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: aiam5480OpenDr. Dimitrios Kallieris Associate Professor and Division Chief Experimental and Forensic Biomechanics Ruprecht-Karls-Universitat Heidelberg Vossstrasse 2 69115 Heidelberg, Germany; Dr. Dimitrios Kallieris Associate Professor and Division Chief Experimental and Forensic Biomechanics Ruprecht-Karls-Universitat Heidelberg Vossstrasse 2 69115 Heidelberg Germany; "Dear Dr. Kallieris: This responds to your FAX to Dr. Rolf Eppinger o NHTSA, requesting an interpretation of the requirements specified in Standard No. 212, Windshield Mounting. The answers to your two questions are provided below. Standard No. 212 sets different windshield retention requirements for a vehicle depending on whether it is equipped with passive or manual restraints. S5.1 of the standard provides that vehicles equipped with passive restraints must retain not less than 50 percent of the windshield periphery after crash testing. S5.2 of the standard provides that vehicles that are not equipped with passive restraints must retain not less than 75 percent of the windshield periphery. You stated that you have conducted 30 m.p.h. crash tests of motor vehicles with freshly adhered windshields. In the test vehicle, two Hybrid III dummies were placed in the front driver and passenger positions. Each dummy was restrained 'by a three-point belt and air bag.' Your first question asked whether the vehicle is subject to the requirements of S5.1 for 'vehicles equipped with passive restraints,' or S5.2 for 'vehicles not equipped with passive restraints.' The answer to your question depends on whether the restraint system in the tested vehicle meets the definition of 'passive restraint system' set forth in S4 of the standard. That term is defined as: a system meeting the occupant crash protection requirements of S5. of Standard No. 208 by means that require no action by vehicle occupants. Section S5 of Standard No. 208 sets occupant protection requirements that must be met in frontal, lateral and rollover crashes. You did not provide much information about the vehicle in question. We assume it is a passenger car. Standard No. 208 (S4.1.4) requires the following of current production passenger cars: (a) At each front outboard designated seating position, each vehicle must meet the standard's frontal crash protection requirements (S5.1) by means that require no action by vehicle occupants (e.g., by means of an air bag or automatic restraints), (b) at the front center designated seating position and at each rear seating position, have a type 1 (lap) or type 2 (lap/shoulder) belt assembly that meet specified requirements, and (c) either meet the lateral and rollover crash protection requirements of Standard No. 208 by means that require no action by vehicle occupants, or at each front outboard designated seating position, have a type 1 or type 2 belt assembly that meets the requirements of S5.1 with front test dummies restrained by the type 1 or type 2 assembly in addition to the means that require no action by the vehicle occupant. We assume that the 'three-point belt and air bag' to which you refer were installed in the front outboard seating positions pursuant to these occupant protection requirements of Standard No. 208. NHTSA's longstanding position is that a vehicle equipped with a type 2 belt assembly and an air bag in those seating positions is equipped with a 'passive restraint system,' and is thus subject to the requirement of S5.1 that 50 percent of the windshield periphery must be retained. (See, e.g., August 18, 1986 letter to Volvo, copy enclosed.) As discussed in the enclosed letter, one of the reasons the agency adopted the 50 percent retention requirement for passive restraint-equipped vehicles was because there could be contact between an air bag system and the windshield, and incidental contact between an air bag-restrained test dummy and the windshield. The Standard No. 208 requirements listed above mean that a vehicle with passive restraints must meet the Standard No. 208 performance critera using only the passive restraints (air bag or automatic seat belt), and using both the passive and manual restraints. This would also be the case for Standard No. 212. The windshield retention would have to be at least 50 percent with the dummies restrained by only the passive restraint, and with the dummies restrained by both the passive and manual restraints. Therefore, your test (which appeared to have been conducted using both the air bag and the type 2 belt assembly) may not have been the worst case situation. Your second question asked whether the windshield displacements described in S5.1 and S5.2 are measured dynamically (i.e., during the crash), or statically (i.e., after the crash). NHTSA determines the portion of the windshield periphery that is retained by the vehicle after the dynamic crash test specified in the standard. I hope this information is helpful. If there are any further questions, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992. Our FAX no. is (202) 366-3820. Sincerely, Philip R. Recht Chief Counsel Enclosure"; |
|
ID: aiam0378OpenMr. H.H. Vischer, Vice President, Bandag Incorporated, 1056 Hershey Avenue, Muscatine, IA 52761; Mr. H.H. Vischer Vice President Bandag Incorporated 1056 Hershey Avenue Muscatine IA 52761; Dear Mr. Vischer: This is in reply to your letter of May 10, 1971, and to confir opinions given by members of this office in subsequent phone conversations with you.; Under the National Traffic and Motor Vehicle Safety Act and regulation issued pursuant to it the treadless casing you import is not considered to be a completed tire until the tread is applied. Therefore, the Bandag dealer applying the tread is considered to be the tire manufacturer and the Korean manufacturer of the casing does not have to put his own 'DOT' number on the casing.; Since you expect many of your dealers will be using this process, i order not to unduly expend the new manufacturer's list, all your dealers are to use your assigned code number 'XX' for the grouping representing the manufacturer's assigned code and their own three symbol retreader's code in the third grouping which is normally considered the optional code:(sic); Your dealers, as manufacturers of the tires are responsible fo maintaining the records of the first purchaser of the tires they manufacturer (sic).; I believe Docket No. 70-12, Notice No. 9 (36 F.R. 9869) answers you question concerning the location of tire identification numbers.; Sincerely, E.T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
|
ID: aiam2715OpenMr. T. V. Barlow, Britax (Wingard) Limited, Chichester West Sussex PO19 2UG; Mr. T. V. Barlow Britax (Wingard) Limited Chichester West Sussex PO19 2UG; Dear Mr. Barlow: This responds to your letter of October 24, 1977, asking whethe Federal safety standards permit passive safety belts to be equipped with conventional buckles for emergency release.; In answer to your question, Standard No. 208, *Occupant Cras Protection*, not only permits buckles on passive belt systems, it requires them. Under paragraphs S4.5.3.3 and S7.2 of the standard, passive seat belt assemblies are required to have a latch mechanism that releases the restraints. The release is required to be at a single point by pushbutton action.; Please contact us if you have any further questions. Sincerely, Joseph J. Levin, Jr., Chief Counsel |
|
ID: aiam0728OpenMr. Cesar E. Cavanna, Chief Engineer, Lox Equipment Company, 355 So. Vasco Road, Livermore, CA 94550; Mr. Cesar E. Cavanna Chief Engineer Lox Equipment Company 355 So. Vasco Road Livermore CA 94550; Dear Mr. Cavanna: This is in reply to your letter of May 17, 1972, concerning problem you are having establishing gross axle weight ratings on vehicles you manufacture. You indicate that the problem occurs because brake drums which you use do not come with manufacturer's ratings, but are merely recommended for use with certain axles. You also ask whether a motor vehicle safety standard will require a 40-foot stopping distance from 20 mph.; Your understanding that brake drum capability does not have to b considered in determining gross axle weight rating is not entirely correct. The gross axle weight rating, which is the load carrying capacity of a single axle system (49 CFR 571.3), is a measure of the safe load-carrying capacity of the entire axle system. Manufacturers should include components in their vehicles that are designed to handle loads up to these ratings. Normally an assembler can rely on the specifications or the advice of a reputable supplier as to the capacity of the supplier's components. We expect manufacturers to exercise due care in ensuring that purchased components are adequate and safe for the vehicles they are used on, in accordance with careful business practices. These do not necessarily have to take the form of formal 'ratings.'; With reference to your question regarding stopping distance, Standar No. 121, Air Brake Systems, effective September 1, 1974 (not July 1, 1972) will, among other things, require a vehicle to stop from 20 mph in 33 and 54 feet on surfaces with skid numbers of 75 and 30 respectively.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam3807OpenMr. Robert Sprafka, EF Technology, 1405 North U.S. 27, St. Johns, MI 48879-0189; Mr. Robert Sprafka EF Technology 1405 North U.S. 27 St. Johns MI 48879-0189; Dear Mr. Sprafka: This is to follow-up on your phone conversation with Stephen Oesch o my staff concerning the application of Standard No. 301, *Fuel System Integrity*, to a school bus that has a natural gas fuel system as original equipment. As discussed below, Standard No. 301 does not apply to a natural gas fuel system.; Standard No. 301 sets fuel system integrity requirements for certai vehicle types, including school buses with a gross vehicle weight rating of 10,000 pounds or more. The standard, however, only applies to those vehicles which use fuel with a boiling point above 32 degrees Fahrenheit. Since natural gas does not have a boiling point above 32 degrees Fahrenheit, the standard would not apply.; Although there are no safety standards applicable to natural gas fue systems, manufacturers are responsible for any safety-related defects in their motor vehicles or items of motor vehicle equipment. Section 151, *et seq*. of the National Traffic and Motor Vehicle Safety Act, a copy of which is enclosed, provide that manufacturers of motor vehicles and motor vehicle equipment must notify owners of vehicles and equipment with safety-related defects and remedy those defects free of charge.; I am also enclosing, for your information, an agency letter discussin the legal responsibilities of persons who converted gasoline fuel systems to use propane and other gas.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam1093OpenMr. Huck Knight, Hyland Manufacturing, Inc. 220 First Street, P.O. Box R, Carlisle, IA 50047; Mr. Huck Knight Hyland Manufacturing Inc. 220 First Street P.O. Box R Carlisle IA 50047; Dear Mr. Knight: This is in response to your letter of March 30, 1973, in which yo asked whether the date a vehicle is completed, with reference to the date of manufacture placed on the vehicle certification label, is the date a vehicle comes off the 'main production line' or the date it comes out of the 'final finish production area'.; On this question we are willing, in light of the wide variety o possible factual situations, to let a manufacturer use his own discretion within reasonable limits. As you have described your situation, either date may be used, up to the point where the last physical operations are completed. The 'final quality control checkout', however, would appear to be an operation taking place after the manufacture as we normally understand it is completed.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam4291OpenMr. Satoshi Nishibori, Engineering Representative, Nissan Motor Co., Ltd., 560 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Satoshi Nishibori Engineering Representative Nissan Motor Co. Ltd. 560 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Nishibori: This is in reply to your letter of March 29, 1972, in which you as whether a Certification label 'which is made of some kind of hard material other than paper and affixed on the required place by using only one rivet and by gluing' will meet the requirements of section 567.4(b) of the Certification regulations.; We would consider such a label to be riveted, and consequently to mee the requirements of section 567.4(b).; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam1569OpenMr. James P. Coughlin, Vice President - Marketing, Bell Helmets Inc., 2850 East 29th Street, Long Beach, CA 90806; Mr. James P. Coughlin Vice President - Marketing Bell Helmets Inc. 2850 East 29th Street Long Beach CA 90806; Dear Mr. Coughlin: This is in reply to your letter of July 25, 1974, asking whether th statement 'Make no modifications' included in the labeling requirements of Standard 218, *Motorcycle Helmets*, would prohibit the after-market installation of a quick release device which may be attached to a helmet's retention strap. You included an illustration of such a device in your letter.; The answer is no. The statement does not restrict after-marke modifications by a first purchaser for purposes other than resale. It only serves to warn the consumer of the danger of making such modifications.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
|
ID: aiam3554OpenMr. Vernon J. Clark, Transportation Supervisor, Nebraska Department of Education, 301 Centennial Mall South, Box 94987, Lincoln, NE 68509; Mr. Vernon J. Clark Transportation Supervisor Nebraska Department of Education 301 Centennial Mall South Box 94987 Lincoln NE 68509; Dear Mr. Clark: This responds to your March 23, 1982, letter asking whether it i permissible to install side-facing seats in school buses designed to transport the handicapped. The answer to your question is yes.; Standard No. 222, *School Bus Passenger Seating and Crash Protection* specifies the requirements for school bus passenger seats and, in general, requires those seats to be forward facing. However, the definition of 'school bus passenger seat' in section S4 of the standard excludes seats installed to accommodate handicapped or convalescent passengers as evidenced by installing those seats longitudinally. Therefore, seats installed in the buses to which you refer in your letter need not comply with the school bus seat requirements if they are designed to accommodate the handicapped and are side facing.; We caution, however, that side-facing seats afford less protection tha forward facing seats. Accordingly, only those seats necessary to accommodate the handicapped should be altered in this manner.; Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam1139OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body Distributors Association, 602 Main Street, Cincinnati, OH 45222; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Association 602 Main Street Cincinnati OH 45222; Dear Mr. Pieratt: In your letter of May 14, 1973, you present the fact situation of a equipment manufacturer who installs lighting equipment on a component which he supplies to distributors or dealers, for installation by them on motor vehicles. For purposes of this letter, I assume that the installation occurs before the first sale of the vehicles for purposes other than resale. You ask what the equipment manufacturer should do to advise the distributor or dealer 'that the lamps and/or reflectors which he has affixed to his product meets the published S.A.E. specs required by Standard 108.'; There is no Federal requirement that an equipment manufacturer in thi fact situation supply compliance information, although covered equipment that he sells must continue to conform. The requirements for certifying or otherwise providing information concerning conformity with Standard No. 108 apply to the manufacturer of the lighting equipment, and the manufacturer(s) (final-stage and others) of the vehicle in question. It may well be that the customers of the supplier you describe will demand assurances of conformity through commercial channels.; Yours truly, Richard B. Dyson, Assistant 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.