[Federal Register: October 7, 2005 (Volume 70, Number 194)]
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 Requirements
AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT.
ACTION: Notice of proposed rulemaking (NPRM); request for comments.
SUMMARY: In response to a petition for rulemaking from the Surge Brake
Coalition, the Federal Motor Carrier Safety Administration proposes to
amend the Federal Motor Carrier Safety Regulations (FMCSRs) to allow
the use of automatic hydraulic inertia brake systems (surge brakes) on
trailers operated in interstate commerce. A surge brake is a self-
contained permanently closed hydraulic brake system activated in
response to the braking action of the tow vehicle. The amount of
trailer braking effort developed is proportional to the total trailer
weight and deceleration rate of the tow vehicle. Currently, surge
brakes are not considered by FMCSA to comply with the FMCSRs specifying
that all brakes with which a motor vehicle is equipped must at all
times be capable of operating, and that a single application valve
must, when applied, operate all the service brakes on the motor vehicle
or combination of motor vehicles. The intent of this rulemaking is to
adopt performance-based brake system requirements to allow the use of
surge brakes on certain combinations of commercial motor vehicles based
upon engineering test data submitted by the Surge Brake Coalition.
DATES: Comments must be received by December 6, 2005.
ADDRESSES: You may submit comments identified by DOT DMS Docket Number
FMCSA-2005-21323 by any of the following methods:
- Web site: http://dms.dot.gov. Follow the instructions for
submitting comments on the DOT electronic site.
- Fax: 1-202-493-2251.
- Mail: Docket Management Facility; U.S. Department of
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401,
Washington, DC 20590-0001.
- Hand Delivery: Room PL-401 on the plaza level of the
Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9
a.m. and 5 p.m., Monday through Friday, except Federal Holidays.
- Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the online instructions for submitting
Instructions: All submissions must include the agency name and
docket number or Regulatory Identification Number (RIN) for this
rulemaking (RIN-2126-AA91). Note that all comments received will be
posted without change to http://dms.dot.gov, including any personal
information provided. Please see the Privacy Act heading for further
Docket: For access to the docket to read background documents or
comments received, go to http://dms.dot.gov at any time or to Room PL-
401 on the plaza level of the Nassif Building, 400 Seventh Street, SW.,
Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday,
except Federal Holidays.
Privacy Act: Anyone is able to search the electronic form for all
comments received into any of our dockets by the name of the individual
submitting the comment (or signing the comment, if submitted on behalf
of an association, business, labor union, etc.). You may review DOT's
complete Privacy Act Statement in the Federal Register published on
April 11, 2000 (65 FR 19477) or you may visit http://dms.dot.gov.
Comments received after the comment closing date will be included
in the docket and we will consider late comments to the extent
practicable. FMCSA may, however, issue a final rule at any time after
the close of the comment period.
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 notice is organized as follows:
I. Legal Basis for the Rulemaking
IV. Regulatory Analyses and Notices
I. Legal Basis for the Rulemaking
This rulemaking is based on the authority of the Motor Carrier Act
of 1935 and the Motor Carrier Safety Act of 1984 (49 U.S.C. 31131, et
The Motor Carrier Act of 1935, as amended, provides that "[t]he
Secretary [[Page 58658]] of Transportation (Secretary) 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 U.S.C. 31502(b)).
This NPRM proposes to amend regulations located at 49 CFR 393.48
entitled "Brakes to be Operative," 49 CFR 393.49 currently entitled
"Single Valve to operate all Brakes," which previously was
interpreted as prohibiting the use of surge brakes on commercial motor
vehicles (CMVs), and to add a definition to Sec. 393.5 for surge
brakes. Section 393.48 states that all brakes with which a motor
vehicle is equipped must at all times be capable of operating. Section
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. The adoption and enforcement of such rules is
specifically authorized by the Motor Carrier Act of 1935. This NPRM
rests squarely on that authority.
The Motor Carrier Safety Act of 1984 provides concurrent authority
to regulate drivers, motor carriers, and vehicle equipment. It requires
the Secretary to "prescribe regulations on commercial motor vehicle
safety. The regulations shall prescribe minimum safety standards for
commercial motor vehicles. 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 vehicles safely;
and (4) the operation of commercial motor vehicles does not have a
deleterious effect on the physical condition of the operators" (49
This NPRM deals with surge brakes. The fundamental purpose of 49
CFR Part 393 Parts and Accessories Necessary for Safe Operation is to
ensure that no employer is allowed to operate a commercial motor
vehicle or cause or permit it to be operated, unless it is equipped in
accordance with the requirements and specifications of this part.
However, nothing contained in part 393 can be construed to prohibit the
use of additional equipment and accessories, not inconsistent with or
prohibited by part 393, provided such equipment and accessories do not
decrease the safety of operation of the motor vehicles on which they
are used. Compliance with the brake regulations is necessary to ensure
vehicles are equipped with adequate braking capability to ensure
control of the CMV. Before prescribing modifications to such
regulations, FMCSA must consider the "costs and benefits" of any
proposal (49 U.S.C. 31136(c)(2)(A)).
The Surge Brake Coalition petitioned FMCSA on February 28, 2002, to
amend Sec. 393.48 entitled "Brakes to be Operative" and Sec. 393.49
entitled "Single Valve to Operate all Brakes," which have been
interpreted as prohibiting the use of surge brakes on commercial motor
vehicles. Coalition members include trailer manufacturers, parts
suppliers, commercial users dependent upon trailers, trailer rental
companies, and trade associations whose memberships comprise distinct
segments of the trailer business. A copy of the petition is included in
the docket referenced at the beginning of this document.
Section 393.48 states that all brakes with which a motor vehicle is
equipped must at all times be capable of operating. Section 393.49
requires a single application valve must, when applied, operate all the
service brakes on the motor vehicle or combination of motor vehicles.
Regulatory guidance previously issued by the Agency (40 FR 50671,
50688, Oct. 31, 1975) \1\ indicates the use of surge brakes on trailers
operated in interstate commerce is inconsistent with the requirements
of Sec. Sec. 393.48 and 393.49.
\1\ The Federal Highway Administration's (FHWA) Bureau of Motor
Carrier Safety (Bureau) (FMCSA's predecessor agency) published these
motor carrier safety interpretations.
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 effect.
Subsequent regulatory guidance published by FHWA on November 17,
1993 (58 FR 60734, 60755) indicated that surge brakes did not comply
with both Sec. Sec. 393.48 and 393.49:
Section 393.48 Brakes to be Operative. Question 1: Do surge brakes
comply with Sec. 393.48? 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 section 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? 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.
This guidance was also included in FHWA's April 4, 1997 (62 FR
16370, 16415 and 16416) publication, "Regulatory Guidance for the
Federal Motor Carrier Safety Regulations."
The Surge Brake Coalition proposed in their petition for rulemaking
that Sec. 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:
Surge brakes. Paragraph (a) of this section does not apply to:
Any trailer with a gross vehicle weight rating (GVWR) of 12,000 lbs
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 lbs, but less than
20,001 pounds (lbs), equipped with inertial surge brakes when the GVWR
does not exceed 1.25 times the GVWR of the towing vehicle.
The Petitioner also requested the following exception be added to
Sec. 393.49: "This requirement shall not apply to trailers equipped
with surge brakes that satisfy the conditions provided in Sec.
The Petitioner argues that surge brakes provide a safe, practical
braking system for commercial motor vehicle 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 rented
separately from towing vehicles, and towing vehicles frequently are not
wired for electric brake controls. The Petitioner indicates that rental
companies believe it is "prohibitively expensive and impractical" to
install or adapt a brake control system on each towing vehicle every
time they rent a trailer or piece of mobile equipment. The Petitioner
estimates that over 25 percent of the rental trailer fleet is equipped
with surge brakes.
The Petitioner believes surge brakes are a popular alternative to
electric brakes because surge brakes activate automatically, adapt to
the weight of the load, have fewer components, and require less
maintenance. These features make surge brakes ideal for flatbed and
van-type trailers with a GVWR of 20,000 lbs or less, and trailers
serving the marine industry. The Petitioner also points out that
manufacturers install approximately 250,000 surge brake systems
annually on small to medium sized trailers.
The Petitioner's Engineering Tests
The Petitioner conducted brake performance tests at Exponent
Failure Analysis Associates' (EFAA) Test and Engineering Center in
Phoenix, Arizona. EFAA tested the braking performance of 16 different
configurations of towing vehicles and trailers. The Petitioner used the
services of a consulting engineer to interpret the test results and
prepare the final report concerning the tests.
1. Straight-line braking: Vehicle combinations were stopped from
speeds of approximately 20 miles per hour (mph) or greater to determine
whether the vehicle could meet the performance requirements under Sec.
393.52. The vehicle combination was required to stay within a 12-foot-
wide lane during the test and the stopping distance was measured.
2. Brake holding on a 20 percent incline: Using only the service
brakes, the combination was stopped going up a 20 percent incline and
required to remain stationary for at least 5 minutes.
3. Braking in a turn: The towing vehicle and trailer were driven on
a circular, 12-foot-wide, 500-foot-radius test track of known
coefficient of friction. The driver then applied the brakes to achieve
maximum deceleration. The average deceleration was calculated.
1999 U-Haul tandem axle auto transport (6,000 lbs GVWR),
equipped with U-Haul surge brake actuator.
2000 Big Tex tandem axle, open cargo area, with side rails
(14,000 lbs GVWR), equipped with Demco model DA20 surge brake actuator.
Two 2001 Wells Cargo flatbed trailers with triple torsion
axles (20,000 lbs GVWR). One trailer was equipped with a Titan model 20
surge brake actuator and the other with a Demco model DA20 surge brake
Towing vehicles (GVWR):
1993 Chevrolet C-1500 (6,100 lbs GVWR), curb weight 4,200
lbs. The vehicle was equipped with front disc brakes and rear drum
brakes. The vehicle was also equipped with a rear-axle antilock braking
2001 Chevrolet K-3500 (11,400 lbs GVWR), curb weight 7,072
lbs. The vehicle was equipped with four-wheel disc brakes and four-
2001 GMC Sierra (11,400 lbs GVWR), curb weight 7,476 lbs.
The vehicle was equipped with four-wheel disc brakes and four-wheel
Towing vehicle & trailer test combinations:
Unladen pickup truck/unladen trailer.
Unladen pickup truck/full GVWR trailer.
Full GVWR pickup truck/unladen trailer.
Full GVWR pickup truck/full GVWR trailer.
Vehicle combinations that included a heavy trailer (GVWR
between 12,001 lbs and 14,600 lbs) complied with FMCSA's brake
performance requirements under 49 CFR 393.52 when the GVWR of the
trailer was 1.25 times that of the towing vehicle or less, including
test runs with the towing vehicle and trailer loaded to their maximum
Vehicle combinations that included a medium-weight trailer
(GVWR up to 12,000 lbs) complied with FMCSA's brake performance
requirements when the GVWR of the trailer was 2 times that of the
towing vehicle or less, including runs with the towing vehicle and
trailer loaded to their maximum GVWR.
Vehicle combinations that fall within the ratios of towing
vehicle GVWR to trailer GVWR are capable of complying with 49 CFR
393.52, demonstrate stability and control during braking-in-a-curve
tests, and are capable of being stopped and held stationary going up a
20 percent grade. On August 13, 2004, FMCSA granted the Surge Brake Coalition's
petition. FMCSA made a preliminary determination that the petitioner
presented sufficient technical information to support its request that
the Agency initiate a rulemaking to allow the use of surge brakes on
certain combinations of vehicles. Although a limited number of vehicle
configurations were tested, the Agency believes the tests adequately
demonstrate safe ratios of the towing vehicle GVWR to the trailer GVWR
that would be used to determine whether surge brakes may be used on a
particular combination of vehicles.
The Agency does not believe that permitting the use of surge
brakes, under the specific conditions noted in this proposal, is
inconsistent with the original intent of Sec. Sec. 393.48 and 393.49.
Section 393.48 requires that brakes be capable of operating at all
times the vehicle is in operation on public roads. The intent of the
requirement is that all commercial motor vehicles operating in
interstate commerce have sufficient braking capability at all times.
Based upon the information provided by the petitioner, FMCSA believes
vehicles equipped with surge brakes, under the conditions being
proposed in this rulemaking notice, would have sufficient braking
capability at all times the vehicle combination is being operated on
public roads, in interstate commerce. While surge brakes automatically
release when the vehicle combination comes to a complete stop, the
weight-ratio between the towing vehicle and the trailer being proposed
today would ensure that the brakes on the towing vehicle are sufficient
to maintain control of the combination when the surge brakes release
automatically. Therefore, the agency believes the original intent of
Section 393.48 would be satisfied by surge brake systems meeting the
The petitioner contends that:
Technological advances in braking systems render the original
purpose of Sec. 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, [[Page 58660]] wheel brakes and their use in conjunction with large tractors or
The Agency agrees with the petitioner that advances in braking
technology, and specifically in the instance of surge brakes, render
the current single valve requirement in the Sec. 393.49 design
restrictive and not necessary or appropriate when considered
specifically in the context of surge brakes installed on the small and
mid-size trailers addressed by this proposal.
The Agency proposes to rename and revise Sec. 393.49 to make its
construction consistent with Sec. 393.48, and to make it easier to
quickly understand the general requirement and the exceptions, which
would include one for surge brakes. A new title of "Control Valves for
Brakes" is proposed for this section to be more representative of the
different types of brake systems addressed.
The Agency is proposing to add a definition for surge brakes to
Sec. 393.5 to ensure a clear understanding of what is meant by the
term "surge brakes," and to facilitate consistent application of the
requirements being proposed.
If the proposed regulatory amendments are adopted, the Agency would
withdraw the existing regulatory guidance provided as Question 1 to
Sec. 393.48 and Question 1 to Sec. 393.49, originally published on
November 17, 1993 (58 FR 60734) and republished on April 4, 1997 (62 FR
16370). These existing guidance questions addressing whether surge
brakes meet the requirements of the standard would be replaced by the
proposed regulatory text. Thus, the existing guidance would be
superseded by the proposed regulatory text, and would be withdrawn.
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 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, 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. 393.52.
IV. 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 due to novel policy
issues in that it is the subject of both a regulatory reform nomination
and an industry petition. This rule has generated a significant amount
of public interest as it has been identified in the 2005 "Regulatory
Reform of the U.S. Manufacturing Sector" as published by the Office of
Management and Budget. We expect the proposed rule would have minimal
costs. The Agency has prepared a preliminary regulatory analysis
analyzing the costs and benefits of this undertaking. A copy of the
preliminary analysis document is included in the docket referenced at
the beginning of this notice.
Regulatory Flexibility Act
In compliance with the Regulatory Flexibility Act (5 U.S.C. 601-
612), the FMCSA has considered the effects of this regulatory action on
small entities and determined on a preliminary basis that this proposed
rulemaking would have 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 would be required to use surge brakes, and
those currently using electric or other types of brakes have the option
to continue with no change.
The change proposed is to allow a braking system that is not
currently allowed. Many of these operations use small or medium
trailers in their daily operations, which are subject to the FMCSRs if
operated in interstate commerce, which currently do not allow the use
of surge brakes. CMVs using such trailers are most likely to be
operated in interstate commerce if the operation is near a State
boundary. This proposed regulatory action would help to promote more
uniform requirements. This is because numerous State agencies
responsible for motor carrier safety are faced with a current dilemma:
specifically, 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 the proposed rule would not have
a significant economic impact on a substantial number of small
Unfunded Mandates Reform Act of 1995
This rulemaking would not impose an unfunded Federal mandate, as
defined by the Unfunded Mandates Reform Act of 1995 (2 U.S.C. 1532, et
seq.), that will result in the expenditure by State, local, and tribal
governments, in the aggregate, or by the private sector, of $100
million or more in any 1 year.
Executive Order 12988 (Civil Justice Reform)
This proposed action would meet 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 has analyzed this proposed action under Executive Order
13045, Protection of Children from Environmental Health Risks and
Safety Risks. We have determined preliminarily that this rulemaking
would not concern an environmental risk to health or safety that may
disproportionately affect children.
Executive Order 12630 (Taking of Private Property)
This proposed rulemaking would not effect a taking of private
property or otherwise have taking implications under Executive Order
12630, Governmental Actions and Interference with Constitutionally
Protected Property Rights.
Executive Order 13132 (Federalism)
This proposed action has been analyzed in accordance with the
principles and criteria contained in Executive Order 13132. The FMCSA
has preliminarily determined that this rulemaking would not have a
substantial direct effect on States, nor would it limit the policy-
making discretion of the States.
Executive Order 12372 (Intergovernmental Review)
Catalog of Federal Domestic Assistance Program Number 20.217, Motor
Carrier Safety. The regulations implementing Executive Order 12372
regarding intergovernmental consultation on Federal programs and
activities do not apply to this program.
Paperwork Reduction Act
This proposed rulemaking would 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
We have analyzed this action for purposes of the National
Environmental Policy Act of 1969 (42 U.S.C. 4321, et seq.) and have
determined preliminarily that this action would not have an effect on
the quality of the environment. However, a preliminary environmental
assessment (EA) has been prepared because the rulemaking is not among
the type covered by a categorical exclusion. A copy of the preliminary
environmental assessment is included in the docket listed at the
beginning of this notice.
Executive Order 13211 (Energy Effects)
We have analyzed this proposed action under Executive Order 13211,
Actions Concerning Regulations That Significantly Affect Energy Supply,
Distribution or Use. We have determined preliminarily that it would not
be a "significant energy action" under that Executive Order because
it would not be economically significant and would not be likely to
have a significant adverse effect on the supply, distribution, or use
In consideration of the foregoing, FMCSA proposes to amend title
49, Code of Federal Regulations, chapter III, as follows:
List of Subjects in 49 CFR Part 393
Highway safety, Motor carriers and Motor Vehicle Safety.
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. 393.48 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.
* * * * *
(d) Surge brakes. Paragraph (a) of this section does not apply to:
(i) Any trailer with a gross vehicle weight rating (GVWR) of 12,000
lbs 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 lbs, but less than
20,001 lbs, equipped with inertial surge brakes when the GVWR does not
exceed 1.25 times the GVWR of the towing vehicle.
4. Revise 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, the date of manufacture of which is
subsequent to 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 393.48(d).
Issued on: October 3, 2005.
Annette M. Sandberg,
[FR Doc. 05-20297 Filed 10-6-05; 8:45 am]
BILLING CODE 4910-EX-P