ID: nht75-5.47

DATE: 05/05/75

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Oshkosh Truck Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This will acknowledge receipt of your request for reconsideration of the NHTSA determination of February 18, 1975, to Oshkosh Truck Corporation that Standard No. 121, Air brake systems, permits the installation of a handoperated service brake control that meets the requirements of the standard.

We will advise you of our determination as soon as possible.

YOURS TRULY,

OSHKOSH TRUCK CORPORATION

April 10, 1975

Richard Dyson Chief Council Office NHTSA

This responds to NHTSA approval of a hand-operated service brake control. Previous correspondence on this subject is attached for your reference.

Oshkosh trucks are equipped with service, emergency and parking brake systems which meet the requirements of FMVSS 121. As an additional parking brake, to be used in lieu of the standard parking brake supplied, a customer has requested a hand-operated control to activate the service brake system. Oshkosh Truck is concerned that installation of this control will circumvent certain FMVSS 121 parking brake and service brake requirements.

Parking brakes must be applied by an energy source not affected by an air pressure loss in the service brake system, as stated in FMVSS 121, Section 5.6.3. The parking brake control must be separate from the service brake control as stated in FMVSS 121, Section 5.6.4. If a truck is equipped with a hand-operated control which activates the service brake system and if this system, rather than the parking brake system, is used to park the truck, then Sections 5.6.3 and 5.6.4 are circumvented.

The service brake system must stop the truck in distances specified by FMVSS 121, Section 5.3.1. The hand-operated service brake control only applies air pressure to the front brakes. If a truck is equipped with a hand-operated control which applies only the front service brakes and if this system, rather than the normal dual service braking system (operating on front and rear brakes) is used to stop the truck, then stopping distances will be exceeded and Section 5.3.1 will be circumvented.

The NHTSA with the advent of FMVSS 121 specifies performance requirements for air brake systems. Oshkosh Truck has taken extraordinary measures to comply with these requirements and we are reluctant to add a component which circumvents any of those requirements, or by-passes any of our carefully engineered systems.

The NHTSA has determined that installation of a hand-operated control lever is acceptable. We are concerned that if this system is used to park a truck or stop a moving truck that it will not meet the requirements of FMVSS 121. Therefore, please reconsider the previous NHTSA determination and reply as soon as possible.

Thank you.

Danny J. Lanzdorf

Supervising Engineer

ID: 21012.ztv

Brandon Billingsley, Vice President Marketing
CRS Electronics
Heavy Duty Bus Parts
17850 I-45
Willis, TX 77318

Dear Mr. Billingsley:

We are replying to your letter of November 19, 1999, with respect to your "new overhead LED warning light system for school buses." You ask whether your product will comply with Federal standards.

You call the new technology "strobing LEDs," and say that you are able to "build a warning light module that combines the 'attention grabbing,' authoritative effect of strobe lights and the long life expectancy of LEDs." You have tested "according to the protocols of SAE J887," and report that your product "does indeed exceed the requirements of SAE J887 for strobe lights."

We assume that you wish to offer your product as original equipment on school buses. The acceptability of your product is determined by Federal Motor Vehicle Safety Standard No. 108, Lamps, Reflective Devices, and Associated Equipment. Paragraph S5.1.4 of Standard No. 108 requires each school bus to be equipped with a system of four red signal (or four red and four amber) lamps designed to conform to SAE Standard J887, July 1964. Under this standard, school bus warning system lamps are required to flash alternately in a range of 60 to 120 flashes a minute. Unlike later versions of J887, an optional flash rate in Hz is not specified.

A few years ago we were asked whether a school bus warning system consisting of strobe lights met Standard No. 108. I enclose a copy of our letter of March 29, 1994, to Harry C. Gough. The system we were asked about was described as flashing "on and off four times in a 255 millisecond period and then stays off for 745 milliseconds, then the lamp on the opposite side of the vehicle repeats the aforementioned pattern." We replied that we believed that the light emanating from a strobe lamp under these performance parameters "will be perceived as a single flash of varying intensity and not as four separate flashes, and that when this is followed by an identical pattern on the other side of the bus, the system is one that is alternatively flashing within the meaning of Standard No. 108."

You did not specify the flash rate of your product, but you may use our 1994 interpretation as a guideline for determining whether the light would be perceived "as a single light of varying intensity," and hence compliant with Standard No. 108. If it would not be so perceived, then your lamps would appear to be noncompliant with the Standard's requirements.

The minimum photometric requirements of the 1964 specification are also the ones that apply to your product. I enclose a copy for your information.

If you have questions, you may call Taylor Vinson of this Office (202-366-5263).

Sincerely,
Frank Seales, Jr.
Chief Counsel
Enclosures
ref:108
d.2/29/2000

ID: 77-3.43

TYPE: INTERPRETATION-NHTSA

DATE: 08/03/77

FROM: AUTHOR UNAVAILABLE; Joseph J. Levin Jr.; NHTSA

TO: State of Connecticut Department of Motor Vehicles

TITLE: FMVSR INTERPRETATION

TEXT: This responds to your June 7, 1977, letter asking whether a school bus manufacturer can sell a bus to a private school or to a contractor for use in the transportation of the handicapped that is not built in compliance with the new school bus safety standards.

The new school bus definition to which you refer in your letter was issued by the National Highway Traffic Safety Administration (NHTSA) at the direction of Congress. The definition requires that all buses carrying more than 10 persons to or from school or related events (other than common carriers in urban transportation) must be constructed in accordance with the school bus safety standards.

The buses to which you refer transport children to and from private schools and also transport the handicapped. There is no distinction between private school and public school for purposes of the application of the school bus safety requirements. Accordingly, a bus designed to carry more than 10 persons to and from a private school must be constructed in accordance with the requirements and must be equipped with the lights, paint, and signs of a school bus. The same situation exists for buses designed for the transportation of the handicapped if they carry more than 10 persons to and from school or related events.

In conclusion, a manufacturer is not permitted to sell a bus designed to transport school children to and from school and related events, unless that bus is contructed in accordance with the requirements. Schools may purchase, however, small vehicles (fewer than 10 passenger) that are not built according to the requirements. These vehicles are not considered school buses for purposes of the application of the requirements.

SINCERELY,

STATE OF CONNECTICUT DEPARTMENT OF MOTOR VEHICLES

June 7, 1977

Joseph Levin, Chief Counsel U.S. Dept. of Transportation National Highway Traffic Safety Administration

This is a request for interpretation of the re-definition of the term "school bus" and how it affects current Connecticut statutes. The recent amendment to the definition of "school bus" that appears in 49 CFR 571.3 defines a school bus as a bus that is sold or introduced into interstate commerce, for purposes that include carrying students to and from school and related events, but does not include a bus designed or sold for operation as a common carrier in urban transportation.

Connecticut legislation, specifically Sections 14-275a and 14-275b (copies enclosed) of the Connecticut Motor Vehicle Laws, Title 14, requires the use of a standard school bus. Section 14-275a does not mandate that private schools must provide a school bus when transporting students under the age of 21 years to and from school, and Section 14-275b exempts the use of a standard school bus when transporting the physically handicapped, providing such vehicle has been approved for such purpose by the Commissioner of the Department of Motor Vehicles.

It is my understanding that because of the recent re-definition of a school bus, the manufacturers of school bus bodies and manufacturers of reconstructed van-type vehicles will no longer sell a vehicle to a prospective customer unless that vehicle meets all the requirements of a school bus, including construction, flashing lights, color, and appropriate labeling. Persons responsible for transporting private school students and the handicapped are now restricted from purchasing vehicles other than school buses because of the manufacturers' policies concerning the sale of vehicles used to transport students to and from school.

The interpretation I am requesting is: Can a manufacturer sell a vehicle in Connecticut other than a school bus to a private school or to a contractor for use in the transportation of the physically handicapped, if the manufacturer is aware of its intended use? Your attention and response to this question is appreciated.

John L. O'Connell Pupil Transportation Administrator

[Legislation Omitted]

ID: 8783

Mr. Han Dinh
Project Manager
United States Postal Service
8403 Lee Highway
Merrifield, VA 22082-8101

Dear Mr. Dinh:

This responds to your letter requesting information about the conversion of postal vehicles to operate on compressed natural gas (CNG). You explained that you are deciding which specifications to apply to the CNG pressure vessels on the converted vehicles. You ask whether we would recommend the American Gas Association's voluntary standard, NGV-2, or the Department of Transportation standard for cylinders which transport CNG.

By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.; Safety Act) to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not approve or certify any vehicles or items of equipment. Instead, the Safety Act establishes a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. NHTSA also investigates safety-related defects in motor vehicles and items of motor vehicle equipment.

At present, NHTSA has not issued any standard applicable to CNG cylinders or vehicles using CNG as a fuel. However, as you know, NHTSA has undertaken rulemaking on a safety standard for CNG tanks and vehicles. (58 FR 5323, January 21, 1993.) In response to our January 1993 proposal, the agency received over 55 comments, which we are currently analyzing. We expect our next regulatory decision in early 1994. Given that this rulemaking has not been completed, NHTSA is unable to recommend to you a particular course of action with respect to the NGV-2 and DOT standards at this time.

If NHTSA were to issue a safety standard for CNG cylinders and vehicles, the standard would apply to new products, and have applicability to vehicle conversions as follows. The cylinder regulation would be an equipment standard. Thus, all cylinders manufactured after the effective date of the standard would be required to comply with its requirements, whether they are placed on new vehicles or on vehicles converted to CNG fuel.

The fuel system regulation would apply to new vehicles as manufactured by original equipment manufacturers or as converted prior to the first sale of the vehicle. Once the vehicle is sold, if the vehicle is converted by a commercial converter, the CNG fuel system regulation would apply if the vehicle was manufactured after the effective date of the standard and thus would have been regulated if it had originally been a CNG vehicle. With this in mind, I have enclosed a discussion that sets forth the implications under Federal law of converting gasoline-powered vehicles to use propane or other gas (such as CNG). That discussion addresses 108(a)(2)(A) of the Safety Act, which prohibits vehicle manufacturers, distributors, dealers and repair businesses from "knowingly rendering inoperative, in whole or in part, any device or element of design installed . . . in compliance" with any FMVSS.

In addition, please be aware that manufacturers of CNG tanks and vehicles are subject to the requirements in sections 151- 159 of the Safety Act concerning the recall and remedy of products with defects related to motor vehicle safety. In the event that NHTSA or the manufacturer of the tank or vehicle determines that the product contains a safety- related defect, the manufacturer would be responsible for notifying purchasers of the defective equipment and remedying the problem free of charge.

Our sister agency in the Department, the Federal Highway Administration (FHWA), has operational and equipment requirements for commercial vehicles used in interstate commerce. For further information about FHWA requirements, you can contact that agency's Chief Counsel's office at (202) 366-0650.

I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw of my staff at this address or by phone at (202) 366-2992.

Sincerely,

John Womack Acting Chief Counsel Enclosure ref:303 d:8/16/93

ID: nht93-6.13

DATE: August 16, 1993

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Han Dinh -- Project Manager, United States Postal Service

TITLE: None

ATTACHMT: Attached to letter dated 6/17/93 from Han Dinh to Steven P. Wood (OCC 8783)

TEXT:

This responds to your letter requesting information about the conversion of postal vehicles to operate on compressed natural gas (CNG). You explained that you are deciding which specifications to apply to the CNG pressure vessels on the converted vehicles. You ask whether we would recommend the American Gas Association's voluntary standard, NGV-2, or the Department of Transportation standard for cylinders which transport CNG.

By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S1381 et seq.; Safety Act) to issue Federal motor vehicle safety standards that set performance requirements for new motor vehicles and items of motor vehicle equipment. NHTSA does not approve or certify any vehicles or items of equipment. Instead, the Safety Act establishes a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. NHTSA also investigates safety- related defects in motor vehicles and items of motor vehicle equipment.

At present, NHTSA has not issued any standard applicable to CNG cylinders or vehicles using CNG as a fuel. However, as you know, NHTSA has undertaken rulemaking on a safety standard for CNG tanks and vehicles. (58 FR 5323, January 21, 1993.) In response to our January 1993 proposal, the agency received over 55 comments, which we are currently analyzing. We expect our next regulatory decision in early 1994. Given that this rulemaking has not been completed, NHTSA is unable to recommend to you a particular course of action with respect to the NGV-2 and DOT standards at this time.

If NHTSA were to issue a safety standard for CNG cylinders and vehicles, the standard would apply to new products, and have applicability to vehicle conversions as follows.

The cylinder regulation would be an equipment standard. Thus, all cylinders manufactured after the effective date of the standard would be required to comply with its requirements, whether they are placed on new vehicles or on vehicles converted to CNG fuel.

The fuel system regulation would apply to new vehicles as manufactured by original equipment manufacturers or as converted prior to the first sale of the vehicle. Once the vehicle is sold, if the vehicle is converted by a commercial converter, the CNG fuel system regulation would apply if the vehicle was manufactured after the effective date of the standard and thus would have been regulated if it had originally been a CNG vehicle. With this in mind, I have enclosed a discussion that sets forth the implications under Federal law of converting gasoline-powered vehicles to use propane or other gas (such as CNG). That discussion addresses S108 (a)(2)(A) of the Safety Act, which prohibits

vehicle manufacturers, distributors, dealers and repair businesses from "knowingly rendering inoperative, in whole or in part, any device or element of design installed . . . in compliance" with any FMVSS.

In addition, please be aware that manufacturers of CNG tanks and vehicles are subject to the requirements in sections 151-159 of the Safety Act concerning the recall and remedy of products with defects related to motor vehicle safety. In the event that NHTSA or the manufacturer of the tank or vehicle determines that the product contains a safety-related defect, the manufacturer would be responsible for notifying purchasers of the defective equipment and remedying the problem free of charge.

Our sister agency in the Department, the Federal Highway Administration (FHWA), has operational and equipment requirements for commercial vehicles used in interstate commerce. For further information about FHWA requirements, you can contact that agency's Chief Counsel's office at (202) 366-0650.

I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw of my staff at this address or by phone at (202) 366-2992.

ID: 14516.ztv

Mr. Larry C. Lavender
Fleetline Products, Inc.
P.O. Box 298
Springfield, TN 37172

Dear Mr. Lavender:

This is in reply to your letter of March 28, 1997, asking for an interpretation of Federal Motor Vehicle Safety Standard No. 108.

You state that you have received "verbal" answers to certain questions from the Office of Safety Performance Standards and need a written confirmation of these answers from the Office of Chief Counsel. You wish to supply parts to "heavy duty truck manufacturers" that meet Standard No. 108, and are concerned with sheeting to be applied to the rear fenders, mud flaps or mud flap support brackets.

My initial comment is that we encourage manufacturers to seek written interpretations directly from the Office of Chief Counsel. Only the written interpretations of the Office of Chief Counsel are binding.

My second comment is to note that the conspicuity requirements of Standard No. 108 apply only to heavy trailers and to truck tractors that are 80 or more inches in overall width. Thus, a manufacturer wishing to add conspicuity sheeting to rear fenders, mud flaps or mud flap brackets of a straight truck need not follow Standard No. 108. Nevertheless, in the belief that standardization enhances safety, we encourage voluntary compliance with the conspicuity requirements for straight trucks as well.

The interpretations for which you seek confirmation are:

"The sheeting must be in a pattern of alternating red and white segments. The individual segments must be 300mm long plus or minus 150mm, i.e. from 150mm to 450mm long."

Yes. The specifications stated in paragraph S5.7.1.3(a) and (b) for the side and rear of trailers and truck tractors apply also to rear fenders, and mud flaps and their support brackets.

"There is no requirement for the color pattern to begin or end in either color. The inboard and outboard segments may be either red or white."

You are correct. The text of Standard No. 108 speaks of "alternating white and red color segments" (S5.7.1.3(a)) while Figure 30-1 through Figure 30-4 show red and white segments installed. However, there is no requirement that the color pattern begin or end with either color, or that inboard and outboard segments be red or white.

"There is no requirement for the tape to be completely free of discontinuities. On the brackets which have a 45 degree angle, the tape does not have to be cut in a miter joint."

Paragraph S5.7.1.4(a) specifies that sheeting "need not be applied to discontinuous surfaces" and provides several examples of these. We assume that this is what you mean by your statement. There is no requirement that tape be cut in a miter joint.

"Minor trimming of the tape to conform to the shape of a bracket is acceptable, provided the length measured on the center line of the tape is a minimum of 600mm. On the drawing included with this memorandum one corner of the tape is trimmed. This is acceptable."

Minor trimming of the tape is acceptable, as shown on your drawing. The length measured on the center line of the sheeting may be any length from 600mm to 900mm. (300mm +/- 150mm x 2).

"The drawing included with this memorandum illustrates a proposed bracket satisfying FMVSS 571.108."

The drawing shows an acceptable solution to mounting conspicuity material on a mud flap bracket.

If you have any further questions, you may refer them to Taylor Vinson of this Office (202-366-5263).

Sincerely,
John Womack
Acting Chief Counsel
ref:5/28/97
d:5/28/97

ID: nht76-5.12

DATE: 11/10/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Anshelewitz, Barr, Ansell & Bonello

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your September 8, 1976, question whether the windows of "recreational vehicles" qualify as "secondary means of egress" and what Federal requirements would apply to them if they do so qualify.

The only Federal requirement for the provision of emergency exists apply to buses (Standard No. 217, Bus Window Retention and Release, 49 CFR 571.217 (copy enclosed)). "Bus" is defined by our regulations to mean "a motor vehicle with motive power, except a trailer, designed for carrying more than 10 persons" (49 CFR 571.3). Thus, Standard No. 217 would apply to the vehicle you describe if it is designed to carry more than 10 persons (including the driver) while the vehicle is in motion.

The standard does not use the term "secondary means of egress" but specifies a minimum area of unobstructed opening that may be provided by several means (e.g., emergency door, "push-out window").

SINCERELY,

ANSCHELEWITZ BARR ANSEL & BONELLO

SEPTEMBER 8, 1976

U.S. Department of Transportation National Highway Traffic Safety Administration Motor Vehicle Program

Att: Conrad Cooke

Re: Feimster v. Concord Motor Homes Our file #14247

Pursuant to Mr. Williams' telephone conversation with this office on 7 September 1976, he informed me that you have conducted an investigation relative to recreational vehicles having secondary means of egress.

Concord Motor Homes, the defendant in the above-captioned matter, alleges that the windows of their recreational vehicle quali as secondary means of egress in that one can break the tempered glass and climb out. The windows involved in this accident were not the "pop-out" type.

I do not agree with Concord Motor Homes' assumption that these windows qualify as a secondary means of egress.

I would appreciate it if you would forward to me any information you may have with regard to whether or not windows of recreational vehicles qualify as secondary means of egress, and, if so, the standards said windows must comply with as a secondary means of egress. If there is a charge for this information, please advise and I will forward you a check at once.

Thank you very much.

Richard B. Ansell

ID: nht88-4.44

TYPE: INTERPRETATION-NHTSA

DATE: 12/19/88 EST

FROM: ERIKA Z. JONES -- NHTSA CHIEF COUNSEL

TO: I. ROBERT EHRLICH -- ENGINEER

ATTACHMT: MEMO DATED 5-5-88, FROM I. ROBERT EHRLICH, TO RICHARD STROMBOTNE, OCC-2077

TEXT: This responds to your letter addressed to Dr. Richard Strombotne, concerning side impact protection. You requested copies of our two January 1988 proposals, and stated that you are particularly interested in whether or not the proposed standards would a pply to stretch limousines. According to your letter, these vehicles are frequently covered by light sheet steel to fill in the gap created by lengthening a conventional passenger car. You stated that this leaves a wide, unprotected gap in the center.

Enclosed are copies of the two proposals. Your question concerning whether the proposals would apply to stretch limousines is addressed below.

By way of background information, the National Traffic and Motor Vehicle Safety Act authorizes the National Highway Traffic Safety Administration (NHTSA) to issue safety standards for new motor vehicles and new motor vehicle equipment. All motor vehicles and items of motor vehicle equipment manufactured or imported for sale in the United States must comply with all applicable safety standards. Manufacturers of motor vehicles must certify compliance of their products in accordance with 49 CFR Part 567, C ertification.

Each safety standard applies to specified "types" of motor vehicles and/or motor vehicle equipment. Motor vehicles are classified into the following types: passenger cars, multipurpose passenger vehicles, trucks, buses, trailers and motorcycles. A defi nition for each motor vehicle type is set forth at 49 CFR Part 571.3.

The two January 1988 notices propose to amend Standard No. 214, Side Door Strength, to upgrade its test procedures and performance requirements. Those amendments, like the current version of Standard No. 214, apply only to passenger cars.

A person who stretches a completed passenger car prior to its first sale to a consumer is considered a vehicle alterer under NHTSA's certification regulation. Part 567.7, Requirements for Persons Who Alter Certified Vehicles, requires alterers to certify that the vehicle, as altered, complies with all applicable safety standards. One issue which sometimes arises when a vehicle is altered is whether it remains the same "type" of vehicle after the alteration, and thus subject to the same standards. We w ould assume ordinarily that the "stretching" of a passenger car would not change the vehicle's classification. Under this assumption, an alterer who stretches a passenger car would be required to certify that the stretched vehicle continues to meet all standards applicable to passenger cars, including Standard No. 214. Thus, in this situation, the proposed amendments would apply to stretch limousines.

I note that it is conceivable that an alterer may be able to demonstrate, depending on the nature of the overall alterations, including alterations other than stretching, that a passenger car which is stretched has changed classification and is considere d a multipurpose passenger vehicle or bus instead of a passenger car. If this were the case, the alterer would be required to certify that the vehicle complies with all standards applicable to the vehicle type for which it is now classified. This would not include Standard No. 214, since, as indicated above, that standard applies only to passenger cars.

A person who stretches a used passenger car is not considered a vehicle alterer and is not required to certify that the modified vehicle continues to meet applicable safety standards. However, manufacturers, distributors, dealers, or motor vehicle repai r businesses modifying a used vehicle are prohibited by section 108(a)(2)(A) of the Safety Act from knowingly rendering inoperative any device or element of design installed on or in a motor vehicle or item of equipment in compliance with an applicable F ederal motor vehicle safety standard.

I hope this information is helpful.

ENCLOSURES

ID: 08-002064drn

ID: nht92-9.29

DATE: February 3, 1992

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Harvey D. Benson -- Chief Engineer, Landoll Corporation

TITLE: None

ATTACHMT: Attached to letter dated 12/5/91 from Harvey D. Benson to Richard Carter (OCC 6764)

TEXT:

This responds to your letter to Mr. Richard Carter of this agency asking about requirements applicable to heavy hauler trailers. You first asked whether such trailers were required to be equipped with spring brakes. You stated that some users of your vehicles have received tickets for not having spring brakes. Your second question asked whether there are requirements about size and impact capacity for bulkhead (i.e., cab protection) on truck chassis beds. You explained that Landoll manufactures slide back beds mounted on single and tandem axle truck chassis. I am pleased to have this opportunity to explain our requirements.

By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approval of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act ("Safety Act"), the manufacturer is responsible for certifying that its vehicles or equipment comply with applicable standards. The following letter represents our opinion based on the facts presented in your letter.

The Safety Act requires NHTSA to promulgate motor vehicle safety standards that specify performance requirements for motor vehicles and motor vehicle equipment. One such safety standard is Standard No. 121, Air Brake Systems, (49 CFR 571.121) which specifies requirements for braking systems on vehicles equipped with air brake systems, including most trailers. In particular, section S5.6 specifies requirements for parking brakes. This section states that the trailer portion of a heavy hauler trailer is required to meet the requirements of section S5.6 or at the manufacturer's option the requirements set forth at 49 CFR S393.43, Breakaway and Emergency Braking (a regulation issued by the Federal Highway Administration (FHWA)).

Spring brakes are used by most manufacturers to comply with the parking brake requirements in S5.6 of Standard No. 121. However, those requirements can be met by other types of brake designs. In addition, as mentioned above, a heavy hauler trailer as defined in S4 of the standard is permitted to comply with the requirements set forth in 49 CFR S393.43.

You mentioned that your trailers have capacities up to 120,000 GVWR. Please be advised that Standard No. 121 applies to such vehicles; however, the standard does not apply to trailers that have both a GVWR of more than 120,000 pounds and bodies that conform to the definition for "heavy hauler trailer" set forth in S4.

As for your comment that some of your customers are being ticketed for not having spring brakes, I do not have sufficient information to address this situation. If you would like us to look into this matter, please provide details concerning specific instances of such ticketing, including the agency responsible for the ticketing and the regulation being applied.

As for your second question about requirements for bulkhead cab protection on truck chassis beds, NHTSA has no regulations about this topic. However, you should review the FHWA's Federal Motor Carrier Safety Regulations, which set forth specific requirements for bulkhead protection in commercial motor vehicles. (49 CFR Part 393.106.)

I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. If you have questions about the FHWA's in-use requirements, you should contact its Office of Motor Carrier Safety at (202) 366-1790.