Parts and Accessories Necessary for Safe Operation: Surge Brake Requirements, 9855-9871 [E7-3815]

Agencies

• Federal Motor Carrier Safety Administration
• DEPARTMENT OF TRANSPORTATION

[Federal Register Volume 72, Number 43 (Tuesday, March 6, 2007)]
[Rules and Regulations]
[Pages 9855-9871]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E7-3815]


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DEPARTMENT OF TRANSPORTATION

Federal Motor Carrier Safety Administration

49 CFR Part 393

[Docket No. FMCSA-2005-21323]
RIN-2126-AA91


Parts and Accessories Necessary for Safe Operation: Surge Brake 
Requirements

AGENCY: Federal Motor Carrier Safety Administration (FMCSA), DOT.

ACTION: Final rule.

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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 
Coalition (Coalition).

DATES: Effective Date: April 5, 2007.

ADDRESSES: Docket: For access to the docket to read background 
documents or comments received, go to https://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 
Federal holidays.

SUPPLEMENTARY INFORMATION: This Final Rule is organized as follows:

I. Legal Basis for the Rulemaking
II. Background
    A. Current Regulatory Environment
    B. Regulatory History
    C. Petition
    D. Analysis of Petition
    E. Notice of Proposed Rulemaking (NPRM)
III. Discussion of Comments to NPRM
    A. Comments Supporting
    B. Comments Opposing
IV. Summary
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 
U.S.C. 31502(b)].
    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 
authority.
    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. 
31136(a)].
    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.

II. Background

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 
occur.
    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.
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    \1\ Certain trailers and trucks are exempted depending on width, 
axle GVWR, maximum speed, and unloaded vehicle weight.
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    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 
as follows:
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    \2\ The Federal Highway Administration's (FHWA) Bureau of Motor 
Carrier Safety (Bureau) (FMCSA's predecessor agency) published these 
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 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 
Sec.  393.49:
    ``This requirement shall not apply to trailers equipped with 
surge brakes that satisfy the conditions provided in Sec.  
393.48(d).''

    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 
electric brakes.
    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 
personal use.
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    \3\ A Break on Brakes, in Trailer Body Builders, August 1, 2004, 
Rick Weber (https://trailer-bodybuilders.com/mag/trucks_break_
brakes/).
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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 tests.
    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.
Test Vehicles

Trailers (GVWR)

     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 
brake actuator.
     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.''

Test Protocol
    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.

Test Results

    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 
included.
    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 
12,000 pounds.
    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 
safe.
    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 
rulemaking.

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 
interstate commerce.
    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 
to:
    (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 
GVWR.
    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 
Division.

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 
under ARA.
    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 
applications.
    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 
SAE. [https://www.sae.org/servlets/productDetail?PROD--
TYP=PAPER&PROD--CD=820135]
---------------------------------------------------------------------------

    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 
brake actuator.
     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 NPRM:

    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 
available actuators.
    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.  
393.52.
    FMCSA finds these additional analyses persuasive and agrees with 
their conclusions.
    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 
distance.
    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.

[[Page 9864]]

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 numero