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 |
|---|---|
ID: aiam1733OpenMr. J.B. Markovich, General Manager, Utility Trailer Sales Co., Railroad and Orange Ave., P.O. Box 3258, Fresno, CA 93776; Mr. J.B. Markovich General Manager Utility Trailer Sales Co. Railroad and Orange Ave. P.O. Box 3258 Fresno CA 93776; Dear Mr. Markovich: This responds to your December 6, 1974, request for a determinatio whether a bulk transport trailer designed for transporting farm commodities from the field to processing plants over private and public roads, qualifies for exemption from Standard No. 121, *Air brake systems*, as an agricultural vehicle.; The vehicle you describe does not qualify as an agricultural vehicl that is excepted from Federal motor vehicle safety standards. The National Traffic and Motor Vehicle Safety Act of 1966 defines motor vehicle as follows:; >>>'Motor vehicle' means any vehicle driven or drawn by mechanica power manufactured primarily for use on the public streets, roads, and highways, except a vehicle operated exclusively on a rail or rails.<<<; We have interpreted this language to mean that a motor vehicle is vehicle which the manufacturer expects to be used on the public highways as part of its intended function. This would include most agricultural vehicles. However, the legislative history of the original Safety Act and S 301 indicate that congress did not intend agricultural machinery to be subject to the safety standards. We have interpreted agricultural machinery to include only vehicles designed as 'implements of husbandry' to perform strictly agricultural functions on farmland. The category does not extend to all vehicles engaged in transporting agricultural products.; The bulk transport trailer you describe appears designed expressly t rransport (sic) the product of an agricultural machine from the field to processing plants over the highways. It does not, therefore, qualify as an agricultural machine.; To expedite any questions you may have regarding the procedure fo temporary exemption, I would advise you to call Mr. Taylor Vinson of this office at (202)426-9511.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam0821OpenMr. Louis C. Lundstrom, Director, Automotive Safety Engineering, General Motors Corporation, General Motors Technical Center, Warren, MI 48090; Mr. Louis C. Lundstrom Director Automotive Safety Engineering General Motors Corporation General Motors Technical Center Warren MI 48090; Dear Mr. Lundstrom: This is in reply to your letter of August 21, 1972, on the subject o the operation of the seat belt warning system when the vehicle is in one of the free start modes allowed by S7.4.3 and S7.4.4 of Standard No. 208.; You are correct in your understanding that S7.3.5.4 does not requir the warning to operate when the ignition switch is in the 'start' position if the conditions described in S7.4.3 and S7.4.4 exist. Under those conditions, the interlock system continues to act as if the operation of the belt systems had not been followed by their release. By the same logic, the warning system activation required by S7.3.5.4 is in abeyance until the ending of the free start conditions.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1699OpenMr. Scott B. Miller, Hadco Engineering, 2000 Camfield Avenue, Los Angeles, CA 90040; Mr. Scott B. Miller Hadco Engineering 2000 Camfield Avenue Los Angeles CA 90040; Dear Mr. Miller: This responds to your November 13, 1974, question whether a combinatio vehicle which consists of an air braked truck tractor and an electrically-braked trailer would be subject to the requirements of Standard No. 121, *Air brake systems*, effective January 1, 1975, for trailers and March 1, 1975, for trucks and buses. The electric brakes on the trailer would be actuated by a Warner Electric brake controller that is designed to be mounted in the truck's air control line and to respond to air brake signals generated by the truck's service brake control.; Standard No. 121 applies to trucks, buses, and trailers equipped wit air brake systems. Therefore, the trailer which is electrically-braked is not required to comply with the standard.; It appears from the Warner literature that you enclosed that the truc tractor would be equipped with air brakes and would therefore have to comply with the standard. I would like to point out that air-braked truck tractors manufactured after March 1, 1975, must be certified to comply with the requirements of the air brake standard. If a person modifies the air brake lines on such a truck tractor before the first retail purchase by the addition of the Warner controller, that person must certify that the truck still meets the standard as modified.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4161OpenMr. Gary D. Clark, John Deere Tractor Works, P.O. Box 3500, Waterloo, IA 50704-3500; Mr. Gary D. Clark John Deere Tractor Works P.O. Box 3500 Waterloo IA 50704-3500; Dear Mr. Clark: This responds to your letter dated February 27, 1986, concerning you projected sale of a strip chassis for the class A motor home industry. The identifying information submitted in your letter is being referred to the Office of Vehicle Safety Standards which keeps records of manufacturer identification in accordance with 49 CFR Part 566.; Under S114 of the National Traffic and Motor Vehicle Safety Act o 1966, as amended, each manufacturer is responsible for certifying that its motor vehicles and motor vehicle equipment comply with all applicable safety standards. This agency does not require that a manufacturer's documents and test data, which form the basis for this certification, be submitted unless requested by the agency.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1363OpenMr. Evan Hammond, Manager - Central Engineering, Trailmobile Technical Center, 5570 Creek Road, Cincinnati, OH, 45242; Mr. Evan Hammond Manager - Central Engineering Trailmobile Technical Center 5570 Creek Road Cincinnati OH 45242; Dear Mr. Hammond: This is in reply to your letters of October 25, and December 14, 1973 I regret that your earlier letter did not arrive.; You stated that your customer wishes to mount rear identification lamp at the same height from the ground as the rear turn signal, stop, tail and clearance lamps, and that, because of the shallowness of the rear header area it is not 'practicable' to mount them there.; Although it may not be 'practicable' to mount the Grote 272 lamp, specified by your customer, in the header area, there may b other conforming lamps that it would be 'practicable' to mount in that location in a three-lamp identification array. If such lamps are available, then Standard No. 108 takes priority over contractual specifications, especially since the clearance lamps will be mounted at a point other than 'as close as practicable to the top of the vehicle'.; Yours truly, Richard By. Dyson, Assistant Chief Counsel |
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ID: aiam1676OpenMemorandum to Interpretation of Certification Regulations (49 CFR Part 567), From Acting Chief Counsel, Subject: Files; Memorandum to Interpretation of Certification Regulations (49 CFR Part 567) From Acting Chief Counsel Subject: Files; In a letter recently mailed by this agency in a current enforcemen action, the following interpretation of 49 CFR Part 567 appeared:; '567.5(g) - The information on the label is not presented in th specified order or form. Your use of a vehicle model designation within the body of the label is unacceptable. However, it is permissible to list your vehicle model after the last statement, which is the vehicle type.'; Richard B. Dyson |
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ID: aiam0964OpenMr. W. G. Milby, Project Engineer, Blue Bird Body Company, Fort Valley, GA 31030; Mr. W. G. Milby Project Engineer Blue Bird Body Company Fort Valley GA 31030; Dear Mr. Milby: In our letter to you of December 7, 1972, regarding Standard 217, Bu Window Retention and Release, we incorrectly stated in the answer to question 5 that an amendment currently being prepared would clarify Figures 1 and 2 to indicate the location of the bus wall in relation to the seat. We do not feel such a clarification is necessary for the purposes of the standard. The intent of those figures is to establish a space envelope containing certain reach distances with respect to the seat, and the location of the wall is therefore not relevant.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2959OpenMr. Frank Tedesco, President, Lifetime Foam Products, Inc. 3001 Cullerton Drive, Franklin Park, IL 60131; Mr. Frank Tedesco President Lifetime Foam Products Inc. 3001 Cullerton Drive Franklin Park IL 60131; Dear Mr. Tedesco: This is in response to your letter of February 8, 1979, requestin confirmation of your understanding of an October 7, 1976, letter of interpretation by our office concerning Safety Standard No. 207, *Seating Systems*. You are correct in your assumption that the standard applies only to completed vehicles and not to vehicle seats as individual equipment.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam4474OpenRusty Mitchell A-Z Bus Sales, Inc. P.O. Box 9389 5555 W. Mission Blvd. Ontario, CA 91762; Rusty Mitchell A-Z Bus Sales Inc. P.O. Box 9389 5555 W. Mission Blvd. Ontario CA 91762; "Dear Mr. Mitchell: This is a response to your letter of November 11 1987, in which you asked for information on the 'application of seat belts in school buses.' I am pleased to have this opportunity to explain our regulations to you. The National Highway Traffic Safety Administration (NHTSA) is responsible for developing safety standards applicable to all new motor vehicles, including school buses. In 1977, we issued a set of motor vehicle safety standards regulating various aspects of school bus performance. Among those standards is Standard 222, School Bus Passenger Seating and Crash Protection. Standard 222 requires large school buses (those with a gross vehicle weight rating over 10,000 pounds) to afford passenger crash protection by means of 'compartmentalization.' Compartmentalization requires large school buses to incorporate certain protective elements into the vehicles' interior construction, thereby reducing the risk of injury to school bus passengers without the need for safety belts. These elements include high seats with heavily padded backs and improved seat spacing and performance. Our regulations require a safety belt for the school bus driver because the driver's position is not compartmentalized. Further, because small school buses (10,000 pounds or less GVWR) experience greater force levels in a crash, Standard 222 requires the added protection of safety belts at each passenger position in a small school bus. School buses continue to have one of the lowest fatality rates for any class of motor vehicle. Large school buses are among the safest motor vehicles because of their size and weight (which generally reduce an occupant's exposure to injury-threatening crash forces), the drivers' training and experience, and the extra care other motorists usually take when they are near a school bus. For these reasons, our regulations do not require safety belts for passengers in large school buses. I enclose a copy of a June 1985 NHTSA publication titled 'Safety Belts in School Buses,' which discusses many of the issues relative to this subject. You also asked whether there is an order form listing available data for safety belts in school buses. This agency does not publish 'order forms' for any data. For further information on this subject, you may wish to contact individual school bus manufacturers to ask for data about safety belts in their buses. I hope you find this information helpful. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam1226OpenMr. C. J. Goode, British Leyland Uk Limited, Meteor Works, Lode Lane, Solihull, Warwickshire B92 8NW; Mr. C. J. Goode British Leyland Uk Limited Meteor Works Lode Lane Solihull Warwickshire B92 8NW; Dear Mr. Goode: In your letter of July 5, 1973, you express two concerns about th treatment of multipurpose passenger vehicles under the Motor Vehicle Information and Cost Savings Act.; Your first concern is that the standards to be issued under the ac will apply to all passenger motor vehicles, and will include multipurpose passenger vehicles unless the agency expressly exempts them. As we stated in the notice of proposed rulemaking on the new bumper standard, we are proposing to exempt multipurpose passenger vehicles from the initial standard. The continuance of this exemption depends on a variety of considerations, and we would appreciate the benefit of your views on the subject.; Your second concern is that the definition of 'multipurpose passenge vehicle' in the safety standards (49 CFR 571.3(b)) differs from the definition of the same term in the Cost Savings Act. Although the definitions are fundamentally similar, the safety standards definition limits the MPV category to vehicles designed to carry 10 persons or less, while the Cost Savings Act definition includes somewhat larger vehicles, up to a capacity of 12 persons. We do not foresee any problems as a result of this difference, but if problems arise, it would be possible through rulemaking to restrict the applicability of a cost savings standard to MPV's having a capacity of 10 persons.; Sincerely, James B. Gregory, Administrator |
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.