[Federal Register Volume 60, Number 47 (Friday, March 10, 1995)]
[Rules and Regulations]
[Pages 13285-13297]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-5413]
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[[Page 13286]]
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 57l
[Docket No. 93-06; Notice 3]
RIN 2127-AD07
Federal Motor Vehicle Safety Standards; Stopping Distance
Requirements for Vehicles Equipped With Air Brake Systems
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.
ACTION: Final rule.
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SUMMARY: This notice reinstates stopping distance performance
requirements in Standard No. 121, Air Brake Systems, for medium and
heavy vehicles that are equipped with air brake systems. The
requirements specify distances in which different types of medium and
heavy vehicle configurations must come to a complete stop from 60 mph
on a high coefficient of friction surface. The requirements are
designed to reduce the number and severity of crashes.
This notice is one part of the agency's comprehensive effort to
improve the braking ability of heavy vehicles. In another final rule
published elsewhere in today's Federal Register, the agency is adopting
identical stopping distance requirements for medium and heavy vehicles
that are equipped with hydraulic brake systems. In a third final rule
that responds to the Intermodal Surface Transportation Efficiency Act
(ISTEA) of 1991, the agency is requiring medium and heavy vehicles to
be equipped with an antilock brake system (ABS) to improve the lateral
stability and control of these vehicles during braking.
DATES: Effective Dates: The amendments become effective on March 1,
1997. Compliance to Sec. 571.121 with respect to trailers and single
unit trucks and buses will be required as of March 1, 1998.
Petitions for Reconsideration: Any petitions for reconsideration of
this rule must be received by NHTSA no later than April 10, 1995.
ADDRESSES: Petitions for reconsideration of this rule should refer to
Docket 93-06; Notice 3 and should be submitted to: Administrator,
National Highway Traffic Safety Administration, 400 Seventh Street SW.,
Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: Mr. George Soodoo, Office of Vehicle
Safety Standards, National Highway Traffic Safety Administration, 400
Seventh Street SW., Washington, DC 20590 (202-366-5892).
SUPPLEMENTARY INFORMATION:
I. Background
A. Brake Related Crashes
B. Braking Devices
II. NHTSA Activities
A. Regulatory History
B. Agency Research
C. Heavy Vehicle Safety Report to Congress
III. Agency Proposal
IV. Comments on the Proposal
V. Agency Decision
A. Overview
B. Stopping Distance Performance
1. Stopping Distance Requirements
2. Stopping Distance Test Conditions
a. Test Surface Specification
b. Wheel Lockup Restrictions
c. Control Trailer
d. Vehicle Loading
e. Initial Brake Temperature
f. Emergency Stopping Distance Requirements
g. Burnish Procedure
h. Parking Brake Test
C. Threshold Pressure Requirement
D. Requirements for Brake Linings
E. Implementation Schedule
F. Intermediate and Final Stage Manufacturers/Trailer
Manufacturers
G. Costs
VI. Rulemaking Analyses and Notices
A. Executive Order 12866 and DOT Regulatory Policies and
Procedures
B. Regulatory Flexibility Act
C. Paperwork Reduction Act
D. National Environmental Policy Act
E. Executive Order 12612 (Federalism)
F. Civil Justice Reform
I. Background
A. Brake Related Crashes
Medium and heavy vehicles1 are involved in thousands of motor
vehicle crashes each year. One of the most important factors that
contributes to these crashes is brake system performance. Crashes in
which braking is a contributory factor can be further subdivided into
(1) crashes due to brake failures or defective brakes, (2) runaways on
downgrades, due to maladjusted or overheated brakes, (3) crashes in
which vehicles are unable to stop in time, and (4) skidding,
jackknifing, or loss-of-control crashes due primarily to locked wheels
during braking.
\1\Hereafter, referred to as heavy vehicles.
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This final rule, reinstating stopping distance requirements for
air-braked vehicles and the companion final rule specifying stopping
distance requirements for hydraulically braked heavy vehicles will
reduce the severity of or prevent crashes attributable to a heavy
vehicle's inability to stop in time.2 In these crashes, the heavy
vehicle's brakes function, but do not stop the vehicle quickly enough
to avoid a crash. One way to reduce the severity or number of such
crashes is to improve heavy vehicle braking performance by reducing the
distance needed to stop a vehicle. Even if crashes of this type were
not totally prevented by such improvements in performance, the
improvements would reduce collision impact speeds, and thus reduce
crash severity.
\2\Today's companion final rule to require heavy vehicles to be
equipped with antilock brake systems (ABS) will prevent braking-
induced loss-of-control crashes.
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The following estimates regarding heavy vehicle crashes are from
NHTSA's 1992 General Estimates System (GES) which is based on data
transcribed from a nationally representative sample of state police
accident reports (PARs) and the Fatal Accident Reporting System (FARS).
NHTSA estimates that in 1992 there were about 168,000 crashes involving
heavy combination vehicles (excluding truck tractors when operating
bobtail, i.e., without a trailer). These crashes resulted in about
13,600 injuries and 387 fatalities to truck occupants and about 51,500
injuries and 2,452 fatalities to occupants of other involved vehicles.
For bobtail truck tractors alone, the agency estimates that there were
about 8,400 crashes resulting in about 1,200 injuries and 39 fatalities
to truck occupants and about 2,600 injuries and 178 fatalities to
occupants of other involved vehicles. For heavy single-unit trucks, the
agency estimates that there were about 192,600 crashes resulting in
about 15,700 injuries and 165 fatalities to truck occupants and about
48,300 injuries and 891 fatalities to occupants of other involved
vehicles. In addition, crashes involving heavy vehicles result in more
expensive and severe property damage than crashes involving light
vehicles.
It is very difficult to quantify the number of crashes in which a
vehicle's brakes are unable to stop the vehicle in time. NHTSA
estimates that in 1992 there were about 18,000 crashes involving heavy
combination vehicles (excluding bobtail truck tractors). These crashes
resulted in about 1,800 injuries and 57 fatalities to truck occupants
and about 8,400 injuries and 754 fatalities to occupants of other
involved vehicles. For bobtail truck tractors alone, the agency
estimates that there were about 260 crashes resulting in about 100
injuries and 7 fatalities to truck occupants and about 240 injuries and
48 fatalities to occupants of other involved [[Page 13287]] vehicles.
For heavy single-unit trucks, the agency estimates that there were
about 30,100 crashes resulting in about 4,200 injuries and 17
fatalities to truck occupants and about 15,000 injuries and 276
fatalities to occupants of other involved vehicles. The Final Economic
Analysis (FEA) provides greater detail about how today's final rules
will reduce injuries and fatalities resulting from such crashes.
The agency emphasizes that not all inability-to-stop-in-time
crashes are preventable. Nevertheless, improvements to heavy vehicle
brake systems should prevent or reduce the severity of a significant
number of these crashes.
B. Braking Devices
In order to understand the discussion of braking in this preamble,
it is necessary to be familiar with several devices used in braking
systems. Therefore, the agency provides a brief explanation of those
devices below.
Automatic front axle limiting valves (ALVs) automatically limit the
amount of braking pressure applied at steering axle brakes. ALVs are
typically installed to allay the concern of some drivers about loss of
steering control due to front wheel lockup during hard braking and to
reduce steering pull due to unequal brake adjustment on the front wheel
brakes. However, these devices can actually increase the likelihood of
drive axle and trailer lockup because the brakes on the front axle do
less than their proportional share of the braking. Therefore, drivers
must apply brakes harder to stop the vehicle. Accordingly, stopping
distance performance could, in most cases, be improved by eliminating
the use of ALVs.
Bobtail proportioning valves (BPVs) automatically reduce brake
application pressure to the drive axles of a bobtail truck tractor,
thereby allowing greater use of the vehicle's steering-axle braking
power. Bobtail tractors demonstrate the worst stopping capability of
all vehicle types, primarily because the braking systems of tractors
are designed to optimize their stopping distance when they are towing a
loaded trailer. Without the trailer, the lack of load on the tractor
drive axles can cause premature wheel lockup and reduced stopping
capability. An agency study found that, on average, the stopping
distance of bobtail tractors is approximately 122 feet longer than that
of tractors when connected to loaded trailers.3 However,
significantly shorter stops have been obtained when bobtails are
equipped with BPVs.
\3\``NHTSA Heavy Duty Vehicle Brake Research Program Report No.
1, ``Stopping Capability of Air Braked Vehicles,'' (DOT HS 806 738,
April 1985) and Report No. 9, ``Stopping Distances of 1988 Heavy
Vehicles.''
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Load-Sensing Proportioning Valves (LSVs) reduce the likelihood of
premature wheel lockup by mechanically sensing drive-axle suspension
deflection that results from weight transfer during braking, and
adjusting brake proportioning based on different loading conditions.
However, LSVs cannot prevent lockup of a vehicle's brakes if they are
applied too hard, particularly on a low coefficient of friction
surface.
Antilock brake systems (ABSs) automatically control the amount of
braking pressure applied to a wheel so as to prevent wheel lock, thus
increasing stability and control in emergency stops by preventing
skidding, spinning, and jackknifing. Today's stability and control
final rule provides a detailed discussion of these devices.
II. NHTSA Activities
A. Regulatory History
In the notice of proposed rulemaking (NPRM) to reinstate stopping
distance requirements for air-braked vehicles, NHTSA provided a
detailed discussion of the regulatory and judicial history of the
stopping distance requirements for air braked vehicles. (58 FR 11009,
February 23, 1993). When last in effect, the stopping distance
requirements in Standard No. 121 required all heavy vehicles to stop
within 293 feet from a speed of 60 mph on a high coefficient of
friction surface (i.e., a nonslippery surface typical of dry concrete).
(41 FR 8783, March 1, 1976).
In response to a suit challenging Standard No. 121's stopping
distance requirements, the United States Court of Appeals for the 9th
Circuit invalidated the Standard's stopping distance and ``no lockup''
requirements for trucks, buses, and trailers in PACCAR v. NHTSA, 573
F.2d 632, (9th Cir. 1978) cert. denied, 439 U.S. 862 (1978). The court
held that NHTSA was justified in promulgating a standard requiring
improved air brake systems and stability mechanisms. However, after
reviewing the record about reliability problems with antilock brake
systems then in use, the court held that the standard was ``neither
reasonable nor practicable at the time it was put into effect.''
The court further stated that:
* * * those parts of the Standard requiring heavier axles and
the antilock device should be suspended. The evidence indicates that
this can be accomplished if we hold, as we do, that the stopping
distance requirements from 60 mph are invalid * * * We hold only
that more probative and convincing data evidencing the reliability
and safety of vehicles that are equipped with antilock and in use
must be available before the agency can enforce a standard requiring
its installation.
The stability and control final rule contains a detailed discussion
about the PACCAR decision and how the agency has responded to the
findings in that decision. The Agency has decided to specify different
stopping distances for different configurations of heavy vehicles.
Today's requirements can further be distinguished from those
invalidated in the 1970s by the fact that manufacturers will not need
to significantly redesign their brakes or use overly aggressive
foundation brakes to comply with the requirements being established in
today's final rule.
Even though the stopping distance requirements being specified in
today's final rule are generally less stringent for some configurations
than those invalidated by the PACCAR decision, the agency believes that
the braking requirements in today's final rules, taken as a whole,
significantly enhance the overall braking performance of air-braked
vehicles given the agency's decision to require these vehicles to be
equipped with ABS.
B. Agency Research
As a part of its review of heavy vehicle braking, NHTSA has issued
two reports on the stopping distance capability of several different
types of heavy air-braked vehicles in various loading conditions.4
The agency also tested some vehicles equipped with ALVs, BPVs, and ABS,
thus allowing comparisons of stopping distances with and without these
devices. The tests were conducted on school buses, transit buses,
single unit trucks, tractor trailers in the loaded and empty conditions
and with various equipment (with ABS activated and deactivated, and
with and without ALVs and BPVs). Among the conclusions reached by the
agency on the basis of the test data were: (1) ALVs significantly
degrade straight line stopping performance, especially in the bobtail
configuration (with stopping distances as long as 531 feet); (2) BPVs
significantly reduce the stopping distances of bobtail tractors; (3)
ABSs are effective in providing short, stable stops in all operating
conditions; (4) ABSs provide the greatest performance gain in the
bobtail configuration, where stable stops as short as 233 feet were
obtained; (5) braking performance of bobtail tractors and empty single
unit [[Page 13288]] trucks could be improved by removing ALVs from both
vehicle types and installing BPVs on bobtails; and (6) a stopping
distance performance requirement for truck tractors with empty trailers
would not provide any additional performance benefits that could not be
achieved through specifying requirements for either the bobtail or
loaded condition.
\4\NHTSA Heavy Duty Vehicle Brake Research Program Report No. 1,
``Stopping Capability of Air Braked Vehicles,'' (DOT HS 806 738,
April 1985) and Report No. 9, ``Stopping Distances of 1988 Heavy
Vehicles.'' DOT HS 807 531, February 1990.
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C. Heavy Vehicle Safety Report to Congress
In response to section 9107 of the Truck and Bus Regulatory Reform
Act of 1988, NHTSA submitted a report to Congress titled ``Improved
Brake Systems for Commercial Vehicles.'' (DOT HS 807 706, April
1991.)5 After discussing crash data concerning heavy vehicle brake
systems, the report explained the factors that are related to braking
effectiveness, stability and control during braking, and braking system
compatibility. The report indicated that stopping distances and vehicle
stability could be improved by not equipping heavy vehicles with ALVs
and instead equipping them with BPVs, load-sensing proportioning
valves, and antilock brake systems.
\5\This report may be examined at the Agency's Technical
Reference Office, room 5108, at no charge. It is available from the
National Technical Information Service (NTIS), Springfield, VA 22161
for a small charge.
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III. Agency Proposal
On February 23, 1993, NHTSA proposed to amend Standard No. 121 to
reinstate stopping distance performance requirements for stops from 60
mph on a high coefficient of friction surface for trucks, truck
tractors, and buses that are equipped with air brake systems (58 FR
11009). Based on testing at VRTC, the Agency proposed different
stopping distances for different configurations of heavy vehicles.
Specifically, the Agency proposed that unloaded single unit trucks and
bobtail tractors stop within 335 feet, loaded single unit trucks stop
within 310 feet, and all buses stop within 280 feet. The Agency
proposed two alternatives for testing a truck tractor in the loaded
condition and stated that one of the alternatives would be chosen for
the final rule. The first alternative proposed that the truck tractor
be tested with a braked control trailer and stop within 280 feet, while
the second alternative proposed that the truck tractor be tested with
an unbraked control trailer and stop within 355 feet. The Agency
explained that its long-term objective is to upgrade the braking
efficiency of heavy vehicles to enable them to make controlled, stable
stops, under all loading and road surface conditions. The Agency
believed that the proposed requirements would reduce the disparity in
braking ability between heavy vehicles and passenger cars. On the same
day, the Agency proposed identical stopping distance requirements for
heavy vehicles equipped with hydraulic brakes (58 FR 11003). The Agency
stated that many vehicles were already able to comply with the proposed
requirements. The inadequate performance of those vehicles that were
not able to comply was due to either poor brake torque balance between
the vehicles' axles resulting in premature lockup of the wheels on the
vehicles' rear axles or a lack of sufficient total brake torque
capability. Those vehicles that exhibited poor brake balance could be
brought into compliance by installing ABS, or by adding BPVs and/or
eliminating ALVs. Those vehicles that lack sufficient total brake
torque capability could be brought into compliance by incorporating
relatively minor changes to their foundation brake components involving
the substitution of other currently available components.
NHTSA proposed that air-braked vehicles would have to come to a
complete stop within a 12-foot-wide lane with restrictions on which
wheels would be permitted to lockup during the stop. The proposal
requested comments about whether and to what degree wheel lockup during
testing would be permitted. Specifically, the Agency proposed to allow
unlimited lockup below 20 mph and defined two types of wheel lockup
allowed above 20 mph: ``permissible wheel lockup,'' which is defined as
100 percent wheel slip of one or more wheels for a duration of one
second or less6 for testing purposes, and ``limited lockup,''
which is defined as lockup of not more than one wheel per axle or two
wheels per tandem. In addition, NHTSA proposed test conditions related
to the road test surface, the use of a braked or unbraked control
trailer, and the initial brake temperature. NHTSA also proposed
specifying a threshold pressure to enhance brake force compatibility
between tractors and trailers.
\6\As explained below, the final rule refers to this concept as
``momentary wheel lockup.''
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IV. Comments on the Proposal
NHTSA received 49 comments in response to the NPRM. Commenters
included heavy vehicle manufacturers, brake manufacturers, safety
advocacy groups, heavy vehicle users, industry trade associations, and
other individuals. The American Automobile Manufacturers Association
(AAMA) submitted joint comments on behalf of the eight major domestic
manufacturers of heavy vehicles: Chrysler, Ford, Freightliner, General
Motors (GM), Mack Trucks, Navistar, PACCAR, and Volvo-GM.
All the commenters supported the Agency's decision to reinstate
stopping distance requirements for heavy vehicles equipped with air
brakes. However, they offered mixed views about the specific stopping
distances being proposed. GM, Navistar, Heavy Duty Brake Manufacturers
Council (HDBMC), and Rockwell WABCO stated that the proposed stopping
distance requirements are appropriate. In contrast, the Insurance
Institute for Highway Safety (IIHS), the Coalition for Consumer Health,
and Advocates for Highway Safety (Advocates) believed that the required
distances should be much shorter for trucks and buses. Advocates stated
that the proposal did little more than ``grandfather'' existing braking
capabilities and therefore would not result in the best available
braking performance for large trucks.
The American Trucking Association (ATA), IIHS and several other
commenters suggested that the Agency should merge the proposed stopping
distance and stability requirements into a common rulemaking, thereby
allowing the industry to implement a more effective test program.
Commenters also addressed specific issues raised in the NPRM,
including vehicle test speed, the test surface specification, the
control trailer, wheel lockup restrictions, the initial brake
temperature, the failed system test, vehicle loading, the threshold
pressure requirements, the parking brake test, the burnish procedures,
and the implementation schedule for the requirements. More specific
discussions of these comments, and the Agency's responses to them, are
set forth below.
V. Agency Decision
A. Overview
Based on the Fatal Accident Reporting System (FARS) and other crash
data, test data from the agency's heavy vehicle brake research program,
comments on the NPRM, and other available information, NHTSA has
decided to amend Standard No. 121 to reinstate stopping distance
performance requirements for heavy vehicles that are equipped with air
brake systems. Separate requirements for stopping from 60 mph on a high
coefficient of friction surface are specified for four different heavy
vehicle configurations. The requirements are designed to reduce the
[[Page 13289]] distance needed for these vehicles to come to a complete
stop, thereby reducing the severity and number of crashes.
As noted above, this notice is one part of the Agency's
comprehensive effort to improve the braking ability of heavy vehicles.
In a second final rule published elsewhere in today's Federal Register,
the Agency is adopting identical stopping distance requirements for
heavy vehicles that are equipped with hydraulic brake systems. The
Agency believes that it is appropriate to specify identical stopping
distance requirements for similar vehicles. In a third final rule, the
Agency is responding to the Intermodal Surface Transportation
Efficiency Act (ISTEA) of 1991 by requiring each heavy vehicle to be
equipped with an antilock brake system to improve its lateral stability
and control during braking.
B. Stopping Distance Performance
1. Stopping Distance Requirements
Based on its testing at VRTC, NHTSA proposed different stopping
distances for various categories of vehicles when tested at a speed of
60 mph on a surface with a peak friction coefficient (PFC) of 0.9, as
follows:
Loaded and Unloaded Buses
280 ft.
Loaded Truck Tractors with Braked Control Trailer
280 ft.
Loaded Truck Tractors with Unbraked Control Trailer
355 ft.
Loaded Single-Unit Trucks
310 ft.
Unloaded Single-Unit Trucks & Truck Tractors (Bobtail)
335 ft.
The agency proposed different requirements, instead of a single
across-the-board requirement like the one invalidated by the PACCAR
court, because a single requirement for all heavy vehicles with fully
operational service brakes would be too stringent for bobtail tractors
and unloaded single unit trucks, but not stringent enough for buses and
for tractor trailers in the loaded condition.
AAMA and most other industry commenters agreed with the stopping
distance values proposed for the various vehicle configurations.
AlliedSignal commented that these requirements are compatible with its
view of using BPVs to achieve increased deceleration on air-braked
tractors, while maintaining lateral stability in the bobtail mode.
Nevertheless, it requested that ALVs not be prohibited since it
believed that these devices are appropriate on some vehicles,
particularly those with large front brakes. AlliedSignal recommended
that if an ALV is used on a vehicle, it should be automatically
deactivated when the tractor is in the bobtail mode. ATA agreed with
the proposal to specify different stopping distances for different
types and loadings of vehicles. It also agreed with specifying the same
stopping distances for air-braked and hydraulically-braked vehicles of
the same type and with the same loading.
Other commenters opposed some of the proposed stopping distance
values on the ground that they were too stringent. HDBMC stated that
certain vehicles would have difficulty complying with the proposed
stopping distances because they are over-braked when the rear axles are
unloaded, and under-braked during emergency system stops. Lucas was
concerned that the service brake stopping distances obtained during the
agency's testing do not have a 10 percent margin less than the proposed
280 feet from 60 mph. In order to obtain an acceptable margin, Lucas
stated that vehicle manufacturers will have to equip certain vehicles
with larger front brakes, which would represent a major change on some
vehicles.
In contrast, other commenters stated that the proposed stopping
distances were not sufficiently stringent. Advocates stated that the
proposed stopping distances simply ratify the braking distances
currently achieved by manufacturers and do not seek to improve real-
world braking performance. It stated that except for the 280-foot
requirement for buses and loaded tractors with a braked control
trailer, all of the other proposed stopping distances are longer than
the 293 feet established before PACCAR. Similarly, IIHS stated that the
proposals do not go far enough toward requiring the best available
braking for heavy vehicles.
Based on the comments and other available information, NHTSA has
decided to adopt the stopping distances proposed in the NPRM for the
following categories of vehicles when tested at a speed of 60 mph on a
surface with a PFC of 0.9:
Loaded and Unloaded Buses7
280 ft.
\7\The final rule amending Standard No. 105 discusses in detail
the stopping distances applicable to hydraulic-braked school buses.
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Loaded Truck Tractors with Unbraked Control Trailer8
355 ft.
\8\As explained in the section below titled ``control
trailers,'' the agency proposed but decided not to adopt a revised
braked control trailer test condition.
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Loaded Single-Unit Trucks
310 ft.
Unloaded Single-Unit Trucks & Truck Tractors (Bobtail)
335 ft.
As it stated in the NPRM, NHTSA agrees with HDBMC that a small
number of vehicles will have to be modified to comply with the
reinstated stopping distance requirements. The agency notes that the
companion final rule requiring heavy vehicles to be equipped with
antilock brake systems will improve the braking of those vehicles whose
braking performance is limited due to poor brake torque balance, and
will enable them to comply with the stopping distance requirements. For
those vehicles that will require changes to their foundation brakes, so
as to provide greater brake torque capability, the agency believes that
adequate leadtime is being provided to minimize the task of achieving
compliance with the requirement.
NHTSA notes that while the companion final rule requiring heavy
vehicles to be equipped with ABSs will reduce the need to eliminate
front axle ALVs on single unit trucks and truck tractors and to install
rear axle BPVs on truck tractors, the agency would still encourage
vehicle manufacturers to do so. Vehicles without ALVs and/or with BPVs
can be braked at higher levels of deceleration before the vehicle's ABS
is activated, which the agency believes will improve the vehicle's
driveability. The Agency is aware of at least one manufacturer of ABSs
that currently recommends the incorporation of BPVs on truck tractors
equipped with ABS.
2. Stopping Distance Test Conditions
a. Test Surface Specification
In the NPRM, NHTSA proposed that the 60-mph stopping distance tests
be performed on a test surface with a PFC of 0.9, which is typical of
dry concrete. In formulating the proposal, the agency considered
whether the proposed test surface specification raises practicability
or objectivity concerns in light of PACCAR. Based on its testing, the
agency tentatively concluded that specifying a test surface with a high
PFC would reasonably represent stopping on a dry surface and would not
be a significant source of variability in the stopping distance tests.
The Agency requested comments on the proposed test surface
specification.
Several commenters addressed the appropriate PFC for the test. AAMA
and Navistar commented that the test surface should be specified at a
PFC of 1.0 because that PFC value would remove the influence of test
road variability from compliance testing. AAMA provided data that
showed that in the course of six months, the PFC varied between 0.85
and 0.95, and averaged 0.90 over ten readings taken approximately twice
each month. According to Navistar, its data showed PFCs that ranged
from 0.91 to 0.98. [[Page 13290]] AAMA argued that since the majority
of actual test surfaces nominally exceed PFC 0.9, a specification of
0.9 would impose a cost burden on manufacturers trying to maintain the
test surface near, but below, the 0.9 value. AAMA stated that
``worldwide support'' has been expressed for specifying a test surface
with a PFC of 1.0. Volvo GM provided results of the Motor Vehicle
Safety Research Advisory Committee (MVSRAC) Antilock Brake System (ABS)
Task Force ``Round Robin'' testing, which showed that on high
coefficient of friction surfaces with PFCs ranging from 0.87 to 1.00,
the stopping distances of the three test vehicles remained relatively
constant when tested in the bobtail condition. This indicates stopping
performance on a dry surface is not significantly affected by
variability. Strait-Stop requested that a tolerance of 0.1
relative to 0.9 should be specified to accommodate real-world
limitations.
Based on the industry-government cooperative testing to evaluate
the effect of fluctuations of PFC on vehicle stopping performance,
NHTSA reaffirms its belief that a PFC of 0.9 reasonably represents a
typical dry surface and will not be a significant source of variability
in the stopping distance tests. (Public Files Docket PF88-01, MVSRAC
ABS Task Force, Round Robin No. 1). Testing indicates that the expected
minor variability of a high coefficient of friction surface appears to
have a negligible impact on vehicle stopping distance performance.
Variation of the average stopping distances for the six different
surfaces (with PFCs ranging from 0.89 to 0.94) was small, with the
deviation from the average being only 5 feet. Accordingly, the agency
believes that any variability in the stopping performance on a high
coefficient of friction surface is more likely due to variation in the
vehicle's performance rather than test surface variability. NHTSA has
decided that a test road surface specification of PFC 1.0 would result
in practicability problems for the agency, since it would have to
conduct compliance testing on a surface with a PFC higher than 1.0.
Such a surface is difficult to find. The agency also notes that General
Motors conducted an extensive survey of actual road surfaces, which
indicated that a PFC of 0.9 is fairly typical.
NHTSA notes that AAMA's claim that there is worldwide support for
specifying a PFC of 1.0 is incorrect. The agency notes that when the
issue was discussed by the ECE in the context of the international
harmonization of brake standards, the decision was to specify a PFC of
0.99. Moreover, when the Organization International des
Constructeurs d'Automobiles (OICA) proposed adopting a PFC of 1.0, no
country supported such a requirement.
\9\Eleventh Informal Meeting on Harmonization of Brake
Standards, August 26-27, 1991 and 29th Meeting of Experts on Brakes
and Running Gear, August 28-30, 1991.
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NHTSA has decided not to adopt Strait-Stop's request to specify a
tolerance for the test surface. The agency notes that in specifying the
test conditions applicable to the test surface, the agency does not
provide a range of permissible test surfaces. Instead, the braking
standards set forth specific, objective criteria for the test surface
according to which the agency conducts its compliance testing.
b. Wheel Lockup Restrictions
In the NPRM, NHTSA proposed that the straight line stopping
distance test be conducted without locking more than one wheel per axle
or two wheels per tandem at speeds greater than 20 mph. In addition,
the agency proposed to allow unlimited lockup at 20 mph or below, and
to allow permissible wheel lockup for testing purposes. NHTSA believed
that allowing limited wheel lockup combined with permissible wheel
lockup at speeds above 20 mph would ensure a safe and reasonably
repeatable test condition, while providing an indication of a vehicle's
stability up to the vehicle's braking performance limit. These
provisions addressing wheel lockup were based on the previously
mentioned stopping distance tests conducted at VRTC. NHTSA requested
comments about the degree to which lockup should be permitted and under
what circumstances, including whether to allow unrestricted wheel
lockup of test vehicles.
Commenters addressed four distinct issues with respect to the wheel
lockup restrictions: (1) Specifying various types of lockup that would
be allowed; (2) applying the wheel lockup restrictions to ABS equipped
axles; (3) applying the wheel lockup restrictions to certain other
axles; and (4) applying the wheel lockup restrictions to emergency
system stops.
AlliedSignal, ATA, AAMA, and Strait-Stop commented that the wheel
lockup restrictions were not clear. AlliedSignal suggested that
``permissible'' and ``limited'' be replaced by one term, and that wheel
lockup be defined as 100 percent wheel slip at both wheels on an axle
or more than two wheels on a tandem for a duration greater than one
continuous second. AAMA requested that ``wheel lock restriction'' be
defined ``as 100 percent wheel slip of both wheels of an axle, or more
than two wheels on a tandem, for a duration greater than one continuous
second.'' Strait-Stop requested that permissible wheel lockup be
defined as lockup of one or more wheels at 100 percent slip for a
reasonable time. ATA stated that the proposed regulatory language does
not clearly indicate whether unlimited wheel lockup is permitted at
speeds below 20 mph.
After reviewing these comments, NHTSA has decided to adopt the
proposed concepts pertaining to wheel lockup restrictions in the
stopping distance test, with some modifications to enhance the
provision's clarity. Aside from defining wheel lockup as 100 percent
slip, and renaming ``permissible wheel lockup'' as ``momentary wheel
lockup,'' NHTSA has decided that it is clearer to specify the concept
directly in the stopping distance requirement in S5.3.1 instead of
defining the various types of lockup (e.g., momentary (permissible)
lockup, limited lockup, unlimited lockup) and then referencing them in
S5.3.1. Accordingly, a vehicle is required to stop with wheel lockup
permitted under the following conditions. At vehicle speeds above 20
mph, one wheel on any axle or two wheels on any tandem may lock up for
any duration. At vehicle speeds above 20 mph, wheels on certain axles
(i.e., nonsteerable axles other than the two rearmost nonliftable,
nonsteerable axles) may lock up for any duration. At vehicle speeds
above 20 mph, any wheel not permitted to lock, as described in the two
conditions above, may lock up repeatedly, with each lockup condition
having a duration of one second or less. At vehicle speeds of 20 mph or
less, any wheel may lock up for any duration. These exceptions allowing
certain types of lockup are based on the above-mentioned tests
conducted at VRTC.
In establishing the requirements applicable to wheel lockup
restrictions, NHTSA examined the commenters' recommended definitions
for wheel lockup restriction. The Agency believes that these
definitions achieve only part of the Agency's objective in establishing
wheel lockup restrictions. The Agency interprets AAMA's definition as
allowing both wheels on an axle to lock up (100 percent slip) for up to
one second. However, AAMA's recommended definition is unclear about
whether one wheel is allowed to remain locked up for the duration of
the stop. NHTSA believes that it would be necessary to add additional
wording to AAMA's definition to achieve the same
[[Page 13291]] objective that is already achieved by the Agency's
requirements.
Several commenters stated that the wheels on any axle controlled by
ABS should be excluded from wheel lockup constraints. Rockwell
International stated that the proposed stopping distance regulation
will become obsolete soon, since the references to permissible and
limited wheel lockup will be superseded by the ABS regulation. Rockwell
WABCO stated that the proposed stability and control rulemaking will
resolve problems with respect to the wheel lockup definitions. AAMA
expressed its concern that imposing wheel lockup constraints on ABS-
equipped vehicles could pose practicability problems during tests. For
example, AAMA said that the test driver could be required to modulate
brake pressure in order to prevent wheel lockup on axles not equipped
with ABS, at the same time the ABS is cycling.
NHTSA believes that the requirements in S5.3.1 continue to be
necessary, notwithstanding the Agency's decision to require heavy
vehicles to be equipped with antilock brake systems. The Agency
believes that the limited lockup and momentary lockup restrictions will
not impose any unreasonable or currently unachievable performance
requirement on antilock systems during the stopping distance test,
since the amount of lockup allowed by these restrictions is
considerably greater lockup than allowed by any currently available
antilock system. The antilock requirement specifies that an ABS on a
truck tractor must control ``the wheels of at least one front axle of
the vehicle and the wheels of at least one rear axle * * *'' Therefore,
if a vehicle is equipped with ABS on only one axle of a rear tandem,
the limited and momentary lockup requirements ensure that the vehicle
can be braked without excessive wheel lockup of the wheels, including
those controlled by ABS. Even if both non-ABS-controlled wheels of the
tandem lock for the duration of the stop (they meet the limited lockup
requirement test), the ABS-controlled wheels would then be allowed to
lock for a duration of one second or less, at speeds above 20 mph. The
Agency, therefore, does not agree with the claims that the backup
restrictions would prohibit ABS on some vehicles, or that they would
pose practicability problems for test drivers.
NHTSA believes that AAMA's concern about problems with specifying
wheel lockup restrictions is unrealistic. The Agency is unaware of any
currently used antilock system that would allow wheel lockups that
would not comply with the above restrictions.
Rockwell WABCO further stated that the wheel lock issue can be
resolved by requiring the vehicle to remain in the 12-foot-wide lane
during testing to the stopping distance requirements.
NHTSA believes that Rockwell WABCO's suggestion that the sole
requirement be that a vehicle stay within a 12-foot-wide lane does not
adequately take into consideration that on a smooth, flat, and straight
surface, a vehicle with locked wheels might possibly stay within the
lane. Accordingly, such a stop would not fully demonstrate the
capability of a vehicle to provide stable stops at the limit of the
vehicle's braking performance.
Several commenters recommended that the wheel lockup restrictions
not be applicable to emergency system stops. AAMA recommended that
wheel lockup constraints only apply to full service stops ``to avoid
compromises to full system performance for the sake of partial system
wheel lock.''
NHTSA agrees with these comments. In its present form, the
restrictions on wheel lockup in Standard No. 121 appear in S5.3.1, and
thus do not apply to the emergency stops specified in S5.7.1. The NPRM
did not propose to extend those restrictions to emergency braking, and
the Agency is not making such a change in this final rule.
c. Control Trailer
In the NPRM, NHTSA proposed two alternatives for testing a truck
tractor in the loaded condition. The first alternative proposed the use
of a braked control trailer, which would be similar to the current
braked control trailer. The second alternative proposed the use of an
unbraked control trailer.
AAMA, ATA, HDBMC and Rockwell WABCO supported the use of an
unbraked control trailer. They believed that its use would eliminate
many sources of test result variability and would produce test results
that are consistent, comparable, and useful. Rockwell WABCO stated that
a braked control trailer with ABS could lead to test performance
variations since there are many different trailer antilock systems now
available. It believed that it would be extremely difficult to define
the required performance of the control trailer and the antilock system
necessary to have a consistent ``test fixture'' for the stopping
distance standard.
Strait-Stop objected to the use of an unbraked control trailer,
stating that its use would render the stopping distance performance of
the combination vehicle meaningless. Trade International Corporation
(TIC) did not explicitly support either of the two control trailer
alternatives, but objected to the mandated use of ``electronically
controlled systems'' to the exclusion of any other type of system, for
the braked control trailer ABS.
NHTSA has decided to specify the use of an unbraked control trailer
to test a truck tractor in the loaded condition. The Agency notes that
this decision, which is consistent with the views of most commenters,
will eliminate test variability and produce test results that are
consistent, comparable, and useful. Contrary to Strait-Stop's
assertion, the Agency, along with most commenters, believes that the
test results on unbraked control trailers provide meaningful
comparative information. This is so because the stopping ability of all
tractors will be evaluated in the same relative context (i.e., all
tractors would be mated to a similar unbraked control trailer). An
unbraked control trailer is easier to standardize than a braked control
trailer since there is no need to specify the foundation brakes and the
antilock brake system. The section on control trailers in the stability
and control final rule provides a more extensive discussion of this
issue.
d. Vehicle Loading
In the NPRM, NHTSA proposed that tractors would be loaded with an
unbraked control trailer, which would be loaded above the kingpin only,
such that the tractor is at GVWR and the trailer's axle is at 4,500
pounds, with the tractor's fifth wheel adjusted so that the load on
each axle is proportional to the axle's respective GAWR. (See
alternative 2, S6.1.10.4.)
AAMA requested that the Agency add the phrase ``without exceeding
the GAWR of any tractor or trailer axle.'' AAMA stated that for some
vehicles, it is impossible to load the tractor to its GVWR through the
kingpin without exceeding the drive axle GAWR. Due to limited fifth
wheel adjustment on some vehicles, virtually all of the ballast added
at the fifth wheel is borne by the tractor's rear axle, with very
little transferred to the front axle.
After reviewing AAMA's comment, NHTSA has decided to amend
S6.1.10.4 to include the phrase ``without exceeding the GAWR of any
tractor or trailer axle.'' The Agency believes that this modification
is consistent with the proposal's intent to have the loading
proportional to each axle's respective GAWR. The Agency is aware that
this modification will result in some tractors being tested slightly
below their GVWR. However, since actual users will be similarly
incapable of loading the vehicle to its GVWR without exceeding
[[Page 13292]] GAWR, the reduced amount should not adversely affect
motor vehicle safety.
e. Initial Brake Temperature
In the NPRM, NHTSA proposed an initial brake temperature of 250
deg.F to 300 deg.F. The Agency tentatively concluded that specifying a
high brake temperature would reduce cooling time between stops and
therefore allow vehicle testing to proceed faster. All the commenters
that addressed this issue opposed the proposed adoption of such a high
initial brake temperature.
Based on these comments and the available test data, NHTSA has
concluded that an initial brake temperature of between 150 deg.F to
200 deg.F range is more appropriate than the proposed temperature
range. As explained in detail in the stability and control final rule,
testing using the 150 deg.F to 200 deg.F temperature range is more
repeatable and results in less variation between runs, compared to
testing conducted at an initial brake temperature of 250 deg.F to 300
deg.F, particularly for the emergency brake stops.
f. Emergency Stopping Distance Requirements
Although the NPRM did not propose to change the current emergency
stopping distance requirements in Standard No. 121, several commenters
recommended changes. AMA, ATA, Allied Signal, HDBMC, and Rockwell
International recommended that the Agency eliminate the stopping
distance performance requirements for a loaded truck tractor's
emergency braking system when tested with an unbraked control trailer.
They stated that a failed primary or a failed secondary brake system
does not realistically simulate any real-world vehicle situation that
can occur during a single brake system failure. They further stated
that this requirement would impose extremely unrealistic loads on the
functioning truck tractor brakes. AAMA stated that the emergency brake
systems are not designed to stop a loaded unbraked control trailer, and
that Standard No. 121 already includes a requirement in S5.7.3(c)
stating that a loss of primary or secondary tractor brakes should not
result in a loss of trailer brakes. Test data submitted by AAMA and
Allied Signal showed stopping distances in excess of 2,000 feet for the
failed primary (rear) brakes on a tractor with a loaded unbraked
control trailer. The stopping test distances submitted for failed
secondary (front) brakes on the tractor with a loaded unbraked control
trailer were within the current requirement of 613 feet. Based on these
considerations, the commenters recommended that the tractor's emergency
brake system be tested in the bobtail configuration only.
After reviewing the comments and other available information, NHTSA
has decided to apply the emergency brake system test for truck tractors
only in the unloaded (bobtail) condition for both the failed primary
and failed secondary conditions. According to test data obtained
through the Agency's testing and provided by commenters, emergency
brake system testing presents a unique problem for a loaded truck
tractor with an unbraked control trailer. With either a primary or
secondary failure of the tractor's brakes, the loaded combination would
be braked only by the front axle or rear axle brakes, since the control
trailer is unbraked. As a result, the stopping distances would be
extremely long, particularly in the case of the failed rear brakes
system. In addition, such a situation does not realistically simulate
failed truck tractor systems since in real-world situations, the
trailer brakes are intact.
g. Burnish Procedure
Even though this rulemaking did not address burnish procedures,
AAMA and HDBMC requested that the Agency indefinitely allow using the
old or the new burnish procedure as an option.
The Agency believes that the effective date for the ``new'' burnish
procedure should be considered in Docket No. 70-27, Notice 33, and
Docket No. 83-07, Notice 5, independently from the stopping distance
effective dates.10 Given that the industry has been aware since
August 1993 that the new burnish procedures would be required after
September 1994, NHTSA believes that vehicle manufacturers have had
sufficient time to conduct any additional testing and to make any
necessary design changes in order to meet the requirements of Standard
No. 121 with the new burnish procedure. Moreover, since the new
procedures have been in effect since September 1, 1994, the issue of
extending the option formerly allowed is moot. Therefore, NHTSA has
decided to terminate the rulemaking on the burnish issue.
\10\ On August 30, 1993, NHTSA issued an interim final rule and
an NPRM addressing whether the old burnish procedures should be
allowed indefinitely (58 FR 45459). Optional compliance with the
``new'' procedures had been permissible since 1988 and was extended
to September 1994. The Agency also proposed extending optional
compliance until March 1996. The Agency requested comments about
whether the new burnish procedures should become the sole specified
procedures or whether the old burnish procedures should be allowed
for an additional period of time.
---------------------------------------------------------------------------
h. Parking Brake Test
AAMA requested that the agency modify the parking brake procedure
in this rulemaking by specifying an initial brake temperature of 150-
200 deg.F, and a ``compounding technique'' for consistency of grade
holding and drawbar procedures. Compounding is described as a full
treadle service brake application preceding the application of the
parking brakes. AAMA claimed that during its testing to respond to the
stopping distance NPRMs, it realized that different manufacturers use
different parking brake test procedures. Therefore, its stated reason
for proposing a change is to avoid having compliance issues arise due
to alleged test procedure ambiguities.
NHTSA has neither addressed this issue in the NPRM nor conducted
research about compounding. Therefore, the Agency has determined that
it would be inappropriate at this time to modify the Standard to
specify such a compounding test procedure. If the Agency were to decide
in the future that it may be desirable to amend the Standard to require
this test condition, it would issue an NPRM to provide the industry and
other interested parties an opportunity to comment about such a
modification.
As discussed above, NHTSA has agreed to AAMA's request to specify
an initial brake temperature of between 150-200 deg.F for the service
brake performance tests. As so modified, the parking brake test
procedure explicitly specifies that the parking brake test be conducted
``under the conditions of S6.1,'' which specifies the initial brake
temperature for the test. Therefore, any ambiguity that allegedly
results from the higher initial brake temperature is no longer present.
C. Threshold Pressure Requirement
In the NPRM, NHTSA proposed to establish a requirement for
threshold pressure11 levels of 6.00.5 psi for truck
tractors and trailers equipped with an air brake system. The Agency
tentatively concluded that such a requirement would improve the brake
balance on combination vehicles and reduce the potential for vehicle
instability when lightly loaded. The Agency requested comments about
the need for establishing threshold pressures and whether the proposed
threshold pressure and its range were appropriate and feasible.
\11\ ``Threshold pressure'' is the brake application pressure at
which the brakes actually begin to generate braking torque.
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All commenters recognized the need to improve tractor trailer
compatibility [[Page 13293]] and supported the intent of the proposed
threshold pressure requirement. However, AAMA, Midland-Grau, and
Rockwell opposed establishing a threshold pressure requirement until
additional research could be conducted.12 The commenters requested
that the Agency not issue such a requirement until a cooperative
industry and government effort can be conducted to better define the
performance and safety improvements of a threshold pressure and
tolerance requirement.
\12\ Only Mr. Robert Crail, a brake engineer, favored adopting a
requirement to improve pressure compatibility between tractors and
trailers.
---------------------------------------------------------------------------
Most commenters believed that selecting a target threshold pressure
value of 6.0 psi, which was approved by the SAE Brake Committee in
1985, would not be realistic for current combination vehicles. In
addition, HDBMC stated that small differences in threshold pressure are
irrelevant to whether a tractor trailer combination can achieve the
prescribed stopping distances. HDBMC noted that SAE Recommended
Practice J1505, ``Brake Force Distribution Test Code'' (May 1985) was
developed primarily to reduce maintenance costs by improving brake drum
and lining life and to enable fleets to standardize threshold
pressures. It further stated that the testing conducted to establish
SAE J1505 was limited to S-Cam brakes and vehicles with a GAWR of
16,000 to 20,000 pounds. S-Cam brakes on larger vehicles, wedge brakes
(which have higher threshold pressures) and disc brakes were not
tested.
Several commenters addressed the threshold pressure level that
should be established if the Agency decided to adopt a threshold
pressure requirement. Mr. Crail recommended that the tolerance range be
increased from 6.00.5 psi to 6.01.0 psi to
accommodate the variation in relay valves, brake chamber return springs
and foundation brake return springs. AAMA stated that a tolerance for
air brake components of 3.73 psi was appropriate. Lucas
suggested a tolerance of +3 psi and that the Agency should apply this
tolerance to only tractor drive axles and trailer axles with 16.5 inch
S-cam drum brakes. ATA recommended a tolerance of between 2 to 11 psi.
After reviewing the comments and other available information, NHTSA
has decided not to establish a pressure threshold requirement at this
time. The Agency notes that additional research and testing needs to be
conducted on this matter since there currently is insufficient
information to set a threshold pressure tolerance for combination
vehicles. The brake components that affect the threshold pressure, such
as internal friction in the relay valves and the return springs in the
brake chamber and foundation brakes, provide a tolerance close to 4
psi. Therefore, establishing a threshold pressure requirement, even
with a broad tolerance, could pose compliance problems for the
industry. In addition, additional research needs to be conducted on
brakes other than S-cam brakes.
NHTSA emphasizes that after additional cooperative testing is
completed, a threshold pressure requirement could be proposed that
would improve the braking performance of a combination vehicle,
particularly at low application pressures typical of normal stops.
D. Requirements for Brake Linings
ATA and Mack Trucks requested that NHTSA issue a rule requiring
replacement brake linings to be of the same quality and have the same
friction characteristics as the linings used by original equipment
manufacturers.
The issue of aftermarket brake linings is the subject of a separate
NHTSA rulemaking action, and will not be addressed by this notice. If
the Agency tentatively concludes that such requirements for aftermarket
brake linings are in the interest of motor vehicle safety, then it will
issue a proposal to adopt such requirements.
E. Implementation Schedule
In the NPRM, NHTSA proposed that the stopping distance requirements
become effective two years after the final rule's publication.
AAMA supported the proposed effective date, provided that the
agency incorporated its recommended modifications in the final rule.
Rockwell recommended that the stopping distance requirements and the
stability performance requirements be combined so that the effective
dates for both rulemakings are concurrent. Several commenters on the
stability and control NPRM, including AAMA, made the same suggestion.
AAMA noted that since ABS can directly influence achievable stopping
distance, it is important to optimize brake system performance by
taking both stopping distance and stability into account.
On April 12, 1994, NHTSA published a supplemental notice of
proposed rulemaking that proposed the following implementation schedule
for both the stopping distance and lateral stability and control
requirements:
Truck tractors--2 years after final rule (1996)
Trailers--3 years after final rule (1997)
Air-braked single unit trucks and buses--3 years after final rule
(1997)
Hydraulic-braked single unit trucks and buses--4 years after final rule
(1998). (59 FR 17326).
The Agency reasoned that making the effective dates for the two
rulemakings concurrent would promote a more orderly implementation
process, avoid the need for manufacturers to redesign the brakes on
individual vehicles twice, and reduce the development and compliance
costs that manufacturers would face as a result of these regulations.
NHTSA requested comments about the implementation schedule proposed in
the supplemental notice.
As the stability and control final rule discusses in detail in the
section titled ``implementation schedule,'' NHTSA has decided to adopt
an implementation schedule similar to the one proposed in the SNPRM.
Specifically, truck tractors manufactured on or after March 1, 1997
will have to be equipped with ABS and comply with the braking-in-a-
curve test and high coefficient of friction stopping distance
requirements; trailers and single-unit air-braked trucks and buses
manufactured on or after March 1, 1998 will have to be equipped with
ABS, and, except for trailers, comply with the high coefficient of
friction stopping distance requirements; and hydraulic-braked trucks
and buses manufactured on or after March 1, 1999 will have to be
equipped with ABS and comply with the high coefficient of friction
stopping distance requirements. The Agency has decided that these
effective dates, which were widely supported by vehicle manufacturers,
brake manufacturers, and safety advocacy groups, will provide for an
efficient implementation of the heavy vehicle braking rulemakings.
F. Intermediate and Final Stage Manufacturers/Trailer Manufacturers
Vehicle manufacturers must certify that each of their vehicles
complies with all applicable Federal motor vehicle safety standards.
While this statutory certification requirement is straightforward with
respect to vehicles produced by a single manufacturer, it is more
complex for vehicles produced in two or more stages. With such
multistage vehicles, one or more manufacturers produce an ``incomplete
vehicle'' which requires further manufacturing operations by another
manufacturer to become a completed vehicle. As defined in 49 CFR 568.3,
an incomplete vehicle includes, at a [[Page 13294]] minimum, a frame
and chassis structure, power train, steering system, suspension system,
and braking system. Incomplete vehicles may be grouped in two
categories: (1) Chassis-cabs (which are incomplete vehicles with fully
completed occupant compartments that require only the addition of
cargo-carrying, work-performing, or load-bearing components to perform
their intended functions and become completed vehicles (49 CFR 567.3))
which are certified by the chassis-cab manufacturer (49 CFR 567.5), and
(2) incomplete vehicles other than chassis-cabs (``non chassis-cabs''),
which are not certified by the incomplete vehicle manufacturer.
The National Truck Equipment Association (NTEA) commented that
manufacturers of multi-stage vehicles may not be able to demonstrate
compliance with the proposed amendments because they may not be able,
in all cases, to ``pass through'' the incomplete vehicle manufacturer's
certification. NTEA claims that these manufacturers will not have a
practicable and objective means of demonstrating compliance, since they
lack the financial resources and capabilities to sponsor testing to the
requirements. Therefore, NTEA suggested that the Agency exclude multi-
stage vehicles from the proposed road testing requirements.
As explained below, NHTSA has concluded that the stopping distance
requirements do not pose an unreasonable burden for final stage
manufacturers. NHTSA is aware of the concerns of final stage
manufacturers about road testing their vehicles. However, the final
stage manufacturers can avoid the necessity of conducting independent
testing by staying within the limits (``the envelope'') set by the
incomplete vehicle manufacturer. In fact, S6 of Standard No. 121
currently provides that ``Compliance of vehicles manufactured in two or
more stages may, at the option of the final-stage manufacturer, be
demonstrated to comply with this standard by adherence to the
instructions of the incomplete manufacturer provided with the vehicle
in accordance with Sec. 568.4(a)(7)(ii) and Sec. 568.5 of title 49 of
the Code of Federal Regulations.''13 In the final rule adding this
provision in response to the 9th Circuit's decision in PACCAR, the
Agency stated that it provides directly in the regulation ``an
alternative to road testing * * * that would constitute `due care' in
certification by any final-stage manufacturer that adopted it, whatever
its resources and engineering expertise.'' (43 FR 48646, October 19,
1978.)
\13\ In today's Federal Register notice amending Standard No.
105 with respect to stopping distances of hydraulically-braked
vehicles, the Agency is also modifying that Standard to include
identical language about compliance by final stage manufacturers so
that this concept expressly applies to hydraulic-braked vehicles
manufactured in two or more stages, as well.
---------------------------------------------------------------------------
With respect to chassis-cabs, the name of each manufacturer in the
chain of production is required to appear on one or more certification
labels that are permanently affixed to the vehicle. (49 CFR Parts 567
and 568.) Under these regulations, certification of an incomplete
vehicle that is a chassis-cab can ``pass through'' to the final stage
manufacturer, provided that the final stage manufacturer takes the
precautions necessary to ensure it does not invalidate the
certification. The final stage manufacturer must ensure that it
completes the vehicle without exceeding the GVWR and GAWRS assigned by
the chassis-cab manufacturer, altering any brake system component,
moving the center of gravity of the completed vehicle with the body
installed outside the ``envelope'' of specifications provided by the
chassis manufacturer, or otherwise violating that envelope. If the
final stage manufacturer complies with all of the chassis-cab
manufacturer's specifications, the final stage manufacturer can base
its certification of compliance with the braking standard entirely upon
the statement of the chassis-cab manufacturer and therefore will not
have to recertify the vehicle.
The provision in S6 also applies to non-chassis-cabs, since the
manufacturer of a non-chassis-cab is required to furnish documentation
that indicates a means of compliance with applicable standards to
intermediate or final stage manufacturers (49 CFR 568.4), and the final
stage manufacturer is required to identify the incomplete manufacturer
on the certification label that the final stage manufacturer places on
the completed vehicle. As with chassis-cabs, the final stage
manufacturer can avoid the necessity of conducting independent testing
by staying within the envelope set by the incomplete manufacturer.
Based on the above considerations, the final stage manufacturer
would only be required to certify compliance independently in those
cases in which the final vehicle violates those specifications. NTEA
commented that there are situations in which the final stage
manufacturer ``must exceed the `envelope' of restrictions provided by
the chassis manufacturer due to customer specifications.'' The Agency
believes that in virtually all such cases the body or equipment that is
specified by the customer could be fitted on a different truck chassis
having a larger ``envelope''. Moreover, when the customer has an
overriding need to specify a particular truck chassis that cannot be
completed with the desired body or equipment without exceeding the
envelope, it is reasonable to expect the customer to bear the
additional cost burden of assuring that the completed vehicle complies
with the standard. In such situations, it is reasonable to require the
final stage manufacturer to accept responsibility for certification,
given the important safety concerns discussed below. The Agency
emphasizes, however, that it is not necessary for final stage
manufacturers to make this choice. They can instead select an
appropriate incomplete vehicle that can be completed without departing
from the envelope specified by the incomplete vehicle manufacturer.
Some of the manufacturers that build multi-stage vehicles and
choose not to stay within the envelope are small businesses that may be
unable to conduct their own road tests. While manufacturers must
certify that their vehicles meet all applicable safety standards, this
does not mean that every final stage manufacturer must independently
conduct the specific tests set forth in an applicable standard. A final
stage manufacturer may also certify compliance to the stopping distance
standard based on, among other things, engineering analyses and
computer simulations. Moreover, manufacturers need not conduct these
operations themselves. They can utilize the services of independent
engineers and testing laboratories. They can also join together through
trade associations to sponsor testing or analysis. Finally, they can
rely on testing and analysis performed by other parties, including
brake manufacturers. Brake manufacturers typically perform extensive
analyses and tests of their products and, in order to sell those
products, have a strong incentive to provide their customers, the
vehicle manufacturers, with information that can be used to certify the
vehicle to the applicable brake standards. Some manufacturers of motor
vehicle components currently provide this type of information to
vehicle manufacturers. Based on the above considerations, NHTSA has
concluded that manufacturers can certify compliance with the stopping
distance requirements by means other than road testing.
Moreover, road testing to establish compliance with the braking
requirements does not involve expensive and destructive crash testing,
which cost $18,000 or more, not [[Page 13295]] including the cost of
the vehicle which is destroyed as a result of the test. Thus, while
brake testing does involve some expense (the Agency estimates that a
complete compliance test series for Standard No. 121 would cost
$5,000), it should be feasible for manufacturers, including small
manufacturers (especially in groups or through associations), to
certify compliance, particularly since the road testing does not
require destruction of their vehicles.
Furthermore, NHTSA is not authorized when establishing safety
standards to differentiate between manufacturers on the basis of their
size or financial resources. While the agency must ``consider whether
any such proposed standard is reasonable, practicable and appropriate
for the particular type of motor vehicle or motor vehicle equipment for
which it is prescribed,'' (49 U.S.C. 30111(b)(3), formerly section
103(f)(3) of the Vehicle Safety Act), the legislative history of the
Vehicle Safety Act reveals that any differences between standards for
different classes of vehicles ``of course [are to] be based on the type
of vehicle rather than its place of origin or any special circumstances
of its manufacturer.'' S. Rept. 1301, 2 U.S. Code, Cong. & Admin. News,
2714 (1966), cited in Chrysler Corp. v. D.O.T., 472 F.2d 659, 679 (6th
Cir. 1972).
Strong policy reasons underlie Congress' refusal to differentiate
between vehicles on the basis of the manufacturers' ``special
circumstances.'' To protect unsuspecting members of the public from
exposure to unreasonable risks posed by unsafe vehicles, there is good
reason to require that every vehicle meet all ``minimum performance
standards'' that are prescribed for vehicles of its type.
Moreover, the statute does not authorize NHTSA to grant permanent
exemptions from safety standards to small manufacturers who otherwise
would be covered by those standards. See Nader v. Volpe, 475 F.2d 916,
918 (D.C. Cir. 1973). While Nader involved a single manufacturer that
sought to be permanently exempted from safety standards, its reasoning
applies equally to classes of manufacturers that seek such exemptions.
Although the Safety Act was amended after the Nader decision to permit
small manufacturers to seek temporary exemptions from safety standards
if they can demonstrate that compliance with the standard would cause
them ``substantial economic hardship'' and that they have made a good
faith effort to comply (49 U.S.C. 30113, formerly section 123 of the
Vehicle Safety Act), Congress has severely restricted the agency's
authority to grant such exemptions to very narrow, limited
circumstances. NTEA is in effect seeking a permanent exemption from
Standard No. 121 that the statute does not permit.
NHTSA emphasizes that there are important safety reasons that
necessitate having a final stage manufacturer certify the completed
vehicle if it does not stay within the envelope set by the incomplete
vehicle manufacturer. For instance, if a final stage manufacturer adds
additional components so that the completed vehicle's GVWR exceeds the
recommended maximum GVWR weight specified in the envelope for the
vehicle, the vehicle's braking performance could be adversely affected.
As an example, a brake system designed to bring a 15,000 pound vehicle
to a stable and short stop would obviously not be able to safely stop a
20,000 pound vehicle. Moreover, the brakes on such an underbraked
vehicle would be prone to overheating. While it is relatively easy to
understand the degradation in performance in such a gross example, the
potential for reduced, safety-related performance also exists in
situations were the ``violation'' of the envelope is much smaller.
Similarly, if the center of gravity is made too high, a vehicle would
likely be overbraked on its rear axle(s) and thus be prone to
instability caused by wheel lockup.
NHTSA emphasizes that the kinds of crashes that result when a heavy
vehicle is unable to stop to avoid another vehicle are very serious. As
part of the cost effectiveness analysis contained in the Final Economic
Analysis (FEA) for this final rule, the agency used 1992 GES data to
identify a group of crashes involving heavy vehicles defined as
``unable-to-stop-in-time'' crashes. The agency examined these crashes
and the number and severity of the resulting injuries in evaluating the
impact of this regulation. One means of comparing the relative severity
of various types of crashes is to ``convert'' the injuries at different
levels of severity into ``equivalent fatalities''\14\ and to divide
that by the number of crashes that resulted in those injuries. The
resulting ratio, equivalent fatalities per crash, can be calculated for
various types of crashes and compared to indicate the relative severity
of different crash types. Using 1992 GES data, estimates were made of
the equivalent fatalities per crash for multiple-vehicle crashes
involving all types of vehicles, 0.01402 equivalent fatalities per
crash, for multiple-vehicle crashes involving heavy vehicles, 0.02089
equivalent fatalities per crash, and for the ``unable-to-stop-in-time''
crashes mentioned above, 0.03634. Comparing the rates of equivalent
fatalities indicate that not only are multiple-vehicle crashes
involving heavy vehicles 49% more severe than all multiple-vehicle
crashes, but the ``unable-to-stop-in-time'' crashes, which are the
types of crashes affected by this final rule, are 159% more severe than
all multiple-vehicle crashes in general. Also using 1992 GES data, the
agency made separate estimates of the rate of equivalent fatalities per
crash for the heavy vehicle occupants and the occupants of other
involved vehicles. This was done for both multiple-vehicle crashes
involving heavy vehicles and for the ``unable-to-stop-in-time''
crashes. The comparison of these rates shows that the ``unable-to-stop-
in-time'' crashes are 31% more severe in terms of injuries to the heavy
vehicle occupant and 79% more severe for the occupants of other
involved vehicles than multiple-vehicle crashes involving heavy
vehicles.
\14\The basic methodology used to convert injuries at various
levels of severity into equivalent fatalities is outlined in the FEA
for this final rule.
---------------------------------------------------------------------------
G. Costs
As explained in detail in the FEA, the costs associated with the
rulemaking involve additional testing costs and hardware/equipment
costs. The agency estimates the minimum initial testing costs
associated with reinstating stopping distance requirements for all
heavy air-braked vehicles would be about $6 million. As noted in the
FEA, the estimated annual compliance testing costs in years following
the effective dates of this final rule are estimated to be about $2
million. Assuming the industry continues to produce about 208,500 heavy
Class 5-8 air-braked vehicles per year (which are the largest heavy
vehicles and tractor trailers), the initial testing cost per vehicle
would be about $29 and for later years the testing cost per vehicle
would be about $10.
The hardware and equipment costs of meeting the proposed stopping
distance requirements for air braked heavy vehicles are based on the
anticipated improvements to heavy vehicles. The agency notes that all
of the changes made to meet these requirements would affect vehicles
operating in the fully loaded, or nearly fully loaded configurations.
These improvements in braking performance, which are achieved by
substituting air chambers, slack adjusters and brake linings, are
estimated to be necessary on about 104,000 air-braked vehicles,
including both truck tractors and single-unit trucks. The average cost
per vehicle of [[Page 13296]] these changes is estimated to be $50,
resulting in a total cost of $5.21 million, which is the total
estimated cost for vehicle modifications necessitated by this final
rule.
The total estimated initial cost impact of this proposal is $11.21
million ($6.0 million in compliance test costs plus $5.21 million in
vehicle modification costs), which for an estimated annual production
of 208,500 air-braked equipped vehicles, is an average of about $54 per
vehicle.
The total estimated outyear cost impact of this proposal is $7.21
million ($2.0 million in compliance test costs plus $5.21 million in
vehicle modification costs), which for an estimated annual production
of 208,500 air braked equipped vehicles, is an average of about $35 per
vehicle.
VI. Rulemaking Analyses and Notices
A. Executive Order 12866 and DOT Regulatory Policies and Procedures
This rulemaking document was not reviewed under E.O. 12866. NHTSA
has considered the impact of this rulemaking action under the
Department of Transportation's regulatory policies and procedures. This
action has been determined to be not ``significant'' under those
policies and procedures.
A FEA setting forth the agency's detailed analysis of the benefits
and costs of this rulemaking (along with the other rules issued today)
has been prepared and been placed in the docket. This rulemaking is
based on the FEA and all additional data available to the agency. The
Agency estimates that reinstating the stopping distance requirements
for Standard No. 121 will result in an average of approximately 3.2
lives saved per year and 84 injuries prevented per year. As mentioned
above, the agency estimates that the initial annual costs attributable
to these requirements are approximately $11.21 million ($6.00 million
for compliance testing and $5.21 million for net equipment costs) and
the outyear annual costs attributable to these requirements are
approximately $7.21 million ($2.00 million for compliance testing and
$5.21 million for net equipment costs).
Based on its analysis, the agency concludes that the requirements
will improve safety by ensuring that all heavy vehicles are capable of
stopping within a specified, safe distance. Based on information
detailed in the previous section, the agency believes that implementing
the stopping distance requirements for heavy vehicles will not result
in significant costs since most of these vehicles currently comply with
the reinstated requirements. For those vehicles that do not currently
comply with the requirements, the agency believes that they could be
upgraded by substituting other with currently produced braking
components for those now used on these vehicles.
Since these components are not significantly more expensive than
those used in poorer performing brake systems, the net cost of
substituting these components will not be significant and is estimated
to be about $50 for each vehicle that requires such changes.
B. Regulatory Flexibility Act
NHTSA has also considered the impacts of this notice under the
Regulatory Flexibility Act. I hereby certify that this rule will not
have a significant economic impact on a substantial number of small
entities. There may be a small number of intermediate and final stage
manufacturers that are small businesses that may be impacted by this
final rule, but as discussed previously, the Agency does not believe
that that impact is substantial, particularly in comparison to the
possible crash-related consequences of vehicles produced by such
manufacturers not complying with the rule.
C. Paperwork Reduction Act
In accordance with the Paperwork Reduction Act of 1980 (P.L. 96-
511), there are no requirements for information collection associated
with this rule.
D. National Environmental Policy Act
NHTSA has also analyzed this rule under the National Environmental
Policy Act and determined that it will not have a significant impact on
the human environment. No changes in existing production or disposal
processes will result, except that there is a reduction in these
factors resulting from the removal of the ALV. There will be a weight
increase of a few pounds per tractor with the installation of a BPV on
tractors, but such a small increase should not have any significant
effect on fuel consumption. Nor should production and disposal
processes have a significant adverse affect on the environment.
E. Executive Order 12612 (Federalism)
NHTSA has analyzed this rule in accordance with the principles and
criteria contained in E.O. 12612, and has determined that this rule
will not have significant federalism implications warranting the
preparation of a Federalism Assessment.
F. Civil Justice Reform
This final rule does not have any retroactive effect. Under 49
U.S.C. 30103, 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. 49 U.S.C. 30161 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.
List of Subjects in 49 CFR Part 571
Imports, Motor vehicle safety, Motor vehicles, Rubber and rubber
products, Tires.
In consideration of the foregoing, this notice amends Standard No.
121, Air Brake Systems, in Title 49 of the Code of Federal Regulations
at Part 571 as follows:
PART 571--[AMENDED]
1. The authority citation for Part 571 continues to read as
follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166,
delegation of authority at 49 CFR 1.50.
Sec. 571.121 [Amended]
2. Section 571.121, is amended by removing the undesignated text
following paragraph (g) in S3; in S4 by adding the definition for
``Wheel lockup;'' by revising S5.3.1, S5.3.1.1, and Table II; by
deleting S5.3.2, S5.3.2.1, and S5.3.2.2; by reserving S5.3.2, and by
revising S5.7.1 to read as follows:
* * * * *
Wheel lockup means 100 percent wheel slip.
* * * * *
S5.3.1 Stopping distance--trucks and buses. When stopped six times
for each combination of vehicle type, weight, and speed specified in
S5.3.1.1, in the sequence specified in Table I, each truck tractor
manufactured on or after March 1, 1997 and each single unit vehicle
manufactured on or after March 1, 1998 shall stop at least once in not
more than the distance specified in Table II, measured from the point
at which movement of the service brake control begins, without any part
of the vehicle leaving the roadway, and with wheel lockup permitted
only as follows: [[Page 13297]]
(a) At vehicle speeds above 20 mph, any wheel on a nonsteerable
axle other than the two rearmost nonliftable, nonsteerable axles may
lock up, for any duration. The wheels on the two rearmost nonliftable,
nonsteerable axles may lock up according to (b).
(b) At vehicle speeds above 20 mph, one wheel on any axle or two
wheels on any tandem may lock up for any duration.
(c) At vehicle speeds above 20 mph, any wheel not permitted to lock
in (a) or (b) may lock up repeatedly, with each lockup occurring for a
duration of one second or less.
(d) At vehicle speeds of 20 mph or less, any wheel may lock up for
any duration.
Table I.--Stopping Sequence
1. Burnish.
2. Stops with vehicle at gross vehicle weight rating:
(a) 60 mph service brake stops on a peak friction coefficient surface
of 0.9, for a truck tractor with a loaded unbraked control trailer,
or for a single-unit vehicle.
(b) 30 mph service brake stops on a peak friction coefficient surface
of 0.5, for a truck tractor with a loaded unbraked control trailer.
(c) 60 mph emergency brake stops on a peak friction coefficient
surface of 0.9, for a single-unit vehicle. Truck tractors are not
required to be tested in the loaded condition.
3. Parking brake test with vehicle loaded to GVWR.
4. Stops with vehicle at unloaded weight plus up to 500 lbs.
(a) 60 mph service brake stops on a peak friction coefficient surface
of 0.9, for a truck tractor or for a single-unit vehicle.
(b) 30 mph service brake stops on a peak friction coefficient surface
of 0.5, for a truck tractor.
(c) 60 mph emergency brake stops on a peak friction coefficient
surface of 0.9, for a truck tractor or for a single-unit vehicle.
5. Parking brake test with vehicle at unloaded weight plus up to 500
lbs.
6. Final inspection of service brake system for condition of adjustment.
S5.3.1.1 Stop the vehicle from 60 mph on a surface with a peak
friction coefficient of 0.9 with the vehicle loaded as follows: (a)
loaded to its GVWR, (b) in the Bobtail configuration (truck-tractors
only) plus up to 500 pounds, and (c) at its unloaded vehicle weight
(except for a truck tractor) plus up to 500 pounds (including driver
and instrumentation). If the speed attainable in two miles is less than
60 mph, the vehicle shall stop from a speed in Table II that is 4 to 8
mph less than the speed attainable in 2 miles.
Table II.--Stopping Distance
[In feet]
Service brake Emergency brake
Vehicle speed in miles per hour -----------------------------------------------------
PFC 0.9 PFC 0.9 PFC 0.9 PFC 0.9 PFC 0.9 PFC 0.9
(1) (2) (3) (4) (5) (6)
----------------------------------------------------------------------------------------------------------------
20........................................................ 32 35 38 40 83 85
25........................................................ 49 54 59 62 123 131
30........................................................ 70 78 84 89 170 186
35........................................................ 96 106 114 121 225 250
40........................................................ 125 138 149 158 288 325
45........................................................ 158 175 189 200 358 409
50........................................................ 195 216 233 247 435 504
55........................................................ 236 261 281 299 520 608
60........................................................ 280 310 335 355 613 720
Note: (1) Loaded and unloaded buses; (2) Loaded single unit trucks; (3) Unloaded truck tractors and single unit
trucks; (4) Loaded truck tractors tested with an unbraked control trailer; (5) All vehicles except truck
tractors; (6) Unloaaded truck tractors.
* * * * *
S5.7.1 Emergency brake system performance. When stopped six times
for each combination of weight and speed specified in S5.3.1.1, except
for a loaded truck tractor with an unbraked control trailer, on a road
surface having a PFC of 0.9, with a single failure in the service brake
system of a part designed to contain compressed air or brake fluid
(except failure of a common valve, manifold, brake fluid housing, or
brake chamber housing), the vehicle shall stop at least once in not
more than the distance specified in Column 5 of Table II, measured from
the point at which movement of the service brake control begins, except
that a truck-tractor tested at its unloaded vehicle weight plus up to
500 pounds shall stop at least once in not more than the distance
specified in Column 6 of Table II. The stop shall be made without any
part of the vehicle leaving the roadway.
* * * * *
Issued on: March 1, 1995.
Ricardo Martinez, M.D.
Administrator.
[FR Doc. 95-5413 Filed 3-7-95; 8:45 am]
BILLING CODE 4910-59-P
