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: aiam4521OpenMrs. Alice Collins 703 Cohassett Ave. Lake Wales, FL 33853; Mrs. Alice Collins 703 Cohassett Ave. Lake Wales FL 33853; "Dear Mrs. Collins: This is a response to your letter of January 15 1988. I apologize for the delay in responding to your letter. In your letter, you described yourself as a parent of school-age children, and as a volunteer who drives children to school-related activities in your 1986 Plymouth Voyager mini-van. You stated that in the 1986-1987 school year, the U.S. Department of Transportation decided that Voyager Mini-Vans were 'unsafe.' You go on to say that 'the classification of M.P.V. was used on all mini-vans,' and suggest that it is a mistake to characterize your Voyager as a multipurpose passenger vehicle (MPV) because it is more like a passenger car than a truck. You concluded by asking us to change the decision that the Plymouth Voyager mini-van is unsafe. You raised other concerns in telephone conversations with Joan Tilghman, a member of my staff. First, I will address the request in your letter that the Department change what you believe is a decision concerning the safety of your vehicle. Then, I will address the matters you raised in conversations with Ms. Tilghman. Let me begin by assuring you that the agency has never stated that the Plymouth Voyager is 'unsafe.' Except in the context of a specific enforcement proceeding, NHTSA does not make blanket determinations that vehicles are 'safe' or 'unsafe.' Instead, we establish safety standards, and manufacturers must certify that each of their vehicles complies with all applicable standards. If we determine that a group of vehicles fails to comply with an applicable standard, or that a group of vehicles contains a defect related to motor vehicle safety, we order the manufacturer to recall the vehicles. Again, we make these determinations only in the context of an enforcement proceeding. There has been no such proceeding with respect to the 1986 Plymouth Voyager. With respect to your suggestion that it was a mistake to classify the Voyager as an MPV, it is the manufacturer's responsibility to determine, in the first instance, what a vehicle's classification should be. Chyrsler has classified the Voyager as an MPV, and so must certify that the Voyager meets all Federal safety standards applicable to that vehicle class. We have no information which suggests that Chrysler's classification of the Voyager is incorrect under our classification criteria. In your conversations with Ms. Tilghman, you explained that the Tallahassee, Florida school district will not permit parents to transport school children to school-sponsored or school-related events in MPVs, such as the Voyager. However, you stated that the district will permit parents to transport children to school-sponsored or school-related events in passenger cars. You said that the school district is following a recommendation by this agency that Florida school districts not condone transporting children to school-related events in buses other than certified school buses. Your understanding is that NHTSA made this recommendation to the State of Florida in an April 25, 1986 letter to Mr. Arnold Spencer, and repeated the recommendation in an August 7, 1986 letter to Mr. Larry McEntire. I have enclosed copies of both letters for your information. As you see, NHTSA made no such recommendation in either letter. Instead, we explained that we do not regulate the use of vehicles by owners, nor do we require the use of particular vehicles for particular purposes. There is no Federal prohibition against vehicle owners using their own vehicles to transport school children to school-related events. We also noted that the individual States have authority to establish any such regulations, in accordance with the principles of federalism set out in our Constitution. The State of Florida had already made its own decision to adopt and implement this policy before we were contacted by either Mr. Spencer or Mr. McEntire on this subject. Any changes to that policy would also reflect a decision by the State of Florida, not the Federal government. In the letter to Mr. Spencer, we made the observation that Florida's policy that school boards not condone transporting school children in vehicles that are not certified as complying with our school bus safety standards, 'is consistent with our belief that school buses certified to our school bus safety standards are the safest means of transportation for school children.' This was not a recommendation to the State of Florida, but a statement of our belief about the superior safety afforded to school children by buses that are certified as complying with our school bus standards. That belief continues to be supported by data showing that school buses continue to have one of the lowest fatality rates for any class of motor vehicle. Large school buses are the safest form of ground transportation in the United States because the passenger seats are 'compartmentalized' (special seat padding and spacing, and high seat backs), and because of the vehicle's 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. I am sending you information on the agency's New Car Assessment Program (NCAP). NCAP is an experimental program in which we test light-duty vehicles, MPVs among them, to see how well they perform in a high-speed crash. You will find test results for vehicles that NHTSA has tested over the past few years, including results for the 1984 and 1987 Plymouth Voyager. Also, you will find the agency's April, 1988 report to Congress titled, 'Safety Programs for Light Trucks and Multipurpose Passenger Vehicles.' I hope you find this information helpful. If you have further questions, please contact Joan F. Tilghman, of my staff, at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel Enclosures"; |
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ID: aiam3127OpenMr. G. Frinken, Manager, Automotive Engineering Europe, Uniroyal GmbH, Postfach 410, 5100 Aachen 1, West Germany; Mr. G. Frinken Manager Automotive Engineering Europe Uniroyal GmbH Postfach 410 5100 Aachen 1 West Germany; Dear Mr. Frinken: This is in response to your letter of October 12, 1979, asking whethe the character height of 5/32nds of an inch, stated in the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104, Figure 1), is considered by the National Highway Traffic Safety Administration (NHTSA) to specify the only acceptable height for UTQG sidewall molding, or whether the agency interprets this measurement as a minimum value.; The specification of 5/32nds of an inch tire sidewall characters wa intended by NHTSA to establish a minimum requirement to assure readability of the UTQG information presented. The agency has no objection to the use of characters of a height greater than 5/32nds of an inch, so long as all characters used to convey UTQG information are of the same height.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2439OpenMr. Pao-Yeh Hu, Manager, TYM Industries Co., Ltd., No. 2-26, Yeng Hang, Yongkang, Tainan-Hsian, Taiwan; Mr. Pao-Yeh Hu Manager TYM Industries Co. Ltd. No. 2-26 Yeng Hang Yongkang Tainan-Hsian Taiwan; Dear Mr. He: This is in reply to your letter of September 27, 1976, to the Nationa Highway Traffic Safety Administration, concerning lighting requirements for mopeds.; The headlamp must be designed to conform to SAE Standard J584 'Motorcycle and Motor Driven Cycle Headlamps,' April 1964. This Standard does not require a sealed beam headlamp, nor is a minimum wattage specified. Obtaining an AAMVA certificate is probably the best way of insuring that a State raises no obstacles to registry of your vehicle.; There is no minimum wattage for the taillamp or stop lamp. These tw lamps may be combined. There is no Federal requirement for SAE identification, however, most lamps are so identified, because of the requirements in the state of Virginia.; Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam3126OpenMr. G. Frinken, Manager, Automotive Engineering Europe, Uniroyal GmbH, Postfach 410, 5100 Aachen 1, West Germany; Mr. G. Frinken Manager Automotive Engineering Europe Uniroyal GmbH Postfach 410 5100 Aachen 1 West Germany; Dear Mr. Frinken: This is in response to your letter of October 12, 1979, asking whethe the character height of 5/32nds of an inch, stated in the Uniform Tire Quality Grading (UTQG) Standards (49 CFR 575.104, Figure 1), is considered by the National Highway Traffic Safety Administration (NHTSA) to specify the only acceptable height for UTQG sidewall molding, or whether the agency interprets this measurement as a minimum value.; The specification of 5/32nds of an inch tire sidewall characters wa intended by NHTSA to establish a minimum requirement to assure readability of the UTQG information presented. The agency has no objection to the use of characters of a height greater than 5/32nds of an inch, so long as all characters used to convey UTQG information are of the same height.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2070OpenMr. John Lomash, United States Testing Co., Inc., 1415 Park Avenue, Hoboken, NJ 07030; Mr. John Lomash United States Testing Co. Inc. 1415 Park Avenue Hoboken NJ 07030; Dear Mr. Lomash: This is in response to your letter of September 11, 1975, in which yo asked whether Standard No. 217 requires a minimum retention or force in pushing out an emergency exit window after activation of the release mechanism.; You should note that the force applications specified in S5.3.2 fo operation of the release mechanism and subsequent extension of the exit by an occupant are maximum requirements. Therefore, a push-out window which only requires enough force to lift the glass and subframe following operation of the release mechanism complies with the requirements of S5.3.2 and S5.4 as long as that force does not exceed the levels specified for the particular reach distance of the release mechanism.; The standard specifies no minimum force requirements for either th operation of the release mechanism or the extension of the exit following release.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam3598OpenMr. Fukuo Takata, Manager, Certifications Regulations Section, Ichikon Industries, Ltd, 80 Itado, Isehara City, Kanagawa 259-11, JAPAN; Mr. Fukuo Takata Manager Certifications Regulations Section Ichikon Industries Ltd 80 Itado Isehara City Kanagawa 259-11 JAPAN; Dear Mr. Takata: This is in reference to your letter of June 30, 1982, to Mr. Elliott o this agency concerning the effective luminous lens area of a front turn signal lamp under Federal Motor Vehicle Safety Standard (FMVSS) No. 108 with respect to three proposed designs.; We assume that you wish to know what is the effective projecte luminous lens area for a front turn signal on vehicles less than 80 inches in overall width. The SAE Standard No. J588e, 'Turn Signal Lamps,' which you quote, imposes no additional requirements for a two compartment front turn signal lamp. Thus, it appears that so long as you meet the minimum of 3.5 square inches for a single compartment lamp, your proposed designs (Case 1 and 2) meet the necessary requirements of FMVSS No. 108. Case 3 would not conform as neither of the two section compartments meets the 3.5 square inch minimum.; Sincerely, Courtney M. Price, Associate Administrator for Rulemaking |
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ID: aiam1236OpenMr. J.W. Kennebeck, Manager,Safety and Development,Volkswagen of America, Inc.,Englewood Cliffs, New Jersey 07632; Mr. J.W. Kennebeck Manager Safety and Development Volkswagen of America Inc. Englewood Cliffs New Jersey 07632; Dear Mr. Kennebeck:#This is in reply to your letter of August 8, 1973 to Mr. Schneider asking for confirmation of your interpretation of two sections of Standard No. 105a.#You ask first whether S5.3.1 requires that the activation of an indicator lamp upon application of 50 pounds of force be instantaneous, or whether a minimal time lag is permissible. You indicated that in a 'panic stop' there is a time lag of approximately 100 milliseconds between application of 50 pounds of force and lamp activities in the VW system. Since, as you state, it is 'humanly impossible' to discern such a minimal time lag, we consider that the VW system complies with S5.3.1, and that the lamp is activated upon application of 50 pounds of force.#You are also correct in your interpretation if S5.2.1 that the 5-minute requirement applies only to vehicles that do not exceed the limit of traction on a 30 percent grade.#Sincerely,Lawrence R. Schneider,Chief Counsel; |
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ID: aiam4264OpenMr. Allen R. Tank, President, Minikin, 606 NE Lincoln Avenue, St. Cloud, MN 56301; Mr. Allen R. Tank President Minikin 606 NE Lincoln Avenue St. Cloud MN 56301; Dear Mr. Tank: This is in reply to your letter of December 29, 1986, with respect t the definition of 'motorcycle' for purposes of compliance with the Federal motor vehicle safety standards. You have asked whether a vehicle with two wheels at the front, and one at the rear with two tires mounted on it, would still be regarded as a motorcycle.; The definition of a motorcycle is 'a motor vehicle with motive powe having a seat or saddle for the use of the rider and designed to travel on not more than three wheels in contact with the ground.' This is techically (sic) inaccurate in part because wheels do not contact the ground. I believe that the drafter of the definition meant to say 'tires' rather than 'wheels.' Thus the configuration about which you have asked is one in which four tires contact the ground, and we therefore conclude that such a vehicle would not be regarded as a motorcycle.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam4767OpenMs. Betsy Dittemore Legislative Liaison Iowa Department of Public Safety Office of the Commissioner Wallace State Office Building Des Moines, Iowa 50319; Ms. Betsy Dittemore Legislative Liaison Iowa Department of Public Safety Office of the Commissioner Wallace State Office Building Des Moines Iowa 50319; "Dear Ms. Dittemore: Thank you for your letter regarding a bil introduced in the Iowa Senate that, among other features, would establish light transmittance limits for 'sunscreening devices' that may be applied to the windows of motor vehicles operated in Iowa. I apologize for the delay in this response. You requested our office's interpretation about whether provisions of this bill would violate or be preempted by Federal Motor Vehicle Safety Standard No. 205, Glazing Materials (49 CFR 571.205). As you are aware, this agency is authorized by section 103 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1392) to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. One of the standards that we have issued under this authority is Standard No. 205, which applies to all new vehicles and all new glazing materials for use in motor vehicles. Among the requirements set forth in Standard No. 205 are specifications for minimum levels of light transmittance (70 percent light transmittance in areas requisite for driving visibility, which includes all windows in passenger cars). Section 108(a)(1)(A) of the Safety Act (15 U.S.C. 1397(a)(1)(A)) specifies that no person may manufacture, import, or sell any vehicle in the United States unless it is in conformity with all applicable safety standards. Pursuant to section 108(b)(1) of the Safety Act (15 U.S.C. 1397(b)(1)), this prohibition no longer applies after the vehicle is sold to a consumer. However, both before and after the first sale, section 108(a)(2) of the Safety Act (15 U.S.C. 1397(a)(2)) provides that 'No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or part, any device or element of design installed on or in a notor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard . . . .' In the case of windows on a passenger car, this provision of Federal law means that no manufacturer, dealer, distributor, or repair business could install window tinting film that would result in a light transmittance of less than 70 percent for any window of the car, because such action would 'render inoperative' the vehicle's compliance with Standard No. 205. This same provision of Federal law prohibits a service station from permanently removing safety belts or permanently disconnecting brake lines on motor vehicles. Please note that the Safety Act does not apply to the actions of vehicle owners. Vehicle owners may alter their own vehicles and operate them on the highways as they please, even if the vehicle's windows no longer comply with the requirements of Standard No. 205. Hence, no provision of a Federal statute or this agency's regulations prevents individual vehicle owners themselves from tinting the windows on their vehicles. The individual States, however, have the authority to regulate the modifications that vehicle owners may make to their own vehicles and to establish requirements for vehicles operated or registered in that State. The Iowa Senate bill enclosed with your letter appears to be an attempted exercise of this inherent authority. You asked for comments on whether this bill, if adopted as law in Iowa, would be preempted by Standard No. 205. I assume you were referring to the provision in this Iowa bill that would prohibit the operation of motor vehicles required to be registered in the State of Iowa if the vehicle has a 'sunscreening device' on the front side windows with light transmittance of less than 35 percent or on the rear window and side windows behind the driver with light transmittance of less than 20 percent. Since the original glazing on the vehicle could have had light transmittance of as little as 70 percent, this provision would permit overall light transmittance levels of as low as 25 percent for the front side windows and 14 percent for the rear windows. This provision in the Iowa bill, and similar provisions in statutes adopted by other States, does not purport to legitimize conduct -- the rendering inoperative of glazing by firms installing window tinting -- that is illegal under Federal law. In other words, firms installing window tinting that results in light transmittance of less than 70 percent on any window of a passenger car would have violated the 'render inoperative' provision in Federal law, even if Iowa had in place a statute that would permit persons to operate and register vehicles whose windows had light transmittance that was far lower. Conversely, the Federal law setting requirements for the manufacture and sale of new vehicles and limiting the modifications commercial enterprises can make to those vehicles does not prohibit the State of Iowa from establishing lesser limits on owner modifications to their own vehicles and as the minimum requirements for vehicles to be operated and registered in the State of Iowa. Thus, there does not appear to be any legal conflict between Federal law and this Iowa bill, and Iowa would be free to enforce the provisions of this bill if it is enacted into law. We would, however, urge the State of Iowa to carefully consider the adverse safety consequences that would result from enacting this bill into law. NHTSA has determined that a 70 percent light transmittance minimum for new vehicles is the appropriate level to assure motor vehicle safety. Your letter indicated that Iowa had also adopted this 70 percent light transmittance minimum as a State requirement for new vehicles. It is not clear why the State of Iowa would conclude that the safety need that justifies requiring not less than 70 percent light transmittance in new vehicles is satisfied by allowing light transmittance levels as low as 25 and 14 percent in vehicles to be operated in the State. I hope that this information is helpful. If you have any further questions or need additional information about this topic, please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam3487OpenMr. Roy Knoedler, Cosco, 2525 State Street, Columbus, IN 47201; Mr. Roy Knoedler Cosco 2525 State Street Columbus IN 47201; Dear Mr. Knoedler: This responds to your letter concerning the application of Standard No 213, *Child Restraint Systems*, to a booster seat that uses a vehicle lap belt or lap/shoulder belt to restrain a child weighing 20 or more pounds. The following discussion answers your questions concerning the application of specific sections of the standard to a booster seat.; Section 4 of the standard defines a 'child restraint system' as 'an device, except Type I or Type II seat belts, designed for use in a motor vehicle to restrain, seat, or position children who weigh not more than 50 pounds.' Since the booster seat you described would be used to seat a child weighing less than 50 pounds in a vehicle, it is a child restraint system and thus must meet the requirements of the standard. The vehicle lap belt (Type I belt) or lap/shoulder belt (Type II belt) used with the system are specifically excluded by the definition of child restraint system and thus are not covered by the requirements of the standard.; You said that the booster seat would have no sides, back or fixed o movable surface directly in front of the child and asked how the standard would apply to such a design. The standard does not require a child restraint to have a back, sides or fixed or movable surface in front of the child. If such surfaces are provided, however, they must comply with the applicable requirements of sections 5.2.2, 5.2.3, and 5.2.4.; Each child restraint is required to meet the minimum head suppor surface requirements of S5.2.1. Section 5.2.1.2, however, exempts forward-facing child restraint (sic) from the minimum head support surface requirement if, 'the target point on either side of the dummy's head is below a horizontal plane tangent to the top of the standard seat assembly when the dummy is positioned in the system and the system is installed on the assembly in accordance with S6.1.2.' Thus, unless your design is within the exception of S5.2.1.2, it would have to comply with the minimum head support requirements of S5.2.1.1. Any head support surface would also have to comply with the applicable requirements of S5.2.3. and S5.2.4.; You asked about the application of S5.4.3.2 to a booster seat. Sectio 5.4.3.2 provides that:; >>>Each belt *that is a part of a child restraint system* and that i designed to restrain a child using the system and to attach the system to the vehicle shall, when tested in accordance with S6.1, impose no loads on the child that result from the mass of the system or the mass of the seat back of the standard seat assembly specified in S7.3. (Emphasis added.); <<>>(c) In the case of each seating system recommended for children ove 20 pounds, crotch restraint in the form of:; (i) a crotch strap connectable to the lap belt or other device used t restrain the lower torso, or; (ii) a fixed or movable surface that complies with S5.2.2.1(c).<<< The purpose of subsection (c) is to require a belt or surface desig that will prevent the child from submarining under the lap belt (i.e., sliding down and forward under the belt). Thus, if a crotch belt is not provided, the surface of the restraint must be designed to prevent submarining and comply with S5.2.2.1(c). For example, the seating surface of the restrain could be designed to prevent submarining.; If you have any further questions, please let me know. Sincerely, Frank Berndt, 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.