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
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ID: aiam3036OpenMr. A. M. Dahm, President, Macdonald Equipment Company, P.O. Box B, 7333 Highway 85, Commerce City, CO 80022; Mr. A. M. Dahm President Macdonald Equipment Company P.O. Box B 7333 Highway 85 Commerce City CO 80022; Dear Mr. Dahm: This responds to your January 2, 1979, letter asking whether it i permissible to mount a snow plow on a vehicle when the weight of the snow plow will cause the vehicle to exceed its gross axle weight rating (GAWR). The answer to your question is no.; The GAWR of a vehicle is determined and established by a vehicle' manufacturer and represents a manufacturer's assessment of the maximum weight that each axle can safely sustain. When this weight rating is exceeded by the addition of equipment to a vehicle, the safety of a vehicle is jeopardized. Over a period of time, the excessive weight borne by the axle could result in unusual wear and eventual failure of the axle.; The National Highway Traffic Safety Administration require manufacturers to label their vehicles with GAWR's to avoid the overload problem that you mention in your letter. The NHTSA has not granted exceptions from this requirement for snow plows. If you mount a snow plow on a new vehicle prior to first purchase, you must be sure that the vehicle continues to comply with all Federal safety standards and regulations. If the weight of the plow exceeds the GAWR of the vehicle, the vehicle would no longer comply with Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. Further, the compliance of other safety standards could be impacted by the addition of that weight.; In the case of used vehicles on which you mount a snow plow, manufacturer, repair business, distributor, or dealer may not knowingly render inoperative the compliance of a vehicle with the safety standards. The attachment of a snow plow that exceeds the gross axle weight rating would render inoperative the compliance of the vehicle with Standard No. 120. Accordingly, whether a vehicle is new or used, the additional weight of a snow plow that would exceed the GAWR of a vehicle would not be permissible.; The NHTSA understands the budgetary constraints of municipalities However, financial considerations must be balanced against the potential loss of life that can occur when vehicles are routinely overloaded. Accordingly, vehicles that have snow plows or other devices mounted on them should have sufficient GAWR's to carry their intended load.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3037OpenMr. A. M. Dahm, President, Macdonald Equipment Company, P.O. Box B, 7333 Highway 85, Commerce City, CO 80022; Mr. A. M. Dahm President Macdonald Equipment Company P.O. Box B 7333 Highway 85 Commerce City CO 80022; Dear Mr. Dahm: This responds to your January 2, 1979, letter asking whether it i permissible to mount a snow plow on a vehicle when the weight of the snow plow will cause the vehicle to exceed its gross axle weight rating (GAWR). The answer to your question is no.; The GAWR of a vehicle is determined and established by a vehicle' manufacturer and represents a manufacturer's assessment of the maximum weight that each axle can safely sustain. When this weight rating is exceeded by the addition of equipment to a vehicle, the safety of a vehicle is jeopardized. Over a period of time, the excessive weight borne by the axle could result in unusual wear and eventual failure of the axle.; The National Highway Traffic Safety Administration require manufacturers to label their vehicles with GAWR's to avoid the overload problem that you mention in your letter. The NHTSA has not granted exceptions from this requirement for snow plows. If you mount a snow plow on a new vehicle prior to first purchase, you must be sure that the vehicle continues to comply with all Federal safety standards and regulations. If the weight of the plow exceeds the GAWR of the vehicle, the vehicle would no longer comply with Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. Further, the compliance of other safety standards could be impacted by the addition of that weight.; In the case of used vehicles on which you mount a snow plow, manufacturer, repair business, distributor, or dealer may not knowingly render inoperative the compliance of a vehicle with the safety standards. The attachment of a snow plow that exceeds the gross axle weight rating would render inoperative the compliance of the vehicle with Standard No. 120. Accordingly, whether a vehicle is new or used, the additional weight of a snow plow that would exceed the GAWR of a vehicle would not be permissible.; The NHTSA understands the budgetary constraints of municipalities However, financial considerations must be balanced against the potential loss of life that can occur when vehicles are routinely overloaded. Accordingly, vehicles that have snow plows or other devices mounted on them should have sufficient GAWR's to carry their intended load.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5419OpenHerr P. Binder ITT Automotive Europe GmbH Bietigheim-Bissingen Germany; Herr P. Binder ITT Automotive Europe GmbH Bietigheim-Bissingen Germany; "FAX 07142/73-2895 Dear Herr Binder: This responds to your FAX of Jul 19, 1994, requesting a reinterpretation of our letter to you of June 21, 1994. You had intended to ask us about taillamps rather than the turn signal lamps which were the subject of our letter. Your latest letter shows a rear motor vehicle lighting array of four lamps, two on the body and two on the tailgate. The lamps on the body contain turn signals, stop lamps, and taillamps. The lamps mounted on the tailgate contain backup lamps, rear fog lamps, and taillamps. Your letter asks for confirmation of your interpretation that: 'This lighting system is a multiple lamp arrangement, therefore the combination of taillamp 1 and taillamp 2 has to be used to meet the photometric requirements for 2 lighted sections (SAE J585e, 3.1 and Table 1).' This is correct. Paragraph 3.1 of SAE J585e states that 'multiple lamps may be used to meet the photometric requirements of a tail lamp.' Note 3 of Table 1 states that 'separately lighted sections . . . may be separate lamps', and that the photometric values are to apply when all sections that provide the tail signal are considered as a unit. 'Visibility will be judged with tailgate closed.' As we advised you in our earlier letter, this is also correct. 'Only taillamp 2 mounted on the tailgate will meet the requirements for an unobstructed projected illuminated area of 12.5 cm2 measured at 45 deg. inboard. This is in accordance with SAE J 585e, Par. 4.' Taillamp 1 and taillamp 2 together comprise the taillamp system. Thus it is not required that taillamp 1 meet the inboard visibility requirements when they are met by taillamp 2. You have also asked some general questions: 'Are there regulations which lamps has to be mounted on the body and which lamps are allowed on the tailgate?' No. Table IV's requirement for the location of rear stop, tail, and turn signal lamps is that they be 'as far apart as practicable.' However, Standard No. 108 does not specify which lamps must be mounted on the body and which are permissible on the tailgate. We encourage manufacturers to mount signal lamps on the body, such as is shown in your drawing. 'Is there a regulation to take an approval test in an authorized test laboratory (e.g. ETL)?' No. NHTSA has no authority to require a manufacturer to take approval tests or to designate test laboratories of which it approves. 'Which US-Authority has to be informed about this test?' A manufacturer is not required to inform NHTSA or any other governmental agency about its tests. However, NHTSA has the authority to ask a manufacturer to provide it with copies of test results, and generally does so if it finds failures to meet Standard No. 108 in its own tests. 'How long is this test valid?' 'After which period has this test to be repeated?' Under our laws, a lamp manufacturer is required to certify compliance of replacement equipment with Standard No. 108, and it is the manufacturer's determination when it should retest a lamp to verify that its certification of compliance remains correct. In our experience, manufacturers will retest when there are design changes to its products. Manufacturers also engage in surveillance testing of products after they have entered production to ensure that design tolerances continue to be met and that the lamp remains in compliance with the specifications of Standard No. 108. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam4617OpenThe Honorable Fred Grandy House of Representatives Washington, DC 20515; The Honorable Fred Grandy House of Representatives Washington DC 20515; "Dear Mr. Grandy: This is in reply to your recent letter to th Administrator Designate, Jerry Curry, on behalf of your constituent Daniel Weichmann, Jr., of Hampton. You enclosed a copy of Mr. Weichmann's letter to this agency with respect to headlamp covers which, regrettably, we have been remiss in answering. You asked that we review this matter and that you be provided a copy of our response. We are pleased to reply directly to you, with a copy to Mr. Weichmann so that he may be apprised immediately of our views. Mr. Weichmann was advised by the Iowa Department of Transportation on October 10, 1988, that 'The department specifically does not approve head lamp covers', because Iowa has adopted 'Federal standards on equipment approval'. Consequently, 'If the headlamp covers in question meet the Federal Standards they would qualify under Iowa law.' Thus, Mr. Weichmann asked us whether headlamp covers are approved by this agency. Headlamp covers are not permissible as items of original motor vehicle equipment. Paragraph S7.7.5 of Federal Motor Vehicle Safety Standard No. l08 Lamps, Reflective Devices, and Associated Equipment, in pertinent part, states that when headlamps are operated they 'shall not have any styling ornament or other feature, such as a translucent cover or grill, in front of the lens.' Although Standard No. l08 was only recently amended to state this prohibition expressly (I enclose a copy of the amended standard), the prohibition has existed since January l968 through the incorporation by reference in Standard No. l08 of an SAE headlamp Standard, J580b, which contained the identical language. The safety reason for the prohibition is the reduced effectiveness of a headlamp beam when it must pass through an extra layer of glazing, particularly if that glazing is tinted, yellowed, or cracked, or if moisture has condensed on the inside of the cover. Thus, headlamp covers are also implicitly prohibited by paragraph S5.1.3 of Standard No. l08 which forbids the installation of optional original equipment that impairs the effectiveness of lighting equipment, such as headlamps, that are required by Standard No. l08. The Iowa DOT's views are consistent with the provisions of the National Traffic and Motor Vehicle Safety Act which permit States to enact State motor vehicle safety standards applicable to new vehicles provided that they are identical to Federal ones covering the same aspect of performance. Although the Federal standards do not regulate operation of a vehicle after it is sold, and hence could not prohibit a vehicle owner in Iowa from installing headlamp covers and operating his vehicle with them, Iowa's enforcement of a headlamp cover prohibition for vehicles in use would be consistent with its prohibition of them as original vehicle equipment. However, we cannot interpret Iowa law, and reach no conclusion as to whether its statutes or regulations have that effect. Should either you or Mr. Weichmann have further questions, we shall be pleased to answer them. Sincerely, Jeffrey R. Miller Acting Administrator Enclosure cc: Daniel Weichmann, Jr. The Honorable Fred Grandy Mason City IA /"; |
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ID: aiam2768OpenMr. Joe Devane, Dorsey Trailers, Inc., Hickman Avenue, Elba, Alabama 36323; Mr. Joe Devane Dorsey Trailers Inc. Hickman Avenue Elba Alabama 36323; Dear Mr. Devane: This responds to your telephone request of February 9, 1978, to Roge Tilton of my staff asking whether Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*, requires that you mount on your vehicles only retreaded tires containing the DOT symbol.; The standard in paragraph S5.1.3 requires that after January 1, 1978 all used tires mounted on vehicles covered by the standard be manufactured in accordance with Standard No. 119 as evidenced by the symbol DOT on the sidewall. Therefore, you would not be permitted to mount used tires on your vehicles that do not contain the DOT symbol.; Retreaded tires are not used tires. Retreaded tires must comply wit all applicable Federal requirements pertaining to them. In the case of retreaded nonpassenger car tires, there are no applicable Federal standards. The DOT symbol is only marked on those tires to which a Federal standard applies. Therefore, retreaded nonpassenger car tires do not need to be marked with the DOT symbol and, in fact, should not be marked with that symbol. Retreaded nonpassenger car tires without DOT Symbols can be mounted on your vehicles in full compliance with Standard No. 120. If the tires in your possession have the DOT symbol on them, they can still be mounted on your vehicles. The tire retreader would be responsible for the misapplication of the DOT symbol to these tires.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2119OpenMr. Frank W. Linnell, Linnell, Choate & Webber, Attorneys at Law, 83 Pleasant Street, Auburn, ME 04210; Mr. Frank W. Linnell Linnell Choate & Webber Attorneys at Law 83 Pleasant Street Auburn ME 04210; Dear Mr. Linnell: This is in further reply to your letter of October 7, 1975, concernin regulations applicable to vehicles which a client of yours proposes to manufacture. A copy of your letter was forwarded to the National Highway Traffic Safety Administration (NHTSA) by the Federal Highway Administration's Bureau of Motor Carrier Safety.; The NHTSA issues Federal motor vehicle safety standards to which moto vehicles must conform. In addition, the agency requires the manufacturer to certify that the vehicle as completed complies with applicable safety standards. A pamphlet summarizing the Federal motor vehicle safety standards is enclosed, along with a copy of the regulations governing vehicle certification and an information sheet entitled 'Where to Obtain Motor Vehicle Safety Standards and Regulations.' The safety standards themselves are set forth in their entirety in Part 571 of Volume 49 of the Code of Federal Regulations.; The NHTSA also investigates safety-related defects and noncompliance with safety standards in motor vehicles and items of motor vehicle equipment. If the agency or the manufacturer determine that a safety-related defect or noncompliance exists, the manufacturer is obligated to notify the vehicle owners and remedy the problem without charge. A copy of the provisions of the National Traffic and Motor Vehicle Safety Act of 1966, as amended, which deal with the responsibilities of manufacturers for safety-related defects and noncompliances in their motor vehicles or item of vehicle equipment (15 U.S.C. SS 1411-1420) is also enclosed.; If you have any questions concerning a specific regulation or standard please write.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5423OpenMr. Karl-Heinz Ziwica General Manager Environmental Engineering BMW of North America, Inc. BMW Plaza Montvale, NJ 07645-1866; Mr. Karl-Heinz Ziwica General Manager Environmental Engineering BMW of North America Inc. BMW Plaza Montvale NJ 07645-1866; "Dear Mr. Ziwica: This responds to your request that the Nationa Highway Traffic Safety Administration (NHTSA) determine that a proposed modification to a previously approved antitheft device on the BMW 7 car line constitutes a de minimis change to the device. The proposed modification is to be effective beginning with the 1995 Model Year (MY). As explained below, the agency concludes that the proposed change to the antitheft device is not a de minimis change. In a Federal Register notice dated October 9, 1986 (51 FR 3633), NHTSA determined that the antitheft device installed as standard equipment on the MY 1988 BMW 7 car line was likely to be as effective as parts marking. In assessing whether changes are de minimis, the agency has focused its inquiry on whether the changed device would continue to provide the same aspects of performance as did the device on which the exemption was based. An example of a de minimis change is the substitution of new components for old components, without changing the aspects of performance provided by the device. NHTSA has also determined that adding a new aspect of performance, making an exempted antitheft device even more effective, while leaving the original aspects undisturbed, is a de minimis change. The change from the original BMW MY 1988 antitheft device to the one proposed for the MY 1995 BMW 7 car line does not present a simple case of either substituting new components for old, without changing the aspects of performance provided, or enhancing the effectiveness of an existing device, by adding a new aspect. Instead, the change is more complex, involving not only the addition of a new aspect (monitoring glass breakage), but also the deletion of some original aspects (monitoring the radio and glove box). The agency is uncertain about the net effect of these changes and is therefore also uncertain whether the new modified device would be at least as effective as the original device. Monitoring glass breakage might decrease the likelihood that a would-be thief would ever enter a vehicle. On the other hand, adding this aspect of performance would not necessarily enhance effectiveness of the antitheft device. If a thief were to gain access to the passenger compartment with a slim-jim or other tool, without breaking the glass, no alarm would sound, making the inside compartment vulnerable to theft. Further, no alarm would sound if the thief then tampered with the radio or glove box, individually. NHTSA believes that the necessity for making judgments about the relative effectiveness of new and removed aspects of performance, and the complexity of the issues underlying those judgments, indicate that the changes are not de minimis. Indeed, these judgments are similar to the ones that the agency must make in considering a new petition for exemption. Accordingly, if BMW wishes the planned MY 1995 device to be the basis for a theft exemption, it must submit a petition with NHTSA pursuant to 49 CFR 543.9(c)(2). Please note that the petition for modification must provide the same information or the modified device as is required under 543.6 for a new device. This includes the statement in 543.6(a)(1) that the antitheft device will be installed as standard equipment on all cars in the line for which an exemption is sought. If you have any questions, please contact Barbara Gray or Rosalind Proctor on (202) 366-1740. Sincerely, Barry Felrice Associate Administrator for Rulemaking"; |
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ID: aiam5408OpenMrs. Carmen Colet Vice President John Russo Industrial, Inc. 575 West San Carlos Street San Jose, CA 95126; Mrs. Carmen Colet Vice President John Russo Industrial Inc. 575 West San Carlos Street San Jose CA 95126; "Dear Mrs. Colet: This responds to your request for an interpretatio whether Standard No. 115, Vehicle identification number - basic requirements or any other Federal Motor Vehicle Safety Standard (FMVSS) applies to your 'aircraft rescue and fire- fighting vehicle.' As explained below, the answer is no. Your letter states that your company is constructing the vehicle 'to satisfy proposed U.S.A.F. and D.O.D.' specifications. The vehicle is made to operate on airfields. You described the unusual configuration of the vehicle as having a 'cockpit' that is 'similar to 117A Stealth Fighter,' having bumpers that are 5 feet high, and having a 'power water turret on top.' You further stated that vehicle uses tires 54 inches high and over two feet wide, that are made to be run on only for 20 minutes, at a speed of up to 65 miles per hour. Enclosed with your letter is a picture of the vehicle, which you asked be kept confidential. Although your request for confidentiality does not comply with NHTSA's regulations at 49 CFR part 512 Confidential Business Information, in order to save time, I will not publicly disclose the picture. The FMVSSs apply only to 'motor vehicles,' within the meaning of 49 U.S.C. 30102(a)(6). 'Motor vehicle' is defined at section 30102(a)(6) as: a vehicle driven or drawn by mechanical power and manufactured primarily for use on public streets, roads, and highways, but does not include a vehicle operated only on a rail line. We have interpreted this language to mean that vehicles designed and sold solely for off-road use are not considered motor vehicles, even though they may be operationally capable of highway travel. In an interpretation letter of December 28, 1979, to Walter Motor Truck Company, NHTSA determined that the Walter airport crash-fire-rescue vehicle does not qualify as a motor vehicle subject to the FMVSS. Your description of your aircraft rescue vehicle indicates that the vehicle is to be used only within an airfield. In particular, the size and 20 minute running time of the tires, appears to make the vehicle impracticable for highway use. Based on the information you have provided, and our understanding that your vehicles are neither used on public roads nor suitable for such use, we conclude that the 'aircraft rescue and fire-fighting vehicle' is not a 'motor vehicle' within the meaning of the National Traffic and Motor Vehicle Safety Act. Thus, your vehicle is not subject to Standard No. 115. Since you are not a manufacturer of a 'motor vehicle,' you do not have to furnish NHTSA with information pursuant to 49 CFR part 566 Manufacturer Identification. Enclosed with this letter is your picture of the aircraft rescue and fire- fighting vehicle. If you have any questions, please contact Dorothy Nakama of my staff at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosure"; |
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ID: aiam4630OpenMr. Victor Crisci 70 Lenox Road Wayne, NJ 07470; Mr. Victor Crisci 70 Lenox Road Wayne NJ 07470; "Dear Mr. Crisci: This is in reply to your letter of June 28, l989, t the former Chief Counsel of this agency, Erika Jones. You intend to install a 'safety light flasher' on your motorcycle, and would like to know whether it would conflict with DOT regulations. The Federal motor vehicle safety standards do not apply to vehicles in use, such as your motorcycle. Further, the National Traffic and Motor Vehicle Safety Act does not prohibit you, as the motorcycle's owner, from personally modifying your vehicle as you see fit, even if doing so adversely affects equipment or safety features installed pursuant to a Federal safety standard. (The Act does prohibit motor vehicle manufacturers, distributors, dealers and repair businesses from making such modifications if they render inoperative, wholly or partially, equipment or safety features installed in accordance with a Federal safety standard). However, modifications by an owner to his or her vehicle are subject to regulation under State and local laws applicable to vehicles in use on their roadways. We are unable to advise you whether New Jersey law specifically covers the addition of the safety light flasher. However, under the Vehicle Safety Act, any laws enacted by a state regarding motor vehicle lighting must be identical to Federal standards covering the same aspects of vehicle lighting performance. The applicable Federal regulation, as you realize, is Motor Vehicle Safety Standard No. l08, a copy of which is enclosed as you requested. As you describe the operation of the flasher, if the headlamp is on (in either beam), the flasher will flash the headlamp between upper and lower beams for 2 to 4 seconds, then returns the light to the beam it was in when the flasher was activated. If the headlamp is off, the flasher will turn it on and initiate an identical flash cycle. The sequence is initiated by pushing the horn button. Standard No. 108 would appear to preclude the installation of your device on new motorcycle, i.e., prior to its first sale to a consumer, or on a used motorcycle, if installed by one of the four entities listed above in the second paragraph. Although paragraph S5.5.10(c) of the standard provides that 'headlamps and side marker lamps may be wired to flash for signalling purposes', that section does not apply to motorcycles since they are not equipped with side marker lamps. The applicable provision for motorcycles is paragraph S5.5.10(d). This states that ' a motorcycle headlamp may be wired to allow either its upper beam or its lower beam, but not both, to modulate from a higher intensity to a lower intensity'. Your system, on the other hand, flashes between beams, which is not permissible. Moreover, motorcycle headlamp modulating systems must also comply with the requirements of paragraph S5.6, and there is no indication that your system would do so. Thus, the answer to your question is that your system would conflict with the Federal regulation applicable to motorcycle lighting if installed under the circumstances described in the preceding paragraph. However, there is nothing under Federal law that prohibits you personally from installing the device on your motorcycle. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosures"; |
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ID: aiam3481OpenMr. Donald W. Vierimaa, Director of Engineering, Truck Trailer Manufacturers Association, 2430 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. Donald W. Vierimaa Director of Engineering Truck Trailer Manufacturers Association 2430 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Vierimaa: This is in reply to your letter of October 6, 1981, asking for ou concurrence that front clearance lamps 'located at the frame level (about 50 inches above the ground) on platform trailers with permanent front bulkheads conforms with FMVSS 108.'; Clearance lamps are required by Standard No. 108 'to indicate th overall width' of a vehicle, and to be 'as near the top thereof as practicable.' As you noted, NHTSA has commented before that the indication of overall width is the primary function of clearance lamps, with a secondary purpose of indicating overall height. However, because trailers are not required to have identification lamps on their front, the secondary purpose of clearance lamps on trailers is important, especially if the top of the trailer is substantially higher than that of the truck tractor towing it.; You have stated that the top of the trailer is substantially highe than that of the truck tractor towing it.; You have stated that the top of the typical front bulkhead is 8 to feet above the ground, and the identification lamps of truck tractors are typically 10 feet above the ground. We will assume also that the tractor's clearance lamps are also typically 10 feet above the ground. You have also stated that the mounting height of truck tractor rear view mirrors and bulkhead-mounted clearance lamps are essentially the same, and that as a result 'drivers remove the bulb from the clearance lamps or place tape over the lamps.'; The determination of practicability is one that is made by th manufacturer of the trailer. NHTSA will accept a determination that mounting of clearance lamps at the top of the bulkhead is not practicable if such lamps are reflected into the driver's eyes by way of the side view mirror. But if the configuration of a trailer with a permanent front bulkhead is such that the clearance lamps may be located at the top of the bulkhead from without interfering with the vision of the truck tractor's operator, that location would appear to be 'practicable' within the meaning of Standard No. 108 and the situation your letter addresses.; 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.