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: aiam4018OpenNorman Friberg, P.E., Manager, Product Compliance, Volvo Cars of North America, Rockleigh, NJ 07647; Norman Friberg P.E. Manager Product Compliance Volvo Cars of North America Rockleigh NJ 07647; Dear Mr. Friberg: This is to acknowledge receipt of your petition dated June 27, 1985 for a determination that a noncompliance with Federal Motor Vehicle Safety Standard No. 110 is inconsequential as it relates to motor vehicle safety.; Paragraph S4.3 of the standard requires that a specified placard sho the recommended tire size designation. Volvo has provided labels on approximately 3,200 passenger cars which show an incorrect recommended minimum tire size. Thus, these labels state '185/65R15' but the correct information is '185/70R15.' However, Volvo intends to mail correct placards 'to owners of all affected vehicles.'; By providing the corrective placard, Volvo will remedy th noncompliance. Because the noncompliance will no longer exist, the question of whether it has a consequential relationship to safety is moot. The remaining question is the adequacy of the notification which Volvo will provide owners of the affected vehicles. Because the corrective action is such that it may be easily accomplished by the owner (affixing the gummed placard to the car), the agency has concluded that any deviation of the text of the notice from the requirements of 49 CFR Part 577 would be a technical violation only. Therefore, NHTSA does not intend to seek re-notice or civil penalties for such a violation. Consequently, the agency intends no further action on your petition.; The agency's conclusions apply to the facts of this case only and d not necessarily represent the agency's posture in future cases involving forms of notification other than specified by Part 577, for noncompliances.; Our records indicate that Volvo is in technical noncompliance with 4 CFR Part 573, *Defect and Noncompliance Reports*, by failing to file a report within 5 days of its determination of the existence of the noncompliances. We will, however, treat the submission of information in your petition as a Part 573 report. Part 573 also requires 6 quarterly reports on the progress of recall campaigns. In your situation, the campaign will be accomplished in a single mailing. We ask that you furnish the agency with a report of the number of letters sent and the number of letters returned as undeliverable in lieu of the Part 573 quarterly reports.; Sincerely, Erika Z. Jones, 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: 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"; |
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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: aiam3557OpenJoseph R. Karner, Project Engineer, M.A.N. Truck & Bus Corporation, 3000 Town Center, Southfield, MI 48075; Joseph R. Karner Project Engineer M.A.N. Truck & Bus Corporation 3000 Town Center Southfield MI 48075; Dear Mr. Karner: This responds to your October 1, 1981, letter asking whether it woul be permissible to attach a label to a door stating 'To Open Door in Emergency Pull Down'. You indicate that the door is not an emergency door in compliance with Standard No. 217, *Bus Window Retention and Release*. You question whether the addition of the label in conformance to a contract with the Chicago Transit Authority (CTA) would make the door an emergency door that would be required to comply with the standard. The CTA requires that door to be so labelled because it desires the door to be used as a means of escape.; The standard states that buses shall be equipped with a minimum numbe of emergency exits and that all emergency exits shall be labelled properly and comply with the requirements of the standard. One purpose of the standard is to provide sufficient emergency exits. Another purpose is to provide uniform emergency exit markings and operating instructions. You have stated that your vehicle has the requisite number of emergency exits, properly marked, so that the door in question is not required in counting the total number of exits for purposes of complying with the standard.; As you know, not all doors are required to be emergency exits. Fo example, the front entrance door of a vehicle need not be an emergency exit. If it is not labelled an emergency exit, it need not comply with the requirements of the standard relative to emergency exits. Similarly, the door to which you refer need not comply with the emergency exit requirements if it is not labelled as an emergency exit. However, since your proposed label refers to the emergency nature of the door, it appears to place the door within the category of an emergency exit that would be required to comply with the standard. The CTA intends the door to be used as an emergency exit and the label will indicate to riders that the door is suitable for such purposes. You may not, therefore, refer to the door as an emergency door unless the door complies with all of the requirements.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2886OpenMr. William M. Nettles, Rome Engineering & Manufacturing Co., P.O. Box 707, Claxton, GA 30417; Mr. William M. Nettles Rome Engineering & Manufacturing Co. P.O. Box 707 Claxton GA 30417; Dear Mr. Nettles: This responds to REMCO's September 14, 1978, request to know th Federal braking requirements for an air-braked or pulpwood trailer.; In addition to the requirements of Standard No. 106-74, *Brake Hoses* the only Federal Motor Vehicle Safety Standard regulating the braking of air-braked vehicles is Standard No. 121, *Air Brake Systems*. As you know, Federal Motor Carrier Safety Standards also apply to the use of air-braked vehicles in interstate commerce.; All of the requirements of Standard No. 121 apply to the manufacture o a logging or pulpwood trailer except for the 'no lockup' provision of S5.3.2. Specifically, S5.3.2.2 of the standard states:; >>>S5.3.2.2 When stopped in accordance with S5.3.2, any traile designed exclusively for harvesting logs or pulpwood and constructed with a skeletal frame and no means for attachment of a solid bed, body, or container, and with an arrangement of air control lines and reservoirs designed to minimize damage in off- road operations, need not meet the requirements relating to wheel lockup, but must nevertheless meet the requirements of staying within the 12-foot lane.<<<; There is no exclusion from the parking brake requirements of S5.6 Therefore, a parking brake capability using an energy source unaffected by loss of service brake air pressure is required. The standard specifies performance, not design, and does not require installation of a spring brake design. I have enclosed a copy of a recent proposal that would modify the requirements so that pulpwood trailers would not be required to provide parking brake capability. The reasons for this proposal are listed in the preamble to the notice. This proposal has not been made final.; For clarification, I would add that 'heavy hauler' trailers ar excluded from the entire standard until January 1, 1979. Heavy hauler trailers are defined to include the so-called 'pole trailers' used in logging that have air brake lines that adapt to fore-and-aft extension of the trailer.; I am also enclosing a *Federal Register* notice that explains th effect of a recent court decision on the 'no lockup' requirement for trailers.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam4518OpenMr. Amnon Shomlo President, A.A.S. 3364 Catamaran Way Jacksonville, FL 32217; Mr. Amnon Shomlo President A.A.S. 3364 Catamaran Way Jacksonville FL 32217; Dear Mr. Shomlo: This is in reply to your letter of March 25, 1988 enclosing a 'Peace' decal designed to be affixed to the center highmounted stop lamp. The letters and design are in white, printed on transparent plastic, 'in an effort to preserve the basic requirements for an effective projected luminous area of the lens and the specified candela.' You have asked what 'Federal/Legal authorizations we need to obtain, stating that we comply with all the regulations and the requirements regarding this product.' There are no regulations that apply directly to the decal, nor any Federal restrictions on its sale. Thus you cannot state in any sales materials that the product meets Federal requirements, for there are none. If a center highmounted brake lamp would continue to meet all applicable requirements of Motor Vehicle Safety Standard No. 108 after installation of your decal, there are no restrictions on its use. Although you intend the product to preserve the requirements of Federal Motor Vehicle Safety Standard No. 108, it is not certain that this will occur. The decal has the potential of obscuring light from some of the l3 test points at distances where candela photometrics must be measured and the specified minima met. However, its actual effect can be determined only through laboratory tests on lamps of different sizes and lens and reflector designs. Although you have no liability under Federal law for selling this decal, a violation of the National Traffic and Motor Vehicle Safety Act will result if the decal creates a noncompliance and if it is applied by a manufacturer, distributor, or dealer before the first sale of the vehicle. A violation will also occur if the decal creates a noncompliance and if it is applied after the vehicle's first sale by any of these persons or by a motor vehicle repair business. There is no violation of Federal law if the decal is applied by a person other than those named above, such as the vehicle owner. In the absence of a violation of Federal law there may nonetheless be State statutes restricting the application of the decal under any circumstances. We are unable to advise you on State laws. I hope that this answers your question. Sincerely, Erika Z. Jones Chief Counsel; |
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ID: aiam1034OpenMr. Robert E. Bauer, Harnischfeger Corporation, 4400 West National Avenue, Milwaukee, WI 52346; Mr. Robert E. Bauer Harnischfeger Corporation 4400 West National Avenue Milwaukee WI 52346; Dear Mr. Bauer: This is in reply to your letter of January 25, 1973, to Gordo Lindquist, Regional Administrator, NHTSA, asking whether Federal standards require the installation of seat belts on certain vehicles you manufacture. According to brochures you have submitted, these vehicles are your RH 25 3-cu. yd. heavy duty hydraulic shovel, R-150-1 15-ton hydraulic crane, W-350 35-ton hydraulic swinger crane, and T-150 15-ton fully hydraulic truck crane.; With reference to the first three vehicles, the RH 25, R-150-1 an W-350, the NHTSA does not consider these vehicles to be manufactured primarily for use on the public roads. Therefore, they are not 'motor vehicles' subject to regulation under the National Traffic and Motor Vehicle Safety Act of 1966. We view them as construction equipment whose use of the public roads is incidental to their primary work-performing purpose.; THe NHTSA believes, however, based on the information you hav submitted, that the T-150 hydraulic truck crane is a motor vehicle under the Safety Act, and a 'truck' under the motor vehicle safety standards. We base this determination on the vehicle's speed capability, that its manufacturer classifies it as a 'truck crane', and that its overall appearance appears to be that of a vehicle designed to be used on the highway. As a truck, the vehicle is required to be equipped with seat belts as specified in Motor Vehicle Safety Standard No. 208, Occupant Crash Protection (49 CFR 571.208, copy enclosed). It is required also to conform to safety requirements specified in other safety standards and regulations. Copies of the standards can be obtained as described in the enclosed, 'Where to obtain Motor Vehicle Safety Standards and Regulations'.; Our decision as to whether this vehicle is a motor vehicle is base only on that information which you have provided us. Other relevant factors which can be taken into consideration are set forth in the enclosed interpretation regarding mini- bikes. If you have further information which you believe we should also consider we will be glad to review it.; Sincerely, Lawrence R. Schneider, 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 |
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.