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: aiam1453OpenMr. Erik Sundelin, Tire Department, Trellaborgs Gummifabriks Aktiebolag, S-23101 Trelleborg-Sweden; Mr. Erik Sundelin Tire Department Trellaborgs Gummifabriks Aktiebolag S-23101 Trelleborg-Sweden; Dear Mr. Sundelin: This responds to your February 20, 1974 request for a determination o whether two of your motorcycle treadwear indicator designs conform to the S6.4 requirements of Standard 119 *New pneumatic tires for vehicles other than passenger cars.*; The treadwear indicator requirements have been amended by deleting al of the portio of S6.4 that begins 'The indicators shall, as a minimum'. this means that the manufacturer determines for himself the location and design of the six treadwear indicators requires (three in the case of motorcycle tires). He must assure himself that when the indicator is reached, the tread at that point o the tire is worn to a depth of on-sixteenth of an inch (or one-thirty-second of an inch in the case of motorcycle tires).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4201OpenMr. David M. Wise, Gary Precision Products, 530 Old Post Road No. 3, Greenwich, CT 06830; Mr. David M. Wise Gary Precision Products 530 Old Post Road No. 3 Greenwich CT 06830; Dear Mr. Wise: This is in reply to your letter of August 7, 1986, asking if Federa Motor Vehicle Safety Standard No. 108, or any other Federal regulation applies to a plastic ice scraper with a reflector on it that you may manufacture.; Although the title of Standard No. 108 is *Lamps, Reflective Devices and Associated Equipment*, the reflective devices covered by the standard are those that are mounted on the rear and side of a motor vehicle, which are necessary for signalling and the safe operation of vehicles during darkness and other times of reduced visibility. It does not apply to ice scrapers. Nor does the other Federal motor vehicle safety standard dealing with reflectivity, Standard No. 125 'Warning Devices,' or any other regulation of this Department.; I hope this answers your question. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1003OpenMr. R. O. Sornson, Manager, Environmental & Safety Relations, Chrysler Corporation, Detroit, MI 48231; Mr. R. O. Sornson Manager Environmental & Safety Relations Chrysler Corporation Detroit MI 48231; Dear Mr. Sornson: In response to your letter of November 15, 1972, requestin interpretations of the amendments to Standard No. 108 published on October 7, 1972 (37 FR 21328), I enclose an order of the Administrator responsive to your request.; A correction will be published in the near future reinstating th designation 'S5.1' and changing the designation of paragraph S5.3, adopted on January 4, 1973, to 'S5.2'.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam3897OpenMr. Hiroshi Shimizu, Assistant Manager, Overseas Operations Dept., Tokai Rika Co., Ltd., Oguchi-Cho, Aichi Pref., 480-01, Japan; Mr. Hiroshi Shimizu Assistant Manager Overseas Operations Dept. Tokai Rika Co. Ltd. Oguchi-Cho Aichi Pref. 480-01 Japan; Dear Mr. Shimizu: This responds to your letter of December 19, 1984, concerning th requirements of Federal Motor Vehicle Safety Standard No. 209, *Seat Belt Assemblies*. You noted that section S4.1(e) of the standard provides that 'A Type 1 or Type 2 seat belt assembly shall be provided with a buckle or *buckles* readily accessible to the occupant....' [Emphasis added.] You asked whether the standard would permit a seat belt assembly with two buckles as shown in the schematic attached to your letter. The answer is that while Standard No. 209 would permit such an assembly, whether such an assembly can be installed in a particular vehicle is determined by Standard No. 208, *Occupant Crash Protection*.; Standard No. 208 specifies performance requirements for the protectio of occupants in a crash. Section S4.1.2.3.1 provides that Type 2 lap and shoulder belt systems used in passenger cars must have a nondetachable shoulder belt. Likewise, S4.2.2 provides that certain trucks and buses with Type 2 belts must have a nondetachable shoulder belt. The belt system you illustrated in your diagram consists of one continuous loop of webbing which serves as both the lap and shoulder belt. However, your design provides a separate buckle for the shoulder anchorage and thus an occupant could release the shoulder buckle and use the belt solely as a lap belt. Thus, we would not consider your design to have a nondetachable shoulder belt.; In addition, section S7.2 of the standard sets requirements for th latch mechanism of non-automatic seat belt assemblies used in passenger cars and certain trucks and buses. Section S7.2(c) requires that the latch mechanism of non-automatic seat belt assemblies used in passenger cars and certain trucks and buses. Section S7.2(c) requires that the latch mechanism used in those vehicles must release at a single point. Therefore, a two buckle system could not be used in those vehicles.; I hope this answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5040OpenMr. Timber Dick Safeline Children's Products Co. 5335 W. 48th, Suite 300 Denver, CO 80212; Mr. Timber Dick Safeline Children's Products Co. 5335 W. 48th Suite 300 Denver CO 80212; "Dear Mr. Dick: This responds to your letter concerning Standard No 213, 'Child Restraint Systems,' and the Sit'n'Stroll child restraint system you manufacture. The restraint is designed to be rear-facing for children weighing up to 25 pounds. Your letter relates to our April 22, 1992 interpretation to Mr. Mark Sedlack regarding rear-facing restraints for children weighing up to 25 pounds. In that letter, I stated that under Standard No. 213, such a restraint could be tested with either the six-month-old or the three-year-old dummy in the agency's compliance tests. I further stated that the restraint must physically permit the dummies to be positioned in accordance with the procedures in S6.1.2.3.1 of Standard No. 213. If the restraint cannot permit the dummies to be so positioned, the restraint cannot be recommended for children weighing more than 20 pounds. You ask whether we would consider the Sit'n'Stroll as permitting the proper positioning of the three-year-old dummy. The photographs enclosed with your letter show the dummy in the restraint with its legs at a right angle to the torso. The backs of the dummy's heels rest on the standard seat assembly's seat back, about five inches below the top of the seat back. At the outset, I must note that NHTSA cannot provide you with an unqualified answer on whether your restraint accommodates the three-year-old dummy, because we do not know the details of your design. However, we can offer general guidance on the positioning of the dummy's legs, an aspect of the dummy's positioning that is of particular concern to you. S6.1.2.3.1(b) and (d) of Standard No. 213 specify the procedure for positioning the three-year-old dummy's legs in the child restraint. S6.1.2.3.1(b) states: '... Extend the legs of the dummy as far as possible in the forward horizontal direction, with the dummy feet perpendicular to the centerline of the lower legs.' S6.1.2.3.1(d) states: '... R otate each dummy limb downwards in the plane parallel to the dummy's midsagittal plane until the limb contacts a surface of the child restraint system or the standard seat .... Position the limbs, if necessary, so that limb placement does not inhibit torso or head movement in the standard's dynamic tests....' Based on the photographs you enclosed, the Sit'n'Stroll permits the dummy's legs to be positioned as specified in S6.1.2.3.1(b). That is, the legs are extended 'as far as possible' in the forward horizontal direction. The standard does not specify whether 'forward' is relative to the standard seat assembly or to the child. However, interpreting 'forward' as relative to the seat assembly would have the effect of disallowing the use of the three-year- old dummy to test a rear-facing restraint, since the positioning procedures would be inappropriate for the restraint. In the absence of language in the standard to that effect, we are disinclined to so conclude. Instead, we conclude 'forward' as used in S6.1.2.3.1(b) is relative to the child. Although the Sit'n'Stroll permits the legs to be positioned in accordance with S6.1.2.3.1(b), under S6.1.2.3.1(d) the leg placement must not inhibit torso or head movement during the dynamic tests of the standard. It does not appear that the dummy's legs would inhibit torso or head movement due to the forward (relative to the seat assembly) movement of the torso and head in the dynamic tests. However, we cannot make a definite determination based on the information in your letter. Please note that it is likely that NHTSA will propose amending Standard No. 213 such that a child restraint designed for use with children weighing up to 25 pounds would be tested with a new array of child test dummies, such as the 9- month-old dummy described in subpart J of our regulations (49 CFR Part 572). It is possible that a future amendment to the standard could specify that a new dummy, such as the 9-month-old, will be used instead of the 3-year-old dummy to test such a child restraint. NHTSA has announced its intention to consider rulemaking on incorporating new dummies, including the 9-month-old, in Standard No. 213 compliance tests. This intention was discussed at length in NHTSA's 'Planning Document on Potential Standard 213 Upgrade,' July 1991. I also would like to note our concern with the ability of your restraint to meet Standard No. 213's occupant excursion requirement (S5.1.3.2). S5.1.3.2 states: 'In the case of each rear-facing child restraint system, in a dynamic test ... no portion of the target point on either side of the dummy's head shall pass through the transverse orthogonal planes whose intersection contains, the forward-most and top-most points on the child restraint system surfaces ....' It appears from your photograph that the restraint's seat back might be too low to enable the restraint to meet S5.1.3.2 in a dynamic test. One means of avoiding any potential compliance problem with the excursion requirement would be for your company to raise the height of the seat back on this child restraint system. I hope this information is helpful. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam2785OpenMr. Donald L. Fowler, Ullman, Fowler & Jeffries, Inc., 2231 Devine Street, Columbia, SC 29205; Mr. Donald L. Fowler Ullman Fowler & Jeffries Inc. 2231 Devine Street Columbia SC 29205; Dear Mr. Fowler: This responds to your March 6, 1978, letter asking about the complianc responsibilities of a final-stage manufacturer who mounts a body on a motor vehicle chassis. In the situation you describe, the chassis would have been tested for compliance with the standards by the chassis manufacturer and the body would have been tested by the body manufacturer. You ask whether the final assembler would be required to crash test the vehicle as assembled.; The chassis manufacturer has responsibilities for compliance wit Federal safety standards that are outlined in Part 567, *Certification*, and Part 568, *Motor Vehicles Manufactured In Two Or More Stages*, of our regulations. The chassis manufacturer must include with its chassis an incomplete vehicle document that describes how to complete the vehicle without impairing the compliance of the chassis with Federal safety standards. Although not required by our regulations, body manufacturers often provide documents addressing the compliance of their vehicle bodies with applicable safety standards. If a body that complies with Federal standards is mounted in accordance with the instructions of the incomplete vehicle document, the final-stage manufacturer can ordinarily assume that the completed vehicle complies with the safety standards. Based upon this assumption, it can certify that the vehicle complies with all applicable standards.; By following the instructions of the incomplete vehicle manufacture and relying upon the statements of the body manufacturer, the final-stage manufacturer would be considered to have exercised due care in ensuring that the vehicle complies. However, if the final-stage manufacturer does not follow the incomplete vehicle manufacturer's instructions or in some way makes a major modification that would affect the compliance of the vehicle, it might become necessary for it to undertake some further testing to ensure continued compliance. The amount of further testing, in these instances, would depend upon the extent of modification of the vehicle body or chassis.; For your information, our safety standards and regulations are locate in Volume 49 of the Code of Federal Regulations Parts 501 *et seq*. I am enclosing a sheet which details the applicability of Federal standards to various vehicles.; If after reading this letter, you still have questions that require meeting, contact Roger Tilton of my staff.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam0242OpenMr. L.C. Lundstrom, Director, Automotive Safety Engineering, General Motors Technical Center, Warren, Michigan 48090; Mr. L.C. Lundstrom Director Automotive Safety Engineering General Motors Technical Center Warren Michigan 48090; Dear Mr. Lundstrom: This is in reply to your letter of May 7, 1970, requesting approval o an equivalent test procedure for interior compartment doors, in place of those specified in S3.3.1(a) and (c) of Standard No. 201.; Since the phrase 'approved equivalent test procedure' appeared in th initial Federal motor vehicle safety standards, the Bureau's position on this subject has undergone some clarification. The manufacturer's primary responsibility is to produce vehicles or equipment that, when tested according to the applicable standards, meet the stated requirements. Although a manufacturer is responsible for ensuring that his products meet all the requirements of the standards, there is nothing in the Act that requires a manufacturer to perform any predetermined series of test. If a particular test is actually 'equivalent' to the procedure described in the standard, in the sense that the test results can be accurately correlated to the standard's requirements, there is no need to requires approval of the Bureau, and there would be no legal significance to the approval if given. Conversely, if the test is not equivalent, so that an item that 'passed' the test might still fail to conform to the standard, the request would be actually for a lowering of the standard, which could not be done without rulemaking procedures. For this reason, we will not grant the approval in the form in which it was requested.; The procedure that you describe does, however, appear to be a distinc improvement in the method of testing this aspect of performance. We intend to initiate rulemaking procedures directed at amending the standard to incorporate that test.; Sincerely, Rodolfo A. Diaz, Acting Associate Director, Motor Vehicl Programs; |
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ID: aiam5410OpenMr. Donald W. Vierimaa Vice President-Engineering Truck Trailer Manufacturers Associations 1020 Princess St. Alexandria, VA 22314; Mr. Donald W. Vierimaa Vice President-Engineering Truck Trailer Manufacturers Associations 1020 Princess St. Alexandria VA 22314; "Dear Mr. Vierimaa: This responds to your letter of June 1, 1994 requesting an interpretation of Motor Vehicle Safety Standard No. 108. You have asked whether the term 'underride protection device' as used in S5.7.1.4.1 in Standard No. 108 'only include the device yet to be required by NHTSA or would it include the device described in TTMA RP No. 92?' At present, the term 'rear underride protection device' as used in Standard No. 108 means the common 'ICC bumper' described by the Federal Highway Administration in 49 CFR 393.86, or a similar device that the manufacturer of a trailer has provided regardless of whether it is required by 49 CFR 393.86. Thus, it presently includes the device described in TTMA RP No. 92. You have informed us that some manufacturers are installing guards with round cross sections, and some with square cross sections rotated 45 degrees which results in a 'diamond' shape orientation. In addition, on some trash trailers, a curved hook grabs and holds the round cross section guard while trash is loaded into the trailers. You have asked whether a 38 mm wide retroreflective strip of sheeting applied to these guards will comply with Standard No. 108. S5.7.1.4.1(c) of Standard No. 108 specifies only that the strip shall be applied 'across the full width of the horizontal member of the rear underride protection device.' Although the reflective material is certified by its manufacturer for photometric conformance in the vertical position, Standard No. 108 has not been interpreted to require structural changes in trailers for the sole purpose of enhancing the conspicuity installation. The agency's decision to avoid exceptions for trailers with unusual configurations was based on the expectation that manufacturers would use their available structures for conspicuity material, rather than re-engineer them. Thus, we believe that the application of 38 mm wide sheeting to either of these guards would comply with S5.7.1.4.1(c). Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam1900OpenMr. J. C. Carruth, President, Canadian Trucking Association, 130 Albert Street, Suite 300, Ottawa, Canada K1P5G4; Mr. J. C. Carruth President Canadian Trucking Association 130 Albert Street Suite 300 Ottawa Canada K1P5G4; Dear Mr. Carruth: The Secretary has asked me to respond to your letter of March 1 (F-50-A) requesting from a provision of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391 et seq.) that prevents operation in the United States of Canadian vehicles which were not manufactured in conformity with Standard No. 121, *Air brake systems*. You request a temporary exclusion from the standard for Canadian-based commercial vehicles operating in the United States, whether or not they are manufactured in Canada.; The National Traffic and Motor Vehicle Safety Act provides that n person shall import into the United States a motor vehicle manufactured on or after the date any applicable Federal motor vehicle safety standard takes effect unless it is in conformity with the standard (S 1397(a)(1)(A)). Sections 1397(b)(3) and (b)(4) specifically address importation:; >>>S 1397 (3) A motor vehicle or item of motor vehicle equipment offered fo importation in violation of paragraph (1)(A) of subsection (a) of this section shall be refused admission into the United States under joint regulations issued by the Secretary of the Treasury and the Secretary; (4) The Secretary of the Treasury and the Secretary may, by join regulations, permit the temporary importation of any motor vehicle or item of motor vehicle equipment after the first purchase of it in good faith for purposes other than resale.<<<; The only exception to these laws is promulgated in Part 12 of th customs regulations (19 CFR S 12.80). One exception permits temporary importation for personal use, but it does not apply to commercial use of U.S. highways.; Section 1392(g) of the Act also mandates that the Bureau of Moto Carrier Safety (referred to in the section as the Interstate Commerce Commission) 'not adopt or continue in effect any safety standard which differs from' our standards unless it is a higher standard of safety. The Bureau has indicated its intent to adopt Standard No. 121 as its performance standard in the regulation of U.S. and foreign motor carriers on U.S. highways.; I conclude that any exclusion of Canadian vehicles from Standard No 121 would be an evasion of the Act's prohibition on importation of noncomplying vehicles. Such an exclusion would reduce the expected benefits of Standard No. 121 and would discriminate against U.S. manufacturers and carriers. For these reasons, your request is denied.; For clarification, I note that the standard applies (with limite exceptions) to air-braked trailers manufactured after January 1, 1975, and air-braked trucks and buses manufactured after March 1, 1975. I am unaware of the significance of the March 31, 1975, date to which you refer.; Sincerely, James B. Gregory, Administrator |
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ID: aiam0612OpenMr. Sanford Davis, Urethane Industry Specialist, BASF Wyandotte Corporation, Wyandotte, MI, 48192; Mr. Sanford Davis Urethane Industry Specialist BASF Wyandotte Corporation Wyandotte MI 48192; Dear Mr. Davis: This is in reply to your letter of February 10, 1972, requesting ou comments relative to the time span over which examination might be contemplated under Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.'; Any vehicle to which a motor vehicle safety standard is applicable i required to conform to the standard until the vehicle has been sold to a purchaser for a purpose other than resale (15 U.S.C. S1397). In the case of Standard No. 302, the standard becomes effective September 1, 1972, and any vehicle manufactured after that date must comply until after its sale to such a purchaser.; Yours truly, Richard B. Dyson, Assistant 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.