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: aiam0179OpenMr. Jim Tydings, Chief Engineer, Perley A. Thomas Car Works, Inc., High Point, NC 27261; Mr. Jim Tydings Chief Engineer Perley A. Thomas Car Works Inc. High Point NC 27261; Dear Mr. Tydings: This is in reply to your letter of August 4, 1969, in which you reques approval of an alternative to the label locations specified in section 367.4(c) of the Certification Regulations that are effective as to vehicles manufactured on or after September 1, 1969.; The location you have selected is not considered to be in the sam general area, left side of the vehicle, as specified. In view of the fact that interested parties will be looking for the label in the general area, to the left of the vehicle, we are approving a label location to the left of the access panel instead of the right as you have shown in your drawing No. 2507-2369.; If there is any reason why you cannot attach your label in the area w have suggested, please advise. It is assumed that our alternative should not impose undue hardship. In the interest of avoiding unnecessary correspondence, no response from you will be interpreted as your acceptance of the above.; Your cooperation is appreciated. Sincerely, Robert Brenner, Acting Director |
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ID: aiam4993OpenMr. Shigeyoshi Aihara Manager, Information Services Ichikoh America, Inc. Suite 220 3025 Boardwalk Drive Ann Arbor, MI 48108-1777; Mr. Shigeyoshi Aihara Manager Information Services Ichikoh America Inc. Suite 220 3025 Boardwalk Drive Ann Arbor MI 48108-1777; Dear Mr. Aihara: This responds to your letter of March 16, 1992 requesting an interpretation of the applicability of the moisture prohibition of S7.4(i)(6) of Federal Motor Vehicle Safety Standard No. 108. Initially, we would like to call your attention to the fact that S7.4(i)(6), which you quoted in its entirety, was amended on March 11, 1991, to delete the requirement that a headlamp meet the photometric requirements after a humidity test. S7.4(i)(6) now states in pertinent part that, after a humidity test conducted in accordance with S8.7, 'the inside of the headlamp shall show no evidence of delamination or moisture, fogging or condensation visible without magnification.' You have attached a drawing of a vented headlamp with an onboard aiming system. The headlamp is available with two different types of bubble indicators. Your first question is: 'After the humidity test, both types . . . show the fogging in the location as shown in attached sketches. But, this fogging is gone at normal temperature. * * * Is such fogging acceptable after the humidity test?' Your second question is whether ''the inside of the housing' means the lens and reflector portions' or 'the entire inside portion of headlamps?' The humidity test was adopted for replaceable bulb headlamps in l983. Allowing humidity or water in headlamps causes slow degradation of the reflector over the long term. The presence of humidity results in spots on the reflector and lens, and eventual photometric failure. The humidity test is designed to assure that the vents in vented headlamps eliminate moisture in the headlamp when exposed to air flow with the headlamps off, thus assuring adequate performance in long term use. The provision for onboard headlamp aiming devices was not adopted until 1989, and, with respect to replaceable bulb headlamps, did not specify that they be located within the headlamp. From the foregoing, it is evident that the humidity test for replaceable bulb headlamps was not adopted to address a problem inherent in the exposure of onboard aiming devices to moisture. These devices were not in use at the time the humidity test was added to Standard No. 108, and they do not contribute directly to the photometric performance of the headlamp. From the diagram you enclosed, the aiming device appears located behind the reflector. It is not possible to determine from your letter whether moisture forms on the exterior or the interior of the aiming device. Although S7.4(i)(6) prohibits moisture 'inside the headlamp' and the aiming device is located inside the headlamp, we would not read the prohibition as extending to the aiming device if the moisture occurs inside that device. Even if the moisture occurs on the exterior of the aiming device, it does not affect the photometric properties of the headlamp. The agency does not wish to impose inadvertent design restrictions that are not directed towards safety, and therefore regards any moisture that may occur on the exterior of the aiming device as outside the prohibition of S7.4(i)(6). This interpretation, however, is limited to the specific design that you have presented. Sincerely, Paul Jackson Rice Chief Counsel; |
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ID: aiam4839OpenMr. James W. Lawrence Manager, Compliance and Technical Legislation Volvo GM Heavy Truck Corporation 7825 National Service Road P.O. Box 26115 Greensboro, NC 27402-6115; Mr. James W. Lawrence Manager Compliance and Technical Legislation Volvo GM Heavy Truck Corporation 7825 National Service Road P.O. Box 26115 Greensboro NC 27402-6115; "Dear Mr. Lawrence: This responds to your letter of June 15, 199 concerning replacement doors. I apologize for the delay in our response. You quote an April 9, l990 interpretation letter to Mr. Rowghani concerning Standard No. 214, Side Door Strength. You note that the letter states that 'there is no requirement that the replacement door restore the vehicle to a condition in which it continues to meet Standard No. 214.' You requested a clarification of this statement as you believe that the 'render inoperative' provision of Section 108(a)(2)(A) of the Act would require 'installation of parts meeting the same performance requirements as OEM parts.' The 'render inoperative' provision of section 108(a)(2)(A) would prohibit any manufacturer, dealer, distributor, or repair business from removing and replacing an undamaged side door, unless the vehicle continued to comply with Standard No. 214. However, that section does not require a manufacturer, dealer, distributor, or repair business to return a vehicle to compliance with a standard if it has been 'rendered inoperative' by another agent, such as a crash. The sentence you quote begins, 'if damage to a vehicle is such that its original door must be replaced.' The interpretation was intended to be limited to situations where damage is so extensive that the vehicle would no longer comply with Standard No. 214. I hope you find this clarification helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel "; |
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ID: aiam2514OpenMr. H. Miyazawa, Director, Automotive Lighting, Engineering Department, Stanley Electric Co., Ltd., 2-9-13 Nakameguro, Meguro-Ku, Tokyo 153, Japan; Mr. H. Miyazawa Director Automotive Lighting Engineering Department Stanley Electric Co. Ltd. 2-9-13 Nakameguro Meguro-Ku Tokyo 153 Japan; Dear Mr. Miyazawa: This is in reply to your letter of February 14, 1977, concerning th symbol 'DOT' as a certification of compliance to FMVSS No. 108.; The symbol 'DOT' is permitted by the Standard to be placed on the ite of equipment in lieu of the certification requirements of Section 114 of the 'National Traffic and Motor Vehicle Safety Act of 1966,' which states, in part '...In the case of an item of motor vehicle equipment such certification may be in the form of a label or tag on such item or on the outside of a container in which such item is delivered...'; DOT' on the individual container does not meet the certificatio requirements. The label or tag must state that the item 'conforms to all applicable Federal motor vehicle safety standards.'; Sincerely, E. T. Driver, Director, Office of Crash Avoidance, Moto Vehicle Programs; |
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ID: aiam0529OpenMr. E. G. Nagle, Vice President, Allen Industries, Inc., Honeywell Building, 17515 West Nine Mile Road, Southfield, MI, 48075; Mr. E. G. Nagle Vice President Allen Industries Inc. Honeywell Building 17515 West Nine Mile Road Southfield MI 48075; Dear Mr. Nagle: This is in reply to your letter of October 28, 1971, requesting a interpretation of paragraph S4.3 of Motor Vehicle Safety Standard No. 302, 'Flammability of Interior Materials.' You ask whether cotton seat padding or jute used on the backing of automobile carpets, when prepared as a test specimen of 1/2-inch thickness as prescribed by the standard, will comply with paragraph S4.3 if it transmits a flamefront across its surface at a rate of more than 4 inches per minute but stops burning in 10 to 20 seconds, and the material does not burn more than 2 inches from the point where timing was started.; On December 18, 1971, you indicated in a phone conversation wit Michael Peskoe of the Office of the Chief Counsel that your letter did not take into account a 'flashing' of the flame across a particular surface of the cotton seat padding for more than 2 inches. You stated that this surface is a tufted surface that is created only when the seat padding, which has a thickness of 4 inches in the vehicle, is cut or separated to the half-inch thickness specified in the procedure of S5.2.1 of the standard.; We consider the 'flashing' of the flame across the tufted surface o the material to be a burning of the material under S4.3 of the standard, and as it did occur for more than 2 inches from the point where timing was started, the material would not comply with paragraph S4.3.; We recognize, however, that the failure of the material to meet th requirements in this case results from the fact that the surface of the material changes because of the test procedure, and we are presently considering possible changes in the standard to alter this result.; Sincerely, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam1292OpenMr. Brian Gill, Assistant Manager, Safety & Environmental Activities, American Honda Motor Co., Inc., P.O. Box 50-100 W. Alondra Blvd., Gardena, California 90247; Mr. Brian Gill Assistant Manager Safety & Environmental Activities American Honda Motor Co. Inc. P.O. Box 50-100 W. Alondra Blvd. Gardena California 90247; Dear Mr. Gill: This is in reply to your letter of October 9, 1973, to Mr. Vinson o this office asking whether S5.2.5 of Standard No. 123 requires footrests to fold automatically when not in use.; The standard does not require automatic folding. S5.2.5 states only th direction in which footrests shall retract, so that if they are inadvertently left down when not in use they will fold rearward and upward should the hit an obstacle while the motorcycle is travelling forward.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4090OpenMr. Ron Luce, President, International Transquip Industries, Inc., P.O. Box 590169, Houston, TX 77259; Mr. Ron Luce President International Transquip Industries Inc. P.O. Box 590169 Houston TX 77259; Dear Mr. Luce: This responds to your request for an interpretation of FMVSS No. 121 *Air Brake Systems*. You asked several questions relating to whether vehicles equipped with 'Mini-Max' brakes, a type of brake produced by your company, comply with the standard. Your questions are responded to below. We note that while Question 4 was not asked directly by your letter, the question is implicit with respect to one of the questions you did ask.; By way of background information, the National Highway Traffic Safet Administration (NHTSA) does not give approvals of motor vehicles or equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles or equipment comply with applicable safety standards. The following represents our opinion based on the facts provided in your letter.; *Question 1: Is delayed mechanical parking permissible under sectio S5.6.3 as long as the requirements of S5.6.1 or S5.6.2 are satisfied?*; The second sentence of section S5.6.3 provides that '(o)nce applied the parking brakes shall be held in the applied position solely by mechanical means.' As discussed by a recent notice granting a petition for rulemaking submitted by the California Highway Patrol (copy enclosed), there are at least two issues relating to whether a braking system such as Mini-Max complies with these requirements.; The first issue is whether the system meets the requirements that onc applied, the parking brakes must be held solely be mechanical means. As currently designed, the Mini-Max parking brake can be held by air and not by mechanical means, solely or otherwise, for many hours. Indeed, since a driver will often park the vehicle for a period of time shorter than that required to obtain mechanical holding, there will be many instances when the vehicle is parked and the parking brake never is held by mechanical means. The second issue is whether the parking brakes are held in the applied position. With the current design of the Mini-Max braking system, the air pressure leaks down over time until the mechanical lock is activated. Since the position of the brake components necessarily changes during this time, resulting in reduced parking brake force, there is an issue whether the parking brake is being held in the applied position.; While NHTSA has never concluded that a brake system resulting in fals parking is safe or provided an interpretation that the current Mini-Max system complies with section S5.6.3, we recognize that some past interpretations, as well as one issued by the Bureau of Motor Carrier Safety, could contribute to ambiguity concerning whether some of the features incorporated in the Mini-Max design are permitted by the standard. In light, of that ambiguity and for the other reasons discussed in the grant notice, NHTSA decided to grant the CHP petition to initiate rulemaking on the delayed mechanical park issue rather than issuing an interpretation whether or not such a brake system complies with these requirements.; *Question 2: Is an external pressure separation assembly consisting o a two-way check valve and accompanying steel hex nipple considered to be a component of a brake chamber housing under section S5.6.3 if the assembly is 'permanently bonded' to the housing?*; The answer to this question is no. Section S5.6.3 provides in relevan part that '(t)he parking brake system shall be capable of achieving the minimum performance specified either in S5.6.1 or S5.6.2 with any single leakage-type failure, in any other brake system, of a part designed to contain compressed air or brake fluid (*except failure of a component of a brake chamber housing*).' (Emphasis added.) The dictionary defines 'housing' as 'a fully enclosed case and support for a mechanism.' See *Random House Dictionary of the English Language* (unabridged edition). Thus, the term 'brake chamber housing' refers to the case enclosing a brake chamber. An external pressure separation assembly does not become part of the brake chamber housing merely because it is attached to the housing, whether by 'permanent bonding' or some other means. However, a brake chamber housing could be cast or molded to include a fitting, serving the same purpose as the external pressure assembly, as an integral part of the brake chamber housing.; *Question 3: Is an internal assembly consisting of a diaphragm with th brake chamber housing considered to be a component of the brake chamber housing under section S5.6.3?*; The answer to this question is no. As discussed above, the term 'brak chamber housing' refers to the case enclosing a brake chamber. A diaphragm within the brake chamber is not a component of the case enclosing the brake chamber.; *Question 4: Does section S5.2.1.1 require that capability of releas must be unaffected or that air pressure in the tank must be unaffected?*; Section S5.2.1.1 provides that '(a) *reservoir shall be provided* tha is capable, when pressurized to 90 p.s.i. of releasing the vehicle's parking brakes at least once *and that is unaffected* by a loss of air pressure in the service brake system.' (Emphasis added.) The word 'unaffected' refers back to reservoir.' Thus, the required reservoir is not permitted to be 'affected' by a loss of air pressure in the service brake system, i.e., it must be protected. A reservoir would not meet this requirement if a loss of air pressure in the service brake system resulted in a loss of air pressure in the reservoir, even if the reservoir was still capable of releasing the parking brakes.; *Question 5: If the emergency brakes on trailers can be modulated so a to provide a driver with several applications and releases to move the disabled vehicle off the road after the signal from the low air warning system that the vehicle has lost its service brake system, is it unnecessary for an S5.2.1.1 reservoir to be capable of releasing the brakes?*; The capability of modulation after activation of the low air warnin system does not satisfy the requirements of section S5.2.1.1 (quoted above). That section requires that the reservoir not be affected by loss of service air, i.e., that it be protected, and that, when pressurized to 90 p.s.i. (a pressure that corresponds to the lower end of the range of pressures maintained by compressors), it be capable of releasing the parking brakes at least once. A vehicle's emergency brakes could be capable of modulation after activation of the low air warning system and not meet either of these requirements.; In addition to the notice granting the CHP petition, we are enclosin copies of interpretation letters concerning the Mini-Max system addressed to Navistar, P.T. Brake Lining Company, and the New Jersey Division of Motor Vehicles.; Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1768OpenMr. F. Maggi,SAIAG, Via Torino 100, 10073 Cirie (Torino) ITALIA; Mr. F. Maggi SAIAG Via Torino 100 10073 Cirie (Torino) ITALIA; Dear Mr. Maggi:#Please forgive the delay in responding to your lette of September 25, 1974, requesting a 'manufacturer designation' for the vacuum brake hose which you manufacture.#S5.2.2(b) of Federal Motor Vehicle Safety Standard No. 106-74, *Brake Hoses*, was amended on January 29, 1974 (39 FR 3680, Docket No. 1-5, Notice 9), and again on February 26, 1974 (39 FR 7425, Docket No. 1-5, Notice 10).In place of an manufacturer's code number, assigned by the National Highway Traffic Safety Administration, S5.2.2(b) of the standard now requires:#>>>A designation that identifies the manufacturer of the hose assembly, which shall be filed in writing with: Office of Standards Enforcement, 'Brake Hose Identification,' National Highway Traffic Safety Administration, 400 Seventh Street S.W., Washington, D.C. 20590. The marking may consist of a designation other than block capital letters required by S5.2.2.<<<#The designation, 'SAIAG', as depicted in your letter, already satisfies this requirement. This designation is now on file in the Office of Standards Enforcement. Please note that the other required label information must still appear on the hose in block capital letters and numerals at least one-eighth of an inch high.#Yours truly,Richard B. Dyson,Acting Chief Counsel; |
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ID: aiam3755OpenMr. Anthony M. Peterson, Lansing Auto Glass Co., 827 E. Michigan Avenue, Lansing, MI 48912; Mr. Anthony M. Peterson Lansing Auto Glass Co. 827 E. Michigan Avenue Lansing MI 48912; Dear Mr. Peterson: This responds to your letter concerning the application of the rende inoperative provisions of section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act to the replacement of vehicle windshields by motor vehicle repair businesses.; As explained in my letter of September 3, 1981, to Mr. Stanley, th agency does not consider fixing a damaged windshield to constitute a rendering inoperative of the windshield with respect to Standard No. 205, *Glazing Materials*. That letter did caution that if a repair shop, in the course of fixing a damaged windshield, renders another part of the vehicle or element of design inoperative with respect to another applicable Federal motor vehicle safety standard, then the repair shop would violate section 108(a)(2)(A).; You specifically asked whether in replacing a windshield a repair sho must use the same method (e.g., setting the glass with urethane) the original equipment manufacturer used to maintain the integrity of the installation. The agency does not consider the replacement of a damaged windshield to constitute a rendering inoperative with respect to Standard No. 212, *Windshield Mounting*, which establishes windshield retention requirements for new vehicles, regardless of the method used to maintain the integrity of the windshield.; Although section 108(a)(2)(A) of the Act would not apply to th replacement of a damaged windshield, product liability concerns dictate that a repair shop ensure that the replacement windshield is mounted securely. Mounting the windshield with the same method used by the vehicle manufacturer presumably would ensure that the replacement windshield had the same integrity as the original windshield installation.; You also asked about the effect of section 108(a)(2)(A) on a repai shop that replaces a windshield for a dealer who will resell the vehicle and a replacement of a windshield for an insurance company for one of its policyholders. Assuming that the repair shop is replacing a damaged windshield, section 108(a)(2)(A) would not apply.; I hope this discussion is of assistance to you. If you have any furthe questions please contact Stephen Oesch of my staff (202-426-1834).; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam2847OpenMr. D. Black, Manager, Alfa Romeo, Inc., 250 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. D. Black Manager Alfa Romeo Inc. 250 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Black: This responds to your recent letter concerning Alfa Romeo's propose designs for Type 2 seat belt assemblies to be used on convertibles. You ask for clarification of the anchorage location requirements specified in Safety Standard No. 210, as they would apply to your proposed designs.; Paragraph S4.1.1 of Safety Standard No. 210, *Seat Belt Assembl Anchorages*, specifies that anchorages for a Type 2 belt shall be installed for each forward-facing outboard designated seating position in passenger cars *other than convertibles*. Manufacturers are permitted to install Type 2 belts in convertibles, however, under paragraph S4.1.2 of the standard which specifies that either a Type 1 or Type 2 belt may be installed for designated seating positions not required to have Type 2 belts under the previous section.; Since convertibles are only required to have Type 1 belts, only th pelvic portion of your proposed Type 2 designs must meet the anchorage location requirements of the standard. These location requirements are specified in S4.3.1, and the pelvic portion of your two proposed designs (Figures 2 and 3 in your letter) appear to fall within the 20 degree - 75 degree acceptable range. The upper torso portions of the belt designs do not have to comply with the 40 degree acceptable range specified in S4.3.2, since those portions are in addition to what is required by the standard.; In response to your general question, 'seat belt anchorage' is define in Standard No. 210 as the 'provision for transferring seat belt assembly loads to the vehicle structure.' For purposes of determining compliance with the anchorage location requirements of the standard, the agency interprets anchorage to include any load-bearing element of the seat belt assembly that is capable of meeting the force requirements of Standard No. 210. For example, in your Figure 1 you state that the lap belt is anchored 'at point 'C' within the 40 degree zone and then passes through a webbing guide anchorage.' The 40 degree zone is not the applicable location requirement for lap belts and if this were the only anchorage, the belt would not comply with the standard. However, since the 'webbing guide anchorage' appears to be within the applicable 20 degree - 75 degree zone, the belt would be in compliance if that anchorage is capable of meeting the force requirements of the standard. The agency considers an assembly to be in compliance if there is one force-complying anchorage within the acceptable ranges specified in the standard, and that anchorage is determinative of the angle the belt crosses the vehicle occupant.; To summarize, both of your proposed Type 2 seat belt assemblies woul comply with the location requirements of Standard No. 210 if used in convertibles, since only the pelvic portions of the assemblies would have to meet the requirements of the standard and the anchorages for those portions appear to be within the acceptable ranges. Further, either assembly design can be used in hard- top automobiles if it has one anchorage capable of meeting the force requirements of the standard that is located in the 40 degree acceptable range for upper torso portions of Type 2 belts.; Please contact Hugh Oates of this office if you have any furthe questions concerning this subject (202-426-2992).; 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.