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Federal Motor Vehicle Safety Standards; Occupant Crash Protection

American Government Special Collections Reference Desk

American Government Topics:  National Highway Traffic Safety Administration, Federal Motor Vehicle Safety Standards

Federal Motor Vehicle Safety Standards; Occupant Crash Protection

Barry Felrice
Federal Register
April 26, 1994

[Federal Register: April 26, 1994]



National Highway Traffic Safety Administration

49 CFR Part 571

[Docket No. 74-14; Notice 88]
RIN 2127-AE48

Federal Motor Vehicle Safety Standards; Occupant Crash Protection

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

ACTION: Notice of proposed rulemaking.


SUMMARY: This notice proposes to require Type 2 safety belts either to 
be integrated with the vehicle seat or to provide a means of 
adjustability to improve the fit and increase the comfort of the belt 
for a variety of different sized occupants. NHTSA believes that some 
occupants who find their safety belts to be uncomfortable, either wear 
their safety belts incorrectly or do not wear their safety belts. NHTSA 
believes that improving safety belt fit will encourage the correct use 
of safety belts and could have the potential to increase the overall 
safety belt usage rate.

DATES: Comment Date: Comments on this notice must be received by NHTSA 
not later than June 27, 1994.
    Effective Date: If adopted, the proposed amendment would become 
effective September 1, 1996.

ADDRESSES: Comments should refer to the docket and notice number set 
forth in the heading of this notice and be submitted to: NHTSA Docket 
Section, room 5109, 400 Seventh Street SW., Washington, DC 20590. The 
NHTSA Docket Section is open to the public from 9:30 am to 4 pm Monday 
through Friday.

FOR FURTHER INFORMATION CONTACT: Mr. Clarke Harper, Frontal Crash 
Protection Division, Office of Vehicle Safety Standards, NRM-12, 400 
Seventh Street SW., Washington, DC 20590. Mr. Harper can be reached by 
telephone at (202) 366-4916.



    Section 2503(4) of the ``Intermodal Surface Transportation 
Efficiency Act of 1991'' requires the NHTSA to address the matter of 
improved design for safety belts (Pub. L. 102-240). In response to this 
statutory mandate, NHTSA issued an advance notice of proposed 
rulemaking (ANPRM) on May 29, 1992 (57 FR 22687). The ANPRM listed 
three rulemaking options and posed ten questions. The options included:

A. Take No Regulatory Action at This Time.
B. Adopt Detailed Regulatory Requirements to Ensure Proper Belt Fit.
C. Adopt a General Requirement that Safety Belts Adjust to Fit 
Different Sized Occupants.

    The ten questions asked for information on costs and benefits, and 
for comments on the test procedure. The ANPRM also included a 
discussion of the types of complaints the agency receives concerning 
belt fit. Finally, the ANPRM explained that any proposal addressing 
safety belt fit will encourage the correct use of safety belts and 
could have the potential to increase safety belt use. Of those persons 
who currently do not use safety belts because of improper fit, some 
would respond to the improved fit by beginning to use their belts or by 
wearing them more frequently.


    Since the ANPRM, the agency has conducted research on the issue of 
safety belt fit. A detailed discussion of this research can be found in 
a technical paper titled ``Improved Design for Safety Belts,'' a copy 
of which has been placed in the docket for this rulemaking. For this 
paper, the agency surveyed eight vehicles with non-adjustable shoulder 
belts and seven vehicles with various types of adjustable shoulder 
belts to determine how well the belts fit a family of dummies (the six-
year-old, the 5th percentile female, the 50th percentile male, and the 
95th percentile male). The survey used the comfort zone described in 
the ANPRM (Option B), modified as appropriate for the different sized 
    In the vehicles with non-adjustable shoulder belts, the belt was 
within the comfort zone 32.3 percent of the time for the six-year-old 
dummy, 94.3 percent for the 5th percentile female, 51.2 percent for the 
50th percentile male, and 57.1 percent for the 95th percentile male. 
For the adult dummies, these results do not correlate with the pattern 
of belt fit complaints received by the agency. The complaints are often 
from shorter adults, suggesting that height may not be the only factor 
that affects safety belt fit. For example, the agency observed that, 
for two persons of the same height, the belt path was higher 
(approaching the neck) on the person with a larger torso. The agency 
also observed that belts tend to ride higher on the torso as the 
relative position of the belt anchorage and seat are changed so that 
the anchorage is farther to the rear in relation to the seat. This 
movement of the belt occurs because the belt tends to seek the 
straightest line path between its anchorages.
    In vehicles with adjustable shoulder belts, the belts were within 
the comfort zone 33.3 percent of the time for the six-year-old dummy, 
95 percent for the 5th percentile female, 85.7 percent for the 50th 
percentile male, and 100 percent for the 95th percentile male. These 
results show that currently available adjustable shoulder belt designs 
do improve safety belt fit for adults. The significantly lower 
percentage of both non-adjustable and adjustable belts within the 
comfort zone for the six-year-old dummy suggests that additional means, 
such as booster seats, are necessary for comfortable belt fit for such 
persons. Booster seats will raise the proper fit to over 80 percent.
    The agency also considered the effectiveness of integrating safety 
belts into seats to provide the necessary comfort. During the research, 
the agency was able to gain access to only a single vehicle equipped 
with an integrated safety belt: The Mercedes Benz 500SL convertible. 
This particular system also included an upper adjustable anchorage on 
the seat. The survey of adult human subjects indicated the safety belt 
did fit the range of adult occupants.
    The vehicles with adjustable shoulder belts were also surveyed 
using live test subjects having the approximate physical dimensions of 
the six-year-old, 5th percentile female, 50th percentile male, and 95th 
percentile male dummies. The six-year-old human test subject reported a 
good fit 10.5 percent of the time, and the 50th percentile male test 
subject 95.7 percent of the time, while the 5th percentile female and 
95th percentile male test subjects reported a good fit 100 percent of 
the time. These results also support the agency's conclusion that 
adjustable shoulder belts can fit a wide range of adult occupants.

Comments on the ANPRM

    The agency received 33 comments in response to the ANPRM. In 
general, the commenting manufacturers did not support continuation of 
this rulemaking, while commenting consumer advocates believed that the 
agency should address the issue of belt fit. Commenters did not provide 
any information on potential benefits other than anecdotal information 
from consumer surveys.
    A number of questions were raised concerning the test procedure for 
Option B. Some commenters stated that it was not appropriate to test 
the six-year-old dummy in the driver's seat. Other commenters stated 
that the 95th percentile adult male dummy might not fit in some rear 
seats. A number of comments were also received concerning the 
positioning procedures for the dummies.
    Commenters also raised questions concerning the test zone described 
in the ANPRM. NHTSA reviewed the test zone as part of the research 
described above and found that the shoulder zone was redundant and the 
chest zone was mislocated on some dummies (e.g., the chest zone 
intersected the neck of the six-year-old dummy). Therefore, for the 
research, the sternum reference point and the width of the shoulder 
zone were modified for each dummy, using the sitting height listed in 
S7.1.3 of Standard No. 208 as a guide to adjust the measurement in 
reference to the 50th percentile male dummy.
    Some commenters expressed concern that attempts to improve seat 
belt fit through providing means of adjustability could lead to 
misadjustment of belts, which could, in turn, increase the potential 
for injury. The agency conducted dynamic sled tests simulating a 48.3 
km/h barrier impact using adjustable shoulder belts that were 
improperly positioned. In some cases dummy measurements improved, while 
in other cases measurements were worse. However, it should be stressed 
that these results were based on an adjustable belt range of 
approximately 16 centimeters, which is much greater than the adjustment 
available in current vehicles or that is required by this proposal. At 
this time, the agency does not have any information on the effect of an 
adjustment in the 5 centimeter range on dummy measurements.


    After reviewing the comments and the research results, NHTSA has 
tentatively concluded that belts which provide better fit, would, in 
turn, promote increased belt usage. Accordingly, the agency is 
proposing to require Type 2 safety belts either to be integrated with 
the vehicle seat or provide a means of adjustability to improve the fit 
and increase the comfort of the belt for a variety of different sized 
    The agency has decided not to propose detailed requirements. First, 
the detailed test procedure in the ANPRM would not provide an adequate 
means of identifying improper fit on the wide variety of sizes and 
shapes of vehicle occupants. As discussed above, the agency research 
showed that the proposed test procedure, using test dummies, had a much 
different result than the comfort levels reported by human subjects 
during the research survey. The human adults were more comfortable with 
the safety belt fit than the dummy fit indicated. Conversely, the human 
child discomfort and misfit were much worse than the dummy fit 
    Next, the results of the agency's research lead to the conclusion 
that currently available non-adjustable belts fit small adults better 
than they fit large adults. This does not correlate well with the 
complaints received by the agency. For these reasons, the agency does 
not believe that the test procedure suggested in the ANPRM addresses 
the cause of real-world fit problems. In addition, comments to the 
ANPRM raised a number of unresolved questions concerning the test 
procedure. These include a potentially uncomfortable location of the 
test zone on human subjects, the need to develop positioning procedures 
for the various dummies, and the need to develop and add specifications 
for the 5th percentile female and 95th percentile male dummies in 49 
CFR Part 572.
    The agency has examined a number of different vehicles that provide 
some means of adjusting the shoulder belt portion of the safety belt. 
For example, Volvo offers a design in which the shoulder belt webbing 
is fed through a slot in the pillar at different angles as increasing 
amounts of webbing are spooled off the retractor. A number of 
manufacturers offer a design in which the upper anchorage can be 
manually moved vertically to a set number of positions. Mercedes Benz 
offers similar designs which adjust automatically as either the seat or 
head rest position is adjusted. Another design used to maintain proper 
shoulder belt position is a design in which the inboard anchorage is 
mounted on the seat and moves with the seat, while the outboard 
anchorage is mounted on the vehicle chassis. Some manufacturers have 
chosen to use both an upper adjustable anchorage and an inboard movable 
anchorage on the same safety belt. NHTSA believes that all of these 
designs offer good degrees of adjustment.
    In addition, some manufacturers have safety belts integrated with 
the seats. While the anchorages for these belts are not adjustable, 
this type of belt appears to provide a good fit for a wide range of 
occupants because the upper and lower anchorages maintain a constant 
position relative to the seat and the occupant, regardless of the seat 
adjustment. As a result of being on the seat, the upper anchorage is 
typically farther forward relative to the occupant than is the upper 
anchorage for belts that are neither adjustable nor integrated. As a 
result, the belt does not ride as high as it attempts to seek the 
straightest line between the anchorages. As discussed previously in 
this notice, the agency's research noted this problem with belt 
anchorages that were far behind the occupant. Therefore, NHTSA is 
proposing that a Type 2 safety belt must either be equipped with an 
adjustable anchorage or be integrated with the seat.
    Some commenters stated that a general requirement that belts be 
adjustable would not be effective because it would allow manufacturers 
to call any design with any degree of movement an ``adjustable'' belt. 
They could do this even if the amount of adjustability did not improve 
safety belt fit for many occupants. NHTSA has observed some safety belt 
designs that might be considered meeting a broad definition of 
``adjustable'' (e.g., rotating D-rings), but which NHTSA believes do 
not offer sufficient adjustment to ensure that the belts would fit a 
wide range of occupants. Agency research found that on eight different 
designs of upper adjustable anchorages, the overall anchorage travel 
ranged from 5.8 centimeters to 10.1 centimeters. For inboard movable 
anchorages, the anchorages all moved more than 19 centimeters, always 
the entire distance of seat travel. Conversely, the rotating D-rings 
provide no travel. Therefore, the value of five centimeters appears to 
be a reasonable lower limit for anchorage adjustment. For this reason, 
NHTSA is specifying that manufacturers installing a means of adjustment 
must use designs that provide at least five centimeters of 
adjustability. NHTSA believes that all of the effective designs 
discussed above provide at least this amount of adjustment.
    Most of the adjustable belts currently available are installed at 
front seating positions. For the rear seats, NHTSA is aware of General 
Motor's ``Child Rerouter.'' This design utilizes a clip through which 
the shoulder belt can be routed to change the shoulder belt angle. 
NHTSA is also aware of the integrated safety belt on the rear seat of 
the Volvo 850 station wagon. Also, a few Mercedes Benz models (300S, 
300SE) incorporate automatically adjusting shoulder anchorages in the 
rear seat. NHTSA requests comments on various designs that may be used 
to comply with the proposed requirements in the rear seats, the 
practicability of these designs, and the costs of these designs. NHTSA 
requests comments on the need for better belt fit for adults at rear 
seating positions.
    As discussed previously in this notice, NHTSA's research shows that 
this requirement alone will not be sufficient to address belt fit 
problems of small children. The agency believes that the need exists 
for the use of belt-positioning child booster seats or another means of 
achieving a good fit, adjustability of the safety belt alone is not 
sufficient. The agency has recently published an NPRM, also mandated by 
the ``Intermodal Surface Transportation Efficiency Act of 1991,'' to 
address issues related to belt-positioning child booster seats (58 FR 
46928; September 3, 1993). The NPRM proposed to amend Standard No. 213, 
``Child Restraint Systems,'' to permit the manufacture and sale of 
belt-positioning seats by removing the impediments in the current 
standard to the production of these seats. The proposal included a test 
procedure and labeling/informational requirements. The comments 
received on that notice are currently being evaluated by the agency.
    NHTSA also requests comments on the regulatory language proposed in 
this notice. Are there any safety belt designs that adjust to fit a 
wide range of occupants but which might not be considered as complying 
with this proposal? Is there any design that could fall within the 
language of the proposal but which a commenter believes should not be 
allowed because it does not fit a sufficiently wide variety of 
occupants? NHTSA requests that commenters address both why a design 
does (or doesn't) comply with the proposed requirements and why the 
design should (or shouldn't) be allowed.
    NHTSA discussed in the ANPRM the increased number of complaints 
concerning safety belt fit in recent years. The agency stated improving 
safety belt fit should increase belt usage and that increased usage 
would, in turn, yield safety benefits. At the same time, the agency 
noted that there might be adverse safety consequences if belts were not 
adjusted by each successive user to provide the appropriate fit. NHTSA 
asked whether it was possible to quantify the benefits of a rule on 
improved safety belt fit, and specifically whether any relevant studies 
or other data were available. The agency did not receive any data or 
analysis regarding the issue of benefits.
    Accordingly, NHTSA again asks commenters to address this issue. 
Would the rule lead to an increase in belt usage? Would the rule result 
in a reduction in belt misuse? For example, would it reduce the 
instances in which occupants place the shoulder belt portion of a lap/
shoulder belt behind their backs or under their arms? What would be the 
net effect of the rule on safety? What relevant studies and data exist? 
For example, do vehicle manufacturers have any information showing a 
decrease in complaints about safety belt fit after vehicle models have 
been equipped with adjustable shoulder belts?
    NHTSA believes that occupants need to have information available on 
the proper use of belt adjustment devices. However, NHTSA also believes 
that the new labeling requirements for air bags should be the focus for 
information in the vehicle. Therefore, NHTSA is not proposing a 
requirement to label vehicles but is proposing instead to require 
information instructions on proper use in the owner's manual for 
vehicles with manually adjustable belts. Because the occupant does not 
have to take any action to ensure proper fit, devices which provide 
automatic adjustment, including integrated seats, would not need such 
instructions. In addition, NHTSA is not proposing specific language for 
this requirement as NHTSA believes that manufacturers are in the best 
position to determine the best means of providing this information.
    If adopted, the agency proposes to make this amendment effective 
September 1, 1996. NHTSA believes many vehicles, currently or in the 
near future, will comply with this safety belt comfort and fit 
requirement to satisfy consumer demand. Additionally, this date is 
concurrent with the beginning of the required phase-in of manual safety 
belts and air bags. Manufacturers will be able to take advantage of the 
redesign process necessary for the air bag requirement to also make any 
design changes necessary to comply with this safety belt fit 
requirement. Considering these two factors, the agency believes that 
two years leadtime would be sufficient.

Rulemaking Analyses and Notices

Executive Order 12866 and DOT Regulatory Policies and Procedures

    NHTSA has considered the impact of this rulemaking action under 
E.O. 12866 and the Department of Transportation's regulatory policies 
and procedures. This rulemaking document was reviewed under E.O. 12866, 
``Regulatory Planning and Review.'' This action has been determined to 
be ``significant'' under the Department of Transportation's regulatory 
policies and procedures. NHTSA estimates that the annual economic 
impact of this proposed rule would be between $69 and $92 million. The 
range reflects cost estimates from NHTSA and the manufacturers, 
respectively, and baseline use of technologies as of model year 1992 
vehicles. The cost estimates assume adjustable upper anchorages will be 
used in the front seat of 4-door vehicles and other vehicles with B-
pillars close to the front seat occupant (e.g., pickups and vans), and 
seat-frame-mounted anchorages for the front seat of 2-door vehicles. 
Child rerouters are assumed to be used in the rear seats of all 
vehicles with rear seating positions. If all occupants that currently 
wear their belt incorrectly wore their belt correctly, an estimated 33 
lives could be saved and 833 moderate to critical injuries could be 
reduced annually.

Regulatory Flexibility Act

    NHTSA has also considered the impacts of this notice under the 
Regulatory Flexibility Act. I hereby certify that this proposed rule 
would not have a significant economic impact on a substantial number of 
small businesses. Few, if any, of the vehicle manufacturers qualify as 
small entities. To the extent that any affected parties would qualify 
as small businesses, the economic impacts associated with this proposal 
would not be significant, as explained above.

Paperwork Reduction Act

    In accordance with the Paperwork Reduction Act of 1980 (Pub. L. 96-
511), there are no requirements for information collection associated 
with this proposed rule.

National Environmental Policy Act

    NHTSA has also analyzed this proposed rule under the National 
Environmental Policy Act and determined that it would not have a 
significant impact on the quality of the human environment.

Executive Order 12612 (Federalism)

    NHTSA has analyzed this proposal in accordance with the principles 
and criteria contained in E.O. 12612, and has determined that this 
proposed rule would not have sufficient federalism implications to 
warrant the preparation of a Federalism Assessment.

Civil Justice Reform

    This notice does not have any retroactive effect. Under section 
103(d) of the National Traffic and Motor Vehicle Safety Act (Safety 
Act; 15 U.S.C. 1392(d)), whenever a Federal motor vehicle safety 
standard is in effect, a State may not adopt or maintain a safety 
standard applicable to the same aspect of performance which is not 
identical to the Federal standard, except to the extent that the State 
requirement imposes a higher level of performance and applies only to 
vehicles procured for the State's use. Section 105 of the Safety Act 
(15 U.S.C. 1394) sets forth a procedure for judicial review of final 
rules establishing, amending or revoking Federal motor vehicle safety 
standards. That section does not require submission of a petition for 
reconsideration or other administrative proceedings before parties may 
file suit in court.

Submission of Comments

    Interested persons are invited to submit comments on the proposal. 
It is requested but not required that 10 copies be submitted.
    All comments must not exceed 15 pages in length. (49 CFR 553.21). 
Necessary attachments may be appended to these submissions without 
regard to the 15-page limit. This limitation is intended to encourage 
commenters to detail their primary arguments in a concise fashion.
    If a commenter wishes to submit certain information under a claim 
of confidentiality, three copies of the complete submission, including 
purportedly confidential business information, should be submitted to 
the Chief Counsel, NHTSA, at the street address given above, and seven 
copies from which the purportedly confidential information has been 
deleted should be submitted to the Docket Section. A request for 
confidentiality should be accompanied by a cover letter setting forth 
the information specified in the agency's confidential business 
information regulation. 49 CFR part 512.
    All comments received before the close of business on the comment 
closing date indicated above for the proposal will be considered, and 
will be available for examination in the docket at the above address 
both before and after that date. To the extent possible, comments filed 
after the closing date will also be considered. Comments received too 
late for consideration in regard to the final rule will be considered 
as suggestions for further rulemaking action. Comments on the proposal 
will be available for inspection in the docket. The NHTSA will continue 
to file relevant information as it becomes available in the docket 
after the closing date, and it is recommended that interested persons 
continue to examine the docket for new material.
    Those persons desiring to be notified upon receipt of their 
comments in the rules docket should enclose a self-addressed, stamped 
postcard in the envelope with their comments. Upon receiving the 
comments, the docket supervisor will return the postcard by mail.

List of Subjects in 49 CFR Part 571

    Imports, Motor vehicle safety, Motor vehicles.


    In consideration of the foregoing, it is proposed that 49 CFR Part 
571 be amended as follows:
    1. The authority citation for part 571 of title 49 would continue 
to read as follows:

    Authority: 15 U.S.C. 1392, 1401, 1403, 1407, delegation of 
authority at 49 CFR 1.50.

    2. Section 571.208 would be amended by designating existing S7.1.2 
and S7.1.3 as S7.1.3 and S7.1.4 and adding a new S7.1.2 to read as 

Sec. 571.208  Standard No. 208, Occupant Crash Protection

* * * * *
    S7.1.2  Except as provided in S7.1.2.1 and S7.1.2.2, for each Type 
2 seat belt assembly which is required by Standard No. 208 (49 CFR 
571.208), the upper anchorage, or the lower anchorage nearest the 
intersection of the torso belt and the lap belt, shall include a 
movable component which provides a minimum of two adjustment positions. 
The distance between the geometric center of the movable component at 
the two extreme adjustment positions shall be not less than five 
centimeters, measured linearly. If the component must be moved 
manually, information shall be provided in the owner's manual to 
explain how to adjust the seat belt and warn that misadjustment could 
reduce the effectiveness of the safety belt in a crash.
    S7.1.2.1  An integrated Type 2 seat belt assembly is not required 
to comply with the requirements of S7.1.2. A Type 2 seat belt assembly 
is considered an integrated assembly if the seat frame is part of each 
of the seat belt assembly anchorages, as defined in S3 of Standard No. 
210 (49 CFR 571.210).
    S7.1.2.2  As an alternative to meeting the requirement of S7.1.2, a 
Type 2 seat belt assembly shall provide a means of automatically moving 
the webbing in relation to either the upper anchorage, or the lower 
anchorage nearest the intersection of the torso belt and the lap belt. 
The distance between the midpoint of the webbing at the contact point 
of the webbing and the anchorage at the extreme adjustment positions 
shall be not less than five centimeters, measured linearly.
* * * * *
    Issued on: April 21, 1994.
Barry Felrice,
Associate Administrator for Rulemaking.
[FR Doc. 94-10056 Filed 4-25-94; 8:45 am]

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