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
| Interpretations | Date |
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ID: aiam0637OpenMr. R. S. Bright, Vice President, Product Development and Purchasing, Chrysler Corporation, Detroit, MI 48231; Mr. R. S. Bright Vice President Product Development and Purchasing Chrysler Corporation Detroit MI 48231; Dear Mr. Bright: Your letter of February 18, 1972, dealt with three aspects of Standar 215 that continue to be of concern to Chrysler and with one feature of Standard 210 that you regard as inappropriate.; Your first problem with Standard 215 is the requirement for corne impacts at heights below 20 inches. Our response to the objections raised by Chrysler and others when this requirement was made a part of the standard was to grant an additional two years for compliance. We did this in the expectation that the additional time would permit the manufacturers to make the necessary changes within their normal tooling cycle.; The agency considered the corner impact requirement to be justified and it is not now persuaded to the contrary. We would be willing, however, to review any additional information you can provide on the subject of the costs and benefits of the improved corners.; Your second concern has also been expressed at several points in th rulemaking process. In response to comments advocating the use of resilient materials in the bumper itself, the standard was amended to specify a broader impact ridge, rather than to specify the resiliency of material with which contact would be permitted. The agency has not considered the styling effects of the pendulum requirement to be sufficient to justify amending the standard to permit cosmetic additions of the type you describe. Of course you are free to submit additional information to support the need for such an amendment.; The photometric requirements from Standard 108 that are proposed fo incorporation in Standard 215 have been the subject of several comments under Notice 10 in Dockets 1-9 and 1-20. The issue has not been resolved by issuance of a final rule and we will therefore consider your remarks as an addition to Chrysler's comments on Notice 10.; In the area of seat belt anchorages, the question of whether to us dynamic or static test methods was resolved in October 1970 by specifying a static test with a 10-second holding period. It was thought that this was the surest means of testing the basic strength of the metal and that it therefore carried out the original intent of the standard. Although it may be that the resulting anchorages are able to withstand barrier crashes at speeds considerably higher than 30 mph, we do not consider this to be sufficient cause for relaxing the anchorage requirement. If you have information concerning the force levels at which accidents are survivable, and the relation of these levels to anchorage strength, we would be glad to receive this information.; Sincerely, Douglas W. Toms, Administrator |
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ID: aiam1925OpenHonorable Carl Albert, Speaker of the House of Representatives, Washington, DC 20515; Honorable Carl Albert Speaker of the House of Representatives Washington DC 20515; Dear Mr. Speaker: The purpose of this letter is to inform the committees on Interstat and Foreign Commerce and on Public Works and Transportation of recent activities and decisions of the National Highway Traffic Safety Administration relating to the establishment of a Uniform Tire Quality Grading Standard (UTQGS). We are pleased to announce that this standard, required by section 203 of the National Traffic and Motor Vehicle Safety Act of 1966 (15 USC 1423), was promulgated on May 20, 1975 (copy enclosed). The rule provides for grading tires in three areas: treadwear, traction, and temperature performance. I believe it will provide the consumer with the information he needs to determine which tire is the best value for him, considering his needs and driving habits.; As I am sure you are aware, we have had our share of problems i developing this rule. It had been our original intention to utilize a control tire against which other tires would be compared. In May of 1974, due to technical problems and time constraints imposed by the court in *Nash* v. *Brinegar*, Civil Action No. 17, D.C. (1974), the decision was made to attempt to utilize a control surface rather than a control tire. In order to investigate the feasibility of this approach, a section of runway at Goodfellow AFB, in San Angelo, Texas, was repaved, to provide a research control surface. At the outset of the research project the question had been raised regarding the applicability of section 301 of the National Traffic and Motor Vehicle Safety Act of 1966 (which provides for specific approval by the above mentioned Committees of the House and their counterparts in the Senate, before constructing facilities for testing in traffic safety) to the construction of the control surfaces. It was then determined that since the action was a short-term effort, and in the nature of a feasibility study, section 301 was not applicable. This research project was successful and forms the basis of the rule.; We have recently obligated a sum of $75,000, in addition to th approximately $750,000 expended for the earlier research project (including $165,000 for the control surface), for the purpose of altering the control surfaces and nearby roadway to enable manufacturers to use these surfaces to meet the requirements of complying with the rule.; Even though the associated conversion costs were less than $100,000, w recognized that alterations to the surfaces in late FY 1976 and FY 1977 will cause total expenditures to rise above that level. Therefore, prior to proceeding with the recent site conversion effort, we focused again on the issue of the applicability of section 301. We determined that the section is inapplicable because the purpose of the control surface is to facilitate testing in a matter which is first and foremost consumer information rather than traffic safety, for, as stated in section 203 of the Act, UTQGS is established 'in order to assist the consumer to make an informed choice in the purchase of motor vehicle tires . . . .'; We will continue to keep you posted on the progress of the UTQGS a manufacturers begin testing. We expect to be able to provide the consumer with information in the near future which will enable him to make the best use of his tire dollars.; Sincerely, James B. Gregory, Administrator |
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ID: aiam3918OpenMr. Robert M. Levy, Manager, Design Engineering, Abex Corporation, Signal-Stat Division, P.O. Box 438, Somerset, NJ 08873-3492; Mr. Robert M. Levy Manager Design Engineering Abex Corporation Signal-Stat Division P.O. Box 438 Somerset NJ 08873-3492; Dear Mr. Levy: This is in reply to your letter of February 25, 1985, to Frank Berndt the former Chief Counsel of this agency, asking for clarification of an interpretation of Safety Standard No. 108 that this agency furnished last year to Wesbar Corp.; On May 16, 1984, Wesbar asked whether the correct minimum effectiv luminous lens area on stop lamps and turn signal lamps was 8 square inches or 12 square inches, when intended for use on trailers whose overall width is 80 inches or greater. This office advised Wesbar on July 3, 1984, that as specified in SAE J586c for stop lamps and SAE J588e for turn signal lamps, the answer was 8 square inches. Your letter calls to our attention the fact that these SAE standards require each stop and turn signal lamp to have a minimum of 12 square inches in those vehicle configurations where two stop or turn signal lamps are mounted on the same side of the vehicle and are closer to each other than 22 inches.; Thank you for calling this oversight to our attention. Indeed, SA J586c and J588e establish this exception to the general minimum requirement of 8 square inches. We are furnishing a copy of this letter to Wesbar and apologize for any confusion that the earlier letter has caused.; Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam5435OpenMs. Barbara Pietra Dabble, Inc. 11368 Homedale St. Los Angeles, CA 90049; Ms. Barbara Pietra Dabble Inc. 11368 Homedale St. Los Angeles CA 90049; "Dear Ms. Pietra: This responds to your letter asking about safet regulations for a device you call a 'Cair Bag.' You describe the Cair Bag as a 'comfort pillow' for children to rest or sleep on while seated in their vehicle seat belt. You explain that the Cair Bag is an 'under-stuffed styrene pellet bag' that attaches to the lap portion of the vehicle's Type II seat belt with a reinforced velcro and nylon strap. You state that you will recommend the product for children over 50 pounds 'to prevent it from being used as a child restraint system.' By way of background information, the National Highway Traffic Safety Administration (NHTSA) has the authority to issue Federal motor vehicle safety standards for new motor vehicles and new items of motor vehicle equipment. NHTSA does not, however, approve or certify any vehicles or items of equipment. You state in your letter that everyone you spoke to at NHTSA 'felt this was a great product.' To avoid any possible misunderstanding about what agency personnel said about your product, I wish to clarify that NHTSA and agency personnel can not and do not endorse any product, or make commendations about products. If you understood them to say NHTSA approves of or believes your product is 'great,' that is incorrect, and we apologize for any confusion. Turning now to your questions, there is currently no Federal motor vehicle safety standard (FMVSS) that directly applies to the Cair Bag. Our standard for 'child restraint systems,' FMVSS 213, applies to 'any device except Type I or Type II seat belts, designed for use in a motor vehicle or aircraft to restrain, seat, or position children who weigh 50 pounds or less.' (S4 of FMVSS 213) We do not consider the Cair Bag to 'position children' in a manner that a child seat positions children to better use a vehicle's belt system. Rather, the Cair Bag is simply a cushion that a child may lean on. Since your product does not 'restrain, seat, or position' children as a child restraint system, the product is not subject to Standard 213 regardless of the weight of the children for whom you recommend the product. However, we share your concern that the Cair Bag must not be used in place of a child restraint system. We recommend that the product be clearly labeled with information to the consumer that the product is not a child restraint system and must not be used as one. While no FMVSS applies to the Cair Bag, your product is considered to be an item of motor vehicle equipment. As a manufacturer of motor vehicle equipment, you are subject to the requirements of 49 U.S.C. 30118-30121 concerning the recall and remedy of products with safety related defects. I have enclosed an information sheet that briefly describes those and other manufacturer responsibilities. In the event you or NHTSA determines that your product contains a safety-related defect, you would be responsible for notifying purchasers of the defective equipment and remedying the problem free of charge. In addition, while it is unlikely that the Cair Bag would be installed by a motor vehicle manufacturer, distributor, dealer or repair business, 49 U.S.C. 30122 prohibits those businesses from installing the device if the installation 'makes inoperative' compliance with any safety standard. Our FMVSS's require specific levels of performance for the belt system in a vehicle. For example, Standard 208 has requirements that ensure that a vehicle's lap and shoulder belts are installed to distribute the crash forces over the skeletal structure of the occupant. The FMVSS also have requirements for belts to automatically lock and retract, ensuring there is no excessive slack in the belt system. Since the Cair Bag attaches to the lap belt, any person listed in 30122 must ensure that compliance of the belt system with these requirements is not degraded. Also, FMVSS 302 specifies flammability resistance requirements for vehicle interiors. Any person listed in 30122 who installs a Cair Bag must ensure that the product does not vitiate the vehicle's compliance with those flammability resistance requirements. The prohibition of 30122 does not apply to individual owners who install equipment in their own vehicles. Thus, individual owners may install any item of motor vehicle equipment regardless of its effect on compliance with Federal motor vehicle safety standards. However, NHTSA encourages vehicle owners not to degrade the safety of their vehicles. I would like to make a further note in closing. The advertising literature you enclosed with your letter described the Cair Bag as 'The Portable `Air Bag'.' We believe this description could be misleading, because the term 'air bag' is widely recognized as describing an inflatable device that provides substantial occupant protection in frontal impacts. We are concerned that calling your device a 'portable air bag' could mislead some consumers into believing your device offers occupant protection similar to that of a vehicle air bag, which of course, is incorrect. To avoid this potential for confusion, please refrain from describing your device as an 'air bag.' I hope this information has been helpful. If you have any other questions, please contact Deirdre Fujita of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam5120OpenMr. M.M. Palkar Senior Manager (Marketing) Kalyani Brakes Limited Aurora Towers, 4th Floor 9 Moledina Road, Pune 411 001 INDIA; Mr. M.M. Palkar Senior Manager (Marketing) Kalyani Brakes Limited Aurora Towers 4th Floor 9 Moledina Road Pune 411 001 INDIA; Dear Mr. Palkar: This responds to your letter asking about Federa requirements for the manufacture of brake hose assemblies. I am pleased to provide this 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. The National Traffic and Motor Vehicle Safety Act ('Safety Act,' copy enclosed) establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable Federal motor vehicle safety standards (FMVSS's). This process requires each manufacturer to determine in the exercise of due care 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 noncompliance or safety- related defect exists, the manufacturer must notify purchasers of its product and remedy the problem free of charge. (This responsibility is borne by the vehicle manufacturer in cases in which your hose is installed on a new vehicle by the vehicle manufacturer.) A manufacturer of a noncomplying product is also subject to a civil penalty of up to $1,000 for each noncomplying item 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, 'Brake Hoses,' applies to new motor vehicles and to 'brake hoses' (which include plastic tubing), 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 and the recall responsibilities mentioned above. You ask that NHTSA 'approve' your assemblies so that you can 'punch DOT on the end fittings of the assemblies.' 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. Your question about 'DOT punching' seems to confuse two options for labeling brake hose assemblies specified in Standard No. 106. The 'DOT' mark is used in the standard to constitute a manufacturer's certification of conformance with all applicable FMVSS's. For hydraulic brake hose assemblies, S5.2.4 of Standard No. 106 requires the DOT mark to be placed on a band (not an end fitting) around the hydraulic brake hose assembly, along with a designation that identifies the assembler. As an alternative to this requirement for a band, S5.2.4.1 permits manufacturers of hydraulic brake hose assemblies to label their assemblies by marking at least one end fitting with the manufacturer designation. Assembly manufacturers choosing to mark their assemblies only with a designation must separately furnish the certification of conformance with the applicable FMVSS's. The certification may be in the form of a label or tag on the completed brake hose assembly or on the outside of a container in which the assembly is delivered. The manufacturer's designation that is marked on either the band or an end fitting of a hydraulic or air brake hose assembly is described in S5.2.4(b) and S7.2.3(b), respectively, of Standard No. 106. The designation assists NHTSA in identifying the manufacturer of noncomplying or defective products. You must file your designation (which may consist of block capital letters, numerals or a symbol) in writing with NHTSA's Crash Avoidance Division at the following address: National Highway Traffic Safety Administration, 400 Seventh St., S.W., Washington, D.C., 20590. You may telephone Mr. Richard Carter of the Crash Avoidance Division at (202) 366-5274 if you have questions about filing your designation. 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 manufacturer 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. You also asked whether you must obtain approval from the American Association of Motor Vehicle Administrators (AAMVA) to sell your assemblies in this country. The answer is no. You must meet only NHTSA's requirements to sell your product in the U.S. Please note, however, that assemblies used on commercial vehicles operating in interstate commerce are subject to the requirements of our sister agency in the Department, the Federal Highway Administration (FHWA). If you are interested in the FHWA's requirements for brake hose assemblies, you can write to that agency at the addressed provided in the enclosed information sheet. I hope this information is helpful. If you have further questions, please contact Ms. Deirdre Fujita of this office at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam0322OpenMr. Harvey H. Hartman, Hartman Mfg. Co., 2717 Sidney Street, St. Louis, MO 63104; Mr. Harvey H. Hartman Hartman Mfg. Co. 2717 Sidney Street St. Louis MO 63104; Dear Mr. Hartman: This is in reply to your letter of April 9, 1971 concerning certai provisions of Motor Vehicle Safety Standard No. 213, 'Child Seating Systems.' In your letter you ask whether S4.4 of the standard requires the child seating system itself to be restrained by the seat belt assembly. You state that S4.5.1 indicates to you that the vehicle seat belt assembly is employed to restrain both the child and the seating system, and request that this issue be clarified.; S4.4(a) of the standard requires each child seating system, whe installed as the manufacturer directs, to be restrained by the vehicle seat belt assembly. The vehicle seat belt assembly may *also* be used to directly restrain the child, but it is not required to do so. When it is used for this purpose, however, it must distribute the restraint forces as specified by S4.5.1 of the standard.; The statement in the preamble of the notice of March 23, 1970 to whic you refer describes the scope of the standard. This statement means that any device for seating children in a motor vehicle that is designed to utilize the vehicle restraint system or provides restraint by itself, or both, is a 'child seating system' and must comply with all the requirements of the standard.; We are pleased to be of assistance. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam0288OpenMr. Michael D. Rocker, Vice President, Century Products, Inc., 2150 W. 114th Street, Cleveland, OH 44102; Mr. Michael D. Rocker Vice President Century Products Inc. 2150 W. 114th Street Cleveland OH 44102; Dear Mr. Rocker: This is in reply to your letter of January 28, 1971, requesting a interpretation of Motor Vehicle Safety Standard No. 213. Although your letter refers to S4.11(d) as the paragraph with which you are concerned, it appears from the text of your letter that you are requesting an interpretation of paragraph S5.1(d).; S5.1 of the standard specifies the test procedure that will be used b NHTSA to determine whether the child seating system meets the force resistance requirements specified in S4.1 of the standard. S5.1(d), the passage in question, reads as follows:; >>>'Apply an increasing load to the torso block in a forward direction not more that 15 degrees and not less that 5 degrees above the horizontal, until a load of 1,000 pounds is achieved. The intersection of the load application line and the back surface of the torso block, at the time that the force removes the slack from the load application system, shall not be more that 8 inches or less that 6 inches above the bottom surface of the torso block. Maintain the 1,000-pound load for 10 seconds.'<<<; Your question is whether the angle at which the force is applied, eve though initially between 5 degrees and 15 degrees above the horizontal, may move outside the range during application of the specified force.; The answer to your question is no. The relevant wording of th standard, that the force is to be applied in a forward direction 'not more than 15 degrees and not less than 5 degrees above the horizontal, *until a load of 1,000 pounds is achieved*,' clearly requires that the direction of the test force remain within the specified angular limits throughout the period of force application.; Please write if you have further questions. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam5570OpenMr. Doug Russel Design Engineer Advance Engineered Products 144 Henderson Drive Regina, Saskatchewan S4V 2B2; Mr. Doug Russel Design Engineer Advance Engineered Products 144 Henderson Drive Regina Saskatchewan S4V 2B2; Dear Mr. Russel: This responds to your letter asking about the brak power requirements in section S5.4.2 of Federal motor vehicle safety standard No. 121, Air Brake Systems (49 CFR 571.121). You asked whether there are any limitations on the pressure which can be used to achieve the required deceleration rate specified in S5.4.2.2. As explained below, the same limitation on the pressure which can be used to achieve the deceleration rate specified in S5.4.2.1 applies to the deceleration in S5.4.2.2. You also asked whether brakes must be capable of meeting the specific deceleration rate specified in S5.4.2.2. The answer to that question is yes. Some background information on Federal motor vehicle safety laws and regulations may be helpful. Congress has authorized this agency the National Highway Traffic Safety Administration (NHTSA), to issue Federal motor vehicle safety standards applicable to new motor vehicles and new items of motor vehicle equipment. NHTSA has used this authority to establish Standard No. 121, which applies to braking systems on vehicles equipped with air brakes. The agency, however, does not approve motor vehicle or motor vehicle equipment, nor does it endorse any commercial products. Instead, Congress has established a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. Standard No. 121's brake power requirements are set forth in section S5.4.2. The purpose of these requirements is to help ensure that brakes retain adequate stopping capability during and after exposure to prolonged or severe use, such as long, downhill driving. The brake power procedure specified by that section is conducted on a dynamometer and is intended to replicate real world brake performance. The specified decelerations are designed to heat the brakes to simulate severe driving conditions. Section S5.4.2 requires that each brake shall be capable of making 10 consecutive decelerations at an average rate of 9 f.p.s.p.s from 50 m.p.h. to 15 m.p.h., at equal intervals of 72 seconds, and shall be capable of decelerating to a stop from 20 m.p.h. at an average deceleration rate of 14 f.p.s.p.s. 1 minute after the 10th deceleration. For the first ten decelerations, section S5.4.2.1 specifies the conditions under which the decelerations must be performed, including that 'The service line air pressure shall not exceed 100 p.s.i. during any deceleration.' For the eleventh deceleration, S5.4.2.2 specifies that 'one minute after the end of the last deceleration required by S5.4.2.1 and with the drum or disc rotating at a speed of 20 m.p.h., decelerate to a stop at an average deceleration rate of 14 f.p.s.p.s.' In asking whether there are any limitations on the pressure which can be used to achieve this eleventh deceleration, you noted that S5.4.2.2, unlike S5.4.2.1, does not explicitly specify a pressure limitation. However, reading section S5.4.2 (including S5.4.2.1 and S5.4.2.2) as a whole, the brake line pressure limitation set forth in S5.4.2.1 applies to the eleventh deceleration as well. Section S5.4.2 specifies a test procedure consisting of a series of events, i.e., preparing the dynamometer for the test including a 100 p.s.i. pressure limit, then making 10 decelerations on the dynamometer under the conditions set forth in S5.4.2.1, then making the eleventh deceleration. Section S5.4.2.2 does not specify any change in the dynamometer pressure limit for the eleventh deceleration. The dynamometer pressure limit specified for the brake power test simply reflects the fact that tractor trailer brakes are typically configured to operate at a maximum nominal brake pressure of approximately 100 psi. Use of a higher brake pressure that differed from a vehicle's actual maximum brake pressure would result in the brake power test not being representative of real world brake performance. In response to your second question, section S5.4.2 specifies that a brake must be capable of decelerating to a stop from 20 m.p.h. at an average deceleration rate of 14 f.p.s.p.s. 1 minute after the 10th deceleration. See also S5.4.2.2. A brake which could not achieve this specified deceleration rate for the eleventh deceleration would not comply with the Standard's requirements. 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. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam0772OpenMr. O. Yamauchi, Manager, Export Sales Department, Mitsubishi Motors Corporation, 33-8, 5-Chome, Shiba, Minato-Ku, Tokyo, Japan; Mr. O. Yamauchi Manager Export Sales Department Mitsubishi Motors Corporation 33-8 5-Chome Shiba Minato-Ku Tokyo Japan; Dear Mr. Yamauchi: This is in replay to your letter of June 7, 1972, concerning whethe thin transparent polyethylene covers used to protect the inside of vehicles until delivery are subject to the requirements of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' You indicate that the material does not conform to the requirements of the standard, and ask whether you may nonetheless utilize it if you place a label in the vehicle directing that the cover be removed before the car is delivered to the customer.; Whether the material must meet the requirements of the standard depend upon the likelihood that it will be retained as a protective cover by the purchaser. If it is installed in a manner that promotes its use by purchasers, we would consider it to be part of any component which it covers, and subject to the standard when used to cover those components enumerated in S4.1 of the standard. Manufacturers must therefore take appropriate steps to see that it is not so used. The use of a label that states that the material must be removed before delivery to a purchaser is one step a manufacturer might take. We believe the manufacturer should also install the material in such a way that purchasers will not wish to use it as a protective covering. If these steps are taken the NHTSA would not consider the material to be required to comply with the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1860OpenHonorable Herman E. Talmadge, United States Senate, Washington, DC 20510; Honorable Herman E. Talmadge United States Senate Washington DC 20510; Dear Senator Talmadge: This responds to your recent communication requesting consideration o a constituent's concern about the National Highway Traffic Safety Administration's standard requiring antiskid devices on new school buses for all states, although some states do not often have icy roads.; The regulation to which your constituent Mr. Smith refers is Federa Motor Vehicle Safety Standard No. 121, *Air brake systems*. This standard which became effective for trailers on January 1, 1975, and trucks and buses on March 1, 1975, specifies minimum performance requirements for service brake systems, emergency brake systems, and parking brake systems utilized on air-braked vehicles. The standard does not specifically require antilock devices, although S5.3.1 of the standard does specify minimum stopping distance and stability requirements on dry and wet roads. Most vehicle manufacturers have decided to utilize antilock devices to meet these requirements. The purpose of these requirements is to enhance vehicle stability during brake application on roads in all conditions, dry and wet, as well as icy. A copy of Standard No. 121 with amendments is enclosed.; Please write again if I can be of further assistance. Sincerely, James C. Schultz, Chief Counsel |
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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.