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 |
|---|---|
| search results table | |
ID: aiam5061OpenMr. Kevin R. Boyne Chief Engineer Dynamics and Durability Engineering Transportation Research Center Inc. East Liberty, OH 43319-0367; Mr. Kevin R. Boyne Chief Engineer Dynamics and Durability Engineering Transportation Research Center Inc. East Liberty OH 43319-0367; "Dear Mr. Boyne: This responds to your letter requesting clarification of the requirements of S4.2.1 of Standard No. 114, Theft Protection. That section sets forth new requirements relating to key removal, which became effective on September 1, 1992. Your letter asks whether a vehicle which operates in the following manner would meet the requirements: Initial Condition - Engine running and shift lever positioned in 'drive'. Action - The operator depresses the thumb button on the left side of the shift lever and moves the shift lever to the 'park' position. Point of Concern - As long as the thumb button is held in the depressed position, the ignition key can be rotated to the lock position and removed. Still holding the thumb button, the shift lever can later be moved to any position. Removal of the key will only occur in the 'park' position. As discussed below, it is our opinion that a system which operates in the manner you described would comply with S4.2.1 of the standard for vehicles manufactured before September 1, 1993, but not for vehicles manufactured after that time. This assumes, for vehicles manufactured before September 1, 1993, that steering is prevented after removal of the key. It also assumes that the system does not otherwise permit removal of the key when the transmission is not locked in park. By way of background information, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment meet applicable standards. The following represents our opinion based on the facts provided in your letter. Section S4.2.1 of Standard No. 114 states: Except as provided in S4.2.2(a) and (b), the key-locking system required by S4.2 in each vehicle which has an automatic transmission with a 'park' position shall prevent removal of the key unless the transmission or transmission shift lever is locked in 'park' or becomes locked in 'park' as the direct result of removing the key. The system which you describe appears to permit removal of the key in a situation when both the transmission and transmission shift lever are not locked in 'park' and when they do not become locked in 'park' as the direct result of removing the key. This conclusion follows from the fact that, following the removal of the key, the shift lever can be moved to any position. Therefore, the system you describe would not comply with S4.2.1 unless one of the exceptions in section S4.2.2(a) and (b) apply. The exception set forth in S4.2.2(a) only applies in the event of electrical failure and is therefore not relevant to the system you describe. S4.2.2(b) of Standard No. 114 reads as follows: (b)(1) Notwithstanding S4.2.1, each vehicle specified therein may have a device which, when activated, permits moving the transmission shift lever from 'park' after the removal of the key provided that steering is prevented when the key is removed. (2) For vehicles manufactured on or after September 1, 1993, the means for activating the device shall either be operable by the key, as defined in S3, or by another means which is covered by a non-transparent surface which, when installed, prevents sight of and activation of the device and which is removable only by use of a screwdriver or other similar tool. NHTSA included this second exception to allow for a manual override of the transmission shift lock so that a disabled vehicle could be moved. The requirement that such devices either be operable by the key or by another means which is covered by a non-transparent surface originally had an effective date of September 1, 1992. However, after considering petitions for reconsideration, NHTSA decided to provide an additional year's leadtime, noting that this would lessen the impacts associated with such redesign of the emergency override buttons of a number of systems. While the agency was primarily concerned about emergency override buttons in drafting S4.2.2(b), it is our opinion that the language in (b)(1) is sufficiently broad to include the thumb button on a transmission shift lever itself, i.e., the button can be considered a device which, when activated, permits moving the transmission shift lever from 'park' after the removal of the key. Therefore, assuming that steering is prevented after the removal of the key, the system you describe would come within the exception provided in S4.2.2(b)(1). Effective September 1, 1993, of course, such a device must also meet the requirements set forth in S4.2.2(b)(2) in order to come within this exception to S4.2.1. The system you describe would not fall within the exception at that time. The thumb button is not 'the key, as defined in S3.' In addition, the thumb button is not 'covered by a non-transparent surface which, when installed, prevents sight of and activation of the device and which is removable only by use of a screwdriver or other similar tool.' Therefore, based on the information you have provided, the system would not comply with S4.2.1 for vehicles manufactured on or after September 1, 1993. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
|
ID: aiam0799OpenMr. J. C. Eckhold, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. J. C. Eckhold Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Eckhold:This is in reply to your letter of July 26, 1972 concerning the adjustment of a tractor's fifth wheel under the test conditions proposed in Docket 70-17, Notice 5.; You state that it is not possible to load the tractor to its GVWR wit the tractor's nonsteerable axles and the trailer's axles at GAWR if the fifth wheel is set in more than one position. If this is the case, and the correct loading can be obtained with the fifth wheel in one position only, then only that position will be used in compliance testing. If more than one position can be used to produce the correct loading, the tractor must conform to the requirements of the standard with the fifth wheel at any such position.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam0263OpenMr. E. W. Bernitt, Vice President Safety and Quality Assurance, American Motors Corporation, Jeep Corporation, 940 North Cove Boulevard, Toledo, OH 43601; Mr. E. W. Bernitt Vice President Safety and Quality Assurance American Motors Corporation Jeep Corporation 940 North Cove Boulevard Toledo OH 43601; Dear Mr. Bernitt: This is in reply to your letter of October 12, 1970, to Mr. Charles A Baker of this office in which you requested an interpretation of the phrase 'effective projected illuminated area.'; Class A turn signal lamps are required by Section S3.1 of Federal Moto Vehicle Safety Standard No. 108, which references SAE Standard J588d in Tables I and III for these lamps. The requirements for the illuminated area of a turn signal lamp are specified in J588d as follows:; >>>'The effective projected illuminated area measured on a plane a right angles to the axle of the lamp must not be less than 12 sq. in. for Class A and 3-1/2 sq. in. for Class B.'<<<; In the 45 degree visibility requirements, this standard further state 'To be considered visible, the lamp must provide an unobstructed projected illuminated area of outer lens surface, including reflex,...'.; Our interpretation of effective projected illuminated area follows: Th effective projected illuminated area is that area of the lens measured on a plane at right angles to the axle of the lamp, including reflex reflector, which is not obstructed by an opaque object such as a mounting screw, mounting ring, or an ornamental basel or trim.; The above interpretation allows the area of rings or othe configurations (raised portions) molded in the lens to be considered part of the total effective area, even if this area does not contribute significantly to the total light output.; Sincerely, Roger Crampton, Director, Office of Operating Systems, Moto Vehicle Programs; |
|
ID: aiam5431OpenMr. Jerry Miller Director of Operations Associated Leasing Handicapable Vans 12117 Riverwood Drive Burnsville, MN 55337; Mr. Jerry Miller Director of Operations Associated Leasing Handicapable Vans 12117 Riverwood Drive Burnsville MN 55337; Dear Mr. Miller: This responds to your letter of May 31, 1994 requesting confirmation that 'there are no rules or regulations on wheelchair tie downs for vehicles other than school buses.' You are correct that Federal motor vehicle safety standard No. 222, School Bus Passenger Seating and Crash Protection, which includes requirements for wheelchair securement devices, applies only to school buses. However, while none of the safety standards apply to wheelchair securement devices for vehicles other than wheelchairs, the manufacturer of the product is subject to federal requirements concerning the recall and remedy of products with defects related to motor vehicle safety (49 U.S.C. 30118-30121). The agency does not determine the existence of defects except in the context of a defect proceeding. You should also be aware that the Department of Transportation has issued a final rule implementing the transportation provisions of the Americans with Disabilities Act. This final rule includes requirements for wheelchair securement devices installed in vehicles required to be accessible by this rule. A copy of the final rule is enclosed with this letter. If you have further questions on these regulations, please contact Mr. Irv Chor of the Federal Transit Administration. Mr. Chor's card is attached to the final rule. I hope you find this information helpful. If you have any other questions concerning NHTSA regulations, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure; |
|
ID: aiam1921OpenMr. Phil Martinez, Trailmaster Tanks, Inc., P.O. Box 13137, Fort Worth, TX 76118; Mr. Phil Martinez Trailmaster Tanks Inc. P.O. Box 13137 Fort Worth TX 76118; Dear Mr. Martinez: This responds to Trailmaster Tank's May 14, 1975, request for discussion of what constitutes the manufacture of a trailer in cases where used components from an existing vehicle are involved.; In response to a similar request from the Truck Trailer Manufacturer Association, the National Highway Traffic Safety Administration recently prepared a comprehensive discussion of this subject, a copy of which is enclosed for your information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam0633OpenAlberto Negro, Manager, D.C.R.S. USA Office, Fiat Motor Company, Inc., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Alberto Negro Manager D.C.R.S. USA Office Fiat Motor Company Inc. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Negro: This is in reply to your letter of March 3, 1972, concerning multipl audible warning requirements.; The audible warning requirements of Federal Motor Vehicle Safet Standards 114 and 208 can be met with the use of one system rather than two separate ones.; Sincerely, E. T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
|
ID: aiam2120OpenMr. Charles A. Webb, President, National Association of Motor Bus Owners, 1025 Connecticut Avenue, N.W., Washington, DC 20036; Mr. Charles A. Webb President National Association of Motor Bus Owners 1025 Connecticut Avenue N.W. Washington DC 20036; Dear Mr. Webb: This is in response to your letters of November 12 and 13, 1975, i which you requested that the National Highway Traffic Safety Administration immediately suspend the effectiveness of Standard No. 121, *Air Brake Systems*, with respect to buses, without waiting until the end of a comment period. In a notice published November 13, 1975, 40 FR 52856, this agency proposed such a suspension with a 30-day comment period ending December 15, 1975.; Secretary Coleman has made clear his commitment to allowing adequat time for public comment on rulemaking actions. The normal minimum time for public comment on Department of Transportation actions has been established as 45 days. In this case, because of the special urgency of the matter, the period was reduced to 30 days. I believe we all recognize that this action is a significant one, affecting the performance and cost of most of the transit and intercity buses in the country. In these circumstances, it is our judgment that the 30-day period is the minimum that can be justified for comment by the interested public, and your request is therefore denied.; We also recognize, as you have pointed out, that for this short perio there may be some uncertainty and some interruption of normal activities within the affected industries. We will make every effort to reach and announce a decision as soon as possible after the end of the comment period.; Sincerely, James B. Gregory, Administrator |
|
ID: aiam2570OpenMr. Dennis G. Moore, Dry Launch, 1113 Greenville Road, Livermore, CA 94550; Mr. Dennis G. Moore Dry Launch 1113 Greenville Road Livermore CA 94550; Dear Mr. Moore: This is in reply to your letter of April 7, 1977, asking for clarification of S4.3.1.1.1 of Standard No. 108. Your initial question of December 27, 1976, was not clear to us hence the reason my answer of March 4, 1977, caused you some confusion.; The diagram in your letter of April 7 clearly depicts the exemptio provided by S4.3.1.1.1 for the specific reasons therein, that when a clearance lamp indicating overall width is not located on the rear of a vehicle it need not be visible at 45 degrees inboard. As the only required points of photometric measurement of a clearance lamp so located are to the rear and at 45 degrees outboard, the lamp need not be visible at any point in the 45 degree arc depicted in your letter.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
|
ID: aiam3731OpenMr. Dale Scott, R.V. Account Executive, Kinder Division, Congoleum Corporation, 2323 South 17th Street, P.O. Box 1207, Elkhart, IN 46515; Mr. Dale Scott R.V. Account Executive Kinder Division Congoleum Corporation 2323 South 17th Street P.O. Box 1207 Elkhart IN 46515; Dear Mr. Scott: This responds to your letter to Mr. Kratzke of my staff, asking for a interpretation concerning Safety Standard No. 302, *Flammability of Interior Materials* (49 CFR S571.302). Specifically, you asked whether innerspring mattresses used in motor homes are subject to the requirements of that standard. You also asked for a definition of the term 'mattress cover.'; Section S4.1 of Standard No. 302 lists the components that are covere by the standard. That list states that mattress covers must comply with the standard's requirements, but not the innerspring mattress itself. Hence, the innerspring mattress with which you are concerned is not subject to the flammability requirements of Standard No. 302. As your letter noted, those mattress (sic) are subject to certain flammability requirements issued by the Consumer Product Safety Commission.; We have previously defined the term 'mattress cover' as including bot a cover that is used generally to enclose a mattress for cleanliness or sanitary purposes *and* the ticking permanently attached to the mattress to enclose the mattress filling or core. Both of these items would have to meet the requirements of Standard No. 302.; Should you have any further questions or need more information on thi subject, please contact Mr. Steve Kratzke of my staff at (202) 426- 2992.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam2823OpenMr. Don H. Pendergrass, Norris Industries, 1225 West Imperial Highway, Brea, California 92621; Mr. Don H. Pendergrass Norris Industries 1225 West Imperial Highway Brea California 92621; Dear Mr. Pendergrass: This responds to your January 7, 1978, letter asking whether final-stage wheel manufacturer is permitted to mark a rim in accordance with Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. The standard currently specifies that rim marking shall be done by a rim manufacturer, not a final-stage wheel manufacturer.; The National Highway Traffic Safety Administration (NHTSA) ha previously determined that a rim manufacturer is the responsible party for rim marking. The language of the standard is specific in this requirement. The agency, however, is reviewing the standard with a view to its possible modification along the lines suggested in your letter. Should the agency decide to amend the standard, a notice proposing such change would first be published in the Federal Register. A final rule would only be issued following analysis of comments submitted by interested parties.; Sincerely, Joseph J. Levin, Jr., 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.