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: aiam0464OpenMr. Stanley Hamilton, Director, Government and Public Affairs, National Association of Motor Bus Owners, 1025 Connecticut Avenue, N.W., Washington, DC 20036; Mr. Stanley Hamilton Director Government and Public Affairs National Association of Motor Bus Owners 1025 Connecticut Avenue N.W. Washington DC 20036; Dear Mr. Hamilton: This is in reply to your letter of August 2 to which you attached letter from Mr. W. Dershko of Motor Coach Industries concerning the certification regulations that go into effect January 1, 1972. (Perhaps by error, you referred to a letter from Mr. Stieber of Greyhound Lines.) Rulemaking concerning gross axle weight rating and gross vehicle weight rating was in process at the time, hence the reason for our delay.; Mr. Dershko asked whether the gross vehicle weight rating must equa the sum of the gross axle weight ratings. The answer is no. The practice described, of stating a GVWR less than the sum of the GAWR's, will be quite proper under the new regulations.; Mr. Dershko also said that he was concerned as to how to interpret th definition of gross axle weight rating, and that 'several factors to consider are the tire capacities, axle assembly capacity, and the coach frame structure capacity.' We agree that all those factors must be considered. The manufacturer must set his gross axle weight ratings in view of the weakest elements in the load-bearing systems of the vehicle.; Let us know if we can be of further assistance. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam5559OpenMr. Ron Hooker Missouri Department of Agriculture P.O. Box 630 Jefferson City, MO 65102-0630; Mr. Ron Hooker Missouri Department of Agriculture P.O. Box 630 Jefferson City MO 65102-0630; "Dear Mr. Hooker: This responds to your question about whether th State of Missouri has authority to promulgate regulations relating to the safety of motor vehicles powered by alternative fuels, particularly compressed natural gas (CNG). The short answer is that while Missouri is generally preempted in this area, it could issue its own more stringent safety standard for State-owned vehicles. Federal law will preempt a State law if (1) there is a Federal safety standard in effect, (2) the State law covers the same aspect of performance as that Federal standard, and (3) the State law is not identical to the Federal standard. Specifically, section 30103(b) of Title 49 of the United States Code states that (b) Preemption. - (1) When a motor vehicle safety standard is in effect under this chapter, a State or political subdivision of a State may prescribe or continue in effect a standard applicable to the same aspect of performance of a motor vehicle or motor vehicle equipment only if the standard is identical to the standard prescribed under this chapter. However, the United States Government, a State, or a political subdivision of a State may prescribe a standard for a motor vehicle or motor vehicle equipment obtained for its own use that imposes a higher performance requirement than that required by the otherwise applicable standard under this chapter. State safety standards applicable to CNG fuel system integrity are generally preempted by Federal law. The National Highway Traffic Safety Administration (NHTSA) has issued Federal motor vehicle safety standard (FMVSS) No. 303, Fuel system integrity of compressed natural gas vehicles. (59 FR 19659, April 25, 1994, copy enclosed). The Standard specifies frontal barrier and rear barrier crash tests conducted at 30 mph and a lateral moving barrier crash test conducted at 20 mph. The Standard applies to passenger cars, multipurpose passenger vehicles, trucks and buses that have a gross vehicle weight rating (GVWR) of 10,000 pounds or less and use CNG as a motor fuel. It also applies to school buses regardless of weight that use CNG as a motor fuel. The Standard takes effect September 1, 1995. Accordingly, after September 1, 1995, Missouri could only issue its own safety standard applicable to CNG vehicle fuel system integrity if the State safety standard is identical to FMVSS No. 303. The one exception to requiring such identical standards is that Missouri could prescribe a standard for motor vehicles obtained for its own use, provided the State law imposed a higher performance requirement than the level of performance prescribed by FMVSS No. 303. Thus, Missouri could issue its own more stringent safety standard for State-owned vehicles. NHTSA further notes that Missouri is free to issue safety standards applicable to the fuel system integrity of vehicles powered by other alternative fuels (e.g., liquid propane, hydrogen), since the agency has not issued any FMVSS applicable to other alternative fuels. 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. Sincerely, John Womack Acting Chief Counsel Enclosure "; |
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ID: aiam1496OpenMr. J. Alec Reinhardt, 100 Erieview Plaza, Cleveland, OH 44114; Mr. J. Alec Reinhardt 100 Erieview Plaza Cleveland OH 44114; Dear Mr. Reinhardt: This is in reply to your letter of May 17, 1974, asking us to approv language to be substituted for the first two sentences of the second paragraph of White's version of the defect notification letter in campaign No. 73-0140, as well as substitute language suggested by the Court.; We would consider the language of either submission to conform to 4 CFR Part 577 if the word 'may' is stricken. The sentence would then read, 'We have found that a defect exists in that . . .' We have interpreted the regulations to require the finding that the defect exists, not that it may exist. However, the notification letter may indicate that the defect may not be present in every vehicle if that is the case.; Sincerely, Frank Berndt, Assistant Chief Counsel |
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ID: aiam2051OpenMr. Albert A. Dawes, Chief, Procurement Law Division, U.S. Army Tank-Automotive Command, Department of the Army, Warren, MI 48090; Mr. Albert A. Dawes Chief Procurement Law Division U.S. Army Tank-Automotive Command Department of the Army Warren MI 48090; Dear Mr. Dawes: This is in response to your letter of August 29, 1975, in which you as whether the exemption provided by 49 CFR S 571.7(c) applies to all commercial vehicles manufactured and sold directly to the Armed Forces of the United States.; All vehicles (including commercial vehicles) meeting the definition o 'motor vehicle' in section 102(3) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S 1392(3)) that are manufactured for, and sold directly to, the Armed Forces of the United States in conformity to contractual specifications are exempt from the Federal Motor Vehicle Safety Standards under 49 CFR S 571.7(c).; We hope this information is of assistance. Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2077OpenMr. A.J. Burgess, Joseph Lucas North America Inc., Two Northfield Plaza, Troy, Michigan 48084; Mr. A.J. Burgess Joseph Lucas North America Inc. Two Northfield Plaza Troy Michigan 48084; Dear Mr. Burgess: #This is in reply to your letter of May 29, 1975 asking whether two of your processes for labeling brake hose may be considered 'permanent' for purposes of Standard No. 106-74. #As used in our standards and regulations, the requirements for a 'permanent' label generally contemplates a label that will remain legible for the expected life of the product under normal conditions. The National Highway Traffic Safety Administration expects a manufacturer to make a reasonable, good- faith determination in this respect. The two labeling samples that you submitted as examples of your processes appear to be permanent. #We are presently re-examining the requirement for permanent labeling of brake hose, and a Federal Register notice in this area may be issued shortly. #Yours truly, Richard B. Dyson, Assistant Chief Counsel; |
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ID: aiam0635OpenMr. Preston W. Grace, White River Distributors, Inc.; Mr. Preston W. Grace White River Distributors Inc.; Dear Mr. Grace: This is in reply to your letter of March 6, 1972, forwarded to us b Tom Pieratt, wherein you discuss certain situations which have arisen regarding the GVWR of chassis you have purchased for completion by adding bodies.; As far as I can determine from the facts you provided in you letter the chassis manufacturers are doing nothing that is contrary to our regulations. Your complaints seem to be that (a) some chassis that you believe to be identical bear differing weight ratings in their accompanying literature, and (b) you have received some chassis that do not have the weight ratings that you want and believed you were ordering. Both problems appear to be matters of communication between you and the manufacturers or their dealers, which might be resolvable by clearly specifying the desired weight ratings in your purchase order.; Your general statements concerning the effect of the Vehicle Safety Ac and the regulations issued thereunder are essentially correct.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1087OpenMr. Alberto Negro, Manager, Research and Development, Fiat Motor company, Inc., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Alberto Negro Manager Research and Development Fiat Motor company Inc. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Negro: This is in reply to your letter of February 22, 1973, requestin confirmation of your understanding that automobile manufacturers may continue to use glazing materials manufactured before April 1, 1973, that do not conform to the recent amendment to Standard No. 205, 'Glazing Materials', effective on that date, in motor vehicles manufactured after that date.; Standard No. 205, an 'equipment standard', applies to glazing material for use in motor vehicles. It does not apply directly to vehicles in which such materials are used. As a consequence, a vehicle manufacturer may use glazing materials that do not conform to Standard No. 205 as it exists on the date the *vehicle* is manufactured. The glazing material must, however, conform to the standard as it exists on the date that the material is manufactured.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2309OpenMr. Byron A. Crampton, Manager of Engineering Services, Truck Body and Equipment Association, Inc., 5530 Wisconsin Avenue, Suite 1220, Washington, D.C. 20015; Mr. Byron A. Crampton Manager of Engineering Services Truck Body and Equipment Association Inc. 5530 Wisconsin Avenue Suite 1220 Washington D.C. 20015; Dear Mr. Crampton: This responds to the Truck Body Equipment Association's May 7, 1976 question whether S5.2.3.2 of Standard No.217, *Bus Window Retention and Release*, requires that the engine starting system of a school bus not operate if an emergency exit other than an emergency door is locked. Section S5.2.3.2 applies to school buses manufactured on or after October 26, 1976.; Section S5.2.3.2 only specifies requirements for the relationship o the engine-starting system to the operation of emergency doors. Reference to any emergency exit' in the first sentence of the section is in error, as the correct reference to emergency door' in the second sentence of the section demonstrates. A correction of this error will be made in the text of the standard shortly.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3861OpenMr. John A. Russo, Mr. Jerome Ramsey, Legal Services of Eastern Missouri, Inc., P.O. Box 4999A, Field Station, 625 N. Euclid Avenue, St. Louis, MI (sic) 63108; Mr. John A. Russo Mr. Jerome Ramsey Legal Services of Eastern Missouri Inc. P.O. Box 4999A Field Station 625 N. Euclid Avenue St. Louis MI (sic) 63108; Dear Mr. Russo and Mr. Ramsey: This is in response to your letter of August 10, 1984, concernin Missouri's odometer disclosure requirements.; The Missouri disclosure form fails to meet federal disclosur requirements. If Missouri wants to use its Certificate of Title in lieu of the separate Federal form, it must refer to the Motor Vehicle Information and Cost Savings Act, 15 U.S.C. S 1981 *et seq*., state the date of the transfer and provide a space for the purchaser's signature. The National Highway Traffic Safety Administration (NHTSA) considers this signature to be essential. It is an acknowledgment that the purchaser was aware of the mileage and prevents the purchaser from later alleging the contrary.; In addition, the Missouri title certificate fails to meet th requirements of 49 C.F.R. S 580.4(c). While it does provide a space for the odometer mileage, it fails to state that the transferor certifies 'that to the best of his knowledge the odometer reading reflects the actual miles or kilometers the vehicle has been driven.' Furthermore, the form must provide alternate statements that the odometer reading reflects the mileage in excess of 99,999 miles or kilometers or that the mileage is not actual and should not be relied upon.; Please be advised that, to date, Missouri has not requested approva from NHTSA for use of its Certificate of Title as a substitute for the Federal form. If you have any additional questions, please do not hesitate to contact Judy Kaleta of my staff at (202) 426-2992.; Sincerely, Kathleen DeMeter, Assistant Chief Counsel for General Law |
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ID: aiam1481OpenMr. William J. Cicero, Supt. of Maintenance, Triboro Coach Corporation, 85-01 24th Avenue, Jackson Heights, NY 11369; Mr. William J. Cicero Supt. of Maintenance Triboro Coach Corporation 85-01 24th Avenue Jackson Heights NY 11369; Dear Mr. Cicero: This is in reply to your letter of April 4, 1974, concerning you request for an exemption from the roof emergency exit requirements (S5.2.1) of Motor Vehicle Safety Standard No. 217 (49 CFR 571.217). We had denied an earlier request on March 27, 1974 following your letter to us of February 13, 1974.; We must again deny your request. The Federal motor vehicle safet standards which apply to motor vehicles (some apply to equipment only) specify safety requirements which apply to vehicle types generally (passenger cars, trucks, buses, etc.) and must of necessity be based on the use to which such vehicle types are generally put. The NHTSA has determined through the administrative rulemaking process that buses, including buses for use in urban environments, must have a roof emergency exit when a rear exit can not be installed due to the configuration of the bus. In most cases, including many urban situations, the roof exit can be an important safety feature, particularly when the bus is overturned on a side. While we do not dispute the facts you present, we view the situation as unusual, and not a suitable basis for modifying a requirement applicable to every urban bus. Our regulations do not permit exemptions from requirements for buses sold to one party.; However, under the National Traffic and Motor Vehicle Safety Act (1 U.S.C. SS1391 *et seq.*) under which Standard No. 217 is issued, a vehicle need not conform to a Federal motor vehicle safety standard after its sale to its ultimate user. Consequently there is no Federal prohibition to your modifying or eliminating the roof exits in these buses if you wish, after you receive them from the manufacturer.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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.