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: aiam2855OpenMr. Bruce Henderson, Vice-President, Motorcycle Trades Association, Inc., 510 N. Washington, P.O. Box 132, Alexandria, VA 22313; Mr. Bruce Henderson Vice-President Motorcycle Trades Association Inc. 510 N. Washington P.O. Box 132 Alexandria VA 22313; Dear Mr. Henderson: This responds to your letter concerning the edge treatment requirements of Safety Standard No. 205, *Glazing Materials*, as they would apply to rigid or flexible plastics to be used for windshields on motorcycles. You asked for confirmation that one-piece plastics are required to meet the edge treatment requirements set forth in the standard for non- laminated glass.; The edge treatment requirements of Standard No. 205 are specified i paragraph S5.2, which incorporates by reference the SAE Recommended Practice J673a, Automotive Glazing,' August 1967. The SAE Practice specifies different requirements for tempered' and laminated' safety glass. The agency interprets the distinctions to apply equally to plastics. Therefore, one-piece plastic materials must meet the edge treatment requirements specified for tempered' glazing, and laminated plastics must meet the requirements specified for laminated' glazing.; Please contact this office if you have any further questions. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam1598OpenMr. J. A. Brown, Manager - Engineering Res. & Dev., Dexter Axle Company, Inc., P. O. Box 250, 2030 South Main St., Elkhart, Indiana 46514; Mr. J. A. Brown Manager - Engineering Res. & Dev. Dexter Axle Company Inc. P. O. Box 250 2030 South Main St. Elkhart Indiana 46514; Dear Mr. Brown: This responds to your August 19, 1974, request to be advised of th steps necessary to acquire a manufacturer code number as required by Standards No. 119, *New pneumatic tires for vehicles other than passenger cars*, and No. 120, *Tire selection ad rims for motor vehicles other than passenger cars*.; Standard No. 119 applies to tires only and its is the responsibility o the tire manufacturer to obtain a code number and label it on his products. As a user of tires, you do not have obligations under this standard.; Standard No. 120 is a proposal which applies to rim construction an the selection of the correct rim for the vehicle it equips. As a manufacturer of rims you would have a responsibility to label your products if this proposal becomes an effective regulation. However, we noted in the preamble to that proposal (copy enclosed) that we will not require manufacturer codes until a separate manufacturer code system has been established.; I am also enclosing a copy of the most recent proposal on manufacture codes.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam1596OpenMr. J.A. Brown, Manager - Engineering Res. & Dev., Dexter Axle Company, Inc., P.O. Box 250, 2030 South Main St. Elkhart, Indiana 46514; Mr. J.A. Brown Manager - Engineering Res. & Dev. Dexter Axle Company Inc. P.O. Box 250 2030 South Main St. Elkhart Indiana 46514; Dear Mr. Brown: This responds to your August 19, 1974, request to be advised of th steps necessary to acquire a manufacturer code number as required by Standard No. 119, *New Pneumatic tires for vehicles other than passenger cars*, and No. 120, *Tire selection and rims for motor vehicles other than passenger cars.*; Standard No. 119 applies to tires-only and it is the responsibility o the tire manufacturer to obtain a code number and label it on his products. As a user of tires, you do not have obligations under this standard.; Standard No. 120 is a proposal which applies to rim constructions an the selection of the correct rim for the vehicle it equips. As a manufacturer of rims you would have a responsibility to label your products if this proposal becomes an effective regulation. However, we noted in the preamble to that proposal (copy enclosed) that we will not require manufacturer codes until a separate manufacturer code system has been established.; I am also enclosing a copy of the most recent proposal on manufacture codes.; Your truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam4606OpenMr. Rod Willaredt President Diamond Cross Lights P.O. Box 3696 Rapid City, SD 57709; Mr. Rod Willaredt President Diamond Cross Lights P.O. Box 3696 Rapid City SD 57709; Dear Mr. Willaredt: This is in reply to your letter to Taylor Vinson o this Office, received by FAX on May l7, l989. You have developed a 'safety light' that displays right and left turn signals, 'and when the caution light/emergency light appears, the formation of such lights indicate a diamond'. The device appears intended for installation on large trucks or trailers. The turn signal lamps are supplementary to a vehicle's original equipment turn signal lamps. I assume that the caution/emergency lamp to which you refer is what we call a hazard warning signal, sometimes known as a 4-way flasher. You have asked for written approval of this device. This agency has no authority to 'approve' or 'disapprove' any motor vehicle or item of equipment. We can, however, advise as to the relationship of equipment to applicable Federal motor vehicle safety standards. I enclose copies of representative letters covering other auxiliary rear lighting for large trucks, such as wide-turn and U-turn indicators, and their relationship to Motor Vehicle Safety Standard No. l08, the National Traffic and Motor Vehicle Safety Act, and State law. These principles are applicable to your safety light as well. If you have any further questions, we shall be happy to answer them. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosures; |
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ID: aiam3310OpenMr. William Tierney, 147 Conrad Morgan Way, Lothian, MD 20820; Mr. William Tierney 147 Conrad Morgan Way Lothian MD 20820; Dear Mr. Tierney: This is to follow-up on your phone conversation of June 10, 1980, wit Stephen Oesch of this office concerning the Federal requirements applicable to the installation of auxiliary fuel tanks in passenger cars.; I am enclosing a copy of a letter of interpretation the agency issue last August which discusses the general implication of such installations under Federal law. If after reviewing this material you have any additional questions, please contact Mr. Oesch.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2454OpenMr. Rex R. Redhair, Shughart, Thomson and Kilroy, 922 Walnut Street, P. O. Box 13007, (sic); Mr. Rex R. Redhair Shughart Thomson and Kilroy 922 Walnut Street P. O. Box 13007 (sic); Dear Mr. Redhair: Your October 20, 1976, letter to the U.S. Department of Transportation Federal Highway Administration, has been referred to this office for reply.; You request data concerning the 10.00-02 'Inland Deep Drive 300,' tha was manufactured by the Mansfield Tire and Rubber Company, Mansfield, OH. Tire Identification Number WLZJAVN 503.; We have enclosed all the Federal Motor Vehicle Safety Standards for: >>>o New Pneumatic Tires, Passenger Cars, Federal Motor Vehicle Safet Standard No. 109; o New Pneumatic Tires for Vehicles Other Than Passenger Cars, Federa Motor Vehicle Safety Standard No. 119; o Part 574 - Tire Identification and Recordkeeping o Tire Code Numbers Assigned New Tire Manufacturers. o Tire Size Codes<<< The tire identification number stated in your letter can be explaine by the use of the above data.; >>>'WL' - is the plant code for the Mansfield, Ohio plant. 'ZJ' - is the tire size code for the 10.00-20 tire size designation. 'AVN' - is an internal code for Mansfield. '503' - means the tire was cured the 50th week of 1973.<<< You also request design and construction information. We do not hav this type of information because it is proprietary. Also enclosed are copies of tire 'Care and Service of Bias and Radial Ply Truck Tires.'; We hope the above has been of some help to you. Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam2985OpenMs. Linda J. Hoffman, Automotive Parts & Accessories Association, 1025 Connecticut Avenue, N.W., Washington, D.C. 20036; Ms. Linda J. Hoffman Automotive Parts & Accessories Association 1025 Connecticut Avenue N.W. Washington D.C. 20036; Dear Ms. Hoffman: This responds to your March 5, 1979, letter concerning th applicability of Safety Standard No. 301-75, *Fuel Systems Integrity*, to replacement fuel tank caps. I am enclosing my letter of interpretation on this subject issued by the agency in 1976 which should answer all of your questions. If, however, you require further information, please contact Hugh Oates of my office at (202) 425-2992.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3427OpenMr. Barry N. Aebischer, Marketing Coordinator, Carabela USA, Inc., 4129 S. Sheridan, Tulsa, OK 74145; Mr. Barry N. Aebischer Marketing Coordinator Carabela USA Inc. 4129 S. Sheridan Tulsa OK 74145; Dear Mr. Aebischer: This is in reply to your letter of June 8, 1981 requesting 'th candlepower rating on a moped headlamp.'; I enclose a copy of SAE Standard J584 *Motorcycle and Motor Drive Cycle Headlamps* April 1964, which contains the information that you request. Most mopeds develop 5 horsepower or less and thus qualify as a 'motor driven cycle.'; If you have any further questions, we shall be pleased to answer them. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4910OpenMr. Martin L. Marinoff 103 Turner Lane Hendersonville, NC 28739; Mr. Martin L. Marinoff 103 Turner Lane Hendersonville NC 28739; Dear Mr. Marinoff: This responds to your letter asking about Federa Motor Vehicle Safety Standard No. 105, Hydraulic Brake Systems. You stated that you believe the standard requires vehicles to have a warning light system that indicates loss of pressure or low fluid level in the braking system and asked if this belief is correct. Your understanding about Standard No. 105 is correct. I have enclosed a copy of that standard for your information. The requirements for brake system indicator lamps are set forth at section S5.3 of the standard. Sincerely, Paul Jackson Rice Chief Counsel Enclosure; |
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ID: aiam0410OpenMr. David A. Phelps, Jr., Group Supervisor, Engineering Services, Blue Bird Body Company, Fort Valley, GA, 31030; Mr. David A. Phelps Jr. Group Supervisor Engineering Services Blue Bird Body Company Fort Valley GA 31030; Dear Mr. Phelps: This is in reply to your letter of July 12 asking whether the 'Safet Backing System' can be 'legally installed and operated under the provisions of FMVSS 108.'; As you know, supplemental lighting is permitted by Standard No. 10 provided it does not impair the effectiveness of the required lighting equipment. Your system is intended to contribute to the effectiveness of back-up lamps, and its installation is permissible under Standard No. 108.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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.