[Federal Register: March 6, 2007 (Volume 72, Number 43)]
[Rules and Regulations]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
DEPARTMENT OF TRANSPORTATION
Federal Motor Carrier Safety Administration
49 CFR Part 393
[Docket No. FMCSA-2005-21323]
Parts and Accessories Necessary for Safe Operation: Surge Brake
AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT.
ACTION: Final rule.
SUMMARY: FMCSA amends the Federal Motor Carrier Safety Regulations to
allow the use of automatic hydraulic inertia brake systems (surge
brakes) on trailers when the ratios of gross vehicle weight ratings
(GVWR) for the towing-vehicle and trailer are within certain limits. A
surge brake is a self-contained permanently closed hydraulic brake
system activated in response to the braking action of the towing
vehicle. The amount of braking force developed by the trailer surge-
brake system is proportional to the ratio of the towing vehicle to
trailer weight and deceleration rate of the towing vehicle. This action
is in response to a petition for rulemaking from the Surge Brake
DATES: Effective Date: April 5, 2007.
ADDRESSES: Docket: For access to the docket to read background
documents or comments received, go to http://dms.dot.gov at any time,
or go to Room PL-401 on the plaza level of the Nassif [[Page 9856]]
Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5
p.m., Monday through Friday, except Federal Holidays.
FOR FURTHER INFORMATION CONTACT: Mr. Luke W. Loy, Vehicle and Roadside
Operations Division, Federal Motor Carrier Safety Administration, 202-
366-0676, 400 Seventh Street, SW., Washington, DC 20590-0001. Office
hours are from 9 a.m. to 5 p.m., e.s.t., Monday through Friday, except
SUPPLEMENTARY INFORMATION: This Final Rule is organized as follows:
I. Legal Basis for the Rulemaking
A. Current Regulatory Environment
B. Regulatory History
D. Analysis of Petition
E. Notice of Proposed Rulemaking (NPRM)
III. Discussion of Comments to NPRM
A. Comments Supporting
B. Comments Opposing
V. Regulatory Analyses and Notices
VI. Regulatory Language for the Final Rule
I. Legal Basis for the Rulemaking
This rule is based on the authority of the Motor Carrier Act of
1935 and the Motor Carrier Safety Act of 1984.
The Motor Carrier Act of 1935 provides that "[t]he Secretary of
Transportation may prescribe requirements for--(1) qualifications and
maximum hours of service of employees of, and safety of operation and
equipment of, a motor carrier; and (2) qualifications and maximum hours
of service of employees of, and standards of equipment of, a motor
private carrier, when needed to promote safety of operation" [49
The amendments to 49 CFR part 393 adopted today deal directly with
the "safety of * * * equipment of[ ] a motor carrier" [sec.
31502(b)(1)] and the "standards of equipment of[ ] a motor private
carrier * * *" [sec. 31502(b)(2)]. The adoption and enforcement of
rules relating to brakes on commercial vehicles was clearly authorized
by the Motor Carrier Act of 1935. This rule rests squarely on that
The Motor Carrier Safety Act of 1984 provides concurrent authority
to regulate drivers, motor carriers, and vehicle equipment. It requires
the Secretary of Transportation to "prescribe regulations on
commercial motor vehicle safety. The regulations shall prescribe
minimum safety standards for commercial motor vehicles." Although this
authority is very broad, the Act also includes specific requirements:
"At a minimum, the regulations shall ensure that--(1) commercial motor
vehicles are maintained, equipped, loaded, and operated safely; (2) the
responsibilities imposed on operators of commercial motor vehicles do
not impair their ability to operate the vehicles safely; (3) the
physical condition of operators of commercial motor vehicles is
adequate to enable them to operate the vehicles safely; and (4) the
operation of commercial motor vehicles does not have a deleterious
effect on the physical condition of the operators" [49 U.S.C.
This rule focuses primarily on the mandate of sec. 31136(a)(1) that
commercial motor vehicles (CMVs) be "equipped * * * and operated"
safely. FMCSA has determined that surge brakes can safely be allowed on
trailers operating in interstate commerce under the conditions set
forth in this final rule. Sections 31136(a)(2) and 31136(a)(4) deal
with the safety and health effects, respectively, of the operational
responsibilities imposed on CMV drivers. The Agency has concluded that
operating a combination vehicle that includes a surge-braked trailer
meeting the requirements of this rule would neither impair a driver's
ability to operate safely nor adversely affect the driver's health.
Finally, sec. 31136(a)(3) deals almost exclusively with a driver's
"physical condition," i.e., medical status. That subject is not
specifically addressed in this rule, and the surge-brake provisions
adopted today would not affect a driver's physical condition.
Before prescribing any regulations, FMCSA must also consider the
"costs and benefits" of its proposal (49 U.S.C. 31136(c)(2)(A) and
31502(d)). Those factors are discussed in the regulatory analysis for
this rule filed separately in the docket.
A. Regulatory History
The National Highway Traffic Safety Administration (NHTSA) has a
legislative mandate under Title 49 of the United States Code, Chapter
301, Motor Vehicle Safety, to issue Federal Motor Vehicle Safety
Standards (FMVSS) and Regulations to which manufacturers of motor
vehicles must conform; manufacturers must certify that their vehicles
and equipment comply with the FMVSSs. These Federal safety standards
are regulations written in terms of minimum safety performance
requirements for motor vehicles or equipment. These requirements are
specified in such a manner that the public is protected against
unreasonable risk of crashes occurring as a result of the design,
construction, or performance of motor vehicles and is also protected
against unreasonable risk of death or injury in the event crashes do
FMVSS No. 121, "Air brake systems," specifies performance and
equipment requirements for trucks, buses, and trailers equipped with
air brake systems, including air-over-hydraulic brake systems, to
ensure safe braking performance under normal and emergency
conditions.\1\ However, there are no requirements in FMVSS No. 121, or
any of the other FMVSSs, relating to the performance of surge brakes,
electric brakes, or parking brakes on trailers.
\1\ Certain trailers and trucks are exempted depending on width,
axle GVWR, maximum speed, and unloaded vehicle weight.
Whereas the FMVSSs--other than FMVSS No. 121--do not specify
performance requirements for trailer braking, Section 393.40 of the
FMCSRs requires each CMV to have brakes adequate to stop and hold the
vehicle or combination of motor vehicles. Trailer braking performance
is specified in Section 393.52(d) of the FMCSRs, and generally requires
property-carrying vehicles and combinations of property-carrying
vehicles used in interstate commerce be able to stop within 40 feet
from 20 miles-per-hour (mph) on a hard surface that is substantially
level, dry, smooth, and free of loose material. However, any
semitrailer, trailer, or pole trailer with a gross weight of 3,000
pounds or less is not required to be equipped with brakes if the axle
weight of the towed vehicle does not exceed 40 percent of the sum of
the axle weights of the towing vehicle. Thus, a combination operating
in interstate commerce would not need brakes on a 3,000-pound trailer
when pulled by a 7,500-pound or heavier towing vehicle (49 CFR
393.42(b) (3)-(4)). In these cases, the vehicle combination must be
able to stop within 35 feet from 20 mph, and the service brakes of the
towing vehicle alone are sufficient to stop the combination.
In 1952, the two requirements regarding brakes that are the subject
of this rulemaking were included in the FMCSRs. Section 393.48 of the
FMCSRs requires that all brakes with which a motor vehicle is equipped
be capable of operating at all times. In addition, Sec. 393.49
requires that a single application valve must, when applied, operate
all the service brakes on the motor vehicle or combination of motor
vehicles. While electric brakes on trailers used in interstate commerce
are considered to meet the requirements of Sec. Sec. 393.48 and
393.49, and have been in use for many years, regulatory guidance issued
by the Agency in 1975 (40 FR [[Page 9857]] 50671, 50688, Oct. 31, 1975) \2\ indicated the use of surge brakes on
trailers operated in interstate commerce was inconsistent with the
requirements of Sec. Sec. 393.48 and 393.49. The 1975 guidance reads
\2\ The Federal Highway Administration's (FHWA) Bureau of Motor
Carrier Safety (Bureau) (FMCSA's predecessor agency) published these
Section 393.48 Brakes to be Operative. The Bureau's position
regarding surge brakes has been that they did not comply with the
requirements of Section 393.48 of the Motor Carrier Safety
Regulations. The cited section requires, in part, that all brakes
with which motor vehicles are required to be equipped must be
operative at all times. A surge brake which is only operative under
certain preset conditions would not be in compliance with this
requirement. In other words, surge brakes, in general, are only
operative when the vehicles are moving in the forward direction.
Section 393.49 Single Valve to Operate All Brakes. A surge brake
would comply with the requirements of Section 393.49 as it
specifically states that the brake system shall be so arranged that
one application valve shall, when applied, operate all of the
service brakes on the motor vehicle or combination of motor
vehicles. When the service brakes on a power unit towing a vehicle
with surge brakes are applied, the brakes on both vehicles would be
applied. The power unit brakes would be applied by its application
valve and the surge brakes on the towed vehicle by the overrunning
Subsequent regulatory guidance published by FHWA on November 17,
1993, (58 FR 60734, 60755) indicated that surge brakes did not comply
with either Sec. 393.48 or Sec. 393.49. It reads as follows:
Section 393.48 Brakes to be Operative.
Question 1: Do surge brakes comply with Sec. 393.48?
Guidance: No. Section 393.48 requires that brakes be operable at
all times. Generally, surge brakes are only operative when the
vehicle is moving in the forward direction and as such do not comply
with Sec. 393.48.
Section 393.49 Single Valve to Operate All Brakes. Question 1:
Does a combination of vehicles using a surge brake to activate the
towed vehicle's brakes comply with Sec. 393.49?
Guidance: No. The surge brake cannot keep the trailer brakes in
an applied position. Therefore, the brakes on the combination of
vehicles are not under the control of a single valve as required by
Sec. 393.49. * * *
The 1993 guidance was also republished in FHWA's April 4, 1997,
publication, "Regulatory Guidance for the Federal Motor Carrier Safety
Regulations." (62 FR 16370, 16415-16416)
Various parties over the years expressed concern about FMCSA's
position on trailer surge brakes. FMCSA advised interested parties to
follow the procedures found at Sec. 389.31 and submit a petition
requesting such a rule change accompanied by sufficient information
supporting the safety performance of their request. The Surge Brake
Coalition (Coalition) submitted such a petition requesting a rulemaking
to change the regulation. FMCSA notes that in contrast to the United
States, Canada allows surge brake systems on trailers used in inter-
Provincial commerce. Today's rule allowing surge brakes will enhance
the uniformity of Canadian and U.S. safety regulations.
B. The Surge Brake Coalition Petition
The Coalition submitted a petition on February 28, 2002, asking
FMCSA to undertake rulemaking to allow surge brakes by amending
Sec. Sec. 393.48 and 393.49. Members of the Coalition include trailer
manufacturers, parts suppliers, commercial users of surge-braked
trailers, trailer rental companies, and trade associations representing
segments of the trailer business. A copy of the Coalition's petition is
included in the docket referenced at the beginning of this document.
The Coalition said:
Technological advances in braking systems render the original
purpose of 393.49 and its "single-valve" criterion overly broad
and excessively restrictive. FHWA [previously] developed this
regulation as a materials-oriented specification to foreclose the
shortcomings of and risks associated with the predominant braking
system of the day, wheel brakes and their use in conjunction with
large tractors or power units.
The Coalition asserted that Congress had declared that DOT's motor
vehicle safety standards must be minimum performance standards, based
upon performance of the vehicle (49 U.S.C. 30102(a)(8) and (9)). The
standards must "meet the need for motor vehicle safety" and must be
"stated in objective terms" (49 U.S.C. 30111(a)). However, FMCSA's
interpretation of how Sec. Sec. 393.48(a) and 393.49 apply to surge
brakes is a prescriptive component specification that does not address
how the trailer braking system performs either as a unit or as part of
a combination vehicle.
The Coalition requested that section 393.48 be amended by:
1. Revising paragraph (a) to read:
"General rule. Except as provided in paragraphs (b), (c), and
(d) of this section, all brakes with which a motor vehicle is
equipped must at all times be capable of operating."
2. Adding a new paragraph (d) to read:
(d) Surge brakes. Paragraph (a) of this section does not apply
to: Any trailer with a gross vehicle weight rating (GVWR) of 12,000
pounds or less, equipped with inertial surge brakes when its GVWR
does not exceed 1.75 times the GVWR of the towing vehicle; or
Any trailer with a GVWR greater than 12,000 pounds, but less
than 20,001 pounds, equipped with inertial surge brakes when the
GVWR does not exceed 1.25 times the GVWR of the towing vehicle.''
The Coalition also requested the following exception be added to
"This requirement shall not apply to trailers equipped with
surge brakes that satisfy the conditions provided in Sec.
The Coalition argued that surge brakes provide a safe, practical
braking system for CMV combinations, especially for scenarios in which
the trailer is likely to be towed by a variety of vehicles. For
example, in the rental market, trailers are commonly rented separately
from towing vehicles, and towing vehicles frequently are not wired for
electric brake controls. The Coalition indicated that rental companies
believe it is "prohibitively expensive and impractical" to install or
adapt an electric brake control system on each towing vehicle every
time they rent a trailer or piece of mobile equipment outfitted with
The Coalition stated that surge brakes are a popular alternative to
electric brakes because they activate automatically when the towing
vehicle brakes are applied, adapt to the weight of the trailer load,
have fewer components, and require less maintenance than trailers with
electric brakes. These features make surge brakes ideal for flatbed and
van-type trailers with a GVWR of 20,000 pounds or less, and boat
trailers serving the marine industry. The Coalition also noted that
manufacturers install approximately 250,000 surge brake systems
annually on such trailers. This includes both in the personal market
and the commercial intrastate market in 7 States, as of their 2002
petition, where the Coalition said surge brakes are allowed in
intrastate commercial applications. (The 2004 article cited in the
Regulatory Evaluation from Trailer Body Builders indicates the number
of such States had risen to 9.\3\) The Coalition estimated that over 25
percent of the rental trailer fleet is equipped with surge brakes.
There are no restrictions in any State on surge-braked trailers for
\3\ A Break on Brakes, in Trailer Body Builders, August 1, 2004,
Rick Weber (http://trailer-bodybuilders.com/mag/trucks_break_brakes/
The Coalition's Engineering Tests
In order to demonstrate systematically that surge brake equipped
trailers meet the safety performance requirements of the FMCSRs, as
well as relevant testing [[Page 9858]] procedures adapted from NHTSA's FMVSS No. 121 that apply to air-braked
trailers, the Coalition retained the services of Mr. Richard H. Klein,
P.E., who is described as a nationally known expert in trailer safety
and testing. Mr. Klein was tasked to develop a test plan, select an
independent testing laboratory, and to oversee the testing of a variety
of tow vehicles and trailers equipped with surge brakes. Mr. Klein
finalized the test protocol, procedures and methods. The tests covered
combinations of representative towing vehicles commonly used by
customers and trailers widely available in the rental market. Special
attention was given to the ratio of the gross vehicle weight rating
(GVWR) of the towing vehicles to that of the trailers when evaluating
braking performance. Mr. Klein then solicited bids to obtain the
services of a qualified, reputable, independent testing lab to execute
The facility selected by Mr. Klein was Exponent Failure Analysis
Associates' (EFAA) Test and Engineering Center in Phoenix, Arizona.
EFAA is an ISO 9001 lab that conducts a wide variety of scientific
testing and research. EFAA has performed compliance testing on various
FMVSSs for NHTSA. Initially, EFAA tested and fully analyzed the data
from the braking performance of 11 different combinations of
instrumented towing vehicles and trailers from the matrix developed by
Mr. Klein. Those 11 combinations were chosen for full analysis from the
20 instrumented combinations initially tested because they represented
a very wide range of towing vehicle to trailer GVWR ratios. Based on
results of those initial tests, two additional vehicle configurations
were tested to determine the performance of trailers over 12,001 pounds
GVWR when the ratio of the simulated trailer GVWR to towing vehicle
GVWR was restricted to 1:1.25.
Mr. Klein interpreted the test data provided to him by EFAA and
prepared the final report. His report is included as part of the
petition submitted by the Coalition, and is, thus, included in the
docket for this rulemaking.
Light. 1999 U-Haul tandem axle auto transport (6,000
pounds GVWR), equipped with U-Haul surge brake actuator.
Medium. 2000 Big Tex tandem axle, open cargo area, with
side rails (14,000 pounds GVWR), equipped with Demco Model DA20 surge
Heavy. Two-2001 Wells Cargo flatbed trailers with triple
torsion axles (20,000 pounds GVWR). One trailer was equipped with a
Titan model 20 surge brake actuator and the other with a Demco DA20
surge brake actuator.
Towing Vehicles (GVWR)
Light. 1993 Chevrolet C-1500 (6,100 pounds GVWR), curb
weight 4,194 pounds. The vehicle was equipped with front disc brakes
and rear drum brakes. The vehicle was also equipped with a rear-axle
antilock braking system (ABS).
Medium. 2001 Chevrolet K-3500 (11,400 pounds GVWR), curb
weight 7,072 pounds. The vehicle was equipped with four-wheel disc
brakes, four-wheel ABS and dual rear tires.
Medium. 2001 GMC Sierra (11,400 pounds GVWR), curb weight
7,476 pounds. The vehicle was equipped with four-wheel disc brakes,
four-wheel ABS and dual rear tires.
Note: The petition referred to the Chevrolet K-3500 and GMC
Sierra as "heavy" vehicles. This document labels them as medium
weight vehicles to distinguish them from the later discussion of a
towing vehicle with a 16,000-pound GVWR, which we term ``heavy.''
The Coalition developed a test plan modeled on the procedures
employed by NHTSA. It was designed to check brake performance in three
areas of particular concern for surge brake equipped trailers.
1. Straight-line braking: Vehicle combinations were tested to see
whether their stopping distance from 20 mph could meet the straight
line performance requirements under Sec. 393.52. The vehicle
combination was required to stay within a 12-foot-wide lane during the
test and not exceed the 40-foot stopping distance limit.
2. Braking in a curve: FMVSS Nos. 105 and 121 both require testing
of brakes in a 500-foot radius curve from 30 mph on wet pavement to
determine functionality of the ABS brakes on what would be the towing
vehicles in this rulemaking. This requirement does not apply since
functioning of ABS brakes is not the subject of this rulemaking.
Although the FMVSS do not have a specification for braking-in-a-curve
tests for trailers, the Coalition decided to include such tests of
combination vehicles on a dry surface (as required by Sec. 393.52) to
check for jack-knifing tendencies and any other sources of instability.
Testing consisted of driving the towing and trailer combinations at 30
mph on a circular, 12-foot-wide, 500-foot-radius test track. The driver
then applied the brakes to achieve maximum deceleration, and the
vehicle combination was required to stay within a 12-foot-wide lane
during the stop.
3. Brake-holding on a hill: Because surge brakes work by
transforming the trailer's forward momentum into hydraulic braking
pressure, a stationary trailer facing uphill generates no braking
effect. The Coalition, therefore, tested whether a combination that is
required to stop facing uphill on a 20 percent grade can safely remain
stationary using only the service brakes of the towing vehicle. The
issue has practical implications in hilly areas where stop signs or
traffic signals might halt a combination heading uphill. The Coalition
applied the standard normally used for the parking brake, which in this
case is for the towing vehicle, as specified in FMVSS Nos. 105 and 121,
i.e., holding on a 20 percent grade. The combination was required to
remain stationary for at least 5 minutes.
A total of 22 towing vehicle and trailer combinations were tested.
The petition explained that data from 13 instrumented combinations
representing the widest possible range of weight ratios were selected
for detailed analysis and inclusion in Mr. Klein's final report, which
was included in the petition. The petition says that data collected
from the other instrumented vehicle combinations tested were not
included in the report because of budget constraints, but these tests
generated essentially the same performance results as those that were
Initially, three towing vehicles representing two weight classes
were tested with three trailers representing three weight classes.
Subsequently, a fourth medium weight towing vehicle and heavy trailer
were added for two extra tests.
The first three towing vehicles were run both at their unloaded
curb weights of 4,194 pounds, 7,072 pounds and 7,476 pounds, and also
loaded to their approximate GVWR of 6,100 pounds, 11,400 pounds, and
11,400 pounds, respectively. The three trailers were loaded at
different weights to simulate towing vehicle to trailer GVWR ratios of
1:1, 1:1.25, 1:1.5, 1:1.7 and 1:2. The test "curb weights" shown in
the petition for the towing vehicles were measured by driving the
towing vehicles with loaded trailers attached onto the scales just
before starting the test. Thus, the "curb weights" shown in the test
data includes the driver, test equipment, fuel load, and tongue weight.
A reasonable approximation of the tongue weight is 10 percent of the
loaded trailer weight. For example, in a medium towing vehicle with an
unloaded curb weight of [[Page 9859]] 7,072 pounds towing a heavy trailer loaded to 16,540 pounds, the weight
of the driver, fuel and test equipment and tongue weight produced a
test "curb weights" of 9,370 when the towing vehicle began the test.
For similar reasons, a few of the actual test weights for the towing
vehicle slightly exceeded the GVWR of the towing vehicle.
1. Straight-line braking: A light towing vehicle (GVWR of 6,100
pounds), operating both at test curb weight and loaded to full GVWR,
was tested in combination with a light trailer loaded approximately to
its GVWR at 6,030 pounds for a ratio of approximately 1:1. Both of
these combinations stopped from 20 mph well within the 40 feet allowed
by Sec. 393.52.
The light towing vehicle loaded approximately to its GVWR of 6,100
pounds was also tested with a medium weight trailer (14,000 pounds
GVWR) loaded to 9,090 pounds and 12,090 pounds (simulating GVWR ratios
of approximately 1:1.5 and 1:2, respectively). These combinations also
complied with Sec. 393.52 by stopping from 20 mph within 40 feet.
The medium towing vehicles of 11,400 pounds GVWR were tested loaded
to their GVWR with (1) a medium trailer (GVWR 14,000 pounds) partially
loaded to 12,090 pounds for a simulated ratio of approximately 1:1.1,
and (2) a heavy trailer (GVWR 20,000 pounds) partially loaded to 14,600
pounds for a simulated GVWR ratio of approximately 1:1.25. These
combinations complied with Sec. 393.52, demonstrating safe braking
performance when the simulated GVWR of trailers heavier than 12,000
pounds was limited to approximately the requested 1.25 times that of
the towing vehicle, or less.
A medium towing vehicle tested with a heavy trailer (both loaded to
approximately their GVWR for a ratio of 1:1.75) achieved a stopping
distance of 44.7 feet from 20 mph. This combination has a GVWR ratio
that is considerably higher (approximately 40 percent higher) than the
1:1.25 requested by the petitioner for heavier trailers, yet the
vehicle combination still came very close to the stopping distance
requirement of 40 feet, as specified in Sec. 393.52.
This test with a GVWR ratio of 1:1.75 demonstrated that the
Coalition's proposed GVWR ratio of 1:1.25 is conservative, and includes
a substantial safety margin for trailers with a GVWR greater than
2. Braking in a curve: EFAA conducted 39 brake-in-a-curve tests
with 11 combinations. The actual or simulated GVWR ratios varied widely
(from 1:1 to 1:2), depending on the load carried by the trailer. These
tests included all the vehicle combinations described in the straight-
line braking test above, except for the two combinations added later,
i.e., a medium towing vehicle with a trailer loaded to 14,600 pounds
for a weight ratio of 1:1.25. The braking-in-a-curve test was not done
on those combinations because these tests had already been run for that
vehicle at weight ratios up to 1:2.
The combinations included in these tests included: light towing
vehicle and light trailer; the light towing vehicle and the medium
trailer; medium towing vehicle and medium trailer; and medium towing
vehicle and heavy trailer. The reported results indicated that in all
of the 39 tests, the combinations were able to stop from 30 mph within
a 12 foot lane on a 500 foot radius circle without any loss of control.
3. Brake-holding on a hill: Six combinations were parked heading
uphill on a 20 percent grade. In all cases, the service brakes on the
towing vehicle held the entire combination in place for 5 minutes, the
duration of the test. The combinations tested included: A light towing
vehicle both at its test "curb weight" and loaded to its GVWR
attached to a trailer loaded to a simulated GVWR of 12,090 pounds, for
a maximum GVWR ratio of approximately 1:2; a medium towing vehicle
tested at its test "curb weight" with a heavy trailer loaded to
16,540 pounds for a simulated GVWR ratio of approximately 1:1.45; and a
medium towing vehicle loaded approximately to its GVWR and tested with
a heavy trailer loaded to its approximate GVWR of 20,000 pounds,
representing a GVWR ratio of about 1:1.75.
Although surge brakes automatically release when deceleration
stops, the tests showed that the service brakes of a towing vehicle are
more than adequate to hold the combination at a stop even while facing
uphill on a 20 percent grade, even when the GVWR ratios substantially
exceed the limits proposed by the Coalition.
C. Analysis of Petition
The data submitted by the Coalition indicate that approximately
250,000 surge-brake units are installed each year. This large number
creates a considerable population of non-commercial surge-braked
trailers operating on the public roads. Numerous commenters contend
that this trailer braking technology is inherently unsafe, as discussed
in following sections, because--compared to other brake systems--it
increases (1) the risk of brake fires while descending large hills, and
(2) the risk of crashes. FMCSA was unable to find any data to support
those claims. Although surge brakes have been in use for many years, no
government agency or private entity that FMCSA is aware of has found
their performance to be inadequate or contributory to highway crashes.
The absence of such data suggests that the alleged safety problems of
surge brakes are in fact a non-issue for their manufacturers, renters
and insurers of trailers so equipped, and State and local safety
officials. FMCSA believes that the use of surge brakes has proven to be
FMCSA investigated whether crash data could be obtained from either
NHTSA's Fatality Analysis Reporting System (FARS) or the General
Estimates System (GES) to assist in this evaluation. Neither FARS nor
GES identifies the type of brakes used on trailers involved in fatal or
non-fatal crashes and, therefore, cannot reveal whether surge brakes
are under-or over-represented in crash statistics.
FMCSA analyzed the information provided by the Coalition and, as
indicated in the NPRM, made a preliminary determination that the test
results supported a number of conclusions. Vehicles equipped with surge
brakes, subject to the GVWR ratios proposed in the petition and NPRM
(1) have sufficient braking capability to comply with the Agency's
stopping requirements while operating on public roads in interstate
commerce; (2) have no braking stability problems; and (3) are able to
safely hold their position when stopped facing uphill on steep grades,
and then to proceed.
The test results involving a medium towing vehicle and a heavier
trailer were particularly important. The tests demonstrated that
heavier towing vehicles in compliance with FMVSS No. 105, which allows
a longer stopping distance for non-passenger vehicles over 10,000
pounds, would still meet the vehicle braking performance requirements
of Sec. 393.52 if the GVWR ratio of towing vehicle to trailer did not
exceed 1:1.25. The Coalition's petition asked for the break point in
towing vehicle to trailer GVWR ratio to occur at 12,000 pounds. At a
GVWR ratio of 1:1.25, the FMVSS No. 105 definition for towing vehicles
of 10,000 or more pounds would place that break point for trailers with
a GVWR of over 12,500 pounds. FMCSA chose the more conservative 12,000
requested by the Coalition.
Thus, while surge brakes are not "operable at all times," as
required by Sec. 393.48(a), FMCSA concluded that the Coalition's
safety performance test [[Page 9860]] results, which show that towing vehicles pulling surge-braked trailers
were consistently able to stop within the distances required by Sec.
393.52, provided certain GVWR ratios were observed, adequately
demonstrate that the design requirement of Sec. 393.48(a) is
excessively restrictive. The purpose of Sec. 393.48(a) is to maintain
highway safety, and the Coalition's wide-ranging test program showed
that towing vehicles, which are all subject to either FMVSS Nos. 105,
121 or 135, when operated with surge-braked trailers that are within
the specified GVWR ratios, meet all applicable stopping tests. In view
of those performance results, the Agency preliminarily determined that
Sec. 393.48 should not be allowed to bar the operation of surge-braked
trailers in interstate commerce.
FMCSA's analysis of the petition was reviewed by NHTSA, which
concurred in the determination to grant the petition to initiate a
D. Notice of Proposed Rulemaking (NPRM)
FMCSA published an NPRM on October 7, 2005 (70 FR 58657). The
Agency explained that the use of surge brakes, under the conditions
specified in the NPRM, appeared to be consistent with the safety
performance objectives, though not the letter, of Sec. Sec. 393.48 and
393.49. Therefore, the Agency concluded it was appropriate to propose
amending the regulations to allow the use of surge-braked trailers in
The NPRM proposed adding the following definition of ``surge
brake'' to Sec. 390.5:
Surge Brake. A self-contained, permanently closed hydraulic brake
system for trailers that relies on inertial forces, developed in
response to the braking action of the towing vehicle, applied to a
hydraulic device mounted on or connected to the tongue of the trailer,
to slow down or stop the towed vehicle.
The NPRM proposed amending Sec. 393.48 by revising paragraph (a)
and adding paragraph (d) to read as follows:
Sec. 393.48 Brakes To Be Operative
(a) General rule. Except as provided in paragraphs (b), (c), and
(d) of this section, all brakes with which a motor vehicle is
equipped must at all times be capable of operating.
(b) * * *
(c) * * *
(d) Surge brakes. Paragraph (a) of this section does not apply
(i) Any trailer with a gross vehicle weight rating (GVWR) of
12,000 pounds or less, equipped with inertial surge brakes when its
GVWR does not exceed 1.75 times the GVWR of the towing vehicle; or
(ii) Any trailer with a GVWR greater than 12,000 pounds, but
less than 20,001 pounds, equipped with inertial surge brakes when
the GVWR does not exceed 1.25 times the GVWR of the towing vehicle.
The NPRM proposed replacing Sec. 393.49 in its entirety, including
a revised title, to read as follows:
Sec. 393.49 Control Valves for Brakes
(a) General rule. Except as provided in paragraphs (b) and (c)
of this section, every motor vehicle, manufactured after June 30,
1953, which is equipped with power brakes, must have the braking
system so arranged that one application valve must when applied
operate all the service brakes on the motor vehicle or combination
of motor vehicles. This requirement must not be construed to
prohibit motor vehicles from being equipped with an additional valve
to be used to operate the brakes on a trailer or trailers or as
provided in Sec. 393.44.
(b) Driveaway-Towaway Exception. This section is not applicable
to driveaway-towaway operations unless the brakes on such operations
are designed to be operated by a single valve.
(c) Surge brake exception. This requirement is not applicable to
trailers equipped with surge brakes that satisfy the conditions
specified in 49 CFR Sec. 393.48(d).
In view of the representative nature of the simulated GVWR ratios
for towing vehicles and trailers used in the Coalition's tests and the
satisfactory performance results, the NPRM noted that it was
appropriate to conclude that surge-braked vehicles were safe, when
operating within the specified ratios of towing vehicle GVWR to trailer
The petition did not include test data demonstrating that a towing
vehicle with a GVWR of 16,000 pounds or more, towing a 20,000 pounds
trailer, could stop within 40 feet. Therefore, FMCSA noted it was
reasonable to assume such a combination would pass the test, but also
asked for public comment and data either supporting or contradicting
that assumption. Specifically:
The Agency requests comment on whether additional analysis is
needed to support the Petitioner's assertion that vehicle
combinations that include a heavy trailer (GVWR between 14,600
pounds and 20,000 pounds) would satisfy FMCSA's brake performance
requirements under Sec. 393.52 when the GVWR of the trailer is 1.25
times that of the towing vehicle or less. The agency is also
requesting the submission of brake performance data and information
relevant to all the other issues raised in the petition, and the
proposed amendments to Sec. Sec. 393.48 and 393.49.
II. Discussion of Comments to the NPRM
The Agency received 63 individual comments in response to the NPRM.
(In some cases, more than one person from the same organization
submitted similar comments.) Comments were submitted on behalf of the
following organizations: A-1 Rental; A to Z Rental Center; ABC
Equipment Rental; Action Rental; ADH Equipment & Sales; Advocates for
Highway and Auto Safety (Advocates); Aide Rentals & Sales II; All
County Rental Center; All Star Rents; ALTCO Tool Rental, L.L.C.;
American Rental Association (ARA); American Trucking Associations, Inc.
(ATA); Aurora Rents, Inc.; Arapahoe Rental; Bee Gee Rental & Sales; Mr.
Barry Hansel; Bill's Rental Center, Inc.; Bradley Rentals; Bryant's
Rent-All, Inc.; Buttons Rent-It; Carlisle Industrial Brake and Friction
(Carlisle); Construction Rental Inc.; County Corner Rental Center,
Inc.; Do-It-Yourself, Inc.; Equipment Rentals Inc.; Front Range Rents;
Grants Rental; Highway 55 Rental; House of Rental; Jackson Rentals &
Supplies Inc.; Johnson Creek Rentals; Kimps ACE Hardware and Rental;
LEW Corporation; Lew Rents; Lindner Hardware, Inc.; London Road Rental
Center; Maryland State Highway Administration, Motor Carrier Division
(MDSHA/MCD); Mikerentals, Inc.; National Marine Manufacturers
Association (NMMA); the Ohio State Highway Patrol (OSHP); Reading
Rentals, Inc.; Rental World; The Rentit Shop Inc.; S and M Rentals
Inc.; Southwest Rentals, Inc.; Sunstate Equipment Co.; Surge Brake
Coalition (Coalition); Taylor Rental; Taylor Rental Center; Truck
Manufacturers Association (TMA); Tidewater Rental & Sales; Total Rental
Center; Top Quality Rental and Sales, LLC; United Rentals; Wautoma
Rental Center; Wirtz Rentals, Co.; and Wirtz Rentals Co. Summit
A. Comments Supporting the NPRM
Fifty-four (54) commenters identified themselves as members of the
ARA, and provided comments supporting the NPRM. The ARA commenters
stated they rent surge brake equipped trailers, and indicated that
FMCSA's current interpretation of the rules causes problems for both
commercial and non-commercial customers. Specifically, non-commercial
customers may use trailers equipped with surge brakes for private use
without restrictions, while commercial customers are prohibited from
using those same trailers in interstate commerce (or even in intrastate
commerce in 41 States and the District of Columbia) due to the existing
interpretations of the FMCSRs. These 54 commenters are grouped together
1. ARA is a member of the Coalition, and supports its comments to
the docket. ARA's initial comments essentially repeat material included
in [[Page 9861]] the petition for rulemaking. Namely, the proposed modifications to 49
CFR Part 393 will allow commercial trailers to use surge brakes for
specified weight combinations, thus harmonizing braking system
regulations for commercial interstate, commercial intrastate and non-
commercial trailers equipped with surge brakes. ARA believes the
proposed action will simplify enforcement and eliminate the confusion
that trailer rental and sales businesses experience when advising both
commercial and non-commercial customers about appropriate equipment
Under the current regulations, a person operating as a licensed
contractor may not transport equipment on rented trailers equipped with
surge brakes in interstate commerce. The requirement of the Motor
Carrier Safety Assistance Program (MCSAP) that States adopt regulations
compatible with Federal regulations (49 CFR 350.201(a), 350.341) has
resulted in the widespread prohibition of surge-braked trailers for
commercial purposes, even in intrastate commerce. However, the
Coalition points out that an individual can legally use surge-braked
trailers for non-commercial uses. ARA believes this creates a
fundamentally unworkable system for rental businesses.
ARA contends that there are no viable alternatives to surge brakes
for rental businesses, where customers usually own the towing vehicles.
Trailers with electric brake systems are available, but are not
standardized, and towing vehicles are not always equipped with electric
brake controllers and the necessary wiring to operate trailers equipped
with electric brakes. ARA states that trailer brakes are a fundamental
safety requirement, and that use of self-contained surge brakes is the
only viable way rental businesses can meet that requirement.
ARA asserted that safety is a serious concern for its members and
that the safety record of surge-braked rental trailers is good. ARA
said that ARA Insurance Services (AIS), its wholly owned insurance
subsidiary, offers property, casualty and liability insurance to ARA
members. It offered the following information:
AIS writes insurance policies for approximately 40 percent of
the ARA membership. AIS researched all trailer claims in its system
back to 1989. During those 16 years, only six percent of the claims
were for accidents involving trailers or towable equipment. In 91
percent of those claims, AIS was able to determine that on trailers
equipped with surge brakes, the brakes were not the cause of the
accidents. On the remaining nine percent [or 0.54% of all claims],
there was not enough information or evidence available for AIS to
find that surge brakes were a factor, nor to rule out the
possibility that surge brakes were involved. However, within that 9
percent, we [AIS] found only two claims that actually mentioned
surge brakes and neither of those specified that the insured [rental
company] was liable for faulty surge brakes. It is noteworthy that
through 25-plus years in business, AIS has and continues today to
write insurance coverage for ARA members that have surge brake-
equipped trailers in their fleets. There are no special provisions,
premiums, or riders required for insuring surge brake equipped
trailers in rental fleets.
FMCSA Response: As noted earlier, this rule focuses primarily on
the mandate of 49 U.S.C. 31136(a)(1) that CMVs be "equipped * * * and
operated" safely. The fact that ARA's insurance subsidiary (AIS) does
not charge a premium to cover surge-braked rental trailers is a strong
indicator, based on actuarial experience, that trailers with surge
brakes are no less safe than trailers with any other kind of braking
system. The only two claims AIS was able to locate that mentioned surge
brakes do not indicate that they malfunctioned.
Many of ARA's comments addressed the issue of efficiency in
trailer-rental operations that, while not directly related to safety,
were considered in the preparation of this rule, including the
regulatory analysis of its costs and benefits.
2. (a) The Coalition pointed out that surge brake technology has
evolved since the petition was submitted and suggested the definition
of surge brakes may someday require modification. For example, non-
hydraulic surge brake systems have been developed and are entering the
marketplace in Europe. The Coalition proposed that FMCSA consider
deleting "permanently closed hydraulic" and the adjective
"hydraulic" from the definition of surge brakes as proposed in Sec.
390.5 to eliminate any future design restrictions, or the need for
further rulemaking petitions. The bulk of the Coalition comments
responded to the request in the NPRM to provide additional information
on trailers with weights between 14,000 pounds and 20,000 pounds.
(b) The Coalition acknowledged its tests did not include a towing
vehicle with a GVWR exceeding 11,400 pounds. Under the proposal, a
towing vehicle with a minimum GVWR of 16,000 pounds would be required
to tow a trailer with a GVWR of 20,000 pounds. Instead of obtaining a
16,000 pound towing vehicle and running actual tests, the Coalition
hired a national trailer expert, Dr. Michael Graboski, to perform
independent mathematical analyses to predict braking performance from
the data generated by the Coalition's tests. Specifically, Dr. Graboski
used the test data submitted in the petition and analytically predicted
that the combination of a heavy towing vehicle (GVWR of 16,000 pounds
or greater) and a trailer of 20,000 pounds GVWR would comply with the
stopping distance requirements of Sec. 393.52.
The Coalition again asserted that the stopping distance for a
properly matched combination vehicle depends on the ratio of the
towing-vehicle to trailer weight, and not just on the weight of the
trailer. The Coalition argued that the EFAA straight-line braking data
is sufficient to predict that combinations with heavy trailers (14,600
to 20,000 pounds GVWR) would comply with the requirements of Sec.
393.52 at GVWR ratios of 1:1.25 and less. It then reiterated the
following test data results:
Test data showed that the medium towing vehicle loaded to
its approximate test GVWR of 11,730 pounds successfully completed the
braking in a 2curve testing at 30 mph with a test weight trailer of
20,560 pounds. This represents a simulated GVWR ratio of 1:1.75,
compared to the proposed GVWR ratio of 1:1.25.
The towing vehicle loaded to its approximate test GVWR of
11,730 pounds with a test weight trailer of 20,560 pounds also
successfully held the combination facing uphill on a 20 percent grade
for 5 minutes using the service brakes. This is a GVWR ratio of 1:1.75,
compared to the proposed GVWR ratio of 1:1.25.
The towing vehicle loaded to its approximate test GVWR of
11,730 pounds, pulling a test weight trailer of 20,560 pounds, was also
able to stop in a straight line from 20 mph in a distance of 44.7 feet,
which only slightly exceeds the 40 feet stopping distance requirement
of Sec. 393.52. But this combination represents a GVWR ratio of 1:1.75
as compared to the proposed GVWR ratio of 1:1.25 for trailers between
12,001 pounds and 20,001 pounds GVWR.
The towing vehicle (both at test curb weight of 9,260
pounds and loaded to its GVWR of 11,400 pounds) pulling a 20,000 pound
GVWR trailer loaded to 14,600 pounds (ratio of 1:1.28) stopped within
38.5 and 38.9 feet respectively. The test data was used to perform the
two following analytical analyses.
Analysis one: Dr. Graboski analyzed the different combinations of
towing vehicle and trailer load ratios using linear regression. That
analysis predicted a stopping distance of exactly [[Page 9862]]
40 feet for a towing vehicle with a GVWR of 16,000 pounds pulling a
trailer with a GVWR of 20,000 pounds, which meets the standard for
stopping distance allowed by Sec. 393.52.
Analysis two: Dr. Graboski then performed a separate engineering
analysis based upon the mathematical modeling relationship found in the
final report submitted by Klein and Szostak under the 1979 NHTSA
contract (DOT-HS-805-327).\4\ The details regarding surge brake gain
(defined and discussed below) were subsequently published as a Society
for Automotive Engineers (SAE) paper.\5\ This model quantifies the
braking performance of towing vehicles with trailers equipped with
surge brakes. Using the principles of engineering mechanics set forth
in the Klein and Szostak model, Dr. Graboski applied the brake test
data collected by EFAA to calculate the minimum surge brake gain
necessary to achieve the required braking performance for a 16,000
pound GVWR towing vehicle with a 20,000 pound GVWR trailer equipped
with surge brakes.
\4\ Development of Car/Trailer Handling and Braking Standards;
Volume II: Technical Report, November 1979, copy in docket.
\5\ Klein, R.H., Szostak, H.T., "Description and Performance of
Trailer Brake Systems with Recommendations for an Effectiveness Test
Procedure," SAE 820135, 1982. This model quantifies the braking
performance of combination vehicles with trailers equipped with
surge brakes. An abstract of this copyrighted paper has been
included in the docket. Anyone who wishes to examine a hard copy of
this document should contact Mr. Luke Loy at the phone number given
at the beginning of this rule. The paper may be also purchased from
The deceleration of a towing vehicle-trailer combination is the sum
of the towing vehicle and trailer braking forces divided by the sum of
the weights of the towing vehicle and trailer. Surge brake operation
relies on the compression force at the trailer hitch caused by
deceleration of the towing vehicle being delivered to the trailer's
hydraulic actuator to activate the trailer's hydraulic brakes. The
compression force at the hitch is the product of the deceleration of
the towing vehicle and the weight of the trailer minus the brake force
of the trailer surge brakes.
Upon applying the towing vehicle brakes, the surge brake actuator,
located between the trailer and the towing vehicle, receives the
initial compressive force that results from the inertia difference
between the braked towing vehicle and the as-yet-unbraked trailer. The
surge brake actuator drives a piston in the trailer's hydraulic brake
system master cylinder producing hydraulic pressure in the trailer's
braking system proportional to that initial compressive force. The
ratio of the resulting initial braking force applied to the trailer
brakes to the compressive force at the surge brake actuator is termed
the surge brake gain. More simply stated, the gain is the ratio of the
amount of trailer braking force developed per pound of horizontal hitch
force. This is a measure of the performance of that surge brake system.
The value achieved is determined by the design characteristics of that
particular system, including characteristics of the actuator. Although
initial compression force generated at the hitch is subsequently
diminished because of the braking force being applied by the trailer
brakes, the amount of trailer braking force remains dependent on the
gain realized above the remaining force at the hitch.
Dr. Graboski used the Klein and Szostak model to calculate the
minimum required surge brake gain, G, necessary for the combination
vehicle to stop within the 40 feet stopping distance requirement of
Sec. 393.52. That value is 1.48.
Instrument readings from several tests were available from EFAA.
Those readings were used to calculate the initial surge brake gains
that occurred for the two actuators tested for the two 20,000 pound
GVWR 2001 Wells Cargo flatbed trailers. One was equipped with a Titan
Model 20 surge brake actuator and the other with a Demco DA20 surge
Towing vehicle loaded to its approximate test GVWR of
11,300 pounds and the 20,000 pound GVWR trailer loaded to 16,540
pounds, for a simulated GVWR ratio of approximately 1:1.45.
Towing vehicle of 11,400 GVWR at test curb weight of 9,370
pounds and the 20,000 GVWR trailer loaded to 16,540 pounds, for a
simulated GVWR ratio of approximately 1:1.45.
Towing vehicle at approximate test GVWR of 11,730 pounds
and the trailer loaded to its test GVWR of 20,560 pounds, for a GVWR
ratio of approximately 1:1.75.
Towing vehicle at approximately test GVWR of 11,400 pounds
and the 20,000 pounds GVWR trailer loaded to a test 14,600 pounds, for
a simulated GVWR ratio of about 1:1.28.
Towing vehicle of 11,400 GVWR at test curb weight of 9,260
pounds and the 20,000 pounds GVWR trailer loaded to 14,600 pounds, for
a simulated GVWR ratio of approximately 1:1.28.
Using the Klein and Szostak model, the surge brake gain, G,
achieved for each of these surge brake actuators was calculated. It was
1.59 for the Demco DA20 and 1.84 for the Titan Model 20 surge brake
actuators. The surge brake gain achieved by each of these actuators is
thus well above the calculated minimum surge brake gain, G, of 1.48
needed to stop a combination of a 16,000 pound towing vehicle with a
20,000 pound trailer within 40 feet from 20 mph.
Based upon these analyses, the Coalition submits that it is safe to
operate 20,000-pound GVWR trailers with towing vehicles having GVWRs of
16,000 pounds or more with braking characteristics similar to the
vehicles tested. In summary, the Coalition believes that their tests
and analytical evaluation of the data provide sufficient information to
conclude that the proposals in the NPRM should be adopted.
FMCSA Response: (a) No data are available to the Agency regarding
the performance of other surge brake technologies to support the
Coalition's request to remove the word "hydraulic" from the
definition of surge brake. If the Coalition wishes to make such data
available to FMCSA, a modification of this definition may be evaluated.
(b) The additional analysis is consistent with the provision of
Sec. 389.31(b)(4) that requires petitions to contain "* * * any
information and arguments available to the petitioner to support the
action sought." It is also consistent with the following request in
The Agency requests comment on whether additional analysis is
needed to support the Petitioner's assertion that vehicle
combinations that include a heavy trailer (GVWR between 14,600 lbs
and 20,000 lbs) would satisfy FMCSA's brake performance requirements
under Sec. 393.52 when the GVWR of the trailer is 1.25 times that
of the towing vehicle or less. The agency is also requesting the
submission of brake performance data and information relevant to all
the other issues raised in the petition, and the proposed amendments
to Sec. Sec. 393.48 and 393.49.
The Agency notes that the Klein and Szostak model was applied on
the assumption that the sustained braking deceleration of the heavy
towing vehicle with a 16,000-pound GVWR remains the same as the initial
braking deceleration achieved by the medium 11,400-pound GVWR vehicles.
The basis for this assumption is that the 16,000 pound GVWR vehicle is
required by FMVSS No. 105 to comply with the same braking performance
(stopping distance) as the 11,400 pound GVWR vehicle. Therefore, the
total braking capability of the 16,000 pound vehicle must be
proportionally greater than for the 11,400 pound vehicle, making it
more capable of maintaining the initial [[Page 9863]] braking deceleration force when the forward momentum of the trailer
comes to bear upon the trailer hitch.
The assertion by the Coalition that the surge brake gain of both
the Demco and Titan exceeds the minimum necessary for the combination
vehicle to stop within 40 feet is relevant only if these actuators are
reasonably representative of the brake gain provided by other surge
brake actuators available in the market.
FMCSA notes that the Demco and Titan actuators on the test trailers
represent manufacturers with very prominent market shares for heavy
trailer actuators. The technology on which these actuators are based is
quite standardized. The market for surge brake actuators for heavy
trailers (14,600-20,000 pounds) is relatively small. As such, it is
reasonable to assume other competing surge brake actuators in this
weight range will have to provide comparable performance to remain
competitive in the market. Therefore, the Agency believes the measured
surge brake gains of 1.59 and 1.84 are representative, and that it is
reasonable to presume the minimum gain necessary of 1.48 will be met by
The Agency determined that the Coalition has provided sufficient
additional analytical information supporting its original proposal to
allow surge brakes on trailers when the towing vehicle to trailer GVWR
ratio does not exceed 1:1.25 for trailers with GVWRs between 14,600
pounds and 20,000 pounds. The two independent analytical methods used
by the Coalition, in conjunction with available test data, both predict
that combination vehicles towing surge-braked trailers with GVWRs
between 14,600 and 20,000 pounds, but not more than 1.25 times the GVWR
of the towing vehicle, can meet the 40 feet stopping distance of Sec.
FMCSA finds these additional analyses persuasive and agrees with
3. The National Marine Manufacturers Association (NMMA) supports
the use of trailers equipped with surge brakes in interstate
"commercial" applications, and argues the recreational marine
industry has a unique problem regarding surge brakes. NMMA notes that
surge brakes are especially useful and reliable in marine applications
where the boat trailer is expected to be repeatedly immersed in water,
a practice that could damage components of electric brakes. NMMA states
that while the consumer use of surge brakes on boat trailers is exempt
from existing Federal regulations, the same brake system that is
considered a safety feature for consumer use is prohibited when that
boat trailer is used in a technically "commercial" application (for
example, when a boat dealer or repair shop transports a boat to or from
a customer using the customer's trailer). In addition, the FMCSRs may
be violated when a boat dealer or manufacturer transports a boat on a
consumer type surge-braked trailer to or from a boat show.
NMMA believes the current regulation is especially burdensome for
the recreational boat industry, since a consumer boat trailer is often
specifically matched or manufactured for a particular boat and is the
preferred way to transport that boat. NMMA notes that this use of a
surge brake equipped boat trailer, although sometimes commercial in
nature, is in fact identical to the use of the boat trailer by the
consumer. In addition, even if a boat dealer or repair shop did use its
own trailer for these trips, NMMA states that it would be preferable to
use a trailer with surge brakes, since those trailer brakes are
generally considered more durable and suitable for water applications.
FMCSA Response: The NMMA comments explain the marine uses of surge
brakes in detail as well as the problems created by the Agency's
position that surge brakes do not comply with the requirements of Part
393. While much of its discussion centers on the operational
difficulties that NMMA's industry partners face given the current
regulatory requirements, NMMA also addresses the operational safety of
surge brakes through real-world experience.
NMMA specifically states that a large number of private boat owners
are personally using surge brake equipped trailers. Some of those
trailers are for larger boats that would require a GVWR in the heavier
range of 12,001 to 20,000 pounds. The fact that no safety problems
relating to surge brake performance have been reported by the marine
industry or by State and local highway safety officials, as a result of
that usage on the public roads, suggests that these trailers and their
braking systems are safe.
B. Comments Opposing the NPRM
1. The Ohio State Highway Patrol (OSHP) believes surge brakes are a
viable alternative to braking systems currently in use on smaller
commercial motor vehicles, but also commented that:
(a)(i) Additional testing is appropriate, and
(ii) Such testing should be completed by FMCSA, NHTSA, and/or an
independent group other than the Coalition. OSHP recommends that any
additional testing include old vehicles, to the point where the
requirements of Sec. 393.52 cannot be met. OSHP believes that such
testing would provide law enforcement with an acceptable level of
confidence, and a margin of safety, for the use of surge brakes.
(iii) OSHP recommended that testing should also include the
vehicle's ability to stop during backing maneuvers.
(b) OSHP also believes that the criterion set forth in the NPRM,
i.e., that the ratios of the towing vehicle to trailer weight must be
based solely on GVWR, is incomplete, and should include provisions for
using each of the vehicles' actual gross weights to determine
compliance with the proposed regulation. Specifically, OSHP recommended
the inclusion of a provision to allow law enforcement to use either the
vehicles' GVWR or their actual gross weights to determine compliance
with the regulation. OSHP believes that this would keep the operator of
the vehicle ``honest'' and keep unsafe combinations of vehicles from
operating on the highway.
FMCSA Response: (a)(i) FMCSA has reviewed the Coalition's test
procedures and finds them well grounded in modern scientific practice
and sufficient to measure the safety performance of surge brake
systems. The tests were performed in a controlled fashion by a
reputable organization, EFAA, precisely to ensure that the test results
would not be influenced by the Coalition. Further, EFAA is an ISO 9001
compliant facility that has conducted FMVSS testing for NHTSA. FMCSA
does not believe additional testing is required.
(a)(ii) A review of the test results provided by the Coalition
indicates the towing vehicles were not new, and that the more extreme
weight ratio combinations tested failed to achieve the brake
performance requirements of Sec. 393.52(d). The Coalition petitioned
FMCSA to adopt GVWR ratios substantially more stringent than the ratios
at which test combinations failed to meet the required stopping
Manufacturers were required by NHTSA rules and Sec. 393.55(a) to
include ABS systems on new vehicles built after March 1, 1999; the
brake performance of older vehicles manufactured before that date is
essentially grandfathered. FMCSA acknowledges that two of the three
Coalition test vehicles were newer than March 1999 and, thus, were
equipped with ABS on all wheels. The third vehicle was a 1993 model
that only has ABS on the rear axle brakes.
However, such older vehicles are in use towing commercial trailers with
electric brakes, and commercial trailers weighing less than 3,000
pounds that are not required to be equipped with any brakes.
No data were submitted to the docket indicating that towing
vehicles without ABS are a safety hazard. The subject of this
rulemaking is the safety of surge brakes on trailers, not whether the
Agency or anyone else believes that the lack of ABS on a grandfathered
CMV would adversely affect the performance of a trailer equipped with
surge brakes. As a practical matter, surge-braked trailers might
improve the stopping performance of some pre-1999 towing vehicles
(especially unloaded pickups) by putting added weight on the rear tires
and, thus, delaying the onset of lock-up.
The Coalition's test procedures were specifically selected to
address several existing specifications for braking systems. These
include FMVSS No. 105 for Hydraulic Brakes, FMVSS No. 121 for Air Brake
Systems, and Sec. 393.52(d) for the FMCSA vehicle stopping distance
requirements. FMCSA has no reason to believe the test procedures used
by EFAA failed to demonstrate the braking characteristics of
combination vehicles using surge-braked trailers.
The testing performed by EFAA utilized a wide variety of towing-
vehicle and trailer weight combinations, with numerous different
simulated GVWR ratios. Multiple test runs for each combination were
made and measured. The ratios of weights for towing vehicle to trailer
simulated GVWRs covering all ratios proposed in the petition, and
included testing of GVWR ratios exceeding the request. Test data showed
that all combinations were stable while braking in a curve and held
firm on a 20 percent uphill grade while using only the towing vehicle's
service brakes, some at GVWR ratios much higher than those proposed by
the Coalition, in some cases at a ratio of 1:2. The subsequent
mathematical analysis performed by Dr. Michael Graboski also predicted
that the requirements of Sec. 393.52(d) would be met by towing
vehicles with GVWRs of 16,000 pounds or greater, towing surge brake
trailers with a GVWR of 20,000 pounds or less, for a GVWR ratio of
1:1.25 or less.
The FMVSS currently includes manufacturers' performance standards
only for air-braked trailers; there are no such standards for trailers
with electrical, electric over hydraulic, or surge brakes. OSHP
provided no information that the operation of surge brake equipped
trailers for personal use has created undue concern among safety and
law enforcement personnel.
(iii) There are no FMCSA or NHTSA regulatory standards for brake
performance when a vehicle backs up. Rather, brake performance
requirements for motor vehicles are applicable only when a vehicle is
operating in the forward direction. Because vehicles typically operate
in reverse at speeds much lower than when operating in the forward
direction, and only for very short distances, existing tests that
specify brake performance in the forward direction are considered to be
sufficient to ensure that the same vehicle can stop safely when
operating in reverse. As such, none of the FMVSSs or the FMCSRs specify
braking performance requirements for vehicles operating in reverse.
While surge brakes automatically release when deceleration stops--
and therefore, are not operable while the vehicle is operating in
reverse--the brake holding on a hill tests conducted by the Coalition
clearly showed that the service brakes of a towing vehicle alone are
more than adequate to hold the combination at a stop (1) even while
facing uphill on a 20 percent grade, and (2) even when the GVWR ratios
substantially exceeded the limits that had been proposed by the
Coalition. FMCSA considers these brake holding on a hill tests to be a
much more severe test of brake performance than stopping a vehicle/
surge brake equipped trailer combination traveling in reverse at low
speeds or backing down an incline at less than a 20 percent grade.
While recognizing that vehicles are not required to demonstrate the
ability to stop while operating in reverse, as noted in the preceding
paragraph, FMCSA is confident that these test results, in conjunction
with the conservative GVWR ratios specified in this rule, will ensure
that combinations with surge brake equipped trailers will be able to
stop safely while operating at low speeds in reverse.
(b) FMCSA agrees with OSHP that an overloaded surge-braked trailer,
or one without a manufacturer's GVWR certification, could pose safety
risks. Therefore, the Agency has added provisions to the reformatted
Sec. 393.48(d) to deal with missing GVWR labels and overloading. New
paragraphs (2) and (3) are added to read as follows:
(2) The gross vehicle weight (GVW) of a trailer equipped with
surge brakes may be used instead of its GVWR to calculate the weight
ratios specified in this paragraph (d)(1) of this section when the
trailer manufacturer's GVWR label is missing.
(3) The GVW of a trailer equipped with surge brakes must be used
to calculate the weight ratios specified in paragraph (d)(1) of this
section when the trailer's GVW exceeds its GVWR.
General or approximate GVWRs for most models of towing vehicles
covered by this rule are commonly known. FMCSA will ask the Commercial
Vehicle Safety Alliance (CVSA) to make these values available for use
when towing vehicles between 10,000 and 16,000 pounds do not have a
GVWR plate. If OSHP is concerned about overloaded towing vehicles, all
existing enforcement procedures remain in effect for dealing with
vehicles loaded beyond their manufacturer's GVWR. OSHP has the
authority under the State version of Sec. 396.7 (adopted pursuant to
MCSAP) to remove such vehicles from the road, and this provision is
incorporated in the North American Standard (NAS) Out-of-Service
2. Mr. Barry Hansel commented that "surge brakes are better than
no brakes," but he argued:
(a) That surge brakes have numerous shortcomings that do not apply
to electric over hydraulic brake systems \6\ available from numerous
manufacturers. Specifically, Mr. Hansel stated that (i) surge brakes
cannot provide braking when backing down a hill, because they do not
have an electrical solenoid that can be activated, (ii) surge brakes
can be unintentionally activated by backing up a grade of as little as
a 1 percent, (iii) a jack-knifing trailer cannot be straightened out
with a surge brake, and surge brakes can actually create or aggravate a
jack-knife condition, and (iv) when going down steep mountain roads,
surge brakes would activate the trailer brakes and cause them to
overheat or burn out.
\6\ Electric over hydraulic is distinguished from the more
commonly known electric brake systems in that the former consists of
an electric motor, pump, and brake fluid reservoir attached to the
trailer and plumbed into the hydraulic brake system of the trailer.
The brakes are applied by pushing on the brake pedal of the towing
vehicle, which activates the electric brake controller mechanism in
the towing vehicle. This sends an electrical signal to the electric
motor and pump on the trailer, causing the trailer brakes to
pressurize and slow or stop the trailer. With the same controller,
the trailer brakes can be activated by themselves simply by
activating the manual override on the controller.
(b) Mr. Hansel contends that alternative brake technologies for
trailers--specifically electric over hydraulic brake actuators--are
safer because they do not have the shortcomings associated with surge
brakes that were noted above.
(c) Mr. Hansel stated that the stopping distances documented by the
Coalition were most likely achieved under ideal road conditions. He
contends that surge brakes cannot stop a trailer on ice covered, wet,
or dirt roads safely.
(d) He further argues the only reason the Surge Brake Coalition
favors surge brakes is because they are cheaper than electric over
FMCSA Response: (a)(i) As discussed earlier, neither FMCSA nor
NHTSA has any regulatory standard for braking while a vehicle backs up.
Although not a significant safety concern, this issue is largely
addressed by the tests documenting the ability of towing vehicles'
service brakes to hold several combinations facing uphill on a 20
(ii) The amount of braking force applied to the trailer brakes is a
proportional function of the ratio of the towing vehicle and the
trailer weight, and braking inertial forces generated by deceleration
of the towing vehicle. Mr. Hansel is correct that, when a combination
is backed up an incline, the trailer weight/gravity component could
induce a braking effect. The larger inertial force generator is
virtually absent. Additionally, some trailers are equipped with surge
brakes with mechanisms that allow the operator to lock out the braking
effect while backing the trailer. In any case, the Agency does not
believe the presence or absence of this device is a safety issue. If
the brakes should engage during a backing operation, it most likely
would be an annoyance to the operator of these combination vehicles,
not a safety issue associated with operating on public roads.
(iii) It is possible for some combination vehicles with air brakes,
electric brakes, or the electric over hydraulic system described by Mr.
Hansel, to apply the trailer brakes independently, in an effort to
address a jack-knife situation. This technique is not easy to use in an
emergency. Further, neither the FMVSSs nor the FMCSRs require
combination vehicles to have this capability. Surge-braked trailers
cannot be faulted for lacking a system that no other trailer is
required to have.
Surge brakes are designed so that the amount of braking force
applied by the trailer brakes is proportional to the effective braking/
deceleration of the towing vehicle. Thus, the amount of braking of the
trailer adjusts to that of the towing vehicle. If the braking ability
of the towing vehicle is limited by the road conditions, so too is the
brake-gain of the trailer, thus, preventing lock-up of the trailer
brakes. However, in the unlikely case that the trailer brakes locked
up, the driver could release them simply by taking his or her foot off
the brake pedal, exactly the same technique used with electric or
electric over hydraulic trailer brakes.
The braking-in-a-turn tests were specifically included to determine
the inherent stability of each combination evaluated, i.e., whether
there was a tendency to jack-knife. As pointed out in the discussions
above regarding the breaking-in-a-turn test results, all combinations
tested by EFAA passed this stability test.
(iv) With regard to the possibility of surge brake systems
overheating or catching fire going down a steep mountain grade, no such
problems have come to the Department's attention as data in either of
NHTSA's crash databases (FARS or GES), despite the large number of
personal trailers equipped with surge brakes currently in use. This has
not been identified as a safety issue in mountainous regions by
enforcement personnel in such States. While it is incumbent on the
commenter to substantiate claims made, Mr. Hansel did not do so. Thus,
FMCSA must conclude that no available empirical data supports his
(b) FMCSA's role is limited to determining whether a braking system
meets the safety performance requirements of the FMCSRs. Manufacturers
may select any system that complies with Federal standards, including
the electric over hydraulic advocated by Mr. Hansel.
(c) Mr. Hansel is correct that the Coalition's testing was
performed in dry conditions. This is required by Sec. 393.52(c), which
directs that stopping distance tests be performed on a hard surface
that is substantially level, dry, smooth, and free of loose material.
These are the test conditions that apply to all CMVs, including
electric and hydraulic over electric braked trailers.
(d) If the emerging brake technology espoused by Mr. Hansel,
electric over hydraulic, meets the FMCSR safety performance standards,
this final rule does not preclude its development, marketing, and use.
3. TMA acknowledged that surge brakes are well adapted to the
rental market where trailers are towed by a wide variety of vehicles.
(a) TMA expressed general concern, however, that no test results or
other evaluations are available to assess how these trailers would
perform when towed by air- or hydraulically-braked vehicles with GVWRs
exceeding those that were tested by the Coalition. In the absence of
performance standards for trailers equipped with surge brake systems,
TMA said it was unable to predict with certainty whether overall
combination-unit braking performance would be acceptable.
Like OSHP, TMA recommended that FMCSA and NHTSA conduct additional
research, testing, and evaluation prior to amending the standard to
allow the use of surge brakes in interstate commerce.
(b) With regard to stopping distances on public roads, TMA
expressed concern over the potential failure of the towing unit's brake
system. This would reduce deceleration rates, which in turn would
reduce the braking forces generated by the surge-braked trailer, and
the net effect would be even longer stopping distances. TMA cited the
requirements of S5.1.2 and S5.1.3 of FMVSS No. 105, which set
manufacturing standards to deal with partial brake failure and
inoperative power assist units, respectively. TMA also drew attention
to S5.7 of FMVSS No. 121, which sets emergency brake standards for
trucks and buses. The organization acknowledged, however, that FMVSS
No. 105 includes no specific test of vehicle performance after brake
(c) TMA expressed concern that users could unwittingly park
combination units with gross combination weights (GCWs) in excess of
40,000-50,000 pounds facing uphill on grades. In these situations, and
in others less severe, TMA was concerned that the towing vehicle's
parking brake system, which is neither designed nor required to handle
that amount of weight, would not be able to hold the combination
TMA noted that FMCSA's recently revised parking brake requirements
at Sec. 393.41 (70 FR 48008) require the following:
(a) Hydraulic-braked vehicles manufactured on or after September
2, 1983. Each truck and bus (other than a school bus) with a GVWR of
4,536 kg (10,000 pounds) or less which is subject to this part and
school buses with a GVWR greater than 4,536 kg (10,000 pounds) shall
be equipped with a parking brake system as required by FMVSS No.
571.105 (S5.2) in effect at the time of manufacture. The parking
brake shall be capable of holding the vehicle or combination of
vehicles stationary under any condition of loading in which it is
found on a public road (free of ice and snow) (Emphasis added).
Hydraulic braked vehicles which were not subject to the parking
brake requirements of FMVSS No. 571.105 (S5.2) must be equipped with
a parking brake system that meets the requirements of paragraph (c)
of this section.
TMA further noted:
* * * the new FMCSA requirement, Sec. 393.42(c), which applies
to vehicles not subject to FMVSS Nos.105 and 121 on the date of
manufacture (which would be the case with all surge-brake trailers
since NHTSA made it clear in their most recent revision to FMVSS 105
that it does not apply to hydraulic brake trailers), reads in part:
* * * every combination of motor vehicles must be equipped with
a parking brake [[Page 9866]] system adequate to hold the vehicle or combination on any grade on
which it is operated, under any condition of loading in which it is
found on a public road (free of snow and ice).
TMA's reference in its December 2, 2005 letter to NHTSA making it
clear that FMVSS No. 105 does not apply to trailer parking brakes can
be found at (70 FR 37711, June 30, 2005).
TMA stated that since the parking brake system of the towing unit
is neither required to meet, nor likely to be capable of meeting, this
standard by itself, it is not apparent how this requirement could be
met, under particularly adverse conditions, without the trailer having
some type of parking brake system as well. While air-brake equipped
trailers have this capability, TMA noted that trailers equipped with
surge brakes--particularly those at the upper end of the proposed
allowable weight range--generally do not have parking brake systems.
(d) TMA also pointed out concerns similar to those raised by Mr.
Hansel regarding (i) excessive thermal loading of the towing unit's
brakes on a long downhill grade, and (ii) the ability of a towing
vehicle pulling a surge-braked trailer to make an abrupt stop while
backing up at any speed above 1-2 mph.
FMCSA Response: (a) TMA members manufacture trucks weighing 19,500
pounds or more, which include a relatively higher percentage of air
braked vehicles. Although air-braked towing vehicles subject to FMVSS
No. 121 were not tested by EFAA, data available in the rulemaking and
the additional explanations in this final rule should allay TMA's
The heaviest surge-braked trailer allowed by this final rule has a
GVWR of 20,000 pounds. In order to meet the weight ratio specification,
the minimum towing vehicle GVWR allowed for that trailer is 16,000
pounds, for a combined GVWR of 36,000 pounds. A higher combined weight
rating is possible only if the additional GVWR is in the towing
vehicle. Thus, a towing vehicle of 30,000 pounds GVWR would be required
in order to achieve a combined GCWR of 50,000 pounds. If it were
hydraulically braked, it would be subject to FMVSS No. 105, like the
16,000-pound GVWR towing vehicle, with the same stopping distance
requirement. If that towing vehicle were air braked, it would be
subject to FMVSS No. 121. It requires the same stopping distance as
FMVSS No. 105. Thus, there appears to be no basis for TMA's suggestion
that vehicles with higher GVWRs might not match the braking performance
of a vehicle with a 16,000-pound GVWR. The Coalition's analysis, based
on the model by Klein and Szostak, indicates that the braking
performance of a lower GVWR ratio, i.e., a larger towing vehicle in
combination with the same 20,000 pound GVWR trailer, would be better.
This is because the stopping performance of the combination, including
the surge-braked trailer, is dependent on the GVWR ratio of the towing
vehicle to the trailer. The lower the ratio of GVWR of a trailer
compared to that of the towing vehicle, the better the stopping power
of the combination. The GVWR ratio of a 30,000 pound towing vehicle to
a 20,000 pound trailer would be less than 1, i.e., 1:0.66.
In summary, FMVSS Nos. 105 and 121 have the same requirement for
stopping distance. There is no reason to believe that a heavier towing
vehicle with or without air brakes, which thus has a GVWR ratio below
that required by this rule, would not meet the 40-foot stopping
distance required by Sec. 393.52(d), the 30 mph braking-in-a-curve
test, and the 20 percent grade-service brake holding test.
(b) We agree with TMA's conclusion that no specific test applies to
trailer brake performance after brake failure on the towing vehicle.
(c) TMA correctly noted there is no standard in FMVSS No. 105 that
applies to the parking brake capability of hydraulically braked
trailers. Neither is there a parking brake standard for electrically
braked trailers or for trailers weighing less than 3,000 pounds that
are exempted from having any brakes. Only air-braked trailers are
subject to a parking brake standard. NHTSA, not FMCSA, has the
authority to set manufacturing standards. Any rule requiring
retrofitting of parking brakes to trailers already in operation would
be prohibitively expensive, and the results of the tests submitted with
the petition make it clear there would not be commensurate safety
Section 393.41(c) of the FMCSRs says that the parking brake on
combination vehicles must be sufficient to prevent the combination from
rolling backward. Although the rule does not further specify the
performance standard, such as the grade on which roll-back must be
tested, this standard applies to all combinations, including unbraked,
electric braked, and surge-braked trailers. TMA's comments give no
indication that its members have any parking brake problem for
comparable electric-braked trailers, which do not have parking brakes.
If manufacturers have no parking brake problem with similar GVWR
electric-braked trailers, FMCSA is unable to see why there should be a
problem with comparable surge-braked trailers.
(d) As discussed under 2(a)(iv) in response to Mr. Hansel's
comments above, no data have been submitted in this rulemaking which
supports this theoretical concern.
4. Carlisle elaborated on the points raised by Mr. Hansel and TMA.
(a)(i) Carlisle was primarily concerned that testing by EFAA for
the Coalition was conducted on dry road surfaces. Carlisle contends
that because the coefficient of friction drops with moisture or ice on
the road surface, the trailer inertia may act to ``push'' the towing
vehicle, thus, creating conditions where trailer jack-knife is much
more likely to occur.
(ii) Carlisle noted that electric and electric over hydraulic
trailer brake actuators do not rely on towing vehicle inertia to apply
the trailer brakes. In these situations, the trailer brakes are applied
at a proportionate rate whenever the towing vehicle brakes are applied.
The combined braking of the two units minimizes the likelihood of a
jack-knife condition. In addition, unlike surge brakes, the trailer
brakes work when the vehicle backs up.
(b)(i) Carlisle, like Mr. Hansel, pointed out that alternative
braking systems are available from more than one manufacturer,
(ii) They also pointed out that most newer towing vehicles are
wired for easy installation of in-cab brake controllers.
(c) Carlisle also expressed concern regarding elimination of the
requirement, for trailers equipped with surge brakes, of a single
control valve capable of operating all of the service brakes.
(d) Carlisle believes that one of the inherent problems with a
surge brake system is the inability to verify that the system is
working without driving the combination. Like MDSHA/MCD below, Carlisle
questioned how a rental customer or enforcement agent could test a
trailer to verify that the surge brakes are working.
FMCSA Response: (a)(i) As mentioned above, the FMCSRs require that
brake testing be performed on a hard surface that is substantially
level, dry, smooth, and free of loose material. Based on that, the
brake-in-a-curve test, not required for trailers even by FMVSS No. 121,
was also performed on a comparable surface. FMCSA cannot require surge-
braked trailers to meet a different standard than other vehicles.
(ii) It is unclear whether Carlisle is possibly implying that
electric or electric over hydraulic brake systems [[Page 9867]]
may have a more proportional trailer braking force. Carlisle provided
no explanation of what they mean by use of the word ``proportionate,''
and how their system is more or less safe than surge brakes, or how
that relates to jack-knifing.
Surge brakes by their physical design apply a braking force
proportional to that generated by the towing vehicle, that varies
whether empty or loaded to any weight up to its GVWR. In contrast, the
brake gain set on the controller for electric and electric over
hydraulic brake systems has to be manually adjusted based on the load
being carried by trailers equipped with those systems, and the driving
conditions. This is a different meaning for the word proportionate. It
is not apparent from Carlisle's comments how electric or electric over
hydraulic brakes on a trailer would prevent it from jack-knifing in wet
or icy conditions. Historically, a major cause of jack-knifing was
locking up the brakes on the rear axle of the towing vehicle, now
addressed by ABS systems.
(b)(i) The availability of alternative braking systems is not
germane to determining whether surge brake systems meet FMCSA's safety
(ii) Carlisle's assertion that towing vehicles are wired for easy
installation of in-cab electric brake controllers appears to be a
reference to the common manufacturing practice of installing wiring
harnesses that can accommodate optional equipment, such as a controller
for electric trailer brakes. Carlisle fails to mention the cost and
difficulty of purchasing and installing a controller in the cab of the
towing vehicle. A brake expert on a specific model year truck could
perhaps install a controller in 15 minutes. However, thousands of
trailer rental companies are unlikely to (1) have such expertise
readily available, or (2) stock appropriate controllers for all
electric brake systems. While the Agency does not consider the
installation of electric brake controllers ``easy'' based on the above,
the availability of alternative brake systems is not related to the
issue of whether surge brake systems meet the performance requirements
of the FMCSRs.
(c) The rule requiring a single control valve (Sec. 393.49) is
designed to enhance safety. The Coalition's petition argued that the
actual, operational safety performance of surge-braked trailers
demonstrates that this rule need not be applied to surge-braked
trailers. FMCSA granted the petition for a rulemaking and via that
process has now concluded that surge brakes are safe, when limited to
certain GVWR ratios.
(d) Carlisle's concern about the ability of customers and
enforcement personnel to verify that the trailer brakes are working was
shared by MDSHA/MCD below. There are ways to verify that trailer brakes
are operational. The following examples illustrate this:
Canada allows surge-braked trailers to be used for commercial
purposes. Enforcement officers in the Provinces begin by making a
visual inspection of the brake components. They perform the on-road
inspection specified for hydraulic brakes in the NAS Out-of-Service
criteria. Just as for all other hydraulically braked vehicles, this
includes checking for leaks in the hydraulic system, sufficient fluid
in the actuator/master-cylinder reservoir, and whether there are any
unusual component conditions.
Then, if anything in the visual inspection causes concern, it is
possible to physically test the trailer's hydraulic brake system. This
is because combination vehicles--including trailers equipped with surge
brake systems--must also meet the operational brake performance
requirement of Sec. 393.43(d) for trailer breakaway and emergency
braking. A trailer equipped with surge brakes meets this requirement
only if it also includes an emergency release mechanism that would be
actuated on a breakaway. The standard design for surge brake actuators
is for that emergency breakaway capability to work through the
hydraulic actuator to apply the wheel brakes. In some designs the
emergency release mechanism can be manually actuated, and a simple
determination can then be made whether the brakes are operational,
either by attempting to move the trailer, or by jacking up a trailer
wheel and attempting to rotate the tire. In other designs, a different
procedure is used.
Information on applying these approaches is available from the
manufacturers of the surge brake actuators. FMCSA is convinced this
two-stage inspection procedure is adequate for pre-trip and roadside
inspections to insure safety of the braking function.
The current NAS Out-of-Service criteria gives nine different items
the inspector is to check at the roadside for a vehicle with a
hydraulic system. The instructor and student guide give more details on
how to carry out inspections for these criteria.
Instructions very similar to this already exist in the CVSA NAS
Out-of-Service criteria for a Level 1 inspection of electric brakes.
The current instructor and student guides for the NAS Out-of-Service
Electric brakes can be checked for operation by activating a
manual control in the cab without activating the tractor's service
brakes, and attempting to move the vehicle while the brakes are
The Agency will ask CVSA to update the Out-of-Service criteria to
reflect this rule's change in the meaning of Sec. 393.48(a), allowing
surge brakes, and to provide comparably explicit guidance for
inspecting surge-braked trailers as part of the NAS Instructor and
Student guides for Inspection criteria.
5. MDSHA/MCD commented that in 2004, Maryland Vehicle Law was
modified by working with the trailer manufacturing industry to allow
trailers and semi-trailers less than 10,000 pounds equipped with surge
brakes to be used on Maryland highways, but limited to combination
vehicles in intrastate commerce that would not require a CDL.
(a) MDSHA/MCD takes exception to allowing the use of surge brakes
on trailers over 10,000 pounds operated in interstate commerce,
contending that the very limited testing of a few vehicle combinations
fails to justify revising the standards that currently apply. (i)
MDSHA/MCD states the tests performed were not comprehensive enough and
addressed only four towing vehicle and trailer combinations. (ii)
MDSHA/MCD notes that since the NPRM proposed that a trailer may have a
GVWR up to 20,000 pounds, a combination vehicle could include larger or
smaller types of vehicles, including cargo type vans normally used by
small construction and/or landscaping companies. MDSHA/MCD notes that
these, as well as other, vehicles were not tested nor was data provided
to substantiate that towing vehicles like cargo vans would be able to
meet similar requirements for braking in curve from 30 mph, service
brakes holding on a 20 percent uphill grade, and straight line stopping
distance from 20 mph. (iii) MDSHA/MCD stated that no tests were
conducted using towing vehicles that were not equipped with anti-lock
braking systems (ABS). (iv) MDSHA/MCD contends that the amendments
proposed in the NPRM do not address the GCW for the combinations
tested, but only the GVWR ratio for the towing units and trailers
equipped with surge brakes. MDSHA/MCD believes that the limited testing
by the Coalition is not representative of the range of real-world
(b) MDSHA/MCD is concerned that if the proposed amendments are
adopted, enforcement personnel would be unable [[Page 9868]]
to determine if the surge brake system is working properly.
MDSHA/MCD noted that 49 CFR 396.17 provides that periodic
inspections shall be conducted covering those "accessories set forth
in Appendix G of this subchapter." However, MDSHA/MCD states that a
review of Appendix G fails to reveal any guidance and/or methodology
for conducting an inspection of any "surge brake" component to
determine that it is working and/or maintained correctly to some
unidentified accepted standards, e.g., SAE standards. MDSHA/MCD
believes that this omission jeopardizes safety and, absent any
guidance, owners and operators have no way of knowing what methods
should be employed to assure that the surge brake equipment is
(c)(i) MDSHA/MCD, like Carlisle, commented that tests were not
conducted on wet or icy surfaces to determine what could potentially
occur when surge brakes are applied.
(ii) MDSHA/MCD expressed concern that during brake application
under wet or icy road conditions, forward inertia could cause the surge
brake to lock up and the operator to lose control of the combination
vehicle. With electric or other brakes, by contrast, MDSHA/MCD
maintains the operator has the ability to correct a brake lock
condition by lifting his/her foot off the brake pedal.
(d) MDSHA/MCD believes that the revisions to Sec. 393.48 are
flawed, as the proposed amendment to paragraph (a) exempts surge
brakes; therefore, they do not have to work or be capable of working.
MDSHA/MCD contends that Sec. 393.5 needs to be reworded to reflect
that a vehicle and combinations must be equipped with brakes that are
operative. In addition, MDSHA/MCD believes that wording to the effect
that brakes must at all times be capable of operating should not
exclude any system regardless of braking type, as does the proposed
FMCSA Response: (a)(i) As explained in the background information,
the test data submitted by the Coalition meets what FMCSA believes are
reasonable requirements for evaluating the safety performance of
trailer surge brake systems. The Coalition's additional analysis for
trailers in the range of 14,600 to 20,000 pounds GVWR demonstrates that
these trailers, subject to the GVWR ratio limitation of this rule, meet
the safety performance criteria for these braking systems. FMCSA has
determined that the combination of tests performed and analysis
submitted are sufficiently rigorous, and that no further tests or
analysis are required to establish this performance.
(ii) The other types of vehicles MDSHA/MCD mentioned, including
cargo vans, are normally built on a chassis similar to that of a pick-
up truck in that vehicle's class, with similarly sized brake components
meeting the FMVSS No. 105 requirement. For example, the light truck
tested was a Chevrolet C-1500, which serves as the light truck chassis
for the cargo vans built by GM in that model size class. Cargo vans
built on light truck chassis have the same braking system and thus
stopping ability of the truck chassis they are built on. The agency
points out that vehicles like the C-1500 are required by FMVSS No. 105
to have a shorter stopping distance than larger vehicles over 10,000
Further, for the even smaller cargo vans that are built on a truck
chassis like the Chevrolet S-10 pick-up truck, all such vehicles less
than 3,500 kilograms (7,716 pounds) are required by FMVSS No. 135 to
have the same stopping distance performance as required by FMVSS No.
105 for light trucks over 7,716 pounds and less than 10,000 pounds.
The Agency concluded that the braking characteristics of other
towing vehicles, such as cargo vans, will be similar to that of the
vehicles tested by EFAA. As long as the towing vehicle meets the
applicable FMVSS standard, and the combination meets the GVWR ratios of
this rule, all evidence demonstrates that such combinations will have
braking system performance similar to the vehicles tested by the
(iii) As explained above, there is no justification for requiring a
different testing standard for surge brakes than for electric brakes.
Trucks manufactured before March 1, 1999, when the requirement for ABS
brake took effect (see Sec. 393.55), have always been allowed to tow
trailers with electric brakes. These vehicles will be equally safe when
towing surge-braked trailers, within the GVWR ratios required by this
(iv) MDSHA/MCD may have been confused by the repeated use of the
term GVWR in the NPRM. The Coalition tested a variety of simulated GVWR
combinations by loading the trailers to different weights. These were
selected to be representative of or simulate different GVWR
combinations in order to test the safety performance of the associated
surge brake systems. The combinations were tested at simulated towing
vehicle to trailer weight/GVWR ratios from 1:1 up to 1:2. FMCSA
believes that the data provided by the Coalition thoroughly address the
concern of MDSHA/MCD that vehicles be tested at a wide range of GCWs.
(b) Since Maryland allows surge brake systems on trailers up to
10,000 pounds GVWR in intrastate commerce, at least some of the larger
trailers are used as part of combination vehicles over 10,000 pounds.
It appears Maryland felt surge-braked trailers operating in intrastate
commerce are safe without needing a roadside inspection program. Such a
program is feasible, as the response to Carlisle under section 4(d)
Appendix G to Chapter III, Subchapter B of title 49, identifies
hydraulic brake components that must be checked. FMCSA believes
inspection of surge brakes should begin with these hydraulic brake
components. If compromised components are found by the first stage
inspection, it would then be appropriate or necessary to perform a
second stage performance inspection.
(c)(i) As discussed above under section 2(c) of the Agency's
response to Mr. Hansel, the performance regulations require the testing
to be conducted under dry conditions.
(ii) The theory that under icy conditions the surge brakes of the
trailer could lock up requires an assumption that the towing vehicle
has enough friction with the road to create a deceleration force on the
trailer actuator. Thus, the towing vehicle would have to have better
friction contact with the road than the trailer. While this could
momentarily be true, the combination is traveling down the road, and
the trailer wheels will encounter exactly the same friction contact
that the towing vehicle just passed over. Thus, as the trailer wheels
move forward that might have momentarily locked up on ice, they will
encounter the greater traction just experienced by the towing vehicle.
And as MDSHA/MCD pointed out, the operator has the ability to correct a
brake lock condition by lifting his/her foot off the brake pedal.
(d) The MDSHA/MCD expressed concern that the exemption in Sec.
393.48(d) would mean that surge brakes do not have to operate. The NPRM
pointed out that surge brakes will still be subject to the performance
requirements of Sec. 393.52(d), which served as guidance for the tests
performed by the Coalition. The NPRM said:
The Agency emphasizes that the granting of the petition for
rulemaking, and subsequent proposal to amend Sec. Sec. 393.48 and
393.49 should not be construed as an exception to the brake
performance requirements under Sec. 393.52. Therefore, [[Page 9869]]
adoption of a final rule would not relieve motor carriers of their
responsibility to ensure that any commercial motor vehicle, or
combination of commercial motor vehicles, operated in interstate
commerce, comply with the brake performance requirements under Sec.
The NPRM and this final rule also contain a new Sec. 393.40(b)(5)
requiring surge braked trailers to comply with the same existing
provisions required for electric brakes. However, to further clarify
that the surge brakes must operate, FMCSA has added an additional
paragraph to the reformatted Sec. 393.48(d) to read as follows:
(4) The surge brakes must meet the requirements of Sec. 393.40.
6. The American Trucking Associations, Inc. (ATA), on behalf of its
members that manufacture commercial vehicles, expressed the same
concern as TMA above regarding the lack of parking-brake capability
with surge brakes, and the potential that the parking brake system on
the towing vehicle could be overloaded, thus, creating a roll-away
situation. ATA believes this is reason enough to continue to ban the
use of surge brakes on commercial vehicles where they are more likely
to be used beyond the towing vehicles' rated capacities. ATA believes
that additional parking brake
Testing should be completed on situations where the trailer has
the maximum proposed gross vehicle weight rating of 1.75 times the
weight of the towing vehicle for 12,000 pounds or less, and 1.25
times the weight of the towing vehicle for 12,000-20,000 pounds GVWR
to verify if the towing vehicle has the capacity to hold the
combined weight. This testing may have to include a variety of makes
and models as individual vehicles from different manufacturers can
have performance variations.
FMCSA Response: ATA's concern regarding parking brakes is the same
as that addressed in the response to TMA above.
7. Advocates for Highway and Auto Safety (Advocates) opposed the
proposed rulemaking on the grounds that FMCSA moved the petition
immediately into rulemaking, rather than preliminarily asking for
comments and views on the wisdom of changing current regulations to
permit this technology. Advocates regards the subject rulemaking
proposal both as inadequate and premature, as well as failing to meet the
agency's basic responsibilities to conduct its own investigations
and make its own determinations about the merits of major changes to
its safety regulations. Moreover, the agency has failed to offer
this petition for public evaluation in a timely manner through an
earlier notice asking for preliminary information that would be
relevant to determining whether to propose changes to the FMCSR and
exactly what changes are documented by the agency's own tests to be
in the public interest to advance motor carrier and commercial
Advocates contend that a proposed rule is not the occasion for
requesting comment on whether additional analysis is needed to support
the petitioner's assertions.
FMCSA Response: FMCSA followed established procedures in this
rulemaking. Section 389.31, Petitions for Rulemaking, specifies that
any interested person may petition the Administrator to establish,
amend, or repeal a rule. Each petition filed must set forth the text or
substance of the rule or amendment proposed, and include any
information or arguments available to support the action. The Coalition
filed such a petition, and it contained their requested regulatory
changes and their data supporting the safety performance of their
FMCSA determined in accordance with Sec. 389.33(b) that the
petition appeared to have merit, and the Administrator, therefore,
notified the Coalition their petition for rulemaking was granted.
FMCSA subsequently issued the NPRM, asking for specific data
regarding trailers over 14,600 pounds. The NPRM is the official
opportunity for the public to provide comments or data relevant to the
proposed rule. There is nothing unusual about asking potential
commenters who may possess data or analysis to share it with an agency,
nor is there any requirement of administrative law that an agency
digest and republish for an additional round of comments all data
submitted in response to an NPRM.
1. As specified in Part 389, the Surge Brake Coalition submitted a
petition for rulemaking containing safety performance test data
supporting their contention that surge-braked trailers meet the safety
performance requirements of Part 393, and, thus, should not be
2. FMCSA determined that the test data supported the contention of
the Coalition, and that a rulemaking on this subject was warranted.
Therefore, FMCSA granted the petition for a rulemaking.
3. FMCSA then developed and issued an NPRM putting forth the
proposal and asking for any additional information from the public. In
particular, FMCSA requested data regarding the safety performance of
trailers with a GVWR greater than 14,600 pounds.
4. FMCSA analyzed all information submitted to the docket and
developed this final rule specifying that surge-braked trailers subject
to the specified GVWR ratios are allowed as part of combination
commercial motor vehicles operating in interstate commerce.
V. Regulatory Analyses and Notices
Executive Order 12866 (Regulatory Planning and Review) and DOT
Regulatory Policies and Procedures
FMCSA has determined that this action is a significant regulatory
action within the meaning of Executive Order 12866 because it is the
subject of both a regulatory reform nomination and an industry
petition. This rule has generated a significant amount of public
interest and has been listed in the 2005 "Regulatory Reform of the
U.S. Manufacturing Sector" as published by the Office of Management
and Budget. We expect the rule will have minimal costs and small
benefits that outweigh the costs. The Agency has prepared a regulatory
analysis of the costs and benefits of this rulemaking action. A copy of
the analysis is included in the docket referenced at the beginning of
Regulatory Flexibility Act
In compliance with the Regulatory Flexibility Act (5 U.S.C. 601-
612), FMCSA considered the effects of this regulatory action on small
entities and determined that this final rule has a minimal, but
positive impact on a substantial number of small entities. This is
because it removes a regulatory obstacle to the use of surge brakes on
small and medium trailers. There are over 150 firms that manufacture
trailers, about 300 firms that are in the boat delivery service,
thousands of landscape and construction firms that may use trailers,
and over 2,000 rental equipment firms that may offer trailers for rent.
The majority of these firms are small businesses according to the
definition provided by the Small Business Administration. No entity is
required to use surge brakes, and those currently using electric or
other types of brakes have the option to continue with no change.
This final rule allows a braking system that was not allowed in
interstate commerce for a number of years. Many businesses use small or
medium trailers in their daily operations; if these operations are in
interstate commerce, and the vehicle combination meets the definition
of CMV (49 CFR 390.5), they are subject to the FMCSRs, which previously
did not allow the use of surge brakes. CMVs [[Page 9870]]
towing such trailers are most likely to be operated in interstate
commerce if the operation is near a State boundary. This final rule
establishes uniformity without compromising safety. It removes the
dilemma faced by numerous State agencies responsible for motor carrier
safety of enforcing Federal regulations prohibiting the use of surge
brakes on trailers operated in interstate commerce, while allowing
identical trailer combinations to operate on the same roads, under the
same conditions, in intrastate commerce.
Accordingly, FMCSA certifies that this rule does not have a
significant economic impact on a substantial number of small entities.
Unfunded Mandates Reform Act of 1995
This rulemaking does not impose an unfunded Federal mandate, as
defined by the Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1532, et
seq.), that results in the expenditure by State, local, and tribal
governments, in the aggregate, or by the private sector, of $128
million or more in any 1 year.
Executive Order 13175 (Consultation and Coordination With Indian Tribal
In accordance with E.O. 13175, we evaluated possible effects on
federally recognized Indian tribes and have determined there are no
Executive Order 12988 (Civil Justice Reform)
This action meets applicable standards in sections 3(a) and 3(b)(2)
of Executive Order 12988, Civil Justice Reform, to minimize litigation,
eliminate ambiguity, and reduce burden.
Executive Order 13045 (Protection of Children)
FMCSA analyzed this action under Executive Order 13045, Protection
of Children from Environmental Health Risks and Safety Risks. The
Agency determined that this rulemaking does not create an environmental
risk to health or safety disproportionately affecting children.
Executive Order 12630 (Taking of Private Property)
This rulemaking does not effect a taking of private property or
otherwise have taking implications under Executive Order 12630,
Governmental Actions and Interference with Constitutionally Protected
Executive Order 13132 (Federalism)
This action was analyzed in accordance with the principles and
criteria contained in Executive Order 13132. The FMCSA determined this
rulemaking does not have a substantial direct effect on States, nor
does it limit the policy-making discretion of the States. Nothing in
this document preempts any State law or regulation.
Executive Order 12372 (Intergovernmental Review)
The regulations implementing Executive Order 12372 regarding
intergovernmental consultation on Federal programs and activities do
not apply to this program.
Paperwork Reduction Act
This rulemaking does not contain a collection of information
requirement for the purposes of the Paperwork Reduction Act of 1995, 44
U.S.C. 3501, et seq.
National Environmental Policy Act
The Agency analyzed this action for purposes of the National
Environmental Policy Act of 1969 (42 U.S.C. 4321, et seq.) and
determined this action does not have an effect on the quality of the
environment. However, an environmental assessment (EA) supporting this
conclusion was prepared because the rulemaking is not among the type
covered by a categorical exclusion. A copy of the environmental
assessment is included in the docket listed at the beginning of this
Executive Order 13211 (Energy Effects)
The Agency analyzed this action under Executive Order 13211,
Actions Concerning Regulations That Significantly Affect Energy Supply,
Distribution or Use. The Agency determined it would not be a
"significant energy action" under that Executive Order because it is
not economically significant and does not have a significant adverse
effect on the supply, distribution, or use of energy.
List of Subjects in 49 CFR Part 393
Highway safety, Motor carriers and Motor vehicle safety.
VI. Regulatory Language for the Final Rule
In consideration of the foregoing, FMCSA amends title 49, Code of
Federal Regulations, chapter III, as follows:
PART 393--PARTS AND ACCESSORIES NECESSARY FOR SAFE OPERATION
1. The authority citation for part 393 continues to read as follows:
Authority: Section 1041(b) of Pub. L. 102-240, 105 Stat. 1914;
49 U.S.C. 31136 and 31502; and 49 CFR 1.73.
2. Amend Sec. 393.5 by adding a new definition for ``Surge Brake'' in
alphabetical order to read as follows:
Sec. 393.5 Definitions.
* * * * *
Surge Brake. A self-contained, permanently closed hydraulic brake
system for trailers that relies on inertial forces, developed in
response to the braking action of the towing vehicle, applied to a
hydraulic device mounted on or connected to the tongue of the trailer,
to slow down or stop the towed vehicle.
* * * * *
3. Amend Sec. 393.40 by adding paragraph (b)(5), a new specification
of "Surge brake systems," to read as follows:
Sec. 393.40 Required brake systems.
* * * * *
(b) * * *
5) Surge brake systems. Motor vehicles equipped with surge brake
systems must have a service brake system that meets the applicable
requirements of Sec. Sec. 393.42, 393.48, 393.49, and 393.52 of this
* * * * *
4. Amend Sec. 393.48 by revising paragraph (a) and adding paragraph
(d) to read as follows:
Sec. 393.48 Brakes to be operative.
(a) General rule. Except as provided in paragraphs (b), (c), and
(d) of this section, all brakes with which a motor vehicle is equipped
must at all times be capable of operating.
(b) * * *
(c) * * *
(d) Surge brakes. (1) Surge brakes are allowed on:
(i) Any trailer with a gross vehicle weight rating (GVWR) of 12,000
pounds or less, when its GVWR does not exceed 1.75 times the GVWR of
the towing vehicle; and
(ii) Any trailer with a GVWR greater than 12,000 pounds, but less
than 20,001 pounds, when its GVWR does not exceed 1.25 times the GVWR
of the towing vehicle.
(2) The gross vehicle weight (GVW) of a trailer equipped with surge
brakes may be used instead of its GVWR to calculate compliance with the
weight [[Page 9871]] ratios specified in paragraph (d)(1) of this section when the trailer
manufacturer's GVWR label is missing.
(3) The GVW of a trailer equipped with surge brakes must be used to
calculate compliance with the weight ratios specified in paragraph
(d)(1) of this section when the trailer's GVW exceeds its GVWR.
(4) The surge brakes must meet the requirements of Sec. 393.40.
5. Revise Sec. 393.49 to read as follows:
Sec. 393.49 Control valves for brakes.
(a) General rule. Except as provided in paragraphs (b) and (c) of
this section, every motor vehicle manufactured after June 30, 1953,
which is equipped with power brakes, must have the braking system so
arranged that one application valve must when activated cause all of
the service brakes on the motor vehicle or combination motor vehicle to
operate. This requirement must not be construed to prohibit motor
vehicles from being equipped with an additional valve to be used to
operate the brakes on a trailer or trailers or as required for busses
in Sec. 393.44.
(b) Driveaway-Towaway Exception. This section is not applicable to
driveaway-towaway operations unless the brakes on such operations are
designed to be operated by a single valve.
c) Surge brake exception. This requirement is not applicable to
trailers equipped with surge brakes that satisfy the conditions
specified in Sec. 393.48(d).
Issued on: February 26, 2007.
John H. Hill,
[FR Doc. E7-3815 Filed 3-5-07; 8:45 am]
BILLING CODE 4910-EX-P