NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
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ID: nht95-5.23OpenTYPE: INTERPRETATION-NHTSA DATE: July 13, 1995 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Michael A. Norman TITLE: NONE ATTACHMT: ATTACHED TO 6/30/95 LETTER FROM MICHAEL A. NORMAN TO JOHN WOMACK TEXT: Dear Mr. Norman: This responds to your letter of June 30, 1995, with respect to the "Auto Truckers Courtesy Light." This is the device that you discussed with Taylor Vinson of this Office on June 29. You have applied to the Virginia Department of Transportation for evaluation of this product who will make a decision on July 13. We assume that you wish to know whether the product is permitted by Federal regulations. As we understand it from the description, photos, and drawings that you enclosed, the device consists of a large sign with a "thank you" message that would be illuminated by two small amber lamps in the upper corners. The device could be mounted on the rear underride guard of a large truck or trailer, or on the rear cargo door. The purpose of the device is to enable the driver of the vehicle on which it is installed to show appreciation "to a trailing motorist for blinking his lights to assist the truck operator in changing back to the right hand lane after passing." In addition "[the] device operates with audio and visual indicators with three second automatic delay cut off." You told Taylor Vinson that the intent is to sell this product in the aftermarket. As Mr. Vinson indicated, the Federal motor vehicle safety standard on motor vehicle lighting (Standard No. 108) contains no specifications applicable to the manufacture and sale in the aftermarket of supplementary motor vehicle lighting equipment such as this. This means that the device may be manufactured and sold without violating any Federal law administered by the Department of Transportation. There remains, however, the issue of whether its installation and use would violate a Federal proscription that forbids manufacturers, dealers, distributors, and motor vehicle repair businesses from "making inoperative" motor vehicle lighting equipment installed in accordance with Standard No. 108 (or equipment installed that was necessary to comply with any other Federal motor vehicle safety standard). With respect to supplementary lighting equipment, we generally ask ourselves whether the "message" sent by required lighting equipment is likely to be made less effective if it and the device are used simultaneously. The effectiveness of the required lighting equipment is especially important with respect to oversized vehicles such as large trucks and trailers. With respect to your device, we foresee the possibility that the driver of a large vehicle on which it is installed might have to apply the brakes at the moment that the two small amber lamps are activated that illuminate the "thank you" sign, thus impairing the effectiveness of the stop lamps (we would probably reach a different conclusion if the message was related to the brake lamps, i.e., if it said "Stop"). Therefore, the installation of your device by a manufacturer, dealer, distributor, or motor vehicle repair business would appear to violate the Federal proscription against making safety equipment inoperative. The proscription, however, does not apply to the owner of the vehicle which, if a company, could have the device installed in its own private repair facilities, or if the owner is a person, by the owner. This means that the individual States in which the device is to be used may accept or reject the device as they determine to be appropriate. We are unable to advise you how the laws of the individual States would apply to the device, and suggest that you write for an opinion to the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203. If you have further questions, Taylor Vinson will be pleased to assist you (202-366-5263). |
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ID: nht95-5.24OpenTYPE: INTERPRETATION-NHTSA DATE: July 13, 1995 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Douglas Miyashiro -- Northrop Grumman TITLE: NONE ATTACHMT: ATTACHED TO 6/22/95 LETTER FROM DOUGLAS MIYASHIRO TO DOROTHY NAKAMA (OCC 11011) TEXT: Dear Mr. Miyashiro: This is in response to a memo dated June 22, 1995 that you faxed to Coleman Sachs of my staff on July 12, 1995. Your memo states that Northrup Grumman's System Engineering Department is defining design requirements for an Advance Technology Transit Bus (ATTB), and, as part of that effort, researching whether the Federal Bumper Standard found in 49 CFR Part 581 would apply to such vehicles. As noted in your memo, 49 CFR 581.3 states that the standard "applies to passenger motor vehicles other than multipurpose passenger vehicles." The standard itself does not define the term "passenger motor vehicle," but does state, in section 581.4, that "all terms defined in the Motor Vehicle Information and Cost Savings Act . . . are used as defined therein." Section 2(1) of that Act (now codified at 49 U.S.C. @ 32101(10)), defines "passenger motor vehicle" as "a motor vehicle with motive power, designed for carrying twelve persons or less . . ." In light of this definition, the ATTB would not have to comply with the Bumper Standard unless it is designed to carry twelve persons or less. If you have any further questions regarding this issue, feel free to contact Mr. Sachs at the above address, or by telephone at (202) 366-5238. |
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ID: nht95-5.25OpenTYPE: INTERPRETATION-NHTSA DATE: July 15, 1995 FROM: Charles Holmes TO: Office of Chief Council -- NHTSA TITLE: NONE ATTACHMT: ATTACHED TO 9/25/95 LETTER FROM JOHN WOMACK TO CHARLES HOLMES (A43; REDBOOK 2; STD. 206) TEXT: Letter of Interpation: On May 24, 1995 my minor son Justin Holmes, Fell out of a Ford 1 ton truck. This was an 1989 Ford 1 ton with a gross weight of 33,000 lbs. Upon entering the truck, Justin was placed in a seat belt, and I locked the door. Some where along the ride he unhooked the belt, I was in a curve when the door opened, I looked up and Justin was falling out the truck. When Justin was asked what happen he stated, I had my hand over the door handle when daddy started going around, I was tring to hold on and the door came open. Ryder trucks are Rental trucks, Which rents to Families. I had no warning the look was not a safety lock. Ryder said they are not in any way responsible, and Ford has not answered. I would like to know what Regulations you have on a truck that carries the gross weight of 33,000 lbs, the safety regulations which governs door locks and handle? By this being a Rental Vehicle would the regulations fall under passenger vehicles? What Federal Case Laws Reverse or OverRules your Regeulations? And a list of people ever injured in a simular accidents. That is there Names and Addresses. |
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ID: nht95-5.26OpenTYPE: INTERPRETATION-NHTSA DATE: July 18, 1995 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Yoshiaki Matsui -- Manager, Automotive Equipment, Legal & Homologation Section, Stanley Electric Co., Ltd. TITLE: NONE ATTACHMT: ATTACHED TO 06/23/95 LETTER FROM YOSHIAKI MATSUI TO CHIEF COUNSEL (OCC 11017) TEXT: Dear Mr. Matsui: This responds to your letter of June 23, 1995, asking questions about neon high mounted stop lamps. The National Highway Traffic Safety Administration answered these questions in the preamble to a notice of proposed rulemaking that was published on June 19, 1995. We assume that you had not received it by the 23rd, and enclose a copy for your information. You will see (center column, page 31940) that Federal Motor Vehicle Safety Standard (FMVSS) No. 108 allows neon tubes as light sources for the center highmounted lamp. Under our interpretation of paragraph S5.1.1.16, FMVSS No. 108 also allows testing of a neon lamp with or without its ballast, in accordance with the directions of that paragraph. If you have any questions, you may refer them to Taylor Vinson of this Office. |
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ID: nht95-5.27OpenTYPE: INTERPRETATION-NHTSA DATE: July 18, 1995 FROM: John Womack -- Acting Chief Counsel; NHTSA TO: John Renock -- Director of Operations, Central New York Regional Transport Authority TITLE: NONE ATTACHMT: ATTACHED TO 6/15/95 LETTER FROM M. JUDSON BROWN TO JOHN WOMACK (OCC 10992) TEXT: Dear Mr. Renock: Mr. M. Judson Brown, the project manager for your Transit Authority's compressed natural gas (CNG) bus project, requested that I explain the Federal regulation of CNG containers to you. According to Mr. Brown's letter, the Central New York Regional Transit Authority believes that certain CNG fuel containers are required to be re-inspected and hydrostatically retested every three years. The short explanation is that this agency, the National Highway Traffic Safety Administration (NHTSA), has no authority to regulate the reinspection or retesting of CNG containers used to fuel motor vehicles, after the first consumer purchase. With regard to Mr. Brown's inquiry into the authority of the Research and Special Programs Administration (RSPA) to require reinspection and retesting, we are forwarding your letter to RSPA so that officials of that agency can explain their regulations to you. NHTSA has been authorized by Congress to issue Federal Motor Vehicle Safety Standards (FMVSSs) for new motor vehicles and new items of motor vehicle equipment. The agency has used this authority to issue FMVSS No. 304, Compressed natural gas fuel container integrity, (49 CFR 571.304) which specifies requirements for the integrity of new CNG containers used to fuel motor vehicles. Each new CNG container manufactured on or after March 27, 1995 (the date the standard took effect) must comply with FMVSS No. 304 and be certified as complying with that standard when it is sold. However, after the first consumer purchase of a motor vehicle or an item of motor vehicle equipment, NHTSA's authority is much more limited and does not extend to the reinspection or retesting of motor vehicles or such equipment. I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw at this address or by phone at (202) 366-2992. |
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ID: nht95-5.28OpenTYPE: INTERPRETATION-NHTSA DATE: July 20, 1995 FROM: Thomas A. Placey -- Senior Assistant District Attorney, Office of the District Attorney, Cumberland County TO: Office of the Chief Counsel, NHTSA TITLE: Re: Commonwealth v. One 1994 GMC Jimmy 95-258 Miscellaneous Term; VIN: 1GKDT13WR2508404 (true); 1GKDT13W4R2511523 (altered); PSP ID: X4-15565 ATTACHMT: ATTACHED TO 08/11/95 LETTER FROM STEPHEN P. WOOD AND JOHN WOMACK (TO THOMA A. PLACEY (A43; PART 591) TEXT: Sir/Madame: Corporal James Drenning, of the Pennsylvania State Police (PSP), has referred me to you for information on a case currently within my jurisdiction. The nutshell facts are as follows: Auto thief steals a Canadian owned GMC Jimmy in Canada. Thief, without any import or export license, delivers GMC Jimmy to conspirator in Pennsylvania. Conspirator alters VIN and sells to buyer. Police in both countries break auto theft ring. PSP, pursuant to state law, seize vehicle from buyer. Buyer wants GMC Jimmy back and files with local state court for return. The issue, on the federal level, is can this vehicle ever be properly registered in the United States. What are the specific federal laws or regulations that govern such situations. My hearing on the state issue is in September. I know the judge will ask about federal ramifications. It would be extremely helpful if you could point me in the right direction so I may answer the judge's question with specific law or regulation. Thank you for your time and assistance in this matter. |
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ID: nht95-5.29OpenTYPE: INTERPRETATION-NHTSA DATE: July 21, 1995 FROM: Heather Paul -- Executive Director, National Safe Kids Campaign TO: Patricia Breslin, Ph.D. -- Director, Office of Vehicle Safety Standards, NHTSA TITLE: NONE ATTACHMT: ATTACHED TO 9/5/95 LETTER FROM JOHN WOMACK TO ANGELA MICKALIDE (REDBOOK 2; STD. 213; A43) TEXT: Dear Dr. Breslin: As you know, the National SAFE KIDS Campaign and its partners, the National Safety Council, the International Association of Chiefs of Police, and the State and Territorial Injury Prevention Directors Association, will be distributing approximately 38,000 child safety seats to families in need over the next few months. This presents an ideal opportunity for research on the effectiveness of the child safety seat distribution process. The Campaign is submitting a written request to the National Highway Traffic Safety Administration for an interpretation of the Federal Motor Vehicle Safety Standard (FMVqSS) 213. Specifically, the Campaign is interested in modifying the uniform child restraint registration card to collect information about recipient families' sociodemographic profile, the type of cars in which the child safety seats would typically be installed in order to address incompatibility issues, and the comprehensiveness of the educational outreach at the distribution sites (see enclosed draft). The Campaign would require the distribution site coordinators to complete the modified child [Illegible Word] registration card with the recipient family prior to distributing the child safety seat. This would yield almost a 100% child safety seat registration response rate which would allow NHTSA and the manufacturer to more readily notify families about recalls. Distribution site coordinators would mail the cards directly to the manufacturer, who would then tabulate the data for the Campaign's evaluation research purposes. Please call me or Dr. Angela Mickalide, Program Director, as soon as possible in order to resolve this important child safety matter. Thank you in advance for your timely response to the Campaign's request for an interpretation of FMVSS 213. (Enclosure omitted.) |
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ID: nht95-5.3OpenTYPE: INTERPRETATION-NHTSA DATE: December 12, 1995 FROM: Samuel J. Dubbin -- Chief Counsel, NHTSA TO: Tom Byrne -- Vice President, Goodridge (USA) Inc., TITLE: NONE ATTACHMT: 10/3/95 letter from Tom Byrne to John Womack TEXT: This responds to your letter requesting an interpretation of Federal Motor Vehicle Safety Standard No. 106; Brake hoses. According to your letter, you plan to sell a brake hose assembly for hydraulic brake systems that you refer to as "Stainless Steel Br aided Brakelines." n1 You then asked several questions about selling your product in this country. n1 The standard defines a "brake hose assembly" as a "brake hose, with or without armor, equipped with end fittings for use in a brake system . . ." By way of background information, the National Highway Traffic Safety Administration (NHTSA) administers Federal requirements for the manufacture and sale of new motor vehicles and certain items of motor vehicle equipment, including brake hose assemblies . Congress has established a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable Federal motor vehicle safety standards (FMVSSs). This process requires each manufacturer to dete rmine that its products meet all applicable requirements. NHTSA tests vehicles and equipment sold to consumers for compliance with the FMVSS's and investigates defects relating to motor vehicle safety. If a manufacturer or NHTSA determines that a nonco mpliance or safety-related defect exists, the manufacturer must notify purchasers of its product and remedy the problem free of charge. A manufacturer of a noncomplying product is also subject to a civil penalty of up to $ 1,000 for each noncomplying it em it produces. I have enclosed an information sheet that highlights the responsibilities you must meet as a manufacturer of motor vehicle equipment. Standard No. 106 applies to new motor vehicles and to brake hoses, brake hose end fittings, and brake hose assemblies. The standard specifies labeling and performance requirements for these products to reduce the likelihood of brake system failure from ruptures in the brake hose or brake hose assembly. New brake hoses, end fittings, and assemblies must meet these requirements to be sold in or imported into this country. If the items do not comply, the manufacturer is subject to the civil penalties an d the recall responsibilities mentioned above. You first asked NHTSA to "confirm" that an independent laboratory certification is valid for the United States. As explained above, NHTSA does not approve manufacturers' products or conduct pre-sale testing of their products. In the United States, the individual manufacturer must certify that its product complies with all applicable FMVSS's. You then asked NHTSA to confirm that such a brake hose assembly can be used with an adapter into the master cylinder or caliper. Your brake hose assembly can be used at any place in a motor vehicle, provided that in installing it, a vehicle manufacturer , distributor, dealer or repair business does not knowingly make inoperative, in whole or in part, a vehicle or item of equipment which is in compliance with any applicable safety standard. Specifically, inclusion of your brake hose assembly could not m odify a hydraulic brake system subject to FMVSS No. 105, Hydraulic Brake Systems, to the extent that it no longer complies with the standard. Your next question asked whether there are any special marking requirements for brake hose assemblies manufactured for sale in the United States. Section S5.2.4 sets forth labeling requirements for brake hose assemblies. Section S5.2.4 states that Each hydraulic brake hose assembly, except those sold as part of a motor vehicle, shall be labeled by means of a band around the brake hose assembly as specified in this paragraph or at the option of the manufacturer, by means of labeling as specified in S5.2.4.1. The band may at the manufacturer's option be attached so as to move freely along the length of the assembly, as long as it is retained by the end fittings. The band shall be etched, embossed, or stamped in block capital letters, numerals or symbols at least one-eighth of an inch high, with the following information: (a) The symbol DOT constituting certification by the hose assembler that the hose assembly conforms to all applicable motor vehicle safety standards. (b) A designation that identifies the manufacturer of the hose assembly which shall be filed in writing with: Office of Vehicle Safety Standards, Crash Avoidance Division, National Highway Traffic Safety Administration, 400 Seventh Street SW., Washington DC 20590. The designation may consist of block capital letters, numerals or a symbol. In addition, section S5.2.4.1 provides as an option that at least one end fitting be etched, stamped or embossed with a designation at least one-sixteenth of an inch high that identifies the manufacturer of the hose assembly. I have also enclosed copies of two procedural requirements you must satisfy in order to sell your products in this country. The first requirement is NHTSA's regulation for manufacturer identification (49 CFR Part 566). This regulation requires a manufa cturer of equipment to which an FMVSS applies (e.g., brake hoses) to submit its name, address, and a brief description of the items of equipment it manufacturers to NHTSA within 30 days after it first imports its products into the United States. The second requirement is NHTSA's regulation for designations of agents (49 CFR Part 551, Procedural Rules, Subpart D). The regulation requires all manufacturers headquartered outside of the United States to designate a permanent resident of the United States as the manufacturer's agent for service of all process, notices, orders and decisions. This designation should be mailed to me at the following address: Chief Counsel, Room 5219, National Highway Traffic Safety Administration, 400 Seventh St., S. W., Washington, D.C., 20590. The designation must include the following information: 1. A certification that the designation of agent is valid in form and binding on the manufacturer under the laws, corporate-by-laws, or other requirements governing the making of the designation at the time and place where it is made; 2. The full legal name, principal place of business and mailing address of the manufacturer; 3. Marks, trade names, or other designations of origin of any of the manufacturer's products which do not bear its name; 4. A statement that the designation shall remain in effect until withdrawn or replaced by the manufacturer; 5. A declaration of acceptance duly signed by the agency appointed, which may be an individual, a firm or a United States corporation; and, 6. The full legal name and address of the designated agent. 7. In addition, the designation must be signed by a person with authority to appoint the agent. The signer's name and title should be clearly indicated beneath his or her signature. I hope this information is helpful. If you have further questions, please contact Mr. Marvin Shaw of this office at (202) 366-2992. |
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ID: nht95-5.30OpenTYPE: INTERPRETATION-NHTSA DATE: July 24, 1995 FROM: Doug Burnett -- (Office Of Chuck Chvala) TO: Dorothy Nakama -- DOT TITLE: Re: School bus definition language ATTACHMT: ATTACHED TO 8/4/95 LETTER FROM JOHN WOMACK TO CHUCK CHVALA (REDBOOK 2; PART 571) TEXT: The budget language is reproduced below. The plus marks indicate new language and the minus marks indicate deleted language. Our current definition is not statutory, and I was mistaken when I told you that it is in Administrative Rule. Our only references to the definition of a school bus are modified in the language below. I have also attached a copy of the motion which was included in the budget, including a brief analysis of it by the Legislature's budget office. There is also a 1993 memo from our state DOT which discusses some of the issues involved here. Thanks for your help on this and give me a call if you have any questions. 347.40 (2) No person shall operate on a highway any school bus having a passenger-carrying capacity of [- 10 -] [+ 16 +] or more persons [- including -] [+ in addition to +] the operator unless such bus is equipped with at least one mirror which is 7 inches in diameter so located as to enable the operator to see a reflection of the road from the entire front bumper forward to a point where direct observation is possible. 121.555 (2) (a) Insurance. If the vehicle is owned or leased by a school or a school bus contractor, or is a vehicle authorized under sub. (1) (b), it shall comply with s. 121.53. If the vehicle is transporting [- 9 -] [+ 15 +] or less persons in addition to the operator and is not owned or leased by a school or by a school bus contractor, it shall be insured by a policy providing property damage coverage with a limit of not less than $ 10,000 and bodily injury liability coverage with limits of not less than $ 25,000 for each person, and, subject to the limit for each person, a total limit of not less than $ 50,000 for each accident. PUBLIC INSTRUCTION Definition of School Bus Motion: Move to modify the current definition of school bus as follows: 1. Define a school bus as a motor vehicle which carries 16 or more passengers (in addition to the operator).
2. Provide that a school district can use, as an alternative method of transportation, a motor vehicle transporting 15 or less passengers (in addition to the operator). Note: Under current law, a school bus is defined as a motor vehicle which carries 10 or more passengers (in addition to the operator) for the purpose of transporting private and public school pupils to or from school, curricular or extracurricular activities, religious instruction (on days when school is in session). If a school board uses a school bus to transport pupils through a contract or the use of its own motor vehicles, the operation of the bus is subject to certain requirements regarding bus operator licensure and physical examinations, vehicle insurance, school bus painting and traffic safety rules. A school board can use, as an alternative, a motor vehicle transporting 9 or less passengers (in addition to the operator): in such cases, the school district is not subject to the same requirements applicable to the operation of a school bus. [Change to Governor: None] LETTER Ricardo Martinez Administrator, NHTSA Department of Transportation Dear Mr. Martinez, I have been contacted by Wisconsin State Senator Chuck Chvala regarding a provision recently passed in the Wisconsin Legislature's biennial budget. The language included in the legislation changes the state definition of school buses in a manner that is inconsistent with the definition established by the U.S. Department of Transportation. Senator Chvala has inquired as to whether this change in state law and subsequent state regulations would violate any federal laws or regulations with respect to the definition of school buses. I would appreciate a prompt reply to Senator Chvala's inquiry. Please direct your response to: Chuck Chvala Wisconsin State Senator State Capitol P.O. Box 7882 Madison, WI 53707-7882 Russell D. Feingold United States Senator cc: Ms. Carmen Rivera, Legislative Liaison, NHTSA |
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ID: nht95-5.31OpenTYPE: INTERPRETATION-NHTSA DATE: July 25, 1995 FROM: John Womack -- Acting Chief Counsel, NHTSA TO: Larry W. Overbay -- Director, Automotive And Support Equipment Directorate, U.S. Department of the Army TITLE: NONE TEXT: Dear Mr. Overbay: This letter follows up a telephone conversation between Mr. Edward Glancy of my staff and Mr. John Hretz of the U.S. Department of the Army in which Mr. Hretz requested a clarification of a February 17, 1995, letter that we sent to you. In that letter, we discussed the testing of air braked vehicles under Federal Motor Vehicle Safety Standard (FMVSS) No. 121, Air Brake Systems. We explained that, as a result of a court decision, the emergency stopping test requirements, set forth in S5.7.1 of the standard, are not currently applicable to trucks and trailers. As Mr. Glancy explained, subsequent to that letter, the National Highway Traffic Safety Administration (NHTSA) issued a final rule reinstating emergency stopping tests in FMVSS No. 121. The amendments reinstating these tests take effect on March 1, 1997, for truck tractors and March 1, 1998, for other medium and heavy vehicles that are equipped with air brakes. Once these amendments take effect, the provisions in S5.7.1 will again be applicable to air braked vehicles. Mr. Hretz asked whether, in conducting the emergency stopping distance tests, removal of the service air signal line (a non-manifold line which is designed to carry compressed air) from the rear air brake relay valve is considered by NHTSA to be a valid test. Your question is addressed below. Section S5.7.1 states that When stopped six times for each combination of weight and speed specified in S5.3.1.1, except for a loaded truck tractor with an unbraked control trailer, on a road surface having a PFC of 0.9, with a single failure in the service brake system of a part designed to contain compressed air or brake fluid (except failure of a common valve, manifold, brake fluid housing, or brake chamber housing), the vehicle shall stop at least once in not more than the distance specified in Column 5 of Table II. In describing the failure conditions for which stopping distance requirements must be met, S5.7.1 broadly specifies "a single failure in the service brake system of a part designed to contain compressed air or brake fluid," except for certain listed parts. It is our opinion that the failure mode Mr. Hretz described in which one disconnects the service air signal line at the rear service air relay comes within this language. Therefore, a vehicle would not comply with FMVSS No. 121 if it did not meet the specified stopping distance requirements after disconnection of the service air signal line at the rear service air relay. I hope this information has been helpful. If you have any other questions, please contact Marvin Shaw of my staff at this address or by phone at (202) 366-2992. |
Request an Interpretation
You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:
The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.
Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.