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: aiam1042OpenMr. John W. Griffin, Sr., 109 Lakemont Drive, Augusta, GA; Mr. John W. Griffin Sr. 109 Lakemont Drive Augusta GA; Dear Mr. Griffin: This is in response to your letter of February 27, 1973, concerning th effective date of the new Federal odometer law.; The provisions of the law (Public Law 92- 513) went into effect o January 18, 1973, with the exception of the disclosure requirements, which were implemented by regulations adopted by this agency effective March 1, 1973.; The regional office of the National Highway Traffic Safet Administration nearest to you is in Atlanta. The address is Lawrence E. Thompson, Regional Administrator, NHTSA, Suite 400, 1720 Peachtree Road, N.W., Atlanta (sic) Georgia 30309.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5001OpenMs. Anne Volmerange 11041 Vena Ave. Mission Hills, CA 91345; Ms. Anne Volmerange 11041 Vena Ave. Mission Hills CA 91345; "Dear Ms. Volmerange: I have been asked to respond to your letter t Mr. Clarke Harper of our Rulemaking division. Your letter requests authorization from NHTSA to replace the automatic two point shoulder belt installed in your vehicle with a manual lap/shoulder belt. I am pleased to have this opportunity to explain our law and regulations to you. The National Traffic and Motor Vehicle Safety Act (the Safety Act, 15 U.S.C. 1381 et seq.) authorizes this agency to issue Federal motor vehicle safety standards applicable to new motor vehicles and new items of motor vehicle equipment. NHTSA has exercised this authority to establish Standard No. 208, Occupant Crash Protection (49 CFR 571.208). Standard No. 208 sets forth requirements for safety belt installation in all vehicle types. In addition, S4.1.4.1 of Standard No. 208 provides that passenger cars manufactured on or after September 1, 1989 must be equipped with automatic crash protection. Vehicles equipped with automatic crash protection 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, when tested by this agency in a 30 mph barrier crash test. At this time, manufacturers are not required to use a specific design of automatic crash protection to meet the requirements of Standard No. 208. Instead, each automobile manufacturer is allowed to select the particular design for the automatic crash protection installed in its vehicles. The two types of automatic crash protection currently offered on new passenger cars 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). There are several different designs of automatic belts available, and many manufacturers are installing air bags accompanied by conventional manual lap/shoulder safety belts. Based on your description, it appears that the manufacturer of your vehicle has chosen to install diagonal automatic shoulder belts at the front outboard seating positions. The manufacturer has certified that, in a 30 mph frontal crash into a concrete barrier, a test dummy restrained only by the automatic belt in your car would not experience injury-producing forces in excess of the levels specified in Standard No. 208. After a vehicle equipped with automatic crash protection has been sold to a retail purchaser, such as yourself, the provision in Federal law that affects modifications to the automatic crash protection system is section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section provides that: No manufacturer, distributor, dealer, or motor vehicle repair business shall knowingly render inoperative, in whole or in part, any device or element of design installed on or in a motor vehicle ... in compliance with an applicable Federal motor vehicle safety standard. With regard to your vehicle, the automatic safety belts are a 'device or element of design installed in a motor vehicle in compliance with an applicable Federal motor vehicle safety standard.' Removal of the automatic belts would render them inoperative. Therefore, Federal law prohibits your dealer, any other dealer, and any manufacturer, distributor, or motor vehicle repair business from removing the existing automatic belts in your car and replacing them with manual belts. Please note that this Federal prohibition does not prevent you from removing the automatic belts from your own car. However, we encourage vehicle owners not to tamper with the occupant protection systems installed in their vehicles. If you were to remove the automatic belts yourself and improperly install manual belts, you would be putting yourself and other vehicle occupants at substantially greater risk of injury in a crash. I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0203OpenMr. C. L. Eshelman, President, Eshelman, Inc., 621 N.E. 30th Terrace, Miami, FL 33137; Mr. C. L. Eshelman President Eshelman Inc. 621 N.E. 30th Terrace Miami FL 33137; >>>Re: Consumer Information--Certification--Distributons (sic)<<< Dear Mr. Eshelman: This is in reply to your letter of December 20, 1969, in which yo responded to our inquiry concerning consumer information on vehicles sold by your company.; You stated that your Golden Eagle cars are 'made from new mode Chevrolets without any mechanical change,' and that the 'consumer information and the warranty book as supplied by General Motors are passed along to the consumer with the vehicle.' You also stated that you place a label next to the GM certification label, quoting language similar to that specified in the Certification Regulations for the distributor who alters a vehicle, 49 CFR S. 367.6. We are enclosing a copy of the Certification Regulations: please note that the abovementioned distributor statement, if it is applicable, requires that month and year of alteration to be stated immediately after the name of the distributor.; The question whether the procedure you have outlined in respect t certification is acceptable depends on whether the alterations that you perform on the Chevrolets are sufficiently minor to place you in the category of 'distributor' rather than 'manufacturer'. In order to make this determination, we need and would like to receive more detailed information on the work that you do on the vehicles.; The question whether the practice you describe, of passing on th General Motors consumer information, is acceptable depends on whether the information, is acceptable depends on whether the information is actually correct for the vehicles as you alter them. The weight of the final vehicle, for example, is an important factor in the vehicle's performance in all three areas of acceleration, braking, and tire reserve load. We should mention that you are fully responsible, subject to the penalties specified in section 109 of the National Traffic and Motor Vehicle Safety Act, for ensuring that the correctness of the consumer information that you provide with your vehicles is not adversely affected by the work that you do on them, whether you are ultimately paced in the category of manufacturer or distributor.; We are pleased to be of assistance. Sincerely, Lawrence R. Schneider, Assistant Chief Counsel fo Regulations; |
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ID: aiam2394OpenMr. Bing Johnson, 135 Jade Cove Drive, Roswell, GA 30075; Mr. Bing Johnson 135 Jade Cove Drive Roswell GA 30075; Dear Mr. Johnson: This is in response to your letter of August 16, 1976, in which you as about our regulations concerning the modification of 'vans' to make them suitable for camping. The modifications you propose to make include the installation of plumbing, water, electricity, and additional seating.; The National Traffic and Motor Vehicle Safety Act (15 U.S.C. SS 1381 *et seq*.) prohibits the manufacture, offer for sale, sale, introduction in interstate commerce or importation of a motor vehicle that does not comply with all applicable standards in effect on the date of its manufacture. This prohibition does not apply (except for importation) after the first purchase of the vehicle in good faith for purposes other than resale. Under these provisions, you are responsible for the compliance of any vehicle that you modify up to and including the time of first purchase for purposes other than resale.; The manufacturer must comply with all applicable safety standard established by the National Highway Traffic Safety Administration (NHTSA). His certification appears on a completed vehicle. It would be your responsibility to ensure that the vehicle continues to comply with all applicable safety standards after your modifications. Under Part 567 of our regulations, you must attach a label to the vehicle that states that, as altered, the vehicle continued to conform to the standards.; From the description of the modifications you describe, it appears tha you might affect the compliance of the vehicle with the following standards: Standard No. 207, *Seating Systems*, Standard No. 208, *Occupant Crash Protection*, Standard No. 210, *Seat Belt Assembly Anchorages*, and Standard No. 302, *Flammability of Interior Materials*. It should be noted that any additional weight created by your modifications or a change in the distribution of weight could also affect the vehicle's compliance with other safety standards whose test procedures require a barrier crash test.; We also would point out that if you modify a Ford 'Econoline' in al probability you would change the vehicle classification from a truck to a multipurpose passenger vehicle. This should be noted on the certification label that you attach to the vehicle.; I have enclosed an information sheet that explains where you may obtai copies of these regulations.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam5451OpenMr. Joe Kover 463 West Creekside Lane Kaysville, UT 84037; Mr. Joe Kover 463 West Creekside Lane Kaysville UT 84037; Dear Mr. Kover: This responds to your letter of July 25, 1994, to Jer Medlin of this agency. You have presented several questions regarding an electric circuit that you have designed for use in motor vehicles, and which you call a Light Control Unit (LCU). The LCU automatically turns off the headlamps and tail and parking lamps when the ignition is turned off if the lamps have been activated. The LCU also automatically turns on the headlamps and the tail and parking lamps whenever the windshield wipers are turned on. If the LCU fails when the lights are on, a Light Bus Monitor will automatically restore them. You have the following questions: 'Would a motor vehicle operator be in violation of the federal motor vehicle safety standards by maintaining both the head and tail/park lights on during the hours of daylight?' No. The Federal motor vehicle safety standards do not tell an owner when it is or is not permissible to use safety equipment. 'Does the LCU meet the federal motor vehicle safety standards? Could the LCU be integrated into the light system of new production vehicles or currently registered vehicles,' The Federal motor vehicle safety standard on lighting, Standard No. 108, does not apply to supplementary lighting devices such as the LCU. The LCU is permissible on new vehicles provided it does not impair the effectiveness of lighting equipment required by the standard. We do not see that it has this effect. It is permissible to be installed on currently registered vehicles by manufacturers, distributors, dealers or motor vehicle repair businesses provided that it does not make inoperable any part installed in accordance with a Federal motor vehicle safety standard. We do not see that the LCU has this effect either. You have also told us that the LCU may be used to operate lamps as Daytime Running Lamps (DRLs) by maintaining the light switch in the on position when the wiper switch has been turned off. One feature of this function is that the LCU 'allows the operator to turn off either the head lights only or both the head lights and tail/park lights via the light switch.' Your question is 'If the operator should elect to employ the LCU as a DRL unit does it meet the federal motor vehicle safety standards?' Under Standard No. 108, a DRL system is a system of any pair of lamps on the front of a vehicle (other than parking lamps or fog lamps) that is automatically activated and that is automatically deactivated when the operator places the headlamp control in the on position. Further, DRLs can be lower beam headlamps operated at full voltage. Assuming that the LCU turns the lower beam headlamps on rather than the upper beam ones, your system would function as a DRL meeting the requirements of Standard No. 108 when the lower beam headlamps are automatically activated by the windshield wipers and deactivated by turning off the ignition. However, the feature that allows the headlamps to be turned off manually (whether or not simultaneously turning off the parking lamps and taillamps) is not part of a DRL system as specified by Standard No. 108. Your final request is that we 'include the federal specifications for electronic devices.' We are unsure what you mean by this as we have no 'specifications for electronic devices.' I enclose a copy of S5.5.11 of Standard No. 108, the DRL specifications. Sincerely, Philip R. Recht Chief Counsel Enclosure; |
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ID: aiam0653OpenMr. Heinz W. Gerth, Assistant Vice President, Mercedes-Benz of North America, Inc., 158 Linwood Plaza, Fort Lee, NJ 07028; Mr. Heinz W. Gerth Assistant Vice President Mercedes-Benz of North America Inc. 158 Linwood Plaza Fort Lee NJ 07028; Dear Mr. Gerth:#On November 9, 1971, you wrote concerning th requirement in Standard No. 101 that a control be provided to adjust the intensity of control illumination, continuously variable from an 'off' position to a position providing illumination sufficient for the vehicle operator to readily identify controls under conditions of reduced visibility. You asked an interpretation that 'the term 'off' means a control position which provides minimal control illumination which is not distracting to the driver who has adapted to dark ambient roadway conditions.'#In our opinion, the word 'off' means a control position providing no illumination, and we therefore do not concur in your interpretation. You have asked, however, as an alternative, that your letter be considered as a petition for rulemaking to amend Standard No. 101 to provide an option permitting the type of control already incorporated in Mercedes-Benz vehicles.' We have tentatively determined that your petition has merit, and that quantitative levels for control illumination intensity should be established in Standard No. 101. We shall therefore initiate appropriate rulemaking with a proposed effective date of September 1, 1973.#Sincerely, Douglas W. Toms, Administrator; |
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ID: aiam1941OpenMr. Donald W. Taylor, Manager, Product Safety & Quality, Volvo of America Corporation, Rockleigh, NJ 07647; Mr. Donald W. Taylor Manager Product Safety & Quality Volvo of America Corporation Rockleigh NJ 07647; Dear Mr. Taylor: This responds to Volvo of America Corporation's May 9, 1975, reques for reconsideration of the NHTSA's March 31, 1975, determination that a Volvo brake system that 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*.; Having reviewed all of the data submitted with your letter, it i concluded that the Volvo system is an air brake system subject to Standard No. 121. In the development of separate air brake and hydraulic brake system standards, the NHTSA had to make a determination of the status of brake systems which employ both air and hydraulic fluid as a means of transmitting force to the vehicle brakes. The agency decided that use of air as a means of power and transmission of the brake force would qualify the system as an air brake system. This decision permits manufacturers to determine with certainty whether a standard applies to their products.; Since the withdrawal of applicability to trucks of Standard No. 105-75 *Hydraulic brake systems*, our decision has had the beneficial effect of ensuring that 'air over hydraulic' systems are subject to a braking standard. If you are aware of any adverse safety consequences of our decision, I would appreciate hearing from you.; Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam0346OpenMr. Marvin S. Wright, Transportation and Distribution Department, Boise Cascade Corporation, P.O. Box 7757, Boise, ID 83707; Mr. Marvin S. Wright Transportation and Distribution Department Boise Cascade Corporation P.O. Box 7757 Boise ID 83707; Dear Mr. Wright: This is in reply to your letter of April 29, to Mr. Charles West, o the subject of air brake systems on mobile structure trailers. The standard to which you refer does not require air brakes to be installed on trailers, as your associates seem to fear. However, if your company decides on its own initiative to install air brakes on its mobile structure trailers, such brakes must conform to the air brake standard if the trailer is built on or after the effective date of the standard, January 1, 1973.; Please advise us if further clarification is needed. Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam5144OpenMr. L. J. Sharman 314 Lakeside Drive South Surfside Beach, SC 29575; Mr. L. J. Sharman 314 Lakeside Drive South Surfside Beach SC 29575; "Dear Mr. Sharman: This responds to your letter of November 18, 1992 regarding the test procedure in Standard No. 302, Flammability of Interior Materials. Your questions and the answer to each follows. Question 1. MVSS-302, in Section S5.3(e), states that the timing for each specimen be started when the flame from the burning specimen reaches a point 1.5 inches from the open end of the specimen and, in Section S5.3(f), is stopped when the flame progresses to a point 1.5 inches from the clamped end of the specimen. Further, the Standard, in Section S5.2.2, states the specimen is oriented so that the surface closest to the occupant compartment air space faces downward on the test frame. The question that has been raised is whether the timing is started and stopped when the flame reaches the designated points on the surface of the specimen closest to the occupant compartment air space (the surface facing down during the test), or when the flame reaches the designated points on the surface of the specimen facing away from the occupant compartment air space (the surface facing up during the test). You suggest that the timing should be started and stopped when the flame reaches the designated points on the surface facing up during the test. As explained below, NHTSA disagrees. Section S4.3(a) of Standard No. 302 states: When tested in accordance with S5, material described in S4.1 and S4.2 shall not burn, nor transmit a flame front across its surface, at a rate of more than 4 inches per minute. However, the requirement concerning transmission of a flame front shall not apply to a surface created by the cutting of a test specimen for purposes of testing pursuant to S5. Any surface not created by the cutting of the test specimen, including the surface oriented downward pursuant to S5.2.2, is required to comply with the burn-rate requirement of S4.3(a). Surfaces created by the cutting of the test specimen were excluded from this requirement in a final rule published on March 31, 1975 (40 FR 14318). The reasons for the exclusion were stated in the notice as follows: (C)utting certain materials to the prescribed thickness produces a tufted surface upon which a flame front may be propagated at a faster rate than it would be upon the surface of the material before cutting, thereby creating an artificial test condition. Because of this exclusion, the surface facing upward pursuant to S5.2.2 is not required to comply with the burn-rate requirement of S4.3(a) if the surface was created by cutting the material to be tested to the prescribed thickness. In addition, I note that S5.3(b) requires the test specimen to be placed in the center of the cabinet. Therefore, it should not be any more difficult to observe the progress of the flame on the surface facing down than the surface facing up. Question 2. MVSS-302, in Section S5.3(f), states that the flame progression be measured to a point 1.5 inches from the clamped end of the specimen under test. The standard does not specify actions to be taken after timing has stopped. Some laboratories put out the flame using a small amount of water from a spray bottle. The question has been raised as to whether using a small amount of water from a spray bottle to put out the flame is an acceptable procedure. You are correct that Standard No. 302 does not specify a procedure to extinguish the flame after the test. Therefore, spraying a specimen with a small amount of water to extinguish the flame would be acceptable. However, please bear in mind that S5.1.2 states Prior to testing, each specimen is conditioned for 24 hours at a temperature of 70 F. and a relative humidity of 50 percent, and the test is conducted under those ambient conditions. After spraying a specimen in the test cabinet, it would be necessary to ensure that the ambient conditions in the cabinet conform to those specified in S5.1.2 before conducting any additional tests. I hope you find this information helpful. If you have any other questions, please contact Marvin Shaw of my staff at this address or by phone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam2681OpenMr. Jerry McNeil, American Trailers, Inc., 1500 Exchange Avenue, Box 26568, Oklahoma City, OK 73126; Mr. Jerry McNeil American Trailers Inc. 1500 Exchange Avenue Box 26568 Oklahoma City OK 73126; Dear Mr. McNeil: This responds to your July 20, 1977, letter asking whether you certification labels comply with Part 567, *Certification*, and Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other Than Passenger Cars*.; As stated to you in an earlier letter, the National Highway Traffi Safety Administration does not issue approvals of compliance with Federal safety standards and regulations. The agency will, however, give you an informal opinion as to whether your labels appear to comply with the requirements. The agency has determined that the two labels that you submitted do not follow the format established in the regulations and, therefore, do not comply with the requirements. If 'R' denotes radial ply and 'F' denotes load range, the tire designation should be 10.00 R 20(F).; Sincerely, Joseph J. Levin, Jr., 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.