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: aiam4855OpenMr. Gregory J. Vonderheide Vice President Sales Markets Unlimited Group, Inc. P.O. Box 289 Conestoga, PA 17516; Mr. Gregory J. Vonderheide Vice President Sales Markets Unlimited Group Inc. P.O. Box 289 Conestoga PA 17516; Dear Mr. Vonderheide: This responds to your letter of March 6, l99l asking for the 'application(s) necessary for the Department of Transportation approval of a new product.' The product is described only as a 'Safety Light.' The Department has no authority to approve or disapprove items of motor vehicle equipment. Pursuant to the National Traffic and Motor Vehicle Safety Act, the National Highway Traffic Safety Administration establishes the Federal motor vehicle safety standards that apply to motor vehicles and/or motor vehicle equipment, and which must be met by the manufacturers of any vehicles or equipment to which the standards apply. Unless your product is intended to replace an existing light found on motor vehicles, it would not appear to be directly covered by Standard No. 108, which establishes Federal requirements for motor vehicle lighting. If indeed it is intended as an additional light, under Standard No. 108 supplementary lighting equipment is permissible as original equipment on motor vehicles provided that it does not impair the effectiveness of lighting equipment required by the standard. Supplementary lighting equipment is also permissible under the Act for vehicles in use, provided its installation by a manufacturer, distributor, dealer, or motor vehicle repair business does not render wholly or partially inoperative any element of design or device installed in accordance with any Federal motor vehicle safety standard. Without knowing more of your device, we can provide you only this general guidance. The use of equipment on bicycles is under the authority of the Consumer Product Safety Commission, 5401 Westbard Avenue, Bethesda, Md. and we are unable to advise you of their requirements. The use of supplementary lighting equipment is also regulated by the individual States. We are unable to advise you on these laws, and suggest you consult the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, VA 22203. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam2082OpenMr. Daniel J. Wahlen, Director-Engines Engineering, Koher Company, Koher, WI 53044; Mr. Daniel J. Wahlen Director-Engines Engineering Koher Company Koher WI 53044; Dear Mr. Wahlen: This is in response to your letter of September 29, 1975, to Senato Proxmire, concerning the regulations governing the production of motor vehicles, a copy of which was referred to this office.; The National Highway Traffic Safety Administration (NHTSA) issue Federal motor vehicle safety standards to which motor vehicles must conform. In addition, the agency requires that the manufacturer 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. 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.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam2128OpenMr. James J. Schardt, Dayton Wheel Prod., Inc., 2326 E. River Road, Dayton, Ohio 45439; Mr. James J. Schardt Dayton Wheel Prod. Inc. 2326 E. River Road Dayton Ohio 45439; Dear Mr. Schardt: This is in response to your letter of August 27, 1975 (117-1) requesting an interpretation of paragraph S3 of Federal Motor Vehicle Safety Standard No. 211, *Wheel Discs, Wheel Nuts, and Hub Caps.*; Our interpretation of Standard No. 211 is that S3 prohibits winge projections that do not extend beyond the outer edge of the tire rim, as well as those that do.; We hope that this information will be of assistance. If you have an further questions, please contact us.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0115OpenMr. J. M. Wright, Assistant Sales Manager, Blaw-Knox Company, Mattoon, IL 61938; Mr. J. M. Wright Assistant Sales Manager Blaw-Knox Company Mattoon IL 61938; Dear Mr. Wright: Thank you for your letter of July 11, 1968, in which you provide certification information.; With reference to the Service Bulletin dated '4-10-68' in the secon paragraph you state that mixer units mounted at the factory will display a 'Certification of Compliance' plate. Blaw-Knox, when it is the party mounting a mixer to a chassis-cab, must insure compliance with Federal Standard No. 108 in effect on the date of manufacture of the chassis-cab, but it is required to furnish certification only when the completed vehicle is being shipped to a dealer or distributor for sale to the ultimate purchaser. No certification is required when such a purchaser brings a chassis- cab to the factory for mixer installation. With reference to the third paragraph, it is not necessary for you to supply a certification plate for mixer equipment which is shipped from the factory for mounting elsewhere. Compliance with Federal Standard No. 108 is the responsibility of the party who mounts the mixer to the chassis-cab.; Since the chassis-cab manufacturer will have provided serial numbe information sufficient to determine the requirements of Standard No. 108 in effect on the date of manufacture of the chassis-cab, it is not necessary to include the mixer serial number on the certification plate. We would suggest that you may comply with the certification requirements of Section 114 of the Act when you deliver the completed vehicle to a dealer or distributor for sale to the ultimate purchaser by wording your certification as follows:; >>>'Blaw-Knox Company certifies to the distributor or dealer that i has mounted the mixer unit to the chassis and that the completed vehicle conforms with Federal Motor Vehicle Safety Standard No. 108.'<<<; A notice of proposed rule making which will result in more specifi requirements with reference to certification will be published in the Federal Register in the near future. A copy of the notice will be sent Blaw-Knox.; Sincerely, Francis Armstrong, Director, Office of Performance Analysis Motor Vehicle Safety Performance Service; |
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ID: aiam5317OpenMs. Jane L. Dawson Specifications Engineer Thomas Built Buses, Inc. Post Office Box 2450 1408 Courtesy Road High Point, NC 27261; Ms. Jane L. Dawson Specifications Engineer Thomas Built Buses Inc. Post Office Box 2450 1408 Courtesy Road High Point NC 27261; Dear Ms Dawson: This responds to your letter to Walter Myers of thi office in which you posed two questions regarding interpretation of certain provisions of Federal Motor Vehicle Safety Standard (FMVSS) 217, Bus Window Retention and Release. Your first question related to the definition of 'daylight opening' found in the final rule amending FMVSS 217, dated November 2, 1992 (57 FR 49413) (hereinafter Final Rule). Specifically, you asked what constitutes an obstruction and how close does it have to be to the exit to be considered an obstruction. The term 'daylight opening' is defined in the Final Rule as 'the maximum unobstructed opening of an emergency exit when viewed from a direction perpendicular to the plane of the opening.' This refers to the total area of the opening, whether the door or window is open or closed. An obstruction in this context would include any obstacle or object that would block, obscure, or interfere with in any way that opening or any access thereto, as viewed from the middle aisle of the bus. For example, the seatback of a nearby seat that protrudes into the area perpendicular to the plane of the opening would constitute such an obstruction. In your second question you referred to the current provisions of S5.2.3.1(b), FMVSS 217, which provides that a left-side emergency door must be located in the rear half of the bus passenger compartment. You then asked whether that requirement was changed in the Final Rule. The answer is yes. S5.2.3.1, as amended in the Final Rule, provides manufacturers two options for the provision of school bus emergency exits, S5.2.3.1(a) (Option A) and S5.2.3.1(b) (Option B). Option A requires a rear emergency door and, in the sequence of choices for providing the additional emergency exit area, the first specifies a left side door that is required by S5.2.3.2(a)(2) to be located at the midpoint of the bus. Option B requires a left-side emergency door and a pushout rear window, but does not designate a specific location for them. Thus, the locations of exits other than the left side door specified in S5.2.3.1(a)(2)(i) are left to the various design options of the manufacturers and their customers. I hope this information will be of assistance to you. Should you have any further questions or seek additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief counsel; |
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ID: aiam3410OpenMr. J. E. Bingham, British Standards Institution, Maylands Avenue, Hemel Hempstead, Herts HP2 4SQ, England; Mr. J. E. Bingham British Standards Institution Maylands Avenue Hemel Hempstead Herts HP2 4SQ England; Dear Mr. Bingham: This responds to your letters concerning section 4.2(d) of Standard No 209, *Seat Belt Assemblies*. Section 4.2(d) provides that after seat belt webbing has been subjected to an abrasion test, it must have not less than 75 percent of the strength of the unabraded webbing set in section 4.2(b) of the standard. You pointed out that section 5.2(d) is inconsistent with section 4.2(d). As explained below, section 4.2(d) correctly states the requirement intended by the agency and section 5.2(d) needs to be corrected.; The abraded webbing strength test procedure set forth in section 5.2(d of the standard is incorrect. It specifies that the median value of the breaking strengths of the abraded and unabraded webbing are used to determine the percentage of breaking strength retained. Such a test procedure unfairly penalizes a manufacturer that produces webbing with an unabraded breaking strength far in excess of the requirements specified in section 4.2(b).; For example, section 4.2(b) specifies that Type I webbing is to have breaking strength of 6,000 pounds. Assume that the unabraded webbing has a median breaking strength of 8,000 pounds and the abraded webbing has a median breaking strength of 5,600 pounds. The median breaking strength of the abraded webbing is substantially more than 75 percent of the 6,000 pound breaking strength specified in section 4.2(b). However, the median abraded breaking strength is only 70 percent of the median unabraded breaking strength.; The agency intends to modify the standard so that the abraded webbin strength test procedure specifies that the median breaking strength of the abraded webbing is compared to the breaking strength specified in section 4.2(b) to determine the percentage of breaking strength retained.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4785OpenMr. William T. Mullen Undersheriff of McHenry County, Illinois 2200 N. Seminary Ave. Woodstock, IL 60098; Mr. William T. Mullen Undersheriff of McHenry County Illinois 2200 N. Seminary Ave. Woodstock IL 60098; "Dear Mr. Mullen: This responds to your letter asking about Federa requirements for safety belts in police cars. Specifically, you asked if your police department could legally remove the automatic belts that are installed and replace them with manual lap/shoulder safety belts. You stated that the reasons for making such a substitution would be to alleviate two problems your police officers have experienced with the automatic belts that were not present in older models that had manual lap/shoulder belts at the front seating positions. First, you said that the automatic belts result in a blind spot on the driver's left side. Second, you said that the automatic belts 'prevent left arm movements' of your taller officers. I appreciate this opportunity to respond to your concerns. I have enclosed copies of two previous letters we have written on the subject of removing or replacing occupant protection features from police cars. The first of these is a July 29, 1985 letter to Corporal Frank Browne and the other is a May 25, 1989 letter to Senator Harry Reid. These letters explain that new vehicles purchased by police departments must be certified as complying with the occupant crash protection standard (Federal Motor Vehicle Safety Standard No. 208). All cars manufactured on or after September 1, 1989 must provide automatic crash protection for front seat occupants. To date, manufacturers have provided automatic crash protection either by installing air bags or automatic safety belts. General Motors, the manufacturer of the police cars in question, has chosen to comply with the requirement for automatic crash protection by installing automatic safety belts in these cars. Federal law prohibits any manufacturer, distributor, dealer, or motor vehicle repair business from replacing the automatic belts in these police cars with manual lap/shoulder belts. Thus, none of these commercial entities could make such a replacement on behalf of the County without violating Federal law. However, Federal law does not prohibit individual vehicle owners from removing safety features from their own vehicles. Thus, McHenry County itself can replace the automatic belts in its own cars without violating any Federal law, just as any resident of McHenry County can remove any safety equipment they like from their own vehicles without violating any Federal laws. Such actions may, however, violate the laws of the State of Illinois. I recommend that you carefully consider the effects of replacing the automatic belts in your police cars, even though Federal law does not prohibit the County itself from making these modifications to its own vehicles. The automatic belts in these cars help to assure safety belt use by police officers on the job. Particularly since the McHenry County police officers face the possibility of becoming involved in high speed pursuit situations, we believe it is important that they use safety belts for effective protection in case of a crash. If you decide to replace the automatic belts in these vehicles with manual lap/shoulder belts, we would urge you to take some actions to assure that the police officers will use the manual lap/shoulder belts every time they ride in the police cars. I hope this information is helpful. If you have any further questions or need some additional information on this subject, please let me know. Sincerely, Paul Jackson Rice Chief Counsel Enclosures"; |
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ID: aiam3040OpenMr. Maurice H. Allmacher, Project Engineer, Vehicle Regulations, Volkswagen of America, Inc., 7111 East Eleven Mile Road, Warren, MI 48090; Mr. Maurice H. Allmacher Project Engineer Vehicle Regulations Volkswagen of America Inc. 7111 East Eleven Mile Road Warren MI 48090; Dear Mr. Allmacher: This is in response to your letter of June 1, 1979, regarding th provision of Uniform Tire Quality Grading (UTQG) information to vehicle first purchasers (49 CFR 575.104(d)(1)(iii)). You ask whether UTQG information must be provided to first purchasers of vehicles manufactured after the UTQG sidewall molding effective date for the type of tire used on the vehicle, if the vehicle is equipped with tires manufactured prior to the effective date.; Section 575.104(d)(1)(iii) requires that tire grading information b furnished, in the case of bias- ply tires,; >>>'...to the first purchaser of a new motor vehicle, other than motor vehicle equipped with bias-ply tires manufactured prior to October 1, 1979, ...'<<<; Thus, UTQG first purchaser information is not required for vehicle manufactured after the bias-ply sidewall molding effective date of October 1, 1979, but equipped with tires manufactured prior to that date. The regulation applies in the same manner to vehicles equipped with bias-belted and radial tires manufactured prior to April 1, 1980, and October 1, 1980, respectively.; In order to avoid confusion regarding the date of manufacture of tire installed on particular vehicles, manufacturers may choose to supply UTQG information to all first purchasers of vehicles manufactured after the effective date for sidewall molding for the tire type used as standard equipment on the vehicles.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1587OpenMr. Richard D. Henderson, Private Truck Council of America, Inc., 1101 Seventeenth Street, N.W., Washington, D.C. 20036; Mr. Richard D. Henderson Private Truck Council of America Inc. 1101 Seventeenth Street N.W. Washington D.C. 20036; Dear Mr. Henderson: This is in reply to your letters of July 25 and August 26, 1974 requesting information on NHTSA regulations applicable to regrooved tires.; You ask whether companies leasing trucks to other companies may equi the trucks with regrooved tires, and what tire standards apply.; The recent court decision regarding regrooved tires (*NAMBO* v *Volpe*, 483 F. 2d 1294 (D.C. Cir. 1973), *Cert.* *denied*,-- U.S.--(1974)) held that under the National Traffic and Motor Vehicle Safety Act the NHTSA could permit only the sale of regrooved tires. Consequently, the leasing of regrooved tires is now prohibited, as is any other introduction of them into interstate commerce other than by a sale. The NHTSA recently amended its regrooved tire regulations to conform to this Court opinion.; We do not construe the opinion to prohibit the leasing of truck equipped with regrooved tires. The regulation applies only to the manner in which the tires themselves are obtained.; The standards applicable to regrooved tires are fund in the Regroove Tire regulations (49 CFR Prt 569). Regroovable tires manufactured after March 1, 1975, must also conform to Motor Vehicle Safety Standard No. 119.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
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ID: aiam2201OpenMr. Earl C. Sievers, Finance Manager, Layton Paving Equipment Specialists, 4725 Turner Road, Salem, Oregon 97302; Mr. Earl C. Sievers Finance Manager Layton Paving Equipment Specialists 4725 Turner Road Salem Oregon 97302; Dear Mr. Sievers: This is in response to your letter of January 14, 1976, asking whethe your company's paver product must comply with the requirements of Federal motor vehicle safety standards and regulations, particularly Standards No. 119 and 120.; The National Highway Traffic Safety Administration (NHTSA) issue safety standards and regulations for 'motor vehicles.' Section 102(3) of the National Traffic and Motor Vehicle Safety Act defines a motor vehicle as a vehicle 'manufactured primarily for use on the public streets, roads, and highways.' Thus, a motor vehicle is a vehicle which the manufacturer expects will use public highways as part of its intended function. The primary Function of some vehicles is of a mobile, work-performing nature, and, as such, their manufacturer contemplates a primary use of the highway. Mobile cranes, rigs, and towed equipment such as chippers and pull-type street sweepers that travel at a normal highway speed are examples in this area. These motor vehicles qualify as trucks or trailers. As such they are subject to the Federal motor vehicle safety standards and regulations. On the basis of the information you have sent us your company's towed paver appears to be in this category of vehicles, and would therefore be considered a 'motor vehicle.'; There are some vehicles which are excepted from the motor vehicl classification despite their use on the highway. Highway maintenance and construction equipment, lane strippers, *self-propelled* asphalt pavers, and other vehicles whose maximum speed does not exceed 20 mph and whose abnormal configuration distinguished them from the traffic flow are not considered motor vehicles. Your company's paver would not appear to qualify in this category of vehicles since, as a towed paver, it would travel at a speed greater than 20 mph, at least when moving between job sites.; Consequently, your product must comply with the requirements of th Federal standards and regulations. Standard No. 119, *New Pneumatic Tires for Vehicles Other than Passenger Cars*, does not directly impose any duty on you, because it applies to tires rather than vehicles. However, the NHTSA has recently issued Federal Motor Vehicle Safety Standard No. 120, *Tire Selection and Rims for Vehicles Other Than Passenger Cars* (copy enclosed). This standard does require, effective September 1, 1976, that your vehicles be equipped with tires that conform to Standard No. 119 and are of sufficient load rating.; In addition to compliance with the safety standards and regulations you must ensure that your product does not contain a defect relating to motor vehicle safety. Vehicles containing such defects are subject to the notification, remedy, and civil penalty provisions of the National Traffic and Motor Vehicle Safety Act. For example, a vehicle equipped with tires that are designed for speed-restricted use would probably be considered to contain a safety-related defect if the vehicle is expected to travel at higher speeds.; Please contact us if we can be of any further assistance. Yours truly, Richard B. Dyson, Assistant 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.