Federal Motor Vehicle Safety Standards; Air Brake Systems, 44829-44834 [2011-18929]
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Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Rules and Regulations
§ 74.794
Digital emissions.
(a) (1) An applicant for a digital LPTV
or TV translator station construction
permit shall specify that the station will
be constructed to confine out-of-channel
emissions within one of the following
emission masks: Simple, stringent or
full service.
(2) * * *
(iii) Full service mask: (A) The power
level of emissions on frequencies
outside the authorized channel of
operation must be attenuated no less
than the following amounts below the
average transmitted power within the
authorized channel. In the first 500 kHz
from the channel edge the emissions
must be attenuated no less than 47 dB.
More than 6 MHz from the channel
edge, emissions must be attenuated no
less than 110 dB. At any frequency
between 0.5 and 6 MHz from the
channel edge, emissions must be
attenuated no less than the value
determined by the following formula:
Attenuation in dB = ¥11.5([Delta]f +
3.6);
Where:
[Delta] f = frequency difference in MHz from
the edge of the channel.
(B) This attenuation is based on a
measurement bandwidth of 500 kHz.
Other measurement bandwidths may be
used as long as appropriate correction
factors are applied. Measurements need
not be made any closer to the band edge
than one half of the resolution
bandwidth of the measuring instrument.
Emissions include sidebands, spurious
emissions and radio frequency
harmonics. Attenuation is to be
measured at the output terminals of the
transmitter (including any filters that
may be employed). In the event of
interference caused to any service,
greater attenuation may be required.
*
*
*
*
*
■ 12. Section 74.798 is added to subpart
G to read as follows:
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§ 74.798 Digital television transition
notices by broadcasters.
(a) Each low power television, TV
translator and Class A television station
licensee or permittee must air an
educational campaign about the
transition from analog broadcasting to
digital television (DTV).
(b) Stations that have already
terminated analog service and begun
operating in digital prior to effective
date of this rule shall not be subject to
this requirement.
(c) Stations with the technical ability
to locally-originate programming must
air viewer notifications at a time when
the highest number of viewers is
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watching. Stations have the discretion
as to the form of these notifications.
(d) Stations that lack the technical
ability to locally-originate programming,
or find that airing of viewer
notifications would pose some sort of a
hardship, may notify their viewers by
some other reasonable means, e.g.
publication of a notification in a local
newspaper. Stations have discretion as
to the format and time-frame of such
local notification.
[FR Doc. 2011–18742 Filed 7–26–11; 8:45 am]
BILLING CODE 6712–01–P
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety
Administration
49 CFR Part 571
[Docket No. NHTSA–2009–0175]
RIN 2127–AK84
Federal Motor Vehicle Safety
Standards; Air Brake Systems
National Highway Traffic
Safety Administration (NHTSA),
Department of Transportation.
ACTION: Final rule; response to petitions
for reconsideration.
AGENCY:
On July 27, 2009, NHTSA
published a final rule that amended the
Federal motor vehicle safety standard
for air brake systems by requiring
substantial improvements in stopping
distance performance on new truck
tractors. In response, the agency
received eight petitions for
reconsideration. The agency has already
responded to most of the issues raised
in the petitions. This document
responds to the one outstanding issue
raised in the petitions, stopping
distance performance requirements at
lower initial speeds. Based on testing
results and our concern that the current
requirements might not be practicable,
NHTSA is slightly relaxing the stopping
distance requirement for typical loaded
tractors tested from an initial speed of
20 mph by increasing the distance from
30 feet to 32 feet and for unloaded
tractors tested from an initial speed of
20 mph by increasing the distance from
28 feet to 30 feet. We believe no other
changes are necessary.
DATES: This final rule is effective August
1, 2011.
Petitions for reconsideration must be
received not later than September 12,
2011.
SUMMARY:
Petitions for reconsideration
should refer to the docket number and
ADDRESSES:
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44829
must be submitted to: Administrator,
National Highway Traffic Safety
Administration, 1200 New Jersey
Avenue, SE., Washington, DC 20590.
FOR FURTHER INFORMATION CONTACT: For
technical issues, you may contact Jeffrey
Woods, Office of Crash Avoidance
Standards, by telephone at (202) 366–
6206, and by fax at (202) 366–7002.
For legal issues, you may contact
David Jasinski, Office of the Chief
Counsel, by telephone at (202) 366–
2992, and by fax at (202) 366–3820.
You may send mail to both of these
officials at the National Highway Traffic
Safety Administration, 1200 New Jersey
Avenue, SE., Washington, DC 20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Background of the Stopping Distance
Requirement
II. Petitions for Reconsideration
III. Testing Program
IV. Response to Petition
V. Technical Correction
VI. Effective Date
VII. Rulemaking Analyses and Notices
VIII. Regulatory Text
I. Background of the Stopping Distance
Requirement
On July 27, 2009, NHTSA published
a final rule in the Federal Register
amending Federal Motor Vehicle Safety
Standard (FMVSS) No. 121, Air Brake
Systems, to require improved stopping
distance performance for heavy truck
tractors.1 This rule reduced the
maximum allowable stopping distance,
from 60 mph, from 355 feet to 250 feet
for the vast majority of loaded heavy
truck tractors. For a small minority of
loaded very heavy tractors, the
maximum allowable stopping distance
was reduced from 355 feet to 310 feet.
Having come to the conclusion that
modifications needed for ‘‘typical threeaxle tractors,’’ to meet the improved
requirements were relatively
straightforward, NHTSA provided two
years lead time for those vehicles to
comply with the new requirements.
These typical three-axle tractors
comprise approximately 82 percent of
the total fleet of heavy tractors. The
agency concluded that other tractors,
which are produced in far fewer
numbers and may need additional work
to ensure stability and control while
braking, would need more lead time to
meet the requirements. Due to extra
time needed to design, test, and validate
these vehicles, which included two-axle
tractors and severe service tractors, the
agency allowed four years lead time for
1 74 FR 37122; Docket No. NHTSA–2009–0083–
0001.
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Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Rules and Regulations
these tractors to meet the improved
stopping distance requirements.
Requirements in FMVSS No. 121
provide that if the speed attainable by
a vehicle in two miles is less than 60
mph, the speed at which the vehicle
shall meet the specified stopping
distances is four to eight mph less than
the speed attainable in two miles. In the
July 2009 final rule, the agency used an
equation to derive the required stopping
distances for vehicles with initial
speeds of less than 60 mph.2
St = (1⁄2 Vo tr) + ((1⁄2) Vo2/af)—((1⁄24) af tr2)
Where:
St = Total stopping distance in feet
Vo = Initial Speed in ft/sec
tr = Air pressure rise time in seconds
af = Steady-state deceleration in ft/sec2
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For the final rule, the agency selected
an air pressure rise time of 0.45 seconds,
which is equal to the brake actuation
timing requirement in FMVSS No. 121.
The steady-state deceleration was based
on an theoretical deceleration curve in
which vehicle deceleration would
increase linearly during the rise time
portion of the stopping event, followed
by constant steady-state deceleration,
followed by an instantaneous decrease
in acceleration back to zero at the
completion of the stop. Table II in
FMVSS No. 121 sets forth the stopping
distance requirements for speeds from
60 mph down to 20 mph (in increments
of 5 mph) for both typical and severe
service tractors in the loaded conditions
and all tractors in the unloaded
condition derived using that formula.
II. Petitions for Reconsideration
NHTSA received eight timely
petitions for reconsideration in response
to the final rule. Separate petitions were
received from the Truck Manufacturers
Association (TMA); the Heavy Duty
Brake Manufacturers Council of the
Heavy Duty Manufacturers Association
(HDBMC); Bendix Spicer Foundation
Brake LLC (Bendix), a joint venture
between Bendix Commercial Vehicle
Systems and Dana Corporation; and
ArvinMeritor. The agency received four
additional petitions supporting and
incorporating the TMA petition by
reference from Daimler Trucks North
America (Daimler), Kenworth Truck
Company (Kenworth), Peterbilt Motors
Company (Peterbilt), and Navistar Truck
Group (Navistar).
The petitions focused on four main
issues. The main issues included the
stopping distance requirements for
reduced speeds, the omission of fouraxle tractors under 59,600 pounds gross
2 The complete derivation for this equation was
included in the docket. See Docket No. NHTSA–
2005–21462–0039, at 18–22.
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vehicle weight rating (GVWR) from the
listed requirements and the date at
which the improved stopping distance
requirements should apply to those
tractors, the manner in which NHTSA
characterized the typical three-axle
tractor, and the fuel tank fill level
testing specification. Additionally, the
petitioners requested that NHTSA
correct some typographical errors in the
regulatory text.
In a final rule published in the
Federal Register on November 13, 2009,
the agency addressed all of the issues
raised in the petition, except those
related to stopping distance
requirements at reduced speeds.3 We
addressed the other issues first because
the agency omitted lead time
requirements for tractors with four or
more axles and a GVWR of 59,600
pounds or less, which would have
inadvertently required those vehicles to
comply with the upgraded stopping
distance requirements on November 24,
2009. The November 2009 final rule
responded to issues raised in the
petition with these amendments: (1) The
agency accepted the recommendation of
petitioners TMA, HDBMC, and Bendix
and required compliance with the
improved stopping distance
requirements for tractors with four or
more axles and a GVWR of 59,600
pounds or less by August 1, 2013,
thereby giving four years of lead time;
(2) the agency revised the definition of
a ‘‘typical three-axle tractor’’ in the
regulatory text in response to concerns
raised by TMA and ArvinMeritor to
include three-axle tractors having a steer
axle gross axle weight rating (GAWR) of
14,600 pounds or less and a combined
drive axle GAWR of 45,000 pounds or
less; (3) the agency removed the fuel
tank loading specification from the test
procedure in response to TMA’s
petition; (4) the agency made two
typographical corrections identified by
all petitioners.4
TMA, HDBMC, and Bendix each
raised issues in their petitions regarding
stopping distance requirements at
reduced test speeds. TMA, HDBMC, and
Bendix each stated that the new
stopping distance requirements from
speeds lower than 60 mph have not
been validated through actual vehicle
test data. In addition, the agency
received a comment on the November
2009 final rule from Crystal Vangorder,
which supported this assertion. TMA
and Ms. Vangorder requested that the
3 74 FR 58562; Docket No. NHTSA–2009–0175–
0001.
4 The agency made further correcting
amendments to correct an omission in the
November 2009 final rule. See 75 FR 15620 (Mar.
30, 2010); Docket No. 2009–0175–0004.
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agency withdraw the reduced stopping
distance requirements from speeds
lower than 60 mph until test data has
been obtained.
Although HDBMC reviewed NHTSA’s
calculations and assumptions set forth
in the preamble to the final rule and
agreed with the technical approach
taken, HDBMC nevertheless stated that
the brake timing may be too fast for
some vehicle configurations. HDBMC
made reference to its own prior
comments on the agency’s reduced
stopping distance rulemaking in which
it provided tables showing how brake
timing affects stopping distance.5
HDBMC noted that high braking torques
can occur prior to load transfer, which
may cause deep cycling of the antilock
brake system (ABS) resulting in slightly
longer stopping distance. Bendix also
stated that differing opinions on axle
response time and average deceleration
left the results of the calculations open
to speculation. HDBMC noted that
limited initial testing data by its
members showed that vehicle are close
to meeting or are not meeting the
stopping distance from 20 mph of 30
feet within a 10 percent margin.
TMA and HDBMC both stated that
their members were conducting testing
and would provide the agency with data
to supplement any agency testing.
However, no test data has been provided
to the agency.
III. Testing Program
In response to the petitions, NHTSA
conducted testing to evaluate the
stopping distance performance of a
truck tractor from initial test speeds
between 20 and 60 mph. The purpose of
the testing was to acquire test data that,
as stated in the petitions for
reconsideration to the July 2009 final
rule, had not been available to confirm
that the new stopping distance
requirements from speeds less than 60
mph could be achieved. The test
program and results are described in the
technical report, ‘‘Experimental
Measurement of the Stopping
Performance of a Tractor-Semitrailer
from Multiple Speeds.’’ 6
The test plan was to evaluate a tractor
that, when tested while traveling at a
speed of 60 mph, met the reduced
tractor stopping distance requirement of
250 feet for vehicles loaded to GWVR
without any margin. That same tractor
was then tested at lower initial speeds
to compare actual test results with the
new requirements in Table II of FMVSS
5 See
Docket No. NHTSA–2005–21462–0020.
HS 811 488, available at https://
www.nhtsa.gov/DOT/NHTSA/NVS/Vehicle
Research & Test Center (VRTC)/ca/811488.pdf,
Docket No. NHTSA–2009–0175–0005.
6 DOT
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No. 121. The test was also conducted in
a lightly loaded vehicle weight
condition with no trailer attached.
The agency used a 1991 Volvo 6x4
tractor with a 190-inch wheelbase,
equipped with a hybrid disc brake
configuration. The vehicle was used in
the agency’s research to support the
reduced stopping distance rulemaking,
and was chosen because it was expected
to have close to a 250-foot stopping
distance when tested from 60 mph in
the loaded condition. During actual
testing, the vehicle was found to have a
minimum stopping distance of 249 feet
when loaded to GVWR (i.e., the shortest
stop in a series of six stops).7 However,
the vehicle had not been operated for
several years and when the vehicle was
recommissioned for this test program,
the agency found it necessary to adjust
the amount of the ballast load of the
vehicle by lowering it to a modified
GVWR in order to achieve consistent
stopping distance of 250 feet from 60
mph.8 This modified GVWR was used
for the rest of the testing program.
The agency considered using a newer
vehicle and adding ballast to increase
the stopping distance of the vehicle to
250 feet. However, the agency decided
not to follow this approach because it
could have resulted in unusually high
brake temperatures and brake fade
effects or changes in the brake lining
friction characteristics. The agency
believed it would be better to remove
weight from a worse-performing tractor
rather than adding weight to a betterperforming tractor.
A series of six stops was then
conducted for the loaded tractor at
initial speeds ranging from 60 mph
down to 20 mph in five-mph
increments. The average of each six-stop
series was compared to the new
requirements in column (3) of Table II
of FMVSS No. 121. The results
indicated that from initial speeds below
60 mph, the vehicle could achieve
slightly better stopping distances than
those in Table II, except at the lowest
test speed of 20 mph. From an initial
speed of 20 mph, the tractor loaded to
the modified GVWR achieved an
average stopping distance of 31.2 feet,
compared to the FMVSS No. 121
stopping distance requirement of 30
feet.
The test series was then repeated in
the unloaded (bobtail) condition. For
this test series, the agency was unable
7 Repairs were necessary to this vehicle in order
to meet the 0.45 second brake application timing
requirement.
8 The tractor’s GVWR was 50,000 pounds. The
load necessary to meet the 250-foot stopping
requirement with the control trailer attached was
42,840 pounds.
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to devise a practical way of adjusting
the tractor’s braking performance to
provide a zero percent margin of
compliance at 60 mph. These results
were compared to the new requirements
in column (6) of Table II of FMVSS No.
121. The results indicated that the
tractor performed with a 20 to 25
percent margin of compliance at initial
test speeds between 30 and 60 mph.
However, at the two lowest test speeds,
the margin of compliance was less—16
percent at 25 mph and eight percent at
20 mph.
When compared to the theoretical
deceleration curve discussed in the July
2009 final rule, there were differences.
The theoretical deceleration curve has a
linear increase in deceleration during
the rise time, followed by a constant
steady-state deceleration, and then an
instantaneous decrease in deceleration
to zero at the completion of the stop. In
comparison, the test data generally
followed this shape with some
differences. There was substantial signal
noise in the measured deceleration,
which has been observed in other heavy
vehicle braking tests. Because of this
signal noise, the data analyst had to use
judgment in determining the completion
of the rise time. The steady-state
deceleration also was not constant. It
appeared to be higher toward the end of
the stop as the vehicle speed decreased
during the stop. At the end of the stop,
the test data indicated a steep ramp
down in deceleration to zero, but it was
not the instantaneous drop shown in the
theoretical curve.
For the new stopping distance
requirements, the rise time used in the
stopping distance equation was 0.45
seconds, and the preamble of the July
2009 final rule provided the required
steady-state decelerations for the
various initial test speeds that would be
required to achieve the new stopping
distances. For example, for a typical
tractor from an initial speed of 60 mph
with a rise time of 0.45 seconds and a
stopping distance of 250 feet, the
required steady-state deceleration in the
equation was 16.80 ft/sec2.
When compared to the actual test data
in the loaded condition from 60 mph,
the average stopping distance was 251
feet, the rise time was 0.40 seconds, and
the steady-state deceleration was 17.3 ft/
sec2. Although the rise time was slightly
faster and the stopping distance very
slightly worse, the measured steadystate deceleration was higher than
predicted. Deriving the steady-state
deceleration from the equation using the
observed stopping distance and rise
time would result in a predicted steadystate deceleration of 16.6 ft/sec2, which
is four percent lower than what was
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observed. Although the difference is
small, the divergence became greater at
lower initial test speeds. At the lowest
test speed of 20 mph, the measured
steady-state deceleration of the vehicle
was 20 ft/sec2, which is 2.9 ft/sec2 or 17
percent higher than the predicted value
of 17.1 ft/sec2 from the equation.
Similar differences, though not as great
were observed from tests in the
unloaded condition.
The test results also revealed that the
agency was correct in assuming that
higher steady-state deceleration would
be achieved at lower initial test speeds
due to increasing tire adhesion as the
vehicle speed decreases when
considering speeds between 60 and 35
mph. However, for the loaded tractor
tests conducted at the lowest initial
speeds, the measured steady-state
deceleration actually decreased from
21.4 ft/sec2 at an initial test speed of 25
mph to 20.0 ft/sec2 at an initial test
speed of 20 mph. For the unloaded tests,
the steady-state deceleration decreased
from 24.7 ft/sec2 at an initial test speed
of 35 mph to 21.7 ft/sec2 at an initial test
speed of 20 mph. The reduced steadystate deceleration at these lower test
speeds appears to be an influential
factor in the loaded tractor’s not meeting
the new 20 mph stopping distance of 30
feet and in the reduced margin of
compliance for the unloaded tractor
tests at the lowest test speeds of 25 and
20 mph.
The testing also provided data on the
rise times that were achieved for the two
loading conditions at the various test
speeds, although they had to be
determined based on engineering
judgment due to the signal noise. For
the tests in the loaded condition, the
average rise time based on the six stops
at each test speed ranged between 0.39
and 0.56 seconds. The longest average
rise times of 0.50 and 0.56 seconds
occurred at the initial test speeds of 30
and 25 mph, respectively. From an
initial test speed of 20 mph, the average
rise time decreased to 0.42 seconds.
Otherwise, there was no clear trend for
the rise times when compared to initial
test speed. Within each set of six stops
for each test speed, some showed
considerable variability between the six
stops and some did not, with standard
deviations ranging between 0.11
seconds from an initial speed of 30 mph
(minimum 0.37 seconds, maximum 0.60
seconds) to 0.02 seconds from an initial
speed of 40 mph (minimum 0.36
seconds, maximum 0.41 seconds).
The rise times for the unloaded tractor
tests were substantially lower than those
for the loaded tests. There was also
much less variability in the unloaded
tests compared to the loaded tests, with
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average rise times for each six-stop
series ranging between 0.27 and 0.32
seconds. The standard deviation for
each six-stop series ranged between 0.01
seconds and 0.03 seconds.
The agency did not specifically
evaluate ABS cycling during stops.
However, based on a review of the
wheel speed data, we are able to make
some observations. The ABS had the
most activity when the tractor was
tested in the unloaded condition, in
which there were continuous brake
pressure modulations for the drive axles
throughout all of the stops from all
initial test speeds. The intermediate
drive axle was equipped with ABS
wheel speed sensors and the brake
pressures for both drive axles were
modulated based upon the wheel slip
occurring on this drive axle. For tests in
the loaded condition, the wheel speed
data for the drive axles did not show
any indications of substantial wheel slip
on the intermediate drive axle, although
brake pressure modulation was
observed in about half of the stops,
mostly at the beginning of the stop,
indicating that ABS did activate in those
stops. ABS activity on the steer axle was
mixed. Some tests in the loaded
condition showed steer axle brake
pressure modulations of up to 30 psi
followed by stair-stepping pressure
increases. As with the drive axle, there
was much more ABS activity on the
steer axle during the unloaded stops.
However, none of the ABS activity on
the steer or drive axles was considered
to be deep cycling in which the pressure
is modulated to near zero or held at low
pressures for a substantial amount to
time in response to rapid wheel lockup,
and there were no observed lapses in
deceleration resulting from ABS
activity.
IV. Response to Petition
Because of the lack of test data on the
stopping distance for tractors from
reduced stopping distance, the agency
conducted the testing program to
determine the accuracy of the equation
from which the agency derived the
stopping distances and to determine
whether a test tractor could readily
achieve the new reduced stopping
distances from each of the initial test
speeds. Because the agency has
conducted testing that verified the
stopping distance requirements at
reduced test speeds, the agency has
decided not to set aside or withdraw the
stopping distance requirements at
reduced initial test speeds, as requested
by TMA and supported by Ms.
Vangorder.
Regarding the validity of the stopping
distance equation in the final rule that
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was used to derive the stopping
distances from reduced speeds, the
agency concludes that the theoretical
deceleration profile that formed the
basis of the equation had some
inaccuracies.9 Although the testing
demonstrated some slight inaccuracies
in the equation, we have decided not to
pursue refinements to the equation at
this time to improve its accuracy in
order to address the petitions for
reconsideration. The results lead us to
believe that further testing likely would
not suggest a need for any significant
changes to other stopping distance
requirements nor would it lead to
improvements in the robustness of the
equation.
Regarding HDBMC’s comments that
the rise times used in the final rule
would make very fast brake timings
necessary and that could result in high
braking torques occurring prior to load
transfer and deep cycling of the ABS,
and as a result those timings would
contribute to longer stopping distances,
we presume that HDMBC was referring
primarily to the tractor’s steer axle that
experiences the greatest increase in load
transfer during a maximum effort stop.
In response to this concern, we note
three observations from the agency’s
testing. First, the fastest rise times
observed in the testing were in the
unloaded condition and were
approximately 0.30 seconds, which
closely matched the average brake
application timing of 0.31 seconds that
was measured on the steer axle. Second,
the brake application timing was not
particularly fast on the drive axles (0.41
and 0.42 seconds for the rear and
intermediate drive axles respectively),
and the rise times for the tractors tested
in the loaded condition were similar to
the drive axle application timing
(average of 0.43 seconds). Third, deep
cycling of the ABS system was not
observed during any stops in the
unloaded and loaded conditions. The
test tractor was able to meet nearly all
of the stopping distance requirements
without particularly fast brake
application timing. Further, HDBMC
never provided its own test data in
support of its assertion that fast brake
timings would be required to meet the
stopping distance requirements at lower
initial test speeds.
Based on the foregoing, the agency
has decided to increase the stopping
distances set forth in Table II of FMVSS
No. 121 for typical tractors in the loaded
condition (column (3)) and for unloaded
9 We believed that including the stopping
distance equation in preamble to the final rule was
useful to provide the agency’s view on how tractors
are anticipated to meet the stopping distance
requirements at reduced speeds.
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tractors (column (6)) from an initial
speed of 20 mph. For typical tractors in
the loaded condition, the agency is
increasing the stopping distance from an
initial speed of 20 mph from 30 feet to
32 feet. The basis for this change is that
the agency’s testing program showed
decreased steady-state deceleration
performance at this initial test speed
compared to what was predicted. The
agency based the 30-foot stopping
distance on the assumption that lower
initial test speeds would always have a
higher steady-state deceleration when
compared to higher initial test speeds.
The tractor tests showed that this was
the case between initial test speeds of 60
and 35 mph. However, variations
occurred below 25 mph. We believe that
braking tests with initial speeds below
35 mph are of such short duration that
there is insufficient time to attain and
maintain the level of steady-state
deceleration performance that is seen
from higher initial braking speeds.
The agency is also increasing the
stopping distance for tractors in the
unloaded condition from an initial
speed of 20 mph from 28 feet to 30 feet.
In the agency’s testing, the test tractor
exceeded the new stopping distances in
the unloaded condition from initial test
speeds between 60 mph and 30 mph by
a margin of greater than 20 percent. At
25 mph, the compliance margin
narrowed to 16 percent, and at 20 mph,
the compliance margin further narrowed
to eight percent. Increasing the
unloaded stopping distance from 28 feet
to 30 feet would improve the margin of
compliance to 14 percent. The eight
percent margin of compliance stands
out when considering that a tractor that
would not have as good of braking
performance as the tractor tested, such
that it would have lower margins of
compliance at higher initial test speeds.
As we stated above, we were not able to
test an unloaded tractor with a zero
margin of compliance from an initial
test speed of 60 mph. We are making
this change in anticipation that some
atypical tractors with lower margins of
compliance in the unloaded condition
would have difficulty achieving the 28
foot stopping distance.
The agency notes that these changes
are being made based on the testing of
a tractor that was adjusted to just meet
the stopping distance requirements for
the stops from 60 mph in the loaded
condition. We anticipate that tractors
with improved braking performance
will be designed to have a greater-thanzero margin of compliance to the new
stopping distance requirements so that
minor variations in the vehicle
manufacturing process and brake
components can be tolerated. Thus, we
E:\FR\FM\27JYR1.SGM
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Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Rules and Regulations
expect that the stopping distance
performance of vehicles at all initial test
speeds would be slightly better as well.
The agency has received no additional
test data after the petitions for
reconsideration were filed. We are
therefore amending the stopping
distances for reduced initial speeds
based solely upon the agency’s own test
data.
We also wish to clarify that tractors,
trucks, and buses must only meet the
stopping distance requirements at the
initial test speed corresponding to the
highest speed attainable by the vehicle.
As stated in S5.3.1.1 of FMVSS No. 121,
vehicle stops are generally conducted
from 60 mph in both the loaded and
unloaded conditions. However, if the
speed attainable by a vehicle in two
miles is less than 60 mph, the vehicle
is required to stop from a speed in Table
II that is four to eight mph less than the
speed attainable in two miles. Thus,
FMVSS No. 121 does not require that
stops be conducted from all initial test
speeds listed in Table II; rather,
stopping distance tests are conducted
from either 60 mph or from the speed
that is four to eight mph less than the
highest speed attainable within two
miles.
motor vehicle safety standard may not
become effective before the 180th day
after the standard is prescribed or later
than one year after it is prescribed
except when a different effective date is,
for good cause shown, in the public
interest. This rule makes amendments to
regulatory provisions that are subject to
phase-in that were set forth in the July
2009 final rule. These amendments
would not impose new requirements;
rather, these amendments simply adjust
the required maximum stopping
distances at very low speeds by slightly
relaxing them to be consistent with
what the agency intended in the April
2007 final rule. Therefore, good cause
exists for these amendments to be made
effective in the timeframe already in
place concerning the effective dates of
implementation of the reduced stopping
distance requirements in FMVSS No.
121.
VII. Rulemaking Analyses and Notices
VI. Effective Date
Section 30111(d) of title 49, United
States Code, provides that a Federal
mstockstill on DSK4VPTVN1PROD with RULES
V. Technical Correction
In the notes portion of Table II of
FMVSS No. 121, the label for column (6)
is ‘‘Unloaded Tractors (Bobtail),’’ which
is the stopping distance requirements
for unloaded tractors using the service
brakes, whereas the label for column (8)
is ‘‘Unloaded Tractors,’’ which is the
stopping distance requirements for
unloaded tractors using the emergency
brake. The vehicle loading conditions
tested in columns (6) and (8) are
identical. The term ‘‘Bobtail’’ is
included as a parenthetical to the label
for column (6) to make clear that the
stopping distance requirements in that
column are to be met without a trailer
attached. So there is no confusion that
the loading condition for column (8) is
identical to the loading condition for
column (6), we are adding the term
‘‘Bobtail’’ in parenthesis in the label for
column (8).
A. Executive Order 12866, Executive
Order 13563, and DOT Regulatory
Policies and Procedures
The agency has considered the impact
of this rulemaking action under
Executive Orders 12866 and 13563 and
the DOT’s regulatory policies and
procedures. This action was not
reviewed by the Office of Management
and Budget under Executive Order
12866. The agency has considered the
impact of this action under the
Department of Transportation’s
regulatory policies and procedures (44
FR 11034; February 26, 1979), and has
determined that it is not ‘‘significant’’
under them.
This action completes the agency’s
response to petitions for reconsideration
regarding the July 2009 final rule
amending FMVSS No. 121. This final
rule revises the stopping distance table
for vehicles from very low speeds to
reflect agency’s intent in the July 2009
final rule regarding braking performance
level from very low test speeds. Today’s
action will not cause any additional
expenses for vehicle manufacturers.
This action will not have any significant
safety impacts.
B. Privacy Act
Anyone is able to search the
electronic form of all documents
received into any of our dockets by the
name of the individual submitting the
document (or signing the document, if
submitted on behalf of an association,
business, labor union, etc.). You may
review DOT’s complete Privacy Act
Statement in the Federal Register
published on April 11, 2000 (Volume
65, Number 70; Pages 19477–78) or you
may visit https://docketsinfo.dot.gov/.
C. Other Rulemaking Analyses and
Notices
In the July 2009 final rule, the agency
discussed relevant requirements related
to the Regulatory Flexibility Act, the
National Environmental Policy Act,
Executive Order 13132 (Federalism), the
Unfunded Mandates Reform Act, Civil
Justice Reform, the National Technology
Transfer and Advancement Act, the
Paperwork Reduction Act, and
Executive Order 13045 (Protection of
Children from Environmental Health
and Safety Risks). As today’s rule
merely makes minor changes in the
stopping distance at lower speeds to
reflect agency’s intent in the July 2009
final rule regarding braking performance
level from very low test speeds, it will
not have any effect on the agency’s
analyses in those areas.
VIII. Regulatory Text
List of Subjects in 49 CFR Parts 571
Imports, Motor vehicle safety,
Reporting and recordkeeping
requirements, Tires.
In consideration of the foregoing,
NHTSA amends 49 CFR part 571 as
follows:
PART 571—FEDERAL MOTOR
VEHICLE SAFETY STANDARDS
1. The authority citation for part 571
of Title 49 continues to read as follows:
■
Authority: 49 U.S.C. 322, 30111, 30115,
30117, and 30166; delegation of authority at
49 CFR 1.50.
2. In § 571.121, revise Table II to read
as follows:
■
§ 571.121
systems.
Standard No. 121; Air brake
*
*
*
*
*
TABLE II—STOPPING DISTANCE IN FEET
Vehicle speed in miles per
hour
Service brake
Emergency brake
VerDate Mar<15>2010
16:06 Jul 26, 2011
PFC 0.9
PFC 0.9
PFC 0.9
PFC 0.9
PFC 0.9
PFC 0.9
PFC 0.9
(1)
20 .....................................
PFC 0.9
(2)
(3)
(4)
(5)
(6)
(7)
(8)
32
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35
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Fmt 4700
35
Sfmt 4700
38
E:\FR\FM\27JYR1.SGM
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85
44834
Federal Register / Vol. 76, No. 144 / Wednesday, July 27, 2011 / Rules and Regulations
TABLE II—STOPPING DISTANCE IN FEET—Continued
Vehicle speed in miles per
hour
Service brake
Emergency brake
PFC 0.9
PFC 0.9
PFC 0.9
PFC 0.9
PFC 0.9
PFC 0.9
PFC 0.9
(1)
25
30
35
40
45
50
55
60
PFC 0.9
(2)
(3)
(4)
(5)
(6)
(7)
(8)
.....................................
.....................................
.....................................
.....................................
.....................................
.....................................
.....................................
.....................................
49
70
96
125
158
195
236
280
54
78
106
138
175
216
261
310
45
65
89
114
144
176
212
250
54
78
106
138
175
216
261
310
59
84
114
149
189
233
281
335
43
61
84
108
136
166
199
235
123
170
225
288
358
435
520
613
131
186
250
325
409
504
608
720
(1) Loaded and Unloaded Buses.
(2) Loaded Single-Unit Trucks.
(3) Loaded Tractors with Two Axles; or with Three Axles and a GVWR of 70,000 lbs. or less; or with Four or More Axles and a GVWR of
85,000 lbs. or less. Tested with an Unbraked Control Trailer.
(4) Loaded Tractors with Three Axles and a GVWR greater than 70,000 lbs.; or with Four or More Axles and a GVWR greater than 85,000 lbs.
Tested with an Unbraked Control Trailer.
(5) Unloaded Single-Unit Trucks.
(6) Unloaded Tractors (Bobtail).
(7) All Vehicles except Tractors, Loaded and Unloaded.
(8) Unloaded Tractors (Bobtail).
*
*
*
*
*
Issued on: July 21, 2011.
Ronald L. Medford,
Deputy Administrator.
[FR Doc. 2011–18929 Filed 7–26–11; 8:45 am]
BILLING CODE 4910–59–P
DEPARTMENT OF COMMERCE
National Oceanic and Atmospheric
Administration
50 CFR Part 635
[Docket No. 110210132–1275–02]
RIN 0648–XA550
Atlantic Highly Migratory Species;
Atlantic Bluefin Tuna Fisheries;
Northern Area Trophy Fishery
National Marine Fisheries
Service (NMFS), National Oceanic and
Atmospheric Administration (NOAA),
Commerce.
ACTION: Closure.
AGENCY:
NMFS closes the northern
area Angling category fishery for large
medium and giant (‘‘trophy’’) Atlantic
bluefin tuna (BFT) for the remainder of
2011. This action is being taken to
prevent overharvest of the 2011 Angling
category northern area subquota for
large medium and giant BFT.
DATES: Effective 11:30 p.m., local time,
July 29, 2011 through December 31,
2011.
mstockstill on DSK4VPTVN1PROD with RULES
SUMMARY:
FOR FURTHER INFORMATION CONTACT:
Sarah McLaughlin or Brad McHale,
978–281–9260.
VerDate Mar<15>2010
16:06 Jul 26, 2011
Jkt 223001
SUPPLEMENTARY INFORMATION:
Regulations implemented under the
authority of the Atlantic Tunas
Convention Act (16 U.S.C. 971 et seq.)
and the Magnuson-Stevens Fishery
Conservation and Management Act
(Magnuson-Stevens Act; 16 U.S.C. 1801
et seq.) governing the harvest of BFT by
persons and vessels subject to U.S.
jurisdiction are found at 50 CFR part
635. Section 635.27 subdivides the U.S.
BFT quota recommended by the
International Commission for the
Conservation of Atlantic Tunas (ICCAT)
among the various domestic fishing
categories, consistent with the
allocations established in the 2006
Consolidated Highly Migratory Species
Fishery Management Plan (2006
Consolidated HMS FMP) (71 FR 58058,
October 2, 2006) and subsequent
rulemaking.
NMFS is required, under
§ 635.28(a)(1), to file a closure notice
with the Office of the Federal Register
for publication when a BFT quota is
reached or is projected to be reached.
On and after the effective date and time
of such notification, for the remainder of
the fishing year, or for a specified period
as indicated in the notification, fishing
for, retaining, possessing, or landing
BFT under that quota category is
prohibited until the opening of the
subsequent quota period or until such
date as specified in the notice.
The 2011 BFT quota specifications
established a quota of 1.4 mt of large
medium and giant BFT (measuring 73
inches curved fork length or greater) to
be harvested in the northern area, i.e.,
north of 39°18′ N. lat. (off Great Egg
Inlet, NJ) by vessels permitted in the
PO 00000
Frm 00074
Fmt 4700
Sfmt 4700
HMS Angling or Charter/Headboat
category (while fishing recreationally)
(76 FR 39019, July 5, 2011). Earlier this
year, NMFS announced two Angling
category BFT fishery inseason actions,
effective April 2, 2011: a change to the
daily retention limit and closure of the
southern area trophy fishery (76 FR
18416, April 4, 2011). Based on the best
available BFT landings information for
the trophy BFT fishery, NMFS has
determined that the northern area
trophy BFT subquota will be reached by
July 29, 2011. Therefore, through
December 31, 2011, fishing for,
retaining, possessing, or landing large
medium or giant BFT north of 39°18′ N.
lat. by persons aboard vessels permitted
in the HMS Angling category and the
HMS Charter/Headboat category (while
fishing recreationally) must cease at
11:30 p.m. local time on July 29, 2011.
Limited catch and release is permissible
as specified under § 635.26(a) and
described below. This action is taken
consistent with the regulations at
§ 635.28(a)(1). The intent of this closure
is to prevent overharvest of the Angling
category northern area trophy BFT
subquota.
Anglers are reminded that all nontournament BFT landed under the
Angling category quota must be reported
within 24 hours of landing either online
at https://www.hmspermits.gov or by
calling (888) 872–8862. In Maryland and
North Carolina, vessel owners must
report their recreational tuna landings at
state-operated reporting stations. For
additional information on these
programs, including reporting station
locations, please call (410) 213–1351
E:\FR\FM\27JYR1.SGM
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]]>Agencies
[Federal Register Volume 76, Number 144 (Wednesday, July 27, 2011)]
[Rules and Regulations]
[Pages 44829-44834]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: 2011-18929]
=======================================================================
-----------------------------------------------------------------------
DEPARTMENT OF TRANSPORTATION
National Highway Traffic Safety Administration
49 CFR Part 571
[Docket No. NHTSA-2009-0175]
RIN 2127-AK84
Federal Motor Vehicle Safety Standards; Air Brake Systems
AGENCY: National Highway Traffic Safety Administration (NHTSA),
Department of Transportation.
ACTION: Final rule; response to petitions for reconsideration.
-----------------------------------------------------------------------
SUMMARY: On July 27, 2009, NHTSA published a final rule that amended
the Federal motor vehicle safety standard for air brake systems by
requiring substantial improvements in stopping distance performance on
new truck tractors. In response, the agency received eight petitions
for reconsideration. The agency has already responded to most of the
issues raised in the petitions. This document responds to the one
outstanding issue raised in the petitions, stopping distance
performance requirements at lower initial speeds. Based on testing
results and our concern that the current requirements might not be
practicable, NHTSA is slightly relaxing the stopping distance
requirement for typical loaded tractors tested from an initial speed of
20 mph by increasing the distance from 30 feet to 32 feet and for
unloaded tractors tested from an initial speed of 20 mph by increasing
the distance from 28 feet to 30 feet. We believe no other changes are
necessary.
DATES: This final rule is effective August 1, 2011.
Petitions for reconsideration must be received not later than
September 12, 2011.
ADDRESSES: Petitions for reconsideration should refer to the docket
number and must be submitted to: Administrator, National Highway
Traffic Safety Administration, 1200 New Jersey Avenue, SE., Washington,
DC 20590.
FOR FURTHER INFORMATION CONTACT: For technical issues, you may contact
Jeffrey Woods, Office of Crash Avoidance Standards, by telephone at
(202) 366-6206, and by fax at (202) 366-7002.
For legal issues, you may contact David Jasinski, Office of the
Chief Counsel, by telephone at (202) 366-2992, and by fax at (202) 366-
3820.
You may send mail to both of these officials at the National
Highway Traffic Safety Administration, 1200 New Jersey Avenue, SE.,
Washington, DC 20590.
SUPPLEMENTARY INFORMATION:
Table of Contents
I. Background of the Stopping Distance Requirement
II. Petitions for Reconsideration
III. Testing Program
IV. Response to Petition
V. Technical Correction
VI. Effective Date
VII. Rulemaking Analyses and Notices
VIII. Regulatory Text
I. Background of the Stopping Distance Requirement
On July 27, 2009, NHTSA published a final rule in the Federal
Register amending Federal Motor Vehicle Safety Standard (FMVSS) No.
121, Air Brake Systems, to require improved stopping distance
performance for heavy truck tractors.\1\ This rule reduced the maximum
allowable stopping distance, from 60 mph, from 355 feet to 250 feet for
the vast majority of loaded heavy truck tractors. For a small minority
of loaded very heavy tractors, the maximum allowable stopping distance
was reduced from 355 feet to 310 feet. Having come to the conclusion
that modifications needed for ``typical three-axle tractors,'' to meet
the improved requirements were relatively straightforward, NHTSA
provided two years lead time for those vehicles to comply with the new
requirements. These typical three-axle tractors comprise approximately
82 percent of the total fleet of heavy tractors. The agency concluded
that other tractors, which are produced in far fewer numbers and may
need additional work to ensure stability and control while braking,
would need more lead time to meet the requirements. Due to extra time
needed to design, test, and validate these vehicles, which included
two-axle tractors and severe service tractors, the agency allowed four
years lead time for
[[Page 44830]]
these tractors to meet the improved stopping distance requirements.
---------------------------------------------------------------------------
\1\ 74 FR 37122; Docket No. NHTSA-2009-0083-0001.
---------------------------------------------------------------------------
Requirements in FMVSS No. 121 provide that if the speed attainable
by a vehicle in two miles is less than 60 mph, the speed at which the
vehicle shall meet the specified stopping distances is four to eight
mph less than the speed attainable in two miles. In the July 2009 final
rule, the agency used an equation to derive the required stopping
distances for vehicles with initial speeds of less than 60 mph.\2\
---------------------------------------------------------------------------
\2\ The complete derivation for this equation was included in
the docket. See Docket No. NHTSA-2005-21462-0039, at 18-22.
St = (\1/2\ Vo tr) + ((\1/2\)
Vo[sup2]/af)--((\1/24\) af
---------------------------------------------------------------------------
tr[sup2])
Where:
St = Total stopping distance in feet
Vo = Initial Speed in ft/sec
tr = Air pressure rise time in seconds
af = Steady-state deceleration in ft/sec[sup2]
For the final rule, the agency selected an air pressure rise time
of 0.45 seconds, which is equal to the brake actuation timing
requirement in FMVSS No. 121. The steady-state deceleration was based
on an theoretical deceleration curve in which vehicle deceleration
would increase linearly during the rise time portion of the stopping
event, followed by constant steady-state deceleration, followed by an
instantaneous decrease in acceleration back to zero at the completion
of the stop. Table II in FMVSS No. 121 sets forth the stopping distance
requirements for speeds from 60 mph down to 20 mph (in increments of 5
mph) for both typical and severe service tractors in the loaded
conditions and all tractors in the unloaded condition derived using
that formula.
II. Petitions for Reconsideration
NHTSA received eight timely petitions for reconsideration in
response to the final rule. Separate petitions were received from the
Truck Manufacturers Association (TMA); the Heavy Duty Brake
Manufacturers Council of the Heavy Duty Manufacturers Association
(HDBMC); Bendix Spicer Foundation Brake LLC (Bendix), a joint venture
between Bendix Commercial Vehicle Systems and Dana Corporation; and
ArvinMeritor. The agency received four additional petitions supporting
and incorporating the TMA petition by reference from Daimler Trucks
North America (Daimler), Kenworth Truck Company (Kenworth), Peterbilt
Motors Company (Peterbilt), and Navistar Truck Group (Navistar).
The petitions focused on four main issues. The main issues included
the stopping distance requirements for reduced speeds, the omission of
four-axle tractors under 59,600 pounds gross vehicle weight rating
(GVWR) from the listed requirements and the date at which the improved
stopping distance requirements should apply to those tractors, the
manner in which NHTSA characterized the typical three-axle tractor, and
the fuel tank fill level testing specification. Additionally, the
petitioners requested that NHTSA correct some typographical errors in
the regulatory text.
In a final rule published in the Federal Register on November 13,
2009, the agency addressed all of the issues raised in the petition,
except those related to stopping distance requirements at reduced
speeds.\3\ We addressed the other issues first because the agency
omitted lead time requirements for tractors with four or more axles and
a GVWR of 59,600 pounds or less, which would have inadvertently
required those vehicles to comply with the upgraded stopping distance
requirements on November 24, 2009. The November 2009 final rule
responded to issues raised in the petition with these amendments: (1)
The agency accepted the recommendation of petitioners TMA, HDBMC, and
Bendix and required compliance with the improved stopping distance
requirements for tractors with four or more axles and a GVWR of 59,600
pounds or less by August 1, 2013, thereby giving four years of lead
time; (2) the agency revised the definition of a ``typical three-axle
tractor'' in the regulatory text in response to concerns raised by TMA
and ArvinMeritor to include three-axle tractors having a steer axle
gross axle weight rating (GAWR) of 14,600 pounds or less and a combined
drive axle GAWR of 45,000 pounds or less; (3) the agency removed the
fuel tank loading specification from the test procedure in response to
TMA's petition; (4) the agency made two typographical corrections
identified by all petitioners.\4\
---------------------------------------------------------------------------
\3\ 74 FR 58562; Docket No. NHTSA-2009-0175-0001.
\4\ The agency made further correcting amendments to correct an
omission in the November 2009 final rule. See 75 FR 15620 (Mar. 30,
2010); Docket No. 2009-0175-0004.
---------------------------------------------------------------------------
TMA, HDBMC, and Bendix each raised issues in their petitions
regarding stopping distance requirements at reduced test speeds. TMA,
HDBMC, and Bendix each stated that the new stopping distance
requirements from speeds lower than 60 mph have not been validated
through actual vehicle test data. In addition, the agency received a
comment on the November 2009 final rule from Crystal Vangorder, which
supported this assertion. TMA and Ms. Vangorder requested that the
agency withdraw the reduced stopping distance requirements from speeds
lower than 60 mph until test data has been obtained.
Although HDBMC reviewed NHTSA's calculations and assumptions set
forth in the preamble to the final rule and agreed with the technical
approach taken, HDBMC nevertheless stated that the brake timing may be
too fast for some vehicle configurations. HDBMC made reference to its
own prior comments on the agency's reduced stopping distance rulemaking
in which it provided tables showing how brake timing affects stopping
distance.\5\ HDBMC noted that high braking torques can occur prior to
load transfer, which may cause deep cycling of the antilock brake
system (ABS) resulting in slightly longer stopping distance. Bendix
also stated that differing opinions on axle response time and average
deceleration left the results of the calculations open to speculation.
HDBMC noted that limited initial testing data by its members showed
that vehicle are close to meeting or are not meeting the stopping
distance from 20 mph of 30 feet within a 10 percent margin.
---------------------------------------------------------------------------
\5\ See Docket No. NHTSA-2005-21462-0020.
---------------------------------------------------------------------------
TMA and HDBMC both stated that their members were conducting
testing and would provide the agency with data to supplement any agency
testing. However, no test data has been provided to the agency.
III. Testing Program
In response to the petitions, NHTSA conducted testing to evaluate
the stopping distance performance of a truck tractor from initial test
speeds between 20 and 60 mph. The purpose of the testing was to acquire
test data that, as stated in the petitions for reconsideration to the
July 2009 final rule, had not been available to confirm that the new
stopping distance requirements from speeds less than 60 mph could be
achieved. The test program and results are described in the technical
report, ``Experimental Measurement of the Stopping Performance of a
Tractor-Semitrailer from Multiple Speeds.'' \6\
---------------------------------------------------------------------------
\6\ DOT HS 811 488, available at https://www.nhtsa.gov/DOT/NHTSA/NVS/Vehicle Research & Test Center (VRTC)/ca/811488.pdf, Docket No.
NHTSA-2009-0175-0005.
---------------------------------------------------------------------------
The test plan was to evaluate a tractor that, when tested while
traveling at a speed of 60 mph, met the reduced tractor stopping
distance requirement of 250 feet for vehicles loaded to GWVR without
any margin. That same tractor was then tested at lower initial speeds
to compare actual test results with the new requirements in Table II of
FMVSS
[[Page 44831]]
No. 121. The test was also conducted in a lightly loaded vehicle weight
condition with no trailer attached.
The agency used a 1991 Volvo 6x4 tractor with a 190-inch wheelbase,
equipped with a hybrid disc brake configuration. The vehicle was used
in the agency's research to support the reduced stopping distance
rulemaking, and was chosen because it was expected to have close to a
250-foot stopping distance when tested from 60 mph in the loaded
condition. During actual testing, the vehicle was found to have a
minimum stopping distance of 249 feet when loaded to GVWR (i.e., the
shortest stop in a series of six stops).\7\ However, the vehicle had
not been operated for several years and when the vehicle was
recommissioned for this test program, the agency found it necessary to
adjust the amount of the ballast load of the vehicle by lowering it to
a modified GVWR in order to achieve consistent stopping distance of 250
feet from 60 mph.\8\ This modified GVWR was used for the rest of the
testing program.
---------------------------------------------------------------------------
\7\ Repairs were necessary to this vehicle in order to meet the
0.45 second brake application timing requirement.
\8\ The tractor's GVWR was 50,000 pounds. The load necessary to
meet the 250-foot stopping requirement with the control trailer
attached was 42,840 pounds.
---------------------------------------------------------------------------
The agency considered using a newer vehicle and adding ballast to
increase the stopping distance of the vehicle to 250 feet. However, the
agency decided not to follow this approach because it could have
resulted in unusually high brake temperatures and brake fade effects or
changes in the brake lining friction characteristics. The agency
believed it would be better to remove weight from a worse-performing
tractor rather than adding weight to a better-performing tractor.
A series of six stops was then conducted for the loaded tractor at
initial speeds ranging from 60 mph down to 20 mph in five-mph
increments. The average of each six-stop series was compared to the new
requirements in column (3) of Table II of FMVSS No. 121. The results
indicated that from initial speeds below 60 mph, the vehicle could
achieve slightly better stopping distances than those in Table II,
except at the lowest test speed of 20 mph. From an initial speed of 20
mph, the tractor loaded to the modified GVWR achieved an average
stopping distance of 31.2 feet, compared to the FMVSS No. 121 stopping
distance requirement of 30 feet.
The test series was then repeated in the unloaded (bobtail)
condition. For this test series, the agency was unable to devise a
practical way of adjusting the tractor's braking performance to provide
a zero percent margin of compliance at 60 mph. These results were
compared to the new requirements in column (6) of Table II of FMVSS No.
121. The results indicated that the tractor performed with a 20 to 25
percent margin of compliance at initial test speeds between 30 and 60
mph. However, at the two lowest test speeds, the margin of compliance
was less--16 percent at 25 mph and eight percent at 20 mph.
When compared to the theoretical deceleration curve discussed in
the July 2009 final rule, there were differences. The theoretical
deceleration curve has a linear increase in deceleration during the
rise time, followed by a constant steady-state deceleration, and then
an instantaneous decrease in deceleration to zero at the completion of
the stop. In comparison, the test data generally followed this shape
with some differences. There was substantial signal noise in the
measured deceleration, which has been observed in other heavy vehicle
braking tests. Because of this signal noise, the data analyst had to
use judgment in determining the completion of the rise time. The
steady-state deceleration also was not constant. It appeared to be
higher toward the end of the stop as the vehicle speed decreased during
the stop. At the end of the stop, the test data indicated a steep ramp
down in deceleration to zero, but it was not the instantaneous drop
shown in the theoretical curve.
For the new stopping distance requirements, the rise time used in
the stopping distance equation was 0.45 seconds, and the preamble of
the July 2009 final rule provided the required steady-state
decelerations for the various initial test speeds that would be
required to achieve the new stopping distances. For example, for a
typical tractor from an initial speed of 60 mph with a rise time of
0.45 seconds and a stopping distance of 250 feet, the required steady-
state deceleration in the equation was 16.80 ft/sec\2\.
When compared to the actual test data in the loaded condition from
60 mph, the average stopping distance was 251 feet, the rise time was
0.40 seconds, and the steady-state deceleration was 17.3 ft/sec\2\.
Although the rise time was slightly faster and the stopping distance
very slightly worse, the measured steady-state deceleration was higher
than predicted. Deriving the steady-state deceleration from the
equation using the observed stopping distance and rise time would
result in a predicted steady-state deceleration of 16.6 ft/sec\2\,
which is four percent lower than what was observed. Although the
difference is small, the divergence became greater at lower initial
test speeds. At the lowest test speed of 20 mph, the measured steady-
state deceleration of the vehicle was 20 ft/sec\2\, which is 2.9 ft/
sec\2\ or 17 percent higher than the predicted value of 17.1 ft/sec\2\
from the equation. Similar differences, though not as great were
observed from tests in the unloaded condition.
The test results also revealed that the agency was correct in
assuming that higher steady-state deceleration would be achieved at
lower initial test speeds due to increasing tire adhesion as the
vehicle speed decreases when considering speeds between 60 and 35 mph.
However, for the loaded tractor tests conducted at the lowest initial
speeds, the measured steady-state deceleration actually decreased from
21.4 ft/sec\2\ at an initial test speed of 25 mph to 20.0 ft/sec\2\ at
an initial test speed of 20 mph. For the unloaded tests, the steady-
state deceleration decreased from 24.7 ft/sec\2\ at an initial test
speed of 35 mph to 21.7 ft/sec\2\ at an initial test speed of 20 mph.
The reduced steady-state deceleration at these lower test speeds
appears to be an influential factor in the loaded tractor's not meeting
the new 20 mph stopping distance of 30 feet and in the reduced margin
of compliance for the unloaded tractor tests at the lowest test speeds
of 25 and 20 mph.
The testing also provided data on the rise times that were achieved
for the two loading conditions at the various test speeds, although
they had to be determined based on engineering judgment due to the
signal noise. For the tests in the loaded condition, the average rise
time based on the six stops at each test speed ranged between 0.39 and
0.56 seconds. The longest average rise times of 0.50 and 0.56 seconds
occurred at the initial test speeds of 30 and 25 mph, respectively.
From an initial test speed of 20 mph, the average rise time decreased
to 0.42 seconds. Otherwise, there was no clear trend for the rise times
when compared to initial test speed. Within each set of six stops for
each test speed, some showed considerable variability between the six
stops and some did not, with standard deviations ranging between 0.11
seconds from an initial speed of 30 mph (minimum 0.37 seconds, maximum
0.60 seconds) to 0.02 seconds from an initial speed of 40 mph (minimum
0.36 seconds, maximum 0.41 seconds).
The rise times for the unloaded tractor tests were substantially
lower than those for the loaded tests. There was also much less
variability in the unloaded tests compared to the loaded tests, with
[[Page 44832]]
average rise times for each six-stop series ranging between 0.27 and
0.32 seconds. The standard deviation for each six-stop series ranged
between 0.01 seconds and 0.03 seconds.
The agency did not specifically evaluate ABS cycling during stops.
However, based on a review of the wheel speed data, we are able to make
some observations. The ABS had the most activity when the tractor was
tested in the unloaded condition, in which there were continuous brake
pressure modulations for the drive axles throughout all of the stops
from all initial test speeds. The intermediate drive axle was equipped
with ABS wheel speed sensors and the brake pressures for both drive
axles were modulated based upon the wheel slip occurring on this drive
axle. For tests in the loaded condition, the wheel speed data for the
drive axles did not show any indications of substantial wheel slip on
the intermediate drive axle, although brake pressure modulation was
observed in about half of the stops, mostly at the beginning of the
stop, indicating that ABS did activate in those stops. ABS activity on
the steer axle was mixed. Some tests in the loaded condition showed
steer axle brake pressure modulations of up to 30 psi followed by
stair-stepping pressure increases. As with the drive axle, there was
much more ABS activity on the steer axle during the unloaded stops.
However, none of the ABS activity on the steer or drive axles was
considered to be deep cycling in which the pressure is modulated to
near zero or held at low pressures for a substantial amount to time in
response to rapid wheel lockup, and there were no observed lapses in
deceleration resulting from ABS activity.
IV. Response to Petition
Because of the lack of test data on the stopping distance for
tractors from reduced stopping distance, the agency conducted the
testing program to determine the accuracy of the equation from which
the agency derived the stopping distances and to determine whether a
test tractor could readily achieve the new reduced stopping distances
from each of the initial test speeds. Because the agency has conducted
testing that verified the stopping distance requirements at reduced
test speeds, the agency has decided not to set aside or withdraw the
stopping distance requirements at reduced initial test speeds, as
requested by TMA and supported by Ms. Vangorder.
Regarding the validity of the stopping distance equation in the
final rule that was used to derive the stopping distances from reduced
speeds, the agency concludes that the theoretical deceleration profile
that formed the basis of the equation had some inaccuracies.\9\
Although the testing demonstrated some slight inaccuracies in the
equation, we have decided not to pursue refinements to the equation at
this time to improve its accuracy in order to address the petitions for
reconsideration. The results lead us to believe that further testing
likely would not suggest a need for any significant changes to other
stopping distance requirements nor would it lead to improvements in the
robustness of the equation.
---------------------------------------------------------------------------
\9\ We believed that including the stopping distance equation in
preamble to the final rule was useful to provide the agency's view
on how tractors are anticipated to meet the stopping distance
requirements at reduced speeds.
---------------------------------------------------------------------------
Regarding HDBMC's comments that the rise times used in the final
rule would make very fast brake timings necessary and that could result
in high braking torques occurring prior to load transfer and deep
cycling of the ABS, and as a result those timings would contribute to
longer stopping distances, we presume that HDMBC was referring
primarily to the tractor's steer axle that experiences the greatest
increase in load transfer during a maximum effort stop. In response to
this concern, we note three observations from the agency's testing.
First, the fastest rise times observed in the testing were in the
unloaded condition and were approximately 0.30 seconds, which closely
matched the average brake application timing of 0.31 seconds that was
measured on the steer axle. Second, the brake application timing was
not particularly fast on the drive axles (0.41 and 0.42 seconds for the
rear and intermediate drive axles respectively), and the rise times for
the tractors tested in the loaded condition were similar to the drive
axle application timing (average of 0.43 seconds). Third, deep cycling
of the ABS system was not observed during any stops in the unloaded and
loaded conditions. The test tractor was able to meet nearly all of the
stopping distance requirements without particularly fast brake
application timing. Further, HDBMC never provided its own test data in
support of its assertion that fast brake timings would be required to
meet the stopping distance requirements at lower initial test speeds.
Based on the foregoing, the agency has decided to increase the
stopping distances set forth in Table II of FMVSS No. 121 for typical
tractors in the loaded condition (column (3)) and for unloaded tractors
(column (6)) from an initial speed of 20 mph. For typical tractors in
the loaded condition, the agency is increasing the stopping distance
from an initial speed of 20 mph from 30 feet to 32 feet. The basis for
this change is that the agency's testing program showed decreased
steady-state deceleration performance at this initial test speed
compared to what was predicted. The agency based the 30-foot stopping
distance on the assumption that lower initial test speeds would always
have a higher steady-state deceleration when compared to higher initial
test speeds. The tractor tests showed that this was the case between
initial test speeds of 60 and 35 mph. However, variations occurred
below 25 mph. We believe that braking tests with initial speeds below
35 mph are of such short duration that there is insufficient time to
attain and maintain the level of steady-state deceleration performance
that is seen from higher initial braking speeds.
The agency is also increasing the stopping distance for tractors in
the unloaded condition from an initial speed of 20 mph from 28 feet to
30 feet. In the agency's testing, the test tractor exceeded the new
stopping distances in the unloaded condition from initial test speeds
between 60 mph and 30 mph by a margin of greater than 20 percent. At 25
mph, the compliance margin narrowed to 16 percent, and at 20 mph, the
compliance margin further narrowed to eight percent. Increasing the
unloaded stopping distance from 28 feet to 30 feet would improve the
margin of compliance to 14 percent. The eight percent margin of
compliance stands out when considering that a tractor that would not
have as good of braking performance as the tractor tested, such that it
would have lower margins of compliance at higher initial test speeds.
As we stated above, we were not able to test an unloaded tractor with a
zero margin of compliance from an initial test speed of 60 mph. We are
making this change in anticipation that some atypical tractors with
lower margins of compliance in the unloaded condition would have
difficulty achieving the 28 foot stopping distance.
The agency notes that these changes are being made based on the
testing of a tractor that was adjusted to just meet the stopping
distance requirements for the stops from 60 mph in the loaded
condition. We anticipate that tractors with improved braking
performance will be designed to have a greater-than-zero margin of
compliance to the new stopping distance requirements so that minor
variations in the vehicle manufacturing process and brake components
can be tolerated. Thus, we
[[Page 44833]]
expect that the stopping distance performance of vehicles at all
initial test speeds would be slightly better as well. The agency has
received no additional test data after the petitions for
reconsideration were filed. We are therefore amending the stopping
distances for reduced initial speeds based solely upon the agency's own
test data.
We also wish to clarify that tractors, trucks, and buses must only
meet the stopping distance requirements at the initial test speed
corresponding to the highest speed attainable by the vehicle. As stated
in S5.3.1.1 of FMVSS No. 121, vehicle stops are generally conducted
from 60 mph in both the loaded and unloaded conditions. However, if the
speed attainable by a vehicle in two miles is less than 60 mph, the
vehicle is required to stop from a speed in Table II that is four to
eight mph less than the speed attainable in two miles. Thus, FMVSS No.
121 does not require that stops be conducted from all initial test
speeds listed in Table II; rather, stopping distance tests are
conducted from either 60 mph or from the speed that is four to eight
mph less than the highest speed attainable within two miles.
V. Technical Correction
In the notes portion of Table II of FMVSS No. 121, the label for
column (6) is ``Unloaded Tractors (Bobtail),'' which is the stopping
distance requirements for unloaded tractors using the service brakes,
whereas the label for column (8) is ``Unloaded Tractors,'' which is the
stopping distance requirements for unloaded tractors using the
emergency brake. The vehicle loading conditions tested in columns (6)
and (8) are identical. The term ``Bobtail'' is included as a
parenthetical to the label for column (6) to make clear that the
stopping distance requirements in that column are to be met without a
trailer attached. So there is no confusion that the loading condition
for column (8) is identical to the loading condition for column (6), we
are adding the term ``Bobtail'' in parenthesis in the label for column
(8).
VI. Effective Date
Section 30111(d) of title 49, United States Code, provides that a
Federal motor vehicle safety standard may not become effective before
the 180th day after the standard is prescribed or later than one year
after it is prescribed except when a different effective date is, for
good cause shown, in the public interest. This rule makes amendments to
regulatory provisions that are subject to phase-in that were set forth
in the July 2009 final rule. These amendments would not impose new
requirements; rather, these amendments simply adjust the required
maximum stopping distances at very low speeds by slightly relaxing them
to be consistent with what the agency intended in the April 2007 final
rule. Therefore, good cause exists for these amendments to be made
effective in the timeframe already in place concerning the effective
dates of implementation of the reduced stopping distance requirements
in FMVSS No. 121.
VII. Rulemaking Analyses and Notices
A. Executive Order 12866, Executive Order 13563, and DOT Regulatory
Policies and Procedures
The agency has considered the impact of this rulemaking action
under Executive Orders 12866 and 13563 and the DOT's regulatory
policies and procedures. This action was not reviewed by the Office of
Management and Budget under Executive Order 12866. The agency has
considered the impact of this action under the Department of
Transportation's regulatory policies and procedures (44 FR 11034;
February 26, 1979), and has determined that it is not ``significant''
under them.
This action completes the agency's response to petitions for
reconsideration regarding the July 2009 final rule amending FMVSS No.
121. This final rule revises the stopping distance table for vehicles
from very low speeds to reflect agency's intent in the July 2009 final
rule regarding braking performance level from very low test speeds.
Today's action will not cause any additional expenses for vehicle
manufacturers. This action will not have any significant safety
impacts.
B. Privacy Act
Anyone is able to search the electronic form of all documents
received into any of our dockets by the name of the individual
submitting the document (or signing the document, if submitted on
behalf of an association, business, labor union, etc.). You may review
DOT's complete Privacy Act Statement in the Federal Register published
on April 11, 2000 (Volume 65, Number 70; Pages 19477-78) or you may
visit https://docketsinfo.dot.gov/.
C. Other Rulemaking Analyses and Notices
In the July 2009 final rule, the agency discussed relevant
requirements related to the Regulatory Flexibility Act, the National
Environmental Policy Act, Executive Order 13132 (Federalism), the
Unfunded Mandates Reform Act, Civil Justice Reform, the National
Technology Transfer and Advancement Act, the Paperwork Reduction Act,
and Executive Order 13045 (Protection of Children from Environmental
Health and Safety Risks). As today's rule merely makes minor changes in
the stopping distance at lower speeds to reflect agency's intent in the
July 2009 final rule regarding braking performance level from very low
test speeds, it will not have any effect on the agency's analyses in
those areas.
VIII. Regulatory Text
List of Subjects in 49 CFR Parts 571
Imports, Motor vehicle safety, Reporting and recordkeeping
requirements, Tires.
In consideration of the foregoing, NHTSA amends 49 CFR part 571 as
follows:
PART 571--FEDERAL MOTOR VEHICLE SAFETY STANDARDS
0
1. The authority citation for part 571 of Title 49 continues to read as
follows:
Authority: 49 U.S.C. 322, 30111, 30115, 30117, and 30166;
delegation of authority at 49 CFR 1.50.
0
2. In Sec. 571.121, revise Table II to read as follows:
Sec. 571.121 Standard No. 121; Air brake systems.
* * * * *
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 PFC 0.9 PFC 0.9
--------------------------------------------------------------------------------------------------------------------------------------------------------
(1) (2) (3) (4) (5) (6) (7) (8)
-------------------------------------------------------------------------------------------------------
20.............................................. 32 35 32 35 38 30 83 85
[[Page 44834]]
25.............................................. 49 54 45 54 59 43 123 131
30.............................................. 70 78 65 78 84 61 170 186
35.............................................. 96 106 89 106 114 84 225 250
40.............................................. 125 138 114 138 149 108 288 325
45.............................................. 158 175 144 175 189 136 358 409
50.............................................. 195 216 176 216 233 166 435 504
55.............................................. 236 261 212 261 281 199 520 608
60.............................................. 280 310 250 310 335 235 613 720
--------------------------------------------------------------------------------------------------------------------------------------------------------
(1) Loaded and Unloaded Buses.
(2) Loaded Single-Unit Trucks.
(3) Loaded Tractors with Two Axles; or with Three Axles and a GVWR of 70,000 lbs. or less; or with Four or More Axles and a GVWR of 85,000 lbs. or less.
Tested with an Unbraked Control Trailer.
(4) Loaded Tractors with Three Axles and a GVWR greater than 70,000 lbs.; or with Four or More Axles and a GVWR greater than 85,000 lbs. Tested with an
Unbraked Control Trailer.
(5) Unloaded Single-Unit Trucks.
(6) Unloaded Tractors (Bobtail).
(7) All Vehicles except Tractors, Loaded and Unloaded.
(8) Unloaded Tractors (Bobtail).
* * * * *
Issued on: July 21, 2011.
Ronald L. Medford,
Deputy Administrator.
[FR Doc. 2011-18929 Filed 7-26-11; 8:45 am]
BILLING CODE 4910-59-P
