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: aiam5346OpenKen Simons, Esq. P.O. Box 883 Fairmont, WV 26555; Ken Simons Esq. P.O. Box 883 Fairmont WV 26555; "Dear Mr. Simons: This responds to your letter asking about brak requirements for trailers used in tractor trailer combinations. I apologize for the delay in our response. You asked whether all such trailers are required to be equipped with 'maxi' brakes on one or both axles. You state that a 'maxi' brake is found on all road tractors and 'sets the brakes automatically when the air pressure gets down to a minimum level.' Please note that the term 'maxi' brakes ordinarily refers to spring brakes used in parking and emergency brake applications. I further note that most, but not all, trailers are equipped with spring brakes. I am pleased to have this opportunity to explain our requirements. By way of background information, under the National Traffic and Motor Vehicle Safety Act ('Safety Act,' 15 U.S.C. 1392), the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards applicable to new motor vehicles and items of motor vehicle equipment. NHTSA does not approve vehicles or equipment. Instead, manufacturers are required to certify that their vehicles or equipment meet all applicable standards. Standard No. 121, Air Brake Systems (49 CFR 571.121, copy enclosed), specifies performance requirements for trucks, buses and trailers equipped with air brake systems. The purpose of the standard is to insure safe braking performance of vehicles under normal and emergency conditions. While Standard No. 121 does not require manufacturers to use spring brakes or any other particular type of brake system, many manufacturers use spring brakes to comply with the standard's requirements concerning parking brake performance (trucks, buses and trailers, see S5.6), emergency brake performance (trucks and buses only, see S5.7), and trailer pneumatic system failure performance (see S5.8). I note that while the requirements of S5.6 and S5.8 apply to most air-braked trailers, S3 of Standard No. 121 excludes some trailers from all of the standard's requirements. In addition, S5.6 and S5.8 specify alternative requirements for some trailers. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosures"; |
|
ID: aiam3986OpenMr. William Pesce, 8 P Origionals, 2892 Crownview Dr., Rancho Palos Verdes, CA 90274; Mr. William Pesce 8 P Origionals 2892 Crownview Dr. Rancho Palos Verdes CA 90274; Dear Mr. Pesce: Thank you for your May 18, 1985 letter inquiring about the existence o any Federal safety requirements applicable to your projected sale of colored windshield wiper blades.; Under the National Traffic and Motor Vehicle Safety Act, this agenc has issued Federal Motor Vehicle Safety Standard No. 104, *Windshield Wiping and Washing Systems*, applicable to new motor vehicles. While this standard does not regulate wiper color, it does, among other things, require that a wiping system clear a minimum percentage of a vehicle's windshield.; In addition, Standard No. 107, *Reflecting Surfaces*, also applies t new motor vehicles. This standard specifies reflecting surface requirements for certain components, including windshield wiper blades, in the driver's field of view. Its purpose is to reduce the likelihood that unacceptable glare from reflecting surfaces will hinder safe and normal operation of the vehicle.; If a new vehicle equipped with your blade did not comply with Standar No. 104 or Standard No 107 due to some aspect of that blade, the sale of that car to the public would be a violation of the prohibition in section 108(a)(1)(A) of the Act against the sale of noncomplying vehicles.; As to used vehicles, you should be aware that section 108()(2)(A) o the Act prohibits manufacturers, distributors, dealers and vehicle repair businesses from knowingly rendering inoperative equipment or elements of design installed on a vehicle under Federal motor vehicle safety standards. Care should be taken that the installation of your product would not have that effect. A rendering inoperative might occur if, for example, your blade were not large enough to enable the wiping system to clear a sufficient area of the windshield. We urge you therefore to ensure that the substitution of your blade for an original equipment blade provided by a vehicle manufacturer would enable the wiping system to continue to perform as required by Standard No. 104, and would not produce unacceptable glare in the drivers field of view, as required by Standard No. 107.; I hope this information is helpful. Sincerely, Jeffrey R. Miller, Chief Counsel |
|
ID: aiam3960OpenMr. H. Moriyoshi, Executive Vice President and General Manager, Mazda (North America), Inc., 24402 Sinacola Court, Farmington Hills, MI 48018; Mr. H. Moriyoshi Executive Vice President and General Manager Mazda (North America) Inc. 24402 Sinacola Court Farmington Hills MI 48018; Dear Mr. Moriyoshi: This is in reply to your letter of June 3, 1985, asking for a interpretation of Motor Vehicle Safety Standard No. 108 regarding requirements for the center high- mounted stop lamp.; You reference an agency letter of July 30, 1980, to Volkswagen o America in which the Chief Counsel concluded that placement of the stop lamps and taillamps on the deck lid could be viewed as a defect in performance requiring notification and remedy. You have asked, in essence, how this relates to Standard No. 108's present allowance of a center high- mounted stop lamp mounted on a vehicle's decklid, hatch, or tailgate.; The assumption underlying the agency's 1980 letter was that a defec could exist if all a vehicle's stop lamps and taillamps were mounted on the decklid, where their signals could be unobserved or obscured if the lid were in any position other than closed. The center high-mount stop lamp, on the other hand, while an item of required equipment, is nevertheless a supplementary stop lamp. Even if the deck, hatch, or tailgate upon which it is mounted should be open, following drivers may still observe the signals of the primary stop lamps remaining on the body.; You have asked that we also discuss the implications of a stop lamp an taillamp constructed so that a portion is fixed to the body of the vehicle adjacent to the decklid opening and the remaining portion is mounted on the outboard area of the decklid.; Compliance of a vehicle is determined with respect to its norma driving position, that is to say, with the tailgate, hatch, or decklid closed. However, in order to obviate any possibility of the existence of a safety-related defect, we recommend that the portion of the lamp that is mounted on the body itself comply with the minimum requirements of Standard No. 108 for a single compartment stop lamp or taillamp.; I hope that this answers your questions. Sincerely, Jeffrey R. Miller, Chief Counsel |
|
ID: aiam1308OpenMr. Roy Stolpestad, 700 North Bryant Ave., #802, Minneapolis, MN 55411; Mr. Roy Stolpestad 700 North Bryant Ave. #802 Minneapolis MN 55411; Dear Mr. Stolpestad: This is in reply to your letter of October 11, 1973, concerning th 1966 Chrysler you recently purchased from Central Motors in Minneapolis.; As Miss Porter correctly pointed out in her column, the Federal law o odometer fraud enables you to bring a civil action against Central. The amount of recovery in such an action can be substantial. If the court were to accept your estimate of damages of $1490.24, the damages assessable under Federal law would be three times that amount - $4470.72. In no case would damages be less than $1500, a minimum value established by law. In addition, if you are successful, Central must pay your attorney fees as well as all court costs.; I appreciate your concern for the costs of litigation. However, b providing for the payment of attorney fees the odometer law places you in a better position than a personal injury litigant, whose recovery is usually diminished by his attorney's contingency fee. Your best course at this point is therefore to retain counsel if Central persists in its refusal to reimburse you.; By way of advice to your attorney, I would point out that the 'out that Central claims to have taken -- checking the box on the disclosure form that indicates the true mileage is unknown -- was taken too late to be of benefit to them. The Federal regulation governing disclosure requires the disclosure statement to be made 'before executing any transfer of ownership form.' If they mailed the statement the next day, their disclosure was untimely. Moreover, the representations made in the newspaper advertisment (sic) are evidentiary of their representation of 33,000 miles as being the true mileage on the vehicle. Your success in finding the previous owner is also useful in establishing that the actual mileage was greater than shown.; We will be willing to give you or your attorney further advice i questions arise concerning the intent and effect of the Federal odometer law. The enclosed copies of the law and regulations are provided to assist him in representing you.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam3765OpenMs. Patricia Hill, 2150 Hacker Road, Howell, MI 48843; Ms. Patricia Hill 2150 Hacker Road Howell MI 48843; Dear Ms. Hill: This responds to your March 23, 1983, letter asking five specifi questions relating to Standard No. 302, *Flammability of Interior Materials*. Your questions and their answers are listed below:; 1. Provide a definitive interpretation of 'erratic burning' as used i the subject standard that may be related to a test procedure.; 'Erratic burning,' as that term is used in the standard, relates t incidents where the material may soften or bend at the flaming end in a way that would not allow for uniform burning. Erratic burning, therefore, includes, but is not limited to, nonuniform burning as indicated in S5.1.3 of the standard where the use of support wires is mentioned.; 2. Provide a definitive interpretation of the word 'anticipate' as use in TP 302-02. That is, must the expectation of a softening and bending of the flaming end be based upon an actual test of an identical test specimen? A similar test specimen?; In actual practice, a test specimen is observed while burning during compliance test to FMVSS No. 302. If the specimen is found both to soften and bend at the flaming end during testing and also fails to meet the minimum burn rate requirement, a retest is performed using support wires.; 3. Does the agency still plan to issue an interpretive amendmen limiting or clarifying the use of support wires as stated in your 1976 letter? When?; The agency currently has no plans for any modifications of Standard No 302.; 4. How do the procedural requirements of the subject standard apply t a test specimen that bends at the flaming end prior to ignition by a bunsen burner?; We are not certain of the question that you are asking. The materia would not have a flaming end to bend prior to ignition of the bunsen burner. If by this question you mean to ask what we would do about non-flat test specimens, the agency always attempts to test flat specimens only.; 5. Does the NHTSA plan to revise TP 302-02 to reflect your 197 interpretation and your response to this letter? When?; The agency currently has no plans for any modifications to TP 302- 02. Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam2807OpenMs. Susan H. Soodek, 1025 Connecticut Avenue, N.W., Washington, DC 20036; Ms. Susan H. Soodek 1025 Connecticut Avenue N.W. Washington DC 20036; Dear Ms. Soodek: This responds to your recent letter asking whether Federal Safet Standard No. 205 specifies requirements limiting the reflectivity of glazing materials. You are concerned with the lack of uniformity in state laws that prohibit nontransparent or reflective windows in motor vehicles.; The stated purpose of Safety Standard No. 205, *Glazing Materials*, i to reduce injuries resulting from impact to glazing surfaces, to ensure a necessary degree of transparency in motor vehicle windows for driver visibility, and to minimize the possibility of occupants being thrown through the vehicle windows in collisions. The standard does not prohibit reflective glazing, nor does it specify requirements that would limit the degree of reflectivity of glazing materials.; Since reflectivity is not an aspect of performance governed by Federa safety standards, state laws concerning glazing reflectance would not be preempted by Standard No. 205. Safety Standard No. 205 does, however, specify requirements for the luminous transmittance of glazing materials for use in motor vehicles. Therefore, state laws prohibiting nontransparent windows would be preempted if they attempted to regulate the glazing manufacturer or the vehicle manufacturer (15 U.S.C. 1392(d)). State regulations applicable to the vehicle owner or user would not be preempted, on the other hand, since the Federal regulation is only applicable to the manufacturer. Therefore, a state law could prohibit the application of a nontransparent decal on a window by a vehicle owner, for example.; I am enclosing a copy of the California Highway Patrol petition fo rulemaking regarding glazing abrasion requirements and glazing reflectivity. A notice concerning this petition will be issued at some time in the near future.; I must point out that our statutory authority requires all safet standards to be reasonable, objective and to meet the need for motor vehicle safety. The agency cannot, therefore, regulate an aspect of motor vehicle performance or design if there is no data or evidence indicating that a safety problem exists.; I hope this has been responsive to your inquiry. Please contact Hug Oates of my office if you have any further questions.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
|
ID: aiam4068OpenThe Honorable Leon E. Panetta, Member, U.S. House of Representatives, 380 Alvarado Street, Monterey, CA 93940; The Honorable Leon E. Panetta Member U.S. House of Representatives 380 Alvarado Street Monterey CA 93940; Dear Mr. Panetta: This responds to your request that we review the concerns expressed b one of your constituents, Mr. Joseph Loschiavo, about certain van seats. According to Mr. Loschiavo, the Monterey County Van Program for senior citizens uses vans with seats that are very low and close together, making it difficult for persons to get up out of the seats. He suggested that either the seats be raised about eight inches or that special seats be provided for persons who have problems with the present seats.; The National Highway Traffic Safety Administration (NHTSA) issues moto vehicle safety standards. Federal Motor Vehicle Safety Standard No. 207, *Seating Systems*, establishes requirements to minimize the possibility of seat failure during vehicle collisions. However, NHTSA does not have any standards concerning the height or spacing of van seats.; The Monterey County Van Program has several options in obtaining van with appropriate seating. In purchasing new vans, the Program may either select from among the variety of vans offered by the major vehicle manufacturers, or go to one of a number of companies that customize vans to purchasers' specifications. A number of companies also modify used vehicles.; We note that new vans, including vans which are modified prior to firs sale, are required to be certified to comply with applicable Federal motor vehicle safety standards. The specific certification requirements are set forth at 49 CFR Part 567, *Certification*. If a used vehicle is modified by a business such as a garage, the business is not required to attach a certification label. However, it would have to make sure that it did not knowingly render inoperative the compliance of the vehicle with any safety standard. This is required by section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act. Thus, if a business replaced a van's existing seats with higher seats, it would need to make sure that it was not rendering inoperative the vehicle's compliance with Standard No. 207 or any other Federal motor vehicle safety standard.; I hope this information is helpful. Sincerely, Erika Jones, Chief Counsel |
|
ID: aiam1006OpenMr. Carl Monk, 428 Southland Boulevard, Louisville, Kentucky 40214; Mr. Carl Monk 428 Southland Boulevard Louisville Kentucky 40214; Dear Mr. Monk: Dr. Brinegar asked that I review and respond to your letter of Decembe 23, 1972, regarding warning devices.; As you know from previous correspondence, the National Highway Traffi Safety Administration (NHTSA) issued a Notice of Proposed Rule Making on a standard for warning devices in November 1970. One of our major concerns in issuing this standard was the great variety of warning devices of all sizes, shapes, forms and configurations that were available to the motoring public. While many of these provided varying degrees of effectiveness, the great variety also created confusion and misunderstanding to the motoring public. Standardization of these devices was therefore of prime importance.; In response to this notice many comments, designs and recommendation were suggested for inclusion in the standard. All responses were carefully reviewed and evaluated before we issued the final rule in March 1972. Federal Motor Vehicle Safety Standard No. 125 represents an attempt to achieve a balance between many factors including shapes, size, cost, visibility, stability and weight. Since these triangle are designed for ultimate use in all kinds of vehicles, from passenger cars to heavy trucks, we had to be careful not to specify requirements that would put them beyond the reach of the average motoring public.; We are appreciative of your comments to the docket and your subsequen correspondence of the Department of Transportation, regarding the wind stability requirement of the device. Vehicles traveling at 70 mph do not create an effective wind velocity of 70 mph off the roadside. Research data shows that warning devices designed to withstand wind velocities of approximately 40 mph will be sufficient for the majority of wind conditions created by truck turbulence and atmospheric wind velocities without unnecessary penalties in weight and cost. However, Standard No. 125 will in no way restrict the manufacture and sale of devices with higher wind-resistance capabilities for special uses. These are *minimum* standards.; Again, we appreciate your interest in this aspect of motor vehicle safety. it is the ideas and opinions of concerned individuals, such as yourself, that enable us to ensure rules and regulations that are meaningful and worthwhile to the motoring public. Thank you for writing E.T. Driver, Director, Office of Operating Systems, Motor Vehicle Programs; |
|
ID: aiam2918OpenHonorable Bud Shuster, House of Representatives, Washington, DC 20515; Honorable Bud Shuster House of Representatives Washington DC 20515; Dear Mr. Shuster: This responds to your inquiry dated November 29, 1978, on behalf of on of your constituents, Mr. C. Stake, requesting information about Federal safety standards concerning door locks on automobiles. Specifically, Mr. Stake is concerned that the doors on his 1977 Mercury Monarch can be unlocked by a child from the inside by lifting the door handle.; I am enclosing a copy of Safety Standard No. 206 (49 CFR 571.206) which specifies performance requirements for side door locks and side door retention components to minimize the likelihood of occupants being thrown from the vehicle as a result of impact. That standard specifies that each door on a passenger car shall be equipped with a locking mechanism with an operating means in the interior of the vehicle. Paragraph S4.1.3.1 of the standard specifies that when the locking mechanism on a side *front* door is engaged, the outside door handle or other outside latch release control shall be inoperative. For side *rear* doors, however, paragraph S4.1.3.2 requires both the outside and inside door handles to be inoperative when the locking mechanism is engaged.; This latter requirement was specifically included in the standard t address Mr. State's concern, that is, to prevent children from unlocking rear doors by means of the door handle. The design restriction was limited to rear doors on the basis that the danger arises primarily with unattended children sitting in the rear seat. A child sitting in the front seat is likely under the watchful eye of the driver. Further, there is the consideration that in emergency situations the driver may need to unlock his front door as easily and quickly as possible.; Since the Standard No. 206 requirements have been in effect for som time, we assume that the situation Mr. Stake describes is true only of the front doors of his Mercury Monarch. As noted above, however, there are competing safety considerations involved with door locks on front side doors.; Please contact our office if your constituent has any further question concerning this matter, or have him contact us directly.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
|
ID: aiam1890OpenMr M. J. Denholm, Power Controls Division, Midland-Ross Corporation, 490 South Chestnut Street, Owosso, MI 48867; Mr M. J. Denholm Power Controls Division Midland-Ross Corporation 490 South Chestnut Street Owosso MI 48867; Dear Mr. Denholm: This responds to Midland-Ross' March 19, 1975, questions whether S5.7. of Standard No. 121, *Air brake systems*, (as effective September 1, 1976) specifies reservoirs that are charged to 100 psi before or after introduction of a failure as specified in S5.7.1, static or dynamic testing of emergency brake system application and release, and design limits of 1 to 60 psi for emergency brake system application and release. You also asked whether S5.7.4(c) requires modulation of the towed vehicle emergency system in cases of control line failure, and whether such a failure qualifies as a 'single failure in the service brake system' for purposes of emergency brake system performance under S5.7.1.; Section S5.7.3 specifies emergency application and release capabilit with all air reservoirs charged to 100 psi, followed by introduction of a failure. The vehicle is tested for this application and release capability statically. In our reconsideration of this amendment, NHTSA will consider a clarification of this language.; The maximum of 1 psi for pressure release and minimum 60 psi fo pressure application are intended only as objective measures of what constitute an application or a release. In the petitions for reconsideration of this amendment, it has been suggested that the ability to move the vehicle and then stop it after an emergency brake application would permit greater design freedom in the design of emergency brake systems. This issue will be addressed in our response to petitions for reconsideration.; Section S5.7.4(c) requires that a towing vehicle be capable o modulating the air in the supply or control line following a single failure in the service brake system on the towing vehicle, but does not require modulation of the towed vehicle emergency brake system under any circumstance (including control line failure).; This language is intended to assure that a single failure in the truc itself will not prevent modulation of an unimpaired system from the tractor protection system rearwards. A clarification of this language may be necessary.; 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.