's vehicle-to-vehicle crash tests demonstrated a trend in 
increased vehicle aggressivity towards collision partners in five of 
the six redesigned vehicle models tested. The AIAM and the Alliance 
concurred that the results justify a cautious approach in considering a 
frontal offset crash test requirement. The AIAM noted that there were 
instances of injury measures increasing in the struck vehicle, for 
every type of striking vehicle tested (passenger car, minivan, SUV, and 
pickup), when comparing the older and newer designs of the striking 
vehicle. The AIAM stated that the results raise questions regarding 
possible safety disbenefits resulting from design measures that are 
intended to improve frontal offset crash performance.
    Conversely, the IIHS disagreed with the results of the agency's 
crash tests and concluded that the agency should ignore these test 
results in deciding whether to move ahead with a frontal offset crash 
test. The IIHS stated that, in theory, such tests could isolate the 
effects on driver dummy injury risk with changes in vehicle stiffness 
associated with improved crash test performance. However, it stated 
that most tests confounded changes in vehicle stiffness with changes in 
other important vehicle characteristics, such as mass and ride height. 
The IIHS cited this finding because it considers NHTSA's 30-degree 
frontal oblique test to be more characteristic of a side impact test 
with respect to the timing of the Honda Accord driver peak injury 
measures. It stated that injury measures reported by the Hybrid III 
dummy are unlikely to capture the full injury threat to a human 
occupant from such an impact because the lateral loading conditions are 
inconsistent with dummy design and sensor orientation.
    We agree that some of the vehicle-to-vehicle tests confounded 
changes in vehicle stiffness with changes in mass, ride height, and 
other factors. However, our study was not targeted at solely examining 
vehicle stiffness. Whether the changes were increases in mass, 
stiffness, ride height, or combinations of these or other factors, the 
fact remains that five out of six redesigned vehicles that demonstrated 
improved performance in a frontal offset crash test indicated increased 
aggressivity toward its collision partner. Consequently, we do not 
agree that the tests should be ignored. The vehicle-to-vehicle test 
configuration was identified by field data as representing frontal 
crashes with a high risk of serious injury or fatality.\16\ 
Additionally, NHTSA's research has shown that the test configuration is 
able to show a good correlation between target vehicle driver injury 
measures and bullet vehicle aggressivity metrics.\17\ We further 
believe the Hybrid III dummy is the most-appropriate surrogate to 
evaluate injury risk in this frontal crash test configuration, with an 
11 o'clock principle direction of force. Since the same dummy type was 
used in each of the vehicle-to-vehicle crash tests, we believe the 
relative differences in results should be reasonable for comparative 
purposes.
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    \16\ Stucki, Hollowell, and Fessahaie, ``Determination of 
Frontal Offset Test Conditions Based on Crash Data,'' Proceedings of 
the 16th International Technical Conference on the Enhanced Safety 
of Vehicles, 1998.
    \17\ Summers, Prasad, Hollowell, `` NHTSA's Vehicle 
Compatibility Research Program,'' SAE Paper 1999-01-0071, SAE 
International Congress and Exposition, Detroit, MI, 1999.
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    Furthermore, our concerns were reinforced by vehicle manufacturers' 
comments that suggested vehicles might become more aggressive as a 
result of a frontal offset crash test requirement. GM provided examples 
of crash test data from vehicle models designed with countermeasures to 
enable them to perform well in a high speed frontal offset crash test. 
According to GM, the data shows that vehicle structure has gotten 
stiffer in order to perform well in offset testing. Honda referenced 
its 1998 study \18\ where it predicted the occurrence of a potential 
increased stiffness trend, based on vehicle weight, if a high speed 
offset crash test were added to other frontal crash tests. Ford 
similarly stated that countermeasures intended to reduce lower 
extremity injury risk could potentially increase the injury risk for 
occupants, including collision partner occupants, in other crash 
scenarios, such as front-to-front and/or front-to-side impacts. The 
Alliance stated that design approaches that lead to increases in 
vehicle front-end stiffness could degrade full frontal crash 
protection, rear seat occupant protection, particularly child safety 
performance, and might increase the frequency of acceleration-based 
injuries.
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    \18\ Sugimoto, Kadotani, and Ohmura, ``The Offset Crash Test--A 
Comparative Analysis of Test Methods,'' Proceedings of the 16th 
International Technical Conference on the Enhanced Safety of 
Vehicles, 1998.
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    Conversely, the IIHS stated that the assumption that manufacturers 
simply make vehicle front ends stiffer to perform well in the offset 
test is incorrect. It cited a 2001 study where stiffness, as determined 
by U.S. New Car Assessment Program (NCAP) tests, was unrelated to the 
IIHS's structural ratings.\19\ Although it acknowledged that some 
vehicles with improved frontal offset test ratings were ``stiffer'' 
than their predecessors, it said that stiffness typically was evident 
only after about 50 cm of vehicle deformation, when the crash 
deformation had neared the occupant compartment. According to the IIHS, 
this increased stiffness is necessary if the overall safety of the 
vehicle fleet is to improve. To further this point, the IIHS conducted 
a second field data analysis \20\ to determine whether their good-rated 
vehicles contribute to increased vehicle aggressivity toward their 
collision partners. Although the relationships across all rating levels 
were not uniform, it reported that a consistent pattern emerged. Driver 
fatality rates were higher in both the rated vehicle and its collision 
partner when the rated vehicle had a poor rating than when it had a 
good rating. It concluded that this pattern contradicts NHTSA's concern 
that improved frontal offset test performance might lead to increased 
vehicle aggressivity.
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    \19\ Nolan and Lund, ``Frontal Offset Deformable Barrier Crash 
Testing and its Effect on Vehicle Stiffness,'' Proceedings of the 
17th International Technical Conference on the Enhanced Safety of 
Vehicles, 2001.
    \20\ Docket No. NHTSA-15715-20, Appendix.
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    The agency reviewed the IIHS's study and observed that the opposing 
vehicles' fatality risks appear to have been derived without 
controlling for factors such as vehicle make/models, vehicle weights, 
and model years. In our analyses, we have found that these factors 
could dramatically affect the fatality rate estimates. For example, if 
opposing vehicles for one rated group had a different vehicle profile 
(i.e., make-up of make, model and weight) from another rated group, we 
believe that vehicle design may not completely explain the discrepancy 
in opposing vehicle fatality risks. Furthermore, if the weight profile 
of the opposing vehicles for a particular rated group were different 
from that of their rated collision partners, the risk adjustment 
formula for rated vehicles might not be applicable to their opposing 
vehicles. Therefore, we believe it may be misleading to judge 
aggressiveness by directly comparing fatality rates of opposing 
vehicles without controlling for these factors.

[[Page 49252]]

    While we do not dispute the suggestion by IIHS and other commenters 
that there are countermeasures other than stiffening a vehicle's front-
end for achieving good performance in a frontal offset crash test, we 
are cognizant that some potential countermeasures could have adverse 
implications on vehicle weight, aerodynamics, braking effectiveness, 
and fuel economy, making it difficult for vehicle manufacturers to 
pursue them. GM noted that the vehicles with the most constraints are 
full size trucks, due to the breadth of product line, and small/economy 
size vehicles, due to their reduced compartment space/crush room. GM 
stated that additional crush space could only be achieved by adding 
extra length to the front of heavier vehicles; however, it stated that 
such complete engine compartment and front suspension repackaging are 
impracticable. While Honda commented that a forthcoming vehicle model 
employed its new Advanced Compatibility Engineering front 
structure,\21\ Honda stated that it considers this type of structural 
countermeasure when its vehicles undergo a complete redesign. 
Therefore, additional lead-time may be needed to accommodate such 
strategies.
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    \21\ Docket Number NHTSA-03-15715-15, Attachment 13.
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    C. Effect of voluntary compatibility commitments on disbenefits 
concerns: When discussing the agency's compatibility concerns, several 
commenters referred to the Technical Working Group on Front-to-Front 
Compatibility.\22\ The IIHS, a participant in the working group, 
reported that improved structural interaction is the immediate focus of 
the working group for improving vehicle incompatibility. To achieve 
this, vehicle manufacturers have committed to having all light trucks' 
primary energy-absorbing structures overlap the bumper zone of 
passenger cars by September 2009, or, alternatively, have all light 
trucks incorporate a secondary energy absorbing structure.\23\ The AIAM 
noted that further commitments include assessing dynamic test protocols 
for enhanced structural interaction, and evaluating methods for 
determining an appropriate balance between small vehicle interior 
compartment strength and large vehicle energy absorption 
characteristics. The AIAM stated that over time these efforts could be 
expected to reduce aggressivity concerns and achieve significant 
reductions in lower extremity injuries in frontal crashes.
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    \22\ Participants include: BMW, DaimlerChrysler, Ford, General 
Motors, Honda, Hyundai, IIHS, Isuzu, Kia, Mazda, Mitsubishi, Nissan, 
Subaru, Suzuki, Toyota, TRL, and Volkswagen. The vehicle 
manufacturers participating in this program represent over 99 
percent of light vehicle sales in the U.S. and Canada.
    \23\ See http://www.autoallliance.org/archives/commitstatement.pdf..
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    The Alliance and GM recommended that both NHTSA's and the 
industry's compatibility efforts attain a level of maturity before 
regulatory requirements are proposed. GM stated that each would 
contribute considerable insight toward improved lower leg protection, 
and improved occupant crash protection in vehicles and their collision 
partners. Other commenters stated that addressing vehicle aggressivity 
should be treated separately from the frontal offset crash test 
requirement. The IIHS stated that there is nothing to suggest that the 
incorporation of a frontal offset crash test into a standard depends on 
addressing vehicle aggressivity; however, it acknowledged that the 
incompatibility of vehicle structures is an important issue on its own.
    The agency is monitoring the research efforts of the Technical 
Working Group on Front-to-Front Compatibility. We have been informed of 
their objectives, plans and timing for implementation. The potential 
for these efforts to reduce vehicle incompatibility in the fleet, and 
lower extremity injuries in frontal crashes, is dependent upon their 
effective implementation. We also believe that vehicle compatibility 
initiatives and any future frontal offset crash test proposal should be 
closely coordinated and not treated independently, as suggested by the 
IIHS. Our field data studies on vehicle aggressivity and vehicle crash 
test findings have persuaded us to proceed in conjunction with 
compatibility efforts when considering the adoption of a frontal offset 
crash test requirement, particularly for heavier vehicles. Since mass, 
stiffness, and geometric alignment have been identified as vehicle 
parameters that influence partner protection outcomes in our field data 
studies, our frontal offset strategy needs to be cognizant of the 
implications of these factors, so as to not promote countermeasures 
that may adversely affect safety.
    However, we do not necessarily agree with commenters who suggested 
that the compatibility research efforts need to be completed before 
implementing a high speed frontal offset crash test requirement. While 
the industry has been working to develop a set of commitments to reduce 
vehicle aggressivity, the implementation of its first phase of efforts 
(i.e., increased geometric alignment) will not be complete until 
September 1, 2009. The remaining commitments (assessing dynamic test 
protocols for enhanced structural interaction, and test procedures for 
measuring and controlling front-end stiffness characteristics) are only 
commitments for research at this point. In the long term, it is unclear 
what type of lower extremity injury benefits will be promoted by the 
research efforts. In the interim, NHTSA believes that numerous lower 
extremity injuries will continue to occur, and can be addressed through 
a restricted offset test.
    D. Alternative approaches: The Request for Comments sought comments 
on alternative strategies that the agency should consider in 
conjunction with a fixed offset deformable barrier crash test 
requirement. Several vehicle manufacturers suggested strategies aimed 
at improving frontal offset crash protection, while controlling for 
vehicle aggressivity. Honda recommended simultaneously introducing a 64 
km/h frontal offset deformable barrier crash test and a full-width 
deformable barrier crash test into NCAP \24\ to evaluate a vehicle's 
partner protection. Honda stated that this strategy would help match 
the vehicle's principle force and stiffness at the specific interaction 
area where NHTSA, and other countries, require bumpers be located. 
Alternatively, for the long term, Honda and GM supported a moving 
deformable barrier (MDB) frontal offset crash test procedure for 
managing energy and stiffness, while DaimlerChrysler supported a fixed 
offset deformable barrier crash test with a mass-dependent impact 
speed.<SUP>25, 26</SUP> While the IIHS acknowledged that many metrics 
were under consideration by the research community to assess vehicle 
aggressivity and limit incompatibility, it stated that presently there 
are not sufficient data available on which to base a decision.
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    \24\ Honda alternatively proposed to introduce the full-width 
deformable barrier crash test into FMVSS No. 208.
    \25\ A constant energy level would be determined by using an 
average-sized (or representative) passenger vehicle in a fixed 
offset deformable barrier crash test at a prescribed vehicle speed. 
That constant energy level would then be applied when testing the 
remainder of the fleet, such that lighter vehicles would be tested 
at higher speeds, and heavier vehicles would be conducted at lower 
speeds.
    \26\ GM also commented that the intent of making the impact 
speed proportional to the mass is directionally sound, but 
impracticable since the approach will drive slightly different test 
conditions for any vehicle tested and a significant amount of 
confusion could result.
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    In consideration of these proposals, we believe both the MDB and 
fixed offset deformable barrier crash test with a mass-dependent impact 
speed

[[Page 49253]]

approach require extensive research to determine the appropriate energy 
balance (mass and velocity) for which to balance the self and partner 
protection of the fleet. The strategy of combining an offset deformable 
barrier crash test with a full-width deformable barrier has merit for 
consideration; however, we also agree with Honda's belief that its 
approach is not mature enough and/or the fleet-wide effects are not 
understood well enough to include them in a standard at this time.
    Several vehicle manufacturers alternatively suggested the use of 
existing FMVSS No. 208 tests to reduce lower extremity injuries. GM 
suggested adding the Denton/HIII lower leg instrumentation to the 0-40 
km/h offset deformable barrier crash test in FMVSS No. 208. However, 
based on our testing experience in this crash configuration,\27\ we are 
not persuaded that this proposal would drive the design of effective 
countermeasures that would reduce lower leg injuries. DaimlerChrysler 
also suggested adding lower leg instrumentation to the unbelted full 
frontal barrier crash tests of FMVSS No. 208. NHTSA has conducted 16 
unbelted rigid barrier crash tests at 40 km/h with Hybrid III dummies 
having instrumented lower legs. Seven out of 16 vehicles exceeded the 
provisional injury criteria for the lower leg instrumentation. While 
DaimlerChrysler's suggestion may have more potential for reducing lower 
extremity injuries, further testing would be needed to evaluate the 
benefits of this approach, as well as investigate the lower leg 
performance in other crash tests prescribed by FMVSS No. 208.
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    \27\ NHTSA has conducted over 30 crash tests in the 
configuration proposed by GM. In each test, the driver dummy lower 
leg injury measures were far below the provisional injury criteria 
recommended by GM.
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    In the Request for Comments, the agency also discussed limiting the 
vehicle classes or gross vehicle weight rating (GVWR) of the vehicles 
to which a frontal offset crash test requirement would apply as one 
strategy to reduce the potential disbenefits. The example provided was 
to limit the applicability of the frontal offset test requirement to 
passenger cars. NHTSA estimated that approximately 77 percent of the 
benefits of a high speed frontal offset requirement would accrue to 
passenger car occupants since their vehicles would be required to 
maintain compartment integrity and provide improved lower leg 
protection. It was noted that passenger car occupants may also benefit 
from the exclusion of LTVs, since the LTVs striking them may not be 
designed to be as stiff.
    Several commenters on the Request for Comments were conceptually 
supportive of this alternative approach. Ford supported the European 
frontal offset crash test procedure for compact and subcompact 
passenger cars, because it said doing so would harmonize U.S. standards 
with those of the rest of the world. Ford stated that for larger, 
heavier vehicles, a deformable element that can absorb added kinetic 
energy must be developed to provide realistic test results, and vehicle 
design changes that would improve safety. GM and DaimlerChrysler \28\ 
also supported the concept of an offset deformable barrier crash test 
with a mass limitation. GM and DaimlerChrysler suggested that up to 
some mass level, an offset deformable barrier crash test could be 
beneficial to a vehicle without increasing its aggressivity to a 
partner vehicle. Furthermore, the Alliance suggested that the potential 
disbenefits of a high speed frontal offset crash test might be reduced 
if the configuration were harmonized with the Economic Commission for 
Europe (ECE R94) 56 km/h frontal offset crash test, since higher test 
speeds were more prone to partner protection issues in heavier 
vehicles, such as LTVs. Other commenters, however, were against 
creating a distinction between passenger cars and LTVs. The Advocates 
strongly believed that since LTVs are predominantly designed and 
marketed as family vehicles, safety standards should apply to all 
passenger vehicle types, so that benefits to LTV occupants would not be 
discarded.
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    \28\ DaimlerChrysler supported this approach as intermediate 
step towards a mass-dependent impact speed strategy (discussed 
further in the notice).
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    NHTSA believes that a mass exclusion approach addressing lighter 
vehicles would be an intermediate step to address lower extremity 
injury protection, while solutions to aggressivity issues related to 
heavier vehicles are being sought. We agree with Ford's observation 
that applying a frontal offset crash test requirement to compact and 
subcompact classes of passenger cars would be comparable to approaches 
taken in other countries. The results from our 56 km/h offset 
deformable barrier crash test results are also in agreement with the 
Alliance's suggestion that the potential disbenefits may be reduced at 
a lower impact speed. In response to the Advocates, we believe that 
occupant protection for heavier vehicles would still be provided. FMVSS 
No. 208 requires full frontal barrier requirements up to 56 km/h, and a 
fixed offset deformable barrier test up to 40 km/h for vehicles up to a 
loaded GVWR of 3,856 kg. Therefore, we believe concerns regarding crash 
protection to LTV occupants may be partially addressed through existing 
requirements until such time that the agency is ready to move forward 
with a more comprehensive approach.

IV. Rationale for Withdrawal

    Although the agency testing and analyses completed thus far have 
provided a good understanding of the issues associated with frontal 
offset crashes, lower extremity injuries, and dummy instrumentation, 
further studies are needed to allow NHTSA to develop a proposed upgrade 
to FMVSS No. 208 that would effectively provide occupant protection in 
frontal offset crashes without adversely affecting the occupant 
protection of its collision partners. In the agency's Request for 
Comments, NHTSA used data from the 1995-2001 National Automotive 
Sampling System Crashworthiness Data System (NASS-CDS) in estimating 
that approximately 84,811 front seat vehicle occupants annually 
experience AIS 2+ skeletal and joint injuries to the lower extremities 
and hip in frontal offset crashes. Based on the agency's fixed offset 
deformable barrier crash tests conducted to date, and those from the 
IIHS, the agency preliminarily determined that such a test requirement 
would have the potential of annually reducing 1,300 to 8,000 MAIS 2+ 
lower extremity injuries.
    Some aspects of these preliminary benefit projections were based on 
a very limited number of crash tests, as noted by some commenters to 
the request for comments notice. The testing of some crash 
configurations had been limited, to some extent, by the number of 
different research alternatives that the agency had explored (i.e., 
lower leg instrumentation, dummy size, impact speed, etc.). The agency 
also did not have the opportunity to test any advanced air bag 
vehicles, as noted by other commenters. To accumulate the necessary 
data to refine and complete our benefits analysis, we believe that 
additional testing is needed, particularly of newer vehicles reflective 
of those in the current fleet.
    We also remain concerned about increasing vehicle aggressivity and 
fleet incompatibility as a result of adopting a high-speed frontal 
offset crash test, particularly for heavier LTVs. In making our 
decision to withdraw this rulemaking, the agency had also considered 
other alternative approaches suggested by commenters. Energy management 
approaches (MDB and fixed offset deformable barrier tests with

[[Page 49254]]

a mass-dependent impact speed), force application limits, NCAP 
strategies, and lower leg applications in existing FMVSS No. 208 tests 
were among those considered. However, we believe each of these 
alternative approaches needs some degree of research and testing prior 
to consideration for rulemaking.
    Despite this, we are concerned with the large number of lower 
extremity injuries associated with offset frontal crashes, since they 
are the second most costly long-term injuries, after brain injuries. 
Based upon our initial benefit analyses, we have tentatively determined 
that the most effective way to address these injuries while balancing 
the concerns with increased aggressivity is to pursue development of 
requirements in a two-step approach. The first step would be to develop 
offset frontal requirements for a limited segment of the vehicle fleet. 
Our initial cost/benefit estimates indicate that we would be able to 
maximize lower extremity benefits without creating disbenefits due to 
incompatibility by limiting applicability to a segment of the vehicle 
fleet. The second, longer-term step would be to develop requirements 
for those vehicles that are prone to increased aggressivity, perhaps in 
conjunction with compatibility requirements.
    Based upon testing the agency has completed thus far, we believe 
that a fixed offset deformable barrier crash test in the range of 56-60 
km/h using advanced dummy instrumented legs would provide the best 
opportunity to reduce lower extremity injuries without exacerbating 
vehicle incompatibility. However, focused testing under these 
conditions is needed to provide a sufficient basis to develop an offset 
frontal rulemaking proposal. We will examine the number of tests 
needed, including using two dummy sizes and requiring left/right side 
impacts. We also plan to explore new approaches to developing a 
performance metric for compartment intrusion, and its correlation to 
injury during the course of this testing and development.
    The agency will also continue its efforts toward federalization 
\29\ of retrofit instrumented lower legs for both the 5th and 50th 
percentile Hybrid III dummies. On May 3, 2002, the agency published an 
Advance Notice of Proposed Rulemaking (ANPRM) (67 FR 22381) on the 
adoption of the two potential types of lower leg instrumentation for 
assessing lower leg injury in full and offset-frontal crashes. In 
support of the notice, the agency published a technical report \30\ 
describing the leg assemblies and documenting the lab, sled, and 
vehicle test experiences with the two pairs of lower leg 
instrumentation. Based on the ANPRM and subsequent testing, we have 
tentatively decided that the Thor-Lx/HIIIr and Thor-Flx/HIIIr lower leg 
instrumentation appear to have the greatest potential to assess lower 
extremity injuries. The agency is currently moving forward with the 
federalization of these two sets of lower leg instrumentation.
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    \29\ Specifying by regulation at 49 CFR Part 572 Anthropomorphic 
Test Devices.
    \30\ Docket No. NHTSA-2002-11838.
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    The agency also needs to conduct additional frontal high-speed 
offset crash tests to gather sufficient data for fleet representation 
and refined benefit estimates. These crash tests will be conducted with 
vehicle models certified to the advanced air bag requirements of FMVSS 
No. 208. Both 5th percentile female and 50th percentile male Hybrid III 
dummies will be instrumented with Thor-Lx/HIIIr and Thor-Flx/HIIIr 
lower leg instrumentation in the driver and right front passenger 
seating positions. Dummy and intrusion measurements from the tests will 
be compared to the field data experience. With this information, better 
estimates for the injury reduction rates associated with the proposed 
offset frontal requirement will be developed.
    Finally, the agency will conduct an optimization study to determine 
the appropriate applicability limit for which the frontal offset crash 
test requirement should apply in order to maximize self protection, 
while minimizing the amount of risk associated with partner protection.
    In sum, we believe that a fixed offset deformable barrier crash 
test, with applicability limited to a segment of the vehicle fleet and 
in the range of 56-60 km/h using advanced dummy instrumented legs, 
would provide the best opportunity to reduce lower extremity injuries 
without exacerbating vehicle incompatibility. However, focused testing 
under these conditions is needed to develop a sufficient basis for an 
offset frontal rulemaking proposal. Since this additional testing will 
not be completed within a year, we have decided to withdraw rulemaking 
for offset frontal requirements until completion of the testing and 
analysis, and then re-initiate rulemaking when it is completed.

V. Conclusion

    Based on our evaluation of available information, we have concluded 
that further study is needed to have sufficient data to establish the 
appropriate number of tests and dummies, and to refine cost/benefit 
estimates for a definitive rulemaking proposal. Accordingly, we have 
decided that we should remove the frontal offset and lower leg 
instrumentation rulemakings from the Semi-Annual Regulatory Agenda 
(Unified Agenda) because rulemaking action is not anticipated in the 
immediate future. However, during the next year, we will continue the 
testing and analyses necessary to develop a proposal for occupant lower 
extremity protection in offset frontal crashes, and again place it in 
the Unified Agenda when a proposal is imminent.

    Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166; 
delegation of authority at 49 CFR 1.50.

    Issued: August 18, 2005.
H. Keith Brewer,
Director, Office of Crash Avoidance Standards for Rulemaking.
[FR Doc. 05-16721 Filed 8-19-05; 8:45 am]
BILLING CODE 4910-59-P