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: aiam2599OpenMr. R.G. Wilkins, Product Safety & Reliability Analyst, Grove Manufacturing Company, Shady Grove, Pennsylvania 17256; Mr. R.G. Wilkins Product Safety & Reliability Analyst Grove Manufacturing Company Shady Grove Pennsylvania 17256; Dear mr. Wilkins: This responds to your February 17, 1977, letter, concerning Nationa Highway Traffic Safety Administration's (NHTSA) tire labeling requirements contained in Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*. You address the situation in which it is not practicable to affix the information label to the door.; Location of vehicle certification labels and tire information labels i governed by Part 567.4(c). This section provides that the primary location of the required labels is either the hinge pillar, door-latch post, or door edge that meet the door-latch post, next to the drivers seating position, or if none of these locations is practicable, to the left side of the instrument panel. Further, if none of the above locations is practicable, you may request an alternate location from the agency. I am enclosing a copy of Part 567 explaining how to request an alternate location for the information label.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam2433OpenMr. James M. Kommers, P.O. Box 1, Gallatin Block-40 E. Main, Bozeman, MT 59715; Mr. James M. Kommers P.O. Box 1 Gallatin Block-40 E. Main Bozeman MT 59715; Dear Mr. Kommers: This is in response to your letter of October 12, 1976, requestin information concerning the application of Federal standards to bumper systems produced as after-market replacement equipment.; Standard No. 215, *Exterior Protection*, is a motor vehicle safet standard that applies to the performance of bumper systems on cars manufactured after certain dates. The requirements of the standard are not imposed on the manufacturers of bumpers as items of equipment. It is the manufacturer of the car who must certify the compliance of the bumper system with the provisions of Standard 215. Therefore the bumpers manufactured by Mr. Coddou do not fall within the application of the standard.; Section 108 of the National Traffic and Motor Vehicle Safety Act (Pub L. 89-563), as amended (Pub. L. 93-492), prohibits any manufacturer, distributor, dealer, or motor vehicle repair business from knowingly rendering inoperative any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with a motor vehicle safety standard. Thus, even though a replacement bumper is not required to meet the requirements of Standard 215 when it is produced or sold, its installation on a car by one of the above-named persons would invoke the application of section 108 of the Act. With the bumper installed, the car must comply either with the particular safety standard in effect at the time of its manufacture or with the standard in effect at the time the bumper is replaced.; Due to the requirements of section 108 it would be advisable for Mr Coddou to manufacture his bumpers so that they are capable of meeting the requirements of the applicable Federal bumper standard.; Mr. Coddou should note that although Standard 215 is currentl applicable to all passenger cars, a new and more stringent bumper standard, 49 CFR Part 581, *Bumper Standard*, will become effective September 1, 1978. Part 581 is promulgated under the authority of both the National Traffic and Vehicle Safety Act and the Motor Vehicle Information and Cost Savings Act (Pub. L. 92-513) and will supplant Standard 215 when it becomes effective. I have enclosed copies of both Standard 215 and Part 581 for Mr. Coddou's information.; Sincerely, John Womack, Assistant Chief Counsel |
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ID: aiam3672OpenThe Honorable David L. Boren, United States Senate, Washington, DC 20510; The Honorable David L. Boren United States Senate Washington DC 20510; Dear Senator Boren: This responds to your recent letter requesting information on behalf o one of your constituents, Mr. John H. Kiser. Mr. Kiser is concerned about the growing practice of persons installing privacy glass' or one-way plastic films' on passenger car windows. He believes this is a dangerous practice because it prevents law enforcement officers and other drivers from seeing inside the vehicles. Mr. Kiser thinks there should be Federal laws to prevent such installations in passenger cars.; A Federal regulation already exists which, under certain circumstances precludes the practice referred to by Mr. Kiser. The National Highway Traffic Safety Administration has the authority to govern the manufacture of new motor vehicles and motor vehicle equipment. Pursuant to the National Traffic and Motor Vehicle Safety Act, we have promulgated Federal Motor Vehicle Safety Standard No. 205, *Glazing Materials*, which specifies performance and location requirements for glazing used in vehicles. These requirements include specifications for minimum levels of light transmittance (70 percent in areas requisite for driving visibility, which includes all windows in passenger cars) and abrasion resistance. This specification for light transmittance precludes darkly-tinted windows in new automobiles.; The agency has stated in past interpretations that solar films such a the type referred to in Mr. Kiser's letter are not glazing materials themselves, and would not have to comply with Standard No. 205. However, installation of such films on new motor vehicles would be prohibited if the vehicle glazing no longer complied with the light transmittance or abrasion requirements of the standard. If a vehicle manufacturer or a dealer places the film on glazing in a vehicle prior to sale of the vehicle, that manufacturer or dealer has to certify that the glazing continues to be in compliance with the requirements of Standard No. 205. Section 108(a)(1) prohibits any person from offering for sale or selling any motor vehicle or equipment that fails to comply with applicable safety standards.; After a new vehicle has been sold to the consumer, he may alter hi vehicle as he pleases, so long as he adheres to all State requirements. Under Federal law, the owner could install the tinting film on glazing in his vehicle whether or not such installation adversely affected the light transmittance and abrasion resistance of his vehicle's glazing. It should be noted, however, that section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act provides that no manufacturer, distributor, dealer or motor vehicle repair business shall knowingly render inoperative any device or element of design installed on or in a motor vehicle in compliance with an applicable motor vehicle safety standard. Render inoperative' means to remove, disconnect or degrade the performance of a system or element of design installed pursuant to the Federal safety standards. Thus, none of those persons may knowingly install a solar film on a vehicle for its owner if that act would render inoperative the light transmittance or abrasion resistance of the vehicle glazing. Whether this would be the case would have to be determined by the person making the installation. Violation of this section can result in Federal civil penalties up to $1,000 for each violation.; The preceding discussion regarding tinting films would be equall applicable to one-way privacy glass,' if such glass did not have a luminous transmittance of at least 70 percent. This means that such glass could not be installed by a dealer on new passenger cars prior to their first sale, nor by the persons mentioned in section 108(a)(2)(A), on used vehicles, to replace complying glazing.; The individual States must govern the operational use of vehicles b their owners since the agency does not have authority in this area. Thus, it would be up to the States to preclude owners from applying films or one-way glass on their own vehicles. Mr. Kiser may wish to contact the National Committee on Uniform Traffic Laws (555 Clark Street, Evanston, Illinois 60204) to find out which States have laws that would preclude owners from placing solar film on their automobile windows.; I am enclosing a copy of Safety Standard No. 205 for Mr. Kiser' information. Please contact Hugh Oates of my staff if you have any further questions (202-426-2992).; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2960OpenMr. Charles J. Calvin, President, Truck Trailer Manufacturers Association, 2430 Pennsylvania Avenue, N.W., Washington, DC 20037; Mr. Charles J. Calvin President Truck Trailer Manufacturers Association 2430 Pennsylvania Avenue N.W. Washington DC 20037; Dear Mr. Calvin: We regret the delay in responding to your April 18, 1978, lette criticizing the National Highway Traffic Safety Administration's (NHTSA) interpretation concerning the responsibility of a manufacturer for ensuring that its vehicles will not be overloaded when transporting materials for which they are designed. In that interpretation, the agency indicated that a vehicle whose tank cargo volume is of such size that it misrepresents the assigned GVWR and GAWR values of that vehicle, thus, inviting overloading might be considered to have a safety related defect. Please permit me to qualify the interpretation in the light of your criticism.; The NHTSA realizes that overloading is a problem created for the mos part by the operator of a vehicle. Accordingly, it is not intended by the agency's interpretation or regulations to hold a vehicle manufacturer responsible for every situation in which a vehicle is overloaded. Most any type truck can be overloaded by the user. An operator should be aware of this possibility, however, given the amount of space on that vehicle on which cargo can be loaded and the broad range of cargo that can be transported by that vehicle. If a truck designed for the transportation of one specific cargo were misused by the operator to transport another type of cargo not intended by the vehicle manufacturer, then any resultant overloading would be the responsibility of the operator not of the manufacturer. However, when a vehicle designed to transport a specific cargo can be overloaded when filled to its capacity with that cargo, the NHTSA has determined this to be a problem created by the vehicle manufacturer and would consider taking action against a manufacturer to correct the problem. This agency's interpretation that a vehicle be able to safely transport its intended design cargo when fully loaded is an objective and unambiguous requirement and simply places the burden upon a manufacturer to ensure that the design cargo does not exceed the GAWR and GVWR.; Specifically we are concerned that a tank of fixed volumetric capacit could be loaded to exceed the vehicle's GAWR and GVWR values when filled with a commodity of design density simply because of the tank being too large.; When there is reason to believe that the density of a cargo likely t be transported could present a vehicle overloading problem, the manufacturer has a duty to provide a warning and information as a precaution in averting the potential hazard. The NHTSA does not object to the practice of partial loading of tankers and tank compartments for remaining within safe loading limits provided guidelines are furnished by manufacturers for performing approved loading operations. Prescribed precautions hopefully will counteract any tendency to perceive volume as the load limiting criterion. We would agree that loading information as contained in your enclosure would be a satisfactory means of conveying safety information and could be referenced on a conspicuous vehicle label.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam3388OpenNeal J. Patten, Esq., Messrs. Patten & Wornom, P.O. Box 725, Newport News, Virginia 23607; Neal J. Patten Esq. Messrs. Patten & Wornom P.O. Box 725 Newport News Virginia 23607; Dear Mr. Patten: This replies to your letter of December 23, 1980 to the General counse asking if the 'Cool Gear' motorcycle helmet 'has been certified by the Department and whether or not it has met the Z-90.1 1973 standards'.; The Department does not certify motor vehicles or equipment and has n knowledge of whether the Cool Gear meets the Z-90.1 11973 standards.; Any 'Cool Gear' motorcycle helmet that fits head form size C i required, however, to comply with 49 CFR 571.218 (Motor Vehicle Safety Standard No. 218), which incorporates the essence of the Z-90.1 1971 standards, and to bear the manufacturer's own certification of compliance (see paragraph S5.6.1(5), and 15 U.S.C. 1403). The agency has not tested any 'Cool Gear' for compliance with Standard No. 218.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3222OpenMr. William A. Bertolini, President, Bertolini Engineering Co., Inc., Star Route One, Vernon, NJ 07462; Mr. William A. Bertolini President Bertolini Engineering Co. Inc. Star Route One Vernon NJ 07462; Dear Mr. Bertolini: This is in reply to your letter of February 22, 1980, asking for a interpretation of Federal Motor Vehicle Safety Standard No. 108.; You have referenced our letter of May 5, 1977, to Mr. Dennis Moore o Dry Launch. That letter interpreted S4.3.1.1.1 with respect to a rear clearance lamp which indicated overall width though it was not located on the rear of the trailer. In that position it was not required to be visible at 45 degrees inboard. You have asked whether the same inboard visibility requirements may be eliminated for front clearance lamps 'for the same reasons'.; The answer is yes. If a front clearance lamp that indicates overal width is not located at the front of the trailer, S4.3.1.1.1 relieves it of the requirement that it be visible at 45 degrees inboard.; I hope this answers your question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam3808OpenMr. Don Gerken, Senior Product Engineer, Research and Development, COSCO, 2525 State Street, Columbus, IN 47201; Mr. Don Gerken Senior Product Engineer Research and Development COSCO 2525 State Street Columbus IN 47201; Dear Mr. Gerken: This responds to your letter asking for an interpretation of Safet Standard No. 213, *Child Restraint Systems* (49 CFR S 571.213). Specifically, you noted that your company would like to begin producing a child restraint system with a new shield design. The new shield would be substantially smaller than the shield your company currently uses. You noted that this type of shield is already being sold by other companies, and that in your restraint, the harness system, but not the shelf-like shield, would restrain the child's forward movement. A system with that characteristic would not comply with Standard No. 213.; Section S5.2.2.2 of Standard No. 213 specifies that no fixed or movabl surface shall be in front of the child, except surfaces which restrain the child. Since your proposed new shield does not restrain the child, it is expressly prohibited from being mounted on the child restraint.; Even assuming that the proposed new shield did act to restrain th child, there is still a question of whether the shield would comply with section S5.2.2.1(c), since your drawing does not indicate which portions of the shield would restrain a child's torso and thus would need to comply with the 2-inch radius of curvature requirement.; At this time, the Enforcement Division of this agency has severa investigations pending concerning potential violations of the standard by firms using shields along the lines of the shield you propose. These investigations focus primarily on whether such shields satisfy the 2-inch radius of curvature requirement of section S5.2.2.1(c) of Standard No. 213.; Please do not hesitate to contact me if you need further information o have further questions on this matter.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1835OpenMr. Donald W. Taylor, Volvo of America Corp., Rockleigh, NJ 07647; Mr. Donald W. Taylor Volvo of America Corp. Rockleigh NJ 07647; Dear Mr. Taylor: This responds to Volvo of America Corporations's (sic) March 3, 1975 question whether a braking system which employs air pressure modulated by the vehicle operator to provide the energy used to actuate the brakes is an air brake system subject to Standard No. 121, *Air brake systems*.; The answer to this question is yes. We do not agree that such a syste could qualify as a hydraulic brake system under the definition found in Standard No. 105-75, *Hydraulic brake systems*. That definition requires that a hydraulic brake system employ hydraulic fluid as a medium for transmitting force 'from a service brake control to the service brake', which is not the case in the system you describe. The system in question appears to be what is popularly known as an 'air over hydraulic' system. With regard to such systems, NHTSA has stated in a preamble to the air brake standard: 'It should be noted that the term 'air brake system' as defined in this standard applies to the brake configuration commonly referred to as 'air over hydraulic,' in which failure of either medium can result in complete loss of braking ability.' (36 FR 3817, February 27, 1971).; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0727OpenMr. W. G. Milby, Project Engineer, Blue Bird Body Company, Fort Valley, GA, 31030; Mr. W. G. Milby Project Engineer Blue Bird Body Company Fort Valley GA 31030; Dear Mr. Milby: This is in reply to your letter of May 9, 1972, inquiring whethe temporary covering which is used to prevent soiling of upholstery during production, transportation, and sales demonstration must meet the requirements of Standard No. 302.; Whether the material must comply with the standard dependsupon (sic whether it is likely to be used in a significant number of cases by the purchaser as part of the motor vehicle. You have stated that the purpose of the material is to 'prevent soiling during production, transportation, and sales demonstrations.' It is important that this intent be carried out in practice, if the material is not to be considered vehicle interior material subject to the standard. Two criteria which would be considered in determining whether the material is covered by the standard are (1) whether it is placed in the vehicle in a way that its use after purchase is unlikely, and (2) what steps the manufacturer has taken to see that it is removed before sale to the purchaser. If Blue Bird does take steps to ensure that the material will not be used as a seat cover by the purchaser, then the material would not be required to conform to the standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5525OpenMs. Merridy R. Gottlieb 4 Duchess Court Baltimore, MD 21237; Ms. Merridy R. Gottlieb 4 Duchess Court Baltimore MD 21237; Dear Ms. Gottlieb: This responds to your letter of February 14, 1995 requesting an 'exemption' from the National Highway Traffic Safety Administration (NHTSA) to allow a business to modify your motor vehicle. Your letter states: I am disabled and need 3-4' of additional room for the passenger seat to allow my legs to straighten on long trips. I have two replaced hips and arthritis in my knees. If I leave my legs slightly bent for long periods of time, I suffer too much pain to be active at the end of the drive. By allowing my legs to straighten all the way out, there is no pain at all. You state that you were told that this modification cannot be done as it would 'interfere with the functionality of the air bag.' In summary, our answer is that you may have your vehicle modified. NHTSA will not institute enforcement proceedings against a repair business that modifies the seat on your vehicle to accommodate your condition. A more detailed answer to your letter is provided below. I would like to begin by clarifying that there is no procedure by which persons petition for and are granted an exemption from NHTSA to have a motor vehicle repair business modify their motor vehicle. Repair businesses are permitted to modify vehicles without obtaining permission from NHTSA to do so, but are subject to certain regulatory limits on the type of modifications they may make. In certain limited situations, we have exercised our discretion in enforcing our requirements to provide some allowances to a repair business which cannot conform to our requirements when making modifications to accommodate the special needs of persons with disabilities. Since your situation is among those given special consideration by NHTSA, this letter should provide you with the relief you seek. Our agency is authorized to issue Federal Motor Vehicle Safety Standards (FMVSS) that set performance requirements for new motor vehicles and items of motor vehicle equipment. Manufacturers are required to certify that their products conform to our safety standards before they can be offered for sale. Manufacturers, distributors, dealers, and repair businesses are prohibited from 'knowingly making inoperative' any device or element of design installed on or in a motor vehicle in compliance with an applicable FMVSS. In general, the 'make inoperative' prohibition would require repair businesses which modify motor vehicles to ensure that they do not remove, disconnect, or degrade the performance of safety equipment installed in compliance with an applicable FMVSS. Violations of this prohibition are punishable by civil fines up to $1,000 per violation. Moving a seat could affect compliance with Standard No. 208, Occupant Crash Protection. Standard No. 208 sets forth requirements for occupant protection at the various seating positions in a vehicles. Standard No. 208 requires that cars be equipped with automatic crash protection at the front outboard seating positions. Automatic crash protection systems protect their occupants by means that require no action by vehicle occupants. Compliance with the automatic crash protection requirements of Standard No. 208 is determined in a dynamic crash test. That is, a vehicle must comply with specified injury criteria, as measured on a test dummy, in a 30 mph barrier crash test. The two types of automatic crash protection currently offered are automatic safety belts (which help to assure belt use) and air bags (which supplement safety belts and offer some protection even when safety belts are not used). Based on the information in your letter, it appears that the manufacturer of your vehicle installed air bags as the means of complying with Standard No. 208's requirement. Your modifier is concerned that the modification of the seat would 'make inoperative' the air bag. I would like to note that accident data would suggest that a person is at greater risk of injury from an air bag from sitting too close to the air bag, rather than further away from the air bag. However, I understand that, due to the dynamic testing requirement, the modifier will be unable to ensure that the vehicle continues to comply with Standard No. 208's requirements. In situations such as yours where a vehicle must be modified to accommodate the needs of a particular disability, we have been willing to consider any violations of the 'make inoperative' prohibition a purely technical one justified by public need. As I have already noted above, NHTSA will not institute enforcement proceedings against a repair business that modifies the seat on your vehicle to accommodate your condition. We caution, however, that only necessary modifications should be made to the seat, and the person making the modifications should consider the possible safety consequences of the modifications. For example, in moving a seat, it is critical that the modifier ensure that the seat is solidly anchored in its new location. You should also be aware that an occupant of a seat which has been moved rearward may have less protection in a crash if the seat is too far rearward relative to the anchorages of the safety belts for that seat. Finally, if you sell your vehicle, we encourage you to advise the purchaser of the modifications. I hope this information has been helpful. If you have any other questions or need some additional information in this area, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel; |
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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.