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: aiam1502OpenPiaggio & C. Soc. per Az., Via Antonio Cecchi 6, 16129 Genova, Italia; Piaggio & C. Soc. per Az. Via Antonio Cecchi 6 16129 Genova Italia; Gentlemen: This is in reply to your letter of May 13, 1974, asking fo interpretation of Motor Vehicle Safety Standard No. 123, *Motorcycle Controls and Displays*.; You have stated that 'a mark in the front of a line (-) between firs and second indicates the neutral position' and ask whether that is a 'neutral indicator' within the meaning of Standard No. 123. Since the purpose of the mark is to designate the neutral position between first and second gears, it is a 'neutral indicator' and must be illuminated by a green display lamp and identified by the word 'Neutral.'; You also express your opinion that the normal fuel shutoff valv positions should be 'fully clockwise' for 'off,' 'full counterclockwise' for 'reverse' with 'on' between the two, and operational along a transverse axis. This, of course, would not comply with the standard which requires that the control be forwarded when off, upward for reverse, and downward for 'on,' and operational along a longitudinal axis. As the agency commented in denying Japan AMA's petitions for reconsideration of these requirements of the standard (37 F.R. 17474) 'The NHTSA has determined that the control should be standardized by requiring its operation along a longitudinal rather than a transverse axis. In this location there is a greater likelihood that in the event of a crash, the control will be carried by inertia to the off position, thereby shutting of the fuel.' Therefore we do not intend to modify there requirements.; "Yours truly, Richard B. Dyson, Assistant j Chief Counsel" |
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ID: aiam1017OpenMr. J. C. Eckhold, Director, Automotive Safety Office, Ford Motor Company, The American Road, Dearborn, MI 48121; Mr. J. C. Eckhold Director Automotive Safety Office Ford Motor Company The American Road Dearborn MI 48121; Dear Mr. Eckhold: This is in reply to your letter of February 16, 1973, concerning th safety standard applicable to the sling for the upper torso belt used in Ford's 1974 model restraint system.; The schematic drawing attached to your letter shows that the slin attaches to the roof rail and serves the function of an upper torso belt anchorage. We agree with you that the sling is subject to the requirements of Standard No. 210 and not to the requirements of Standard No. 209. Although the sling is made of fabric webbing, its function is that of an anchorage and it is therefore subject to the anchorage standard.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam4215OpenThe Honorable Alan Cranston, United States Senate, 112 Hart Senate Office Building, Washington, DC 20510; The Honorable Alan Cranston United States Senate 112 Hart Senate Office Building Washington DC 20510; Dear Senator Cranston: This responds to your letter on behalf of Mr. Raymond Kesler. He aske for this agency's response to a letter from Mr. Robert R. Philips concerning the bi-focal mirror developed by Mr. Kesler. In his letter, Mr. Phillips asked whether an outside rearview mirror, which has both a planar surface of unit magnification and a convex surface, complies with Standard No. 111, *Rearview MIrrors*. I regret the delay in responding to this letter.; As we understand the information supplied by Mr. Phillips, the bi-foca mirror would be installed on the driver's side of motor vehicles to give the driver a wider field of view by combining a convex mirror and a planar mirror as the outside rearview mirror on the driver's side. The convex portion would abut the planar portion and be located to the left of the planar portion. Thus, both normal and wide-angle vision would be provided at the same horizontal viewing level.; By way of background information, this agency does not give approval of vehicles or their equipment. The National Traffic and Motor Vehicle Safety Act of 1966, as amended (the Act), places the responsibility on the manufacturer to ensure that items of motor vehicle equipment, such as rearview mirrors, comply with any applicable requirements. A manufacturer certifies that its equipment complies with all applicable safety standards.; Mr. Phillips asked this agency to confirm his interpretation that thi bi-focal mirror meets the requirements of Standard No. 111 if its planar or unit magnification surface has an area of at least 19.5 square inches, regardless of the existence of the convex portion. The 19.5 square inch requirement is one applicable to multipurpose passenger vehicles, trucks, and buses (other than schoolbuses) with a GVWR of 10,000 pounds or less. Those types of vehicles are required by S6.1 of the standard either to have a set of inside and outside rearview mirrors that comply with the requirements applicable to passenger cars or to have outside mirrors of unit magnification, each with not less than 19.5 square inches of reflective surface, on both sides of the vehicle. If Mr. Phillips' mirror meets that size requirement, is located on a vehicle so as to provide the required view and is adjustable in the required manner, it complies with S6.1.; There are no minimum size requirements for unit magnification outsid rearview mirrors on passenger cars. Mr. Phillips' mirror can be installed on the driver's side of passenger cars if the mirror's unit magnification portion, independently of the convex portion, meets the field of view and mounting requirements specified in S5.2.; In one drawing accompanying Mr. Phillips' letter, there appears to be warning on the planar portion of his bi-focal mirror stating 'Objects Appear Within Markers: Caution.' There is no requirement in Standard No. 111 for such a warning. The agency is concerned that the message conveyed by this warning is unclear and could confuse motorists. The warning ('CAUTION When Vehicle Appears Here') in Mr. Phillips' other drawing seems more easily understood. He might consider providing purchasers with written instructions explaining that the purpose of the message is to warn drivers that the appearance of a vehicle in the convex portion of the mirror means that the vehicle is so close that a lane change would be unsafe.; Unit magnification and convex mirrors on other types of vehicles mus meet the specific performance and location requirements for those types of vehicles, as set out in the standard. Again, please note that a vehicle manufacturer installing a bi-focal mirror on different types of vehicles must ensure that the unit magnification portion of the mirror meets any applicable requirements of the standard independently of the convex portion.; If Mr. Phillips' mirror meets the requirements of Standard No. 111 fo a particular vehicle type, then it may be installed on new vehicles of that type. It may also be installed on used vehicles of that type.; Conversely, if the mirror does not meet those requirements, then it ma not be installed on new vehicles. Further, manufacturers, distributors, dealers and repair businesses would be prohibited from installing it on used vehicles. However, the Act does not establish any limitations on an individual vehicle owner's ability to alter his or her own used vehicle.; Under Federal law, individual vehicle owners can themselves install an product they want on their used vehicles, regardless of whether that product would render inoperative the compliance of the vehicle's rearview mirrors with the performance or location requirements of Standard No. 111.; I hope this information is helpful to you. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam1447OpenMr. Gerhard P. Riechel, Volkswagen of America, Inc., Englewood Cliffs, NJ 07632; Mr. Gerhard P. Riechel Volkswagen of America Inc. Englewood Cliffs NJ 07632; Dear Mr. Riechel: This responds to your March 8, 1974, letter reviewing our dispositio of Volkswagen's petition to add a new crash protection option to S4.1.2 of Standard 208 (49 CFR 571.208). You requested a determination of whether the seat belt assembly described in that petition constitutes a passive restraint system for purposes of Standard 208, that is, one that requires 'no action' by vehicle occupants.; The Volkswagen assembly consists of a single diagonal belt fo restraint of the upper torso and an energy-absorbing knee bolster. Mounting of the upper torso restraint to the door causes the belt to move forward during occupant entry and then fall back across the occupant's torso when he is seated and the door is closed.; The NHTSA issued an interpretation of what constitutes a 'passive restraint system on May 4, 1971 (36 FR 4600):; >>>The concept of an occupant protection system that requires 'n action by vehicle occupants' as used in Standard No. 208 is intended to designate a system that requires no action other than would be required if the protective system were not present in the vehicle.<<<; The question of what constitutes 'no action by vehicle occupants' in vehicle equipped with (presumptively) passive belts is best considered in two stages: (1) entry and exit from the vehicle, and (2) positioning of the belt for safety and comfort.; Entry and exit action 'that requires no action other than would b required if the protective system were not present in the vehicle' means that a person is not hampered in his normal movements by the presence of the belt system. A test of this is whether a human occupant of approximately the dimensions of the 50th percentile adult male finds it necessary to take additional actions to displace the belt or associated components in order to enter or leave the seating position in question. An example of impermissible action would be the necessity of manually pushing a belt out of the way to gain access to the seat. Displacement of the components incidental to normal entry and exit, or merely for the convenience of the occupant, would not be prohibited. Examples of permissible displacement would be brushing against the upper torso restraint during seating, or grasping the torso restraint to close the door.; The second question relates to the usefulness of the system once th occupant has been seated. The essence of a passive restraint is that it provides at least the minimum level of protection without relying on occupant action to deploy the restraint. At this stage, then, the question is whether an occupant who has seated himself without taking any 'additional action' is in fact protected in a 30 mi/h impact. This can be measured by conducting the impact tests with the belt positioned on the test dummy in the orientation that results when a human occupant enters the vehicle according to the first test described above. It would not be required that the belt position itself for maximum comfort of the human occupant, if it met the safety requirements. For example, if the belt were to fall across the upper arm instead of the clavicle, but still passed the test, the system would be considered conforming.; The procedure for conducting this evaluation would be to have a huma occupant enter the vehicle without taking any 'additional actions' to displace the belt, to note the location of the belt on him before he exits, to position the test dummy in accordance with S8.1 of Standard 208, to position the belt as it positioned itself on the sample occupant, and then to conduct the impact tests. The exit evaluation would require the human occupant to be seated with the restraint normally deployed and then exit the vehicle without needing to take any separate actions to displace the belt.; This discussion is intended to permit you to evaluate your passive bel system under the language of the May 4, 1971, interpretation.; Sincerely, Lawrence R. Schneider, Chief Counsel |
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ID: aiam4645OpenMr. Takayoshi Chikada Manager of Automotive Lighting Engineering Control Dept. Stanley Electric Co., Ltd.; Mr. Takayoshi Chikada Manager of Automotive Lighting Engineering Control Dept. Stanley Electric Co. Ltd.; FAX 03-792-0007 (Japan) Dear Mr. Chikada: This is in reply to you letter of June 16, l989, to Mr. Van Iderstine of this agency, by FAX as you requested. You have asked four questions with respect to the recently amended Federal Motor Vehicle Safety Standard No. 108. We responded to your first two questions in a letter dated June l9 to Mr. Hasegawa of your office. A copy is enclosed for your reference. Since that time, however, in response to a petition by General Motors, we have changed the effective date of paragraph S7.7.5.1(a) to December l, l989, with respect to replaceable bulb headlamp systems. A copy of this notice is also enclosed. Your third question is: How should we prove the confirmation to the requirement of S7.7.2.2? We think the combination of Horizontal and Vertical angle within the aim range will be so huge and it is not practicable to test for all combinations. This paragraph applies to headlamps aimed by moving the reflector relative to the lens and headlamp housing, or vice versa. The agency has frequently advised manufacturers that there is no legal requirement that conformance be demonstrated through the test procedures stated in the standard. While the agency will use those procedures in its compliance testing, the manufacturer may certify compliance with the performance requirements of a standard through engineering studies, computer simulations, mathematical calculations, or other means intended as an exercise of due care and affording a reasonable basis upon which to certify compliance. Your final question is: It is acceptable to set up initial '0' point of S7.7.5.2(a)(2) not mechanically but photometrically? You may determine the 'O' point by whatever means you deem appropriate for the headlighting system, as long as the method achieves a horizontal 'O' point that may be used for the purposes of paragraph S7.7.5.2(a)(2), and any other paragraph in which the horizontal 'O' mark is required to be determined. In the future, please address your requests for interpretations of Standard No. 108 to this office. Sincerely, Stephen P. Wood Acting Chief Counsel Enclosure; |
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ID: aiam3180OpenHonorable Harold Runnels, House of Representatives, Washington, D.C. 20515; Honorable Harold Runnels House of Representatives Washington D.C. 20515; Dear Mr. Runnels: This further responds to your November 14, 1979, letter to th Secretary of Transportation concerning Mr. Richard D. Browning's interest in the conversion of automotive engines to run on propane.; From Mr. Browning's letter, I gather that he seeks to produce an market a converter system which will allow conversion of gasoline motors to propane. I have described below the way in which the legislation and regulations under which the National Highway Traffic Safety Administration operates might apply to Mr. Browning's venture. This agency lacks the authority to deal with any emissions control issues arising from production and use of a propane converter system, but the Environmental Protection Agency may have requirements which would apply to such a system. Therefore, we have also referred your letter to that agency in an attempt to expedite a response on this issue.; To date, the National Highway Traffic Safety Administration (NHTSA) ha not exercised its authority pursuant to the National Traffic and Motor Vehicle Safety Act, as amended 1974 (14 U.S.C. 1381 *et seq.*) (the Act), to issue a safety standard applicable to propane-powered vehicles. Federal Motor Vehicle Safety Standard No. 301-75, *Fuel System Integrity*, applies only to vehicles which use fuel with a boiling point above 32 degrees F., and propane has a boiling point well below this temperature. Despite the absence of safety standards specifically applicable to propane-powered engines, a manufacturer or installer of these systems may be subject to other Federal requirements.; Under the Act (sections 151-158), the manufacturer of a propane fuele engine or of the components used for converting a gasoline-fueled engine to propane would be responsible for any safety-related defects in that equipment regardless of whether it were installed in new or in used vehicles. Upon discovery of a safety-related defect by either the Secretary of Transportation, the NHTSA Administrator, or the manufacturer himself, the manufacturer would be required to notify vehicle owners, purchasers and dealers and provide a free remedy for the defect.; Under NHTSA safety regulations, a person who alters a new vehicle prio to its first purchase in good faith for purposes other than resale is required to attach an additional label to the vehicle certifying that, as altered, the vehicle remains in compliance with all applicable safety standards (49 CFR 567.7). This requirement would apply to a person who alters a new vehicle to install a propane fuel system. (See the enclosed pamphlet listing the Federal motor vehicle safety standards and an information sheet explaining where to obtain copies of the standards.) Additionally, should a noncompliance be caused by the modification, the alterer could be liable for a civil penalty unless he or she could establish that he or she did not have actual knowledge of the noncompliance and that he or she did not have reason to know in the exercise of due care that the vehicle did not comply. (Section 108(b)(2)).; A person who installs a propane-fueled engine or converts th gasoline-fueled engine in a used vehicle is not required to affix an alterer's label. However, if that person is a manufacturer, distributor, dealer, or motor vehicle repair business, he must not in the course of installing the propane components knowingly render inoperative any device or element of design originally installed in the vehicle in compliance with applicable Federal motor vehicle safety standards. (Section 108(a)(2)(A) of the Act); I hope that you will find this response helpful. If you or you constituent have any further questions on this issue, I will be happy to answer them.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1914OpenMr. H. (Speedy) Hirai, Technical Representative, Toyo Kogyo Co., LTd. (MAZDA), Representative Office, 23777 Greenfield Road, Suite 462, Southfield, MI 48075; Mr. H. (Speedy) Hirai Technical Representative Toyo Kogyo Co. LTd. (MAZDA) Representative Office 23777 Greenfield Road Suite 462 Southfield MI 48075; Dear Mr. Hirai: In reply to your letter of April 22, 1975, the 'wheel nuts' covered b Motor Vehicle Safety Standard No. 211 are large, center- mounted hub nuts, one to a wheel, that lock the tire to the axle.; They are not the individual nuts, often six to a wheel, that perfor the same function, and which are generally covered by a wheel disc or hub cap.; Your hub nuts and hub bolts therefore need not be marked with manufacturer's identification code.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3929OpenMr. Joseph L. Hourihan, Vehicle Inspection Services, Room 438, Massachusetts Registry of Motor Vehicles, 100 Nashua Street, Boston, MA 02114; Mr. Joseph L. Hourihan Vehicle Inspection Services Room 438 Massachusetts Registry of Motor Vehicles 100 Nashua Street Boston MA 02114; Dear Mr. Hourihan: This responds to your March 11, 1985 letter to the National Highwa Traffic Safety Administration (NHTSA) concerning our school bus safety standards. You asked who is responsible for determining, at the time of the initial sale of the bus, whether the vehicle's intended use is to transport school children. You also asked who is the party responsible for ensuring that a school bus complies with the motor vehicle safety standards applicable to school buses.; The responsibility for determining whether the vehicle's intended us is to transport school children rests with the seller of the school bus. The Vehicle Safety Act prohibits manufacturers, dealers or distributors from selling new buses for school transportation which do not comply with the Federal school bus safety standards. I have enclosed a Federal Register notice (40 FR 60033) that discusses the responsibility of manufacturers and dealers who know that a vehicle will be used to transport school children to sell school buses that comply with our school bus safety standards. As discussed in that notice, the agency believes that, of all the persons in the chain of distribution who are subject to the Vehicle Safety Act, the seller is most likely to have knowledge of the likely use of the vehicle. Of course, the seller is not held responsible for more than its knowledge of the purpose of the sale.; In response to your second question, under the Vehicle Safety Act, th manufacturer of a new school bus certifies that its vehicle meets the motor vehicle safety standards applicable to school buses. The party selling a new bus for school transportation is responsible for selling a complying school bus.; In your letter, you state that new 10- to 15-passenger buses are bein sold to schools and school districts in Massachusetts for the transportation of students even though they may not comply with our school bus safety standards. We would appreciate learning more about instances in which a noncomplying bus may have been sold. Please provide any information you may have to NHTSA's Office of Vehicle Safety Compliance, Room 6113, at the address given above. With respect to the future purchases of new vehicles, schools and school districts should keep in mind that the dealers are obligated to sell vehicles that meet the school bus safety standards. The dealers should know that they are at risk if they sell noncomplying vehicles.; In a telephone conversation with Ms. Hom of my staff on March 25, yo requested that we send you the Federal Register notice (41 FR 28506) that interpreted the term 'public school buses' to include buses owned and operated by a private contractor under contract with a State to provide transportation for students to and from public schools. You will find that notice enclosed.; Please let me know if you have any further questions. Sincerely, Jeffrey R. Miller, Chief Counsel |
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ID: aiam0606OpenMr. Clyde D. Parrott, Design Engineer, Cosco Household Products, Inc., 2525 State Street, Columbus, IN 47201; Mr. Clyde D. Parrott Design Engineer Cosco Household Products Inc. 2525 State Street Columbus IN 47201; Dear Mr. Parrott: This is in reply to your letter of February 8, 1972, requestin information pertaining to reclining type child seating systems. You describe these seats in your letter as those which allow the child to ride in a semi-recumbent posture by moving the seating surface forward while maintaining the upper back in a more or less fixed location. You state the hip of the child moves forward as a result, while the head remains in roughly the same place.; The questions you asked regarding this type of child seat are repeate below, followed by our responses.; >>>1. Is NHTSA now testing, or does it intend to test, reclining ca seats in both the upright and reclining configurations?; Paragraph S4.11.1(b) of Standard No. 213 requires that each chil seating system in which the attitude of the child is adjustable meet the performance requirements of the standard when placed in each designed adjustment position. Consequently, reclining child seats must meet these requirements in both reclining and upright positions.; 2. Is the allowed twelve-inch excursion to be measured from th reference point of the semi- recumbent dummy, or from the location of this point were the seat assumed to be upright?; The allowable forward movement of the dummy reference point is to b measured using the reference point of the semi-recumbent dummy, and the forward movement must not exceed 12 inches when measured from that point.; 3. Does the NHTSA intend to make a specific statement on th requirements of reclining car seats . . .?; We believe the language of paragraph S4.11.1 of the standard to b sufficiently explicit regarding this requirement.<<<; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam5404OpenGeorge W. Sudenga, Esq. Johnson, Sudenga, Latham & Peglow 118 East Main Street, P.O. Box 1180 Marshalltown, IA 50158-1180; George W. Sudenga Esq. Johnson Sudenga Latham & Peglow 118 East Main Street P.O. Box 1180 Marshalltown IA 50158-1180; Dear Mr. Sudenga: This responds to your letter following up on my Ma 18, 1994, letter to your client, Mr. Neil Rowe, about Mr. Rowe's product, the 'Glad Grip.' In my letter, I provided information about the National Highway Traffic Safety Administration's (NHTSA's) requirements for manufacturers of motor vehicle equipment, and explained that NHTSA has not issued a Federal motor vehicle safety standard (FMVSS) applicable to a product such as the Glad Grip. In your followup letter, you indicated we did not answer your request for 'approval of NHTSA in advance of major marketing efforts,' concerning your client's product. I regret that my earlier letter was unclear on the issue of NHTSA 'approval' of motor vehicles or motor vehicle equipment. NHTSA does not approve motor vehicles or items of motor vehicle equipment, nor does the agency endorse any commercial products. Instead, the National Traffic and Motor Vehicle Safety Act establishes a 'self-certification' process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. As I stated in the earlier letter, the agency has not issued any safety standards for the Glad Grip. Even if there were an applicable FMVSS, NHTSA would not 'approve' the Glad Grip, rather, Mr. Rowe would self-certify his product. 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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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.