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: aiam3985OpenMr. 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 System*, 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 the 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(a)(2)(A) o the Act prohibits manufacturers, distributors, dealers and vehicle repair businesses form 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 driver's field of view, as required by Standard No. 107.; I hope this information is helpful. Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam5607OpenMilford R. Bennett, Director Safety Affairs and Safety & Restraints Center General Motors Corporation 30200 Mound Road Warren, Michigan 48090-9010; Milford R. Bennett Director Safety Affairs and Safety & Restraints Center General Motors Corporation 30200 Mound Road Warren Michigan 48090-9010; Dear Mr. Bennett: This responds to General Motors' (GM's) May 19, 199 letter asking whether a sunshade device is permitted under the 70 percent light transmissibility requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 205, Glazing Materials. You describe the device as a screen-like device that is stowed in the back panel shelf area below the rear window and that can be electrically raised and lowered by a driver operated switch. The light transmissibility through the combination of the rear window and the raised sunshade is less than 70 percent. The short answer to your question is that the device is permitted. Although you note earlier agency interpretations stating that windows with sunshades must still comply with Standard No. 205, you believe that the standard does not apply to your device. You state that those interpretations were distinguishable because the other shading devices were attached to the window, while your device is not. You are correct in your assertion that installation of your sunshade would not cause a noncompliance with Standard No. 205. The purpose of the 70 percent light transmissibility requirements in Standard No. 205 is to ensure that the driver can see 70 percent of the incident light through the windows that are requisite for driving visibility, under all conditions of lighting. However, the test procedures do not incorporate an in-vehicle test. Instead, they contemplate testing only the glazing itself. Your mesh screen sunshade need not comply with the standard (because it does not meet the definition of glazing) or in combination with the rear window (because it is not attached). Although our standards do not prohibit this device, we have some safety-related concerns with its use in inappropriate situations. NHTSA hopes that GM plans to take steps to minimize the likelihood that the sunshade will be raised in such situations. I hope this information is helpful. If you have any further questions, please feel free to contact Paul Atelsek of my staff at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam4295OpenMr. James E. Campbell, 2719 So. 29th Street, Ft. Pierce, FL 33450; Mr. James E. Campbell 2719 So. 29th Street Ft. Pierce FL 33450; Dear Mr. Campbell: This is in reply to your letter of December 17, 1986, in which you hav asked the following question:; 'If someone has a patent on an invention, as in the case of the tur signals, and you at the N.H.T.S.A. make it mandatory that all cars be equipped with that feature, does the inventor retain the marketing rights to that invention, or does he lose those rights once it becomes mandatory?'; The answer to your question is that rights given under a patent issue by the United States Patent Office cannot be divested by the actions of a governmental agency such as the N.H.T.S.A. Were we to require that a patented item of equipment be standard on all passenger cars, the patent holder would retain all rights. However, it is important that you understand that the agency does not mandate the adoption of equipment of a proprietary nature. By law, the Federal motor vehicle safety standards are defined as minimum standards for motor vehicle *performance*, to the extent practicable the standards specify performance requirements to be met (*e.g.*, no more than 5 ounces of fuel spillage in the first 5 minutes following a 30 mph frontal barrier collision), leaving the design solution to the manufacturer who may incorporate proprietary components if he chooses.; The performance requirements of our standards vary in their degree o specificity. In some instances the agency has had to develop fairly specific requirements to ensure uniformity and interchangeability of replacement equipment items such as brake hoses, tires, and lighting equipment. This can increase the likelihood of the incorporation of proprietary elements. Many of the changes which are made to the standard are made in response to petitions from manufacturers of motor vehicles or motor vehicle equipment. This is especially true in the area of motor vehicle lighting which is covered by Standard No. 108. In some instances, a petitioner may request a change which incorporates specifications which are covered by a patent. In these cases, the agency endeavors to insure that the technology is made available on a non-exclusive royalty-free basis to all who wish to use it before amending the standard.; I hope that this answers you question. Sincerely, Erika Z. Jones, Chief Counsel |
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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 |
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ID: aiam4294OpenMr. T. Chikada, Manager, Automotive Lighting, Engineering Control Dept., Stanley Electric Co., Ltd., 2-9-13, Nakemeguro, Meguro-ku, Tokyo 153, Japan; Mr. T. Chikada Manager Automotive Lighting Engineering Control Dept. Stanley Electric Co. Ltd. 2-9-13 Nakemeguro Meguro-ku Tokyo 153 Japan; Dear Mr. Chikada: This is in reply to your letter of March 13, 1987, with respect to th mounting height of driving lamps and front fog lamps. Noting that these Lamps are not equipment required by Federal Motor Vehicle Safety Standard No. 108, you have asked whether they need to be mounted within the range of height which the standard prescribes for headlamps, or may they be mounted, for example, at a height lower than 22 inches such as in the front bumper.; Any lamp that is not required by Standard No. 108 may be added to motor vehicle and located wherever it appears suitable, provided that the lamp at its location does not impair the effectiveness of lighting equipment required by the standard. Headlamps, parking lamps, and turn signal lamps are the lighting equipment required by Standard No. 108 on the front of a passenger car, and any other four-wheeled vehicle of less than 80 inches overall width. Although Standard No. 108 impose a minimum mounting height of 22 inches on headlamps, it allows parking lamps and turn signal lamps to be mount as low as 15 inches above the road surface which means that they could be mounted in the front bumper, or otherwise close to the mounting location of fog lamps and driving lamps. Therefore, compliance with paragraph S4.1..3 of Standard No. 108 would require a manufacturer of a vehicle equipped with fog and driving lamps to ensure that they do not impair the effectiveness of the headlamps, turn signal lamps, and parking lamps.; Because fog lamps and driving lamps are not covered by Standard No 108, the individual States may have their own restrictions on the mounting height of these lamps. We regret that we are unable to advise you on these laws. However, the American Association of Motor Vehicle Administrators (AAMVA), 1201 Connecticut Ave., N.W., Washington, D.C., may be able to advise you.; Sincerely, Erika Z. Jones, Chief Counsel |
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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 |
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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 |
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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 |
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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 |
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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; |
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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.