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: aiam5115OpenThe Honorable Paul David Wellstone United States Senate 2550 University Avenue, West Court International Building St. Paul, MN 55114-1025; The Honorable Paul David Wellstone United States Senate 2550 University Avenue West Court International Building St. Paul MN 55114-1025; Dear Senator Wellstone: Thank you for your letter on behalf of you constituents, Ms. Tutti Sherlock and Ms. Mary Bock, regarding the application of the National Highway Traffic Safety Administration's (NHTSA's) school bus standards to Head Start facilities. Your constituents ask that NHTSA inform the Minnesota Department of Transportation that we do not require school bus manufacturers to provide school bus equipment, such as stop arms and special stop lights, on Head Start buses. They base this request on their belief that in 1985, NHTSA said that states may decide which regulations should apply to Head Start buses. They also believe that stop arms and lights for Head Start buses are unnecessary, and that painting Head Start buses yellow could be confusing. We cannot provide the requested interpretation, because the understanding of your constituents is incorrect. By way of background, your constituents' concerns relate to two sets of regulations, issued under different Acts of Congress. The first of these, the Federal motor vehicle safety standards (FMVSS's) issued under the National Traffic and Motor Vehicle Safety Act ('Safety Act'), apply to the manufacture and sale of new motor vehicles. NHTSA has issued a number of FMVSS's for school buses, including FMVSS's requiring these buses to have a stop arm and warning lights. The Safety Act requires that each person selling a new bus (defined in our regulations as a vehicle designed for 11 or more persons) to a primary, preprimary or secondary school must sell a bus that is certified to the FMVSS's for school buses. State law cannot change this requirement. The question of whether Head Start facilities are 'schools' under the Safety Act has been addressed by NHTSA since the beginning of the school bus FMVSS's. The agency's longstanding position is that Head Start programs are primarily educational in focus rather than custodial, and are therefore 'schools' under the Safety Act. We base this conclusion on a review of the goals and functions of the Head Start program (see, e.g., 45 CFR 1304.1-3), and on past NHTSA interpretations of 'school.' NHTSA has stated its position that Head Start facilities are schools most recently in an August 21, 1992 letter to Mr. Chuck Anderson of the Minnesota Department of Transportation. Any new bus that is sold to a Head Start facility must have the safety features of a school bus at the time of the vehicle's sale, including the stop arm and signal lights. However, the Safety Act does not require Head Start facilities to use school buses or any other particular vehicle, nor does it require school buses to be painted yellow. The maintenance and operational characteristics of school buses are matters left to the individual states. NHTSA's second set of school bus regulations, issued under the Highway Safety Act, is a set of recommendations to the states for developing effective pupil transportation programs. Highway Safety Program Guideline No. 17, 'Pupil Transportation Safety' (copy enclosed), recommends that any vehicle designed for 11 or more persons that is used as a school bus should comply with the FMVSS's for school buses and should be painted yellow. However, Guideline 17 would affect the operation of your constituents' school buses only to the extent that Minnesota has incorporated it into state law. I hope this information will be helpful in responding to your constituents. Sincerely, John Womack Acting Chief Counsel Enclosure; |
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ID: aiam1262OpenHonorable Dewey Bartlett, United States Senate, Washington, DC 20510; Honorable Dewey Bartlett United States Senate Washington DC 20510; Dear Senator Bartlett: This is in reply to your letter of July 23, 1973, forwarding to u correspondence from Mr. G. N. Nichols, President, Midwestern Products, Incorporated, Tulsa, concerning the applicability of Federal regulations to an air suspension auxiliary axle manufactured by Midwestern Products. According to the manufacturer's advertising brochure, this axle, the 'Micro-Air Retractable Safety Axle,' is intended to be used on pick-up and bobtail trucks, particularly in the recreational vehicle and related fields.; There are presently no Federal motor vehicle safety standards o regulations that apply to the manufacture of these axles. However, persons who install them on *new* pick-up trucks or other vehicle types (a 'new' vehicle under the National Traffic and Motor Vehicle Safety Act is one that has not yet been sold to a user) may be considered as vehicle alterers under provisions of NHTSA certification regulations which are to become effective February 1, 1974 (Docket No. 72-27, copy enclosed), and would be required to affix to the vehicle the label described in section 567.7 of those regulations.; Midwestern Products should be aware of these requirements whether i installs the Micro-Air axle or whether the installation is done by other parties. In the former case Midwestern would be responsible for affixing the required label, and in the latter it should provide the relevant information for the label regarding weight ratings to the party making the installation.; The NHTSA does not maintain a mailing list to provide copies of NHTS notices and regulations. Copies are available as indicated on the enclosed sheet, 'Where to Obtain Motor Vehicle Safety Standards and Regulations.'; We are pleased to be of assistance. Sincerely, Robert L. Carter, Associate Administrator, Motor Vehicl Programs; |
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ID: aiam5221OpenMr. Ron Marion Sales Engineer Thomas Built Buses, Inc. P.O. Box 2450 1408 Courtesy Road High Point, N.C. 27261; Mr. Ron Marion Sales Engineer Thomas Built Buses Inc. P.O. Box 2450 1408 Courtesy Road High Point N.C. 27261; "Dear Mr. Marion: This responds to your inquiry about the applicabilit of Standard No. 131, School Bus Pedestrian Safety Devices, to school buses you wish to sell to a customer in the United States Virgin Islands. You stated that these buses will be built as right hand drive vehicles with the entrance door located on the left side, since vehicles are driven on the left side of the road in this jurisdiction. You asked whether you can install, on the right side of the bus, the stop signal arm that is required by FMVSS 131. The answer is yes. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381, 'Safety Act') requires new school buses sold in this country and in the U.S. Virgin Islands to comply with all applicable Federal school bus safety standards. (See, 15 U.S.C. 1391(8) for reference to the Virgin Islands.) Standard No. 131 requires school buses to be equipped with a stop signal arm 'on the left side of the bus.' (S5.4) The purpose of this standard is 'to reduce deaths and injuries by minimizing the likelihood of vehicles passing a stopped school bus and striking pedestrians in the vicinity of the school bus.' (S2) When NHTSA specified that the stop arm must be placed on 'the left side of the bus,' the agency meant the driver's side. Comments to the notice of proposed rulemaking (NPRM) and preamble of NHTSA's final rule all assumed that the left side of the bus meant the driver's side. (56 FR 20363, 20367). For example, while endorsing the proposed requirement for the stop arm, several commenters stated that an arm is needed near the driver's window. Moreover, S5.4.1(b) states that, for locating the arm, 'the top edge of the stop signal arm is parallel to and not more than 6 inches from a horizontal plane tangent to the lower edge of the frame of the passenger window immediately behind the driver's window.' (Emphasis added). This provision indicates that the agency assumed that the 'left' side is the driver's side. Further, a stop arm would not be needed on the non-traffic side of the vehicle. Since the left side is not the driver's side for the school buses in question, the agency's general assumption was incorrect. In light of your letter, we will issue a technical amendment of Standard 131 so that S5.4 will require the stop signal arm on the driver's side of the bus. Until the amendment is issued, we will not take enforcement action regarding a manufacturer's locating a right hand drive school bus with a stop signal arm on the bus's driver's side. I hope this information is helpful. If you have any questions about NHTSA's safety standards, please feel free to contact Marvin Shaw at this address or by telephone at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel"; |
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ID: aiam0023OpenMr. David Busby, Busby and Rivkin, Counsellors at Law, 815 15th Street, N.W., Washington, DC 20005; Mr. David Busby Busby and Rivkin Counsellors at Law 815 15th Street N.W. Washington DC 20005; Dear Mr. Busby: Thank you for your letter of April 26, 1967, concerning th interpretation of Safety Standard Number 210.; Paragraph S3.1.1 of Standard Number 208, specifies that the Type 2 sea belt anchorage shall be installed in each outboard passenger seat position that includes the windshield header within the head impact area. Therefore, the rear seat is not included in this area and no Type 2 belt assembly is required. A copy of the Federal Register published February 3, 1967, is enclosed for your information.; With regard to your comments on *Standard Number 209* and on th provision of Section 108(b)(3) of the Act, please be advised that we anticipate the promulgation of joint regulations with the Secretary of the Treasury, permitting the importation of vehicles upon appropriate assurance that they will be brought into conformity with all applicable Federal standards prior to sale. These regulations or related regulations will prescribe the proper means of certifying such nonconforming vehicles in order to insure their admission through United States Customs.; Sincerely yours, George C. Nield, Acting Director, Motor Vehicle Safet Performance Service; |
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ID: aiam0189OpenMr. E. W. Bernitt, Vice President, Safety and Quality Assurance, American Motors Corporation, 14250 Plymouth Road, Detroit, MI 48232; Mr. E. W. Bernitt Vice President Safety and Quality Assurance American Motors Corporation 14250 Plymouth Road Detroit MI 48232; Dear Mr. Bernitt: We have received your submittal of consumer information in response t the requirements of 49 CFR Part 375. That regulation requires that manufacturers submit their information to the Administrator 30 days in advance of the time it is made available to prospective purchasers. Since we have not required that this advance submittal be in the same form as that given to prospective purchasers, the following comments are only advisory in nature. There are several respects, however, in which your information, if supplied in this form to prospective or actual purchasers, would not satisfy the requirements of the regulations.; >>>1. The Stopping Distance information is presented as a 'range o stopping distances,' both in numerical and graphical form. The regulations clearly require a single stopping distance figure to be provided for a given group, that can be met or exceeded by all vehicles in the group. We do not know, and consumers surely would not know, the significance of the lower figure given. Even if it were clear, the provision of such additional, non-required information in close proximity to the required data would cause confusion in attempting to compare figures between various makes--the main purpose of the information.; 2. The provision of four sets of data in respect to partial failure o the braking system, for 'fronts operative' and 'rears operative,' and for lightly-loaded and maximum-loaded vehicles, is not in accordance with the regulation requirement that information be provided for the 'most adverse combination' of weights and system failures. As stated in item 1, above, the inserting of this additional information, self-serving in every case since only the worst element should be included, would make comparisons difficult and be unfair to competing manufacturers who followed the regulations strictly.; 3. The form of the Stopping Distance information would fail to satisf the requirement that the information be presented 'in essentially the form illustrated in Figure 1' of 49 CFR S 375.101. In particular, we refer to the placing of two columns side by side instead of the single-axis graph depicted in that figure, and the inclusion of other verbiage between the required statements and warnings and the information itself. The reference to shorter stopping distances with wheel lock-up and without restricting pedal effort, between the required information and the graphs, is especially objectionable, since the safety advantages of avoiding wheel skid were a particular concern in developing this regulation. Although the regulations do not prohibit the provision of other than required information in a Consumer Information booklet, they do require that it be separated in such a manner that the required information, both textual and quantitative, is presented in 'essentially the form illustrated.'; 4. The Tire Reserve Load section of the regulations requires that 'th table that is provided for a specific vehicle shall contain only information that is applicable to that vehicle.' This requirement prohibits a large, all-purpose chart such as yours, with information for many vehicles included on it, at least as far as the information given to the actual purchaser of a vehicle is concerned. More generally, the information is not presented in 'essentially the form illustrated in Figure 1' of 49 CFR S 375.102.; 5. The large, all-inclusive bar graph on Acceleration and Passin Ability does not present the information in 'essentially the form illustrated in Figure 1' of 49 CFR S 375.106, as required.<<<; We will be glad to answer any questions that you may have with respec to the requirements of these or other motor vehicle safety regulations and standards.; Sincerely, Robert Brenner, Acting Director |
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ID: aiam4963OpenDr. Carl C. Clark Safety Systems Company 23 Seminole Avenue Baltimore, MD 21228-5638; Dr. Carl C. Clark Safety Systems Company 23 Seminole Avenue Baltimore MD 21228-5638; "Dear Dr. Clark: This responds to your request for an interpretation o Standard No. 205, Glazing Materials (49 CFR 571.205). More specifically, your letter indicated your belief that Standard No. 205 permits a prime glazing material manufacturer to designate an item of glass-plastic glazing that it manufactures as 'Item 14' glazing if that glass- plastic glazing item passes all the tests specified for Item 14 glazing. It is your view that it is irrelevant whether the individual glass layers in the glass-plastic glazing are tempered or annealed glass. Your understanding is correct. Standard No. 205 specifies the performance requirements for Item 14 glazing, through a series of 14 tests designated for that item of glass-plastic glazing material. No test applicable to Item 14 glazing specifies that any individual layer, either glass or plastic, of this laminated glazing is to be tested separately. Instead, the 14 tests applicable to Item 14 glazing set forth performance levels that must be achieved by the glazing as a laminate. One of the 14 tests designated for Item 14 is Penetration Resistance, Test No. 26. You are correct in noting that, effective September 23, 1991, Test No. 26 specifies the glass-plastic specimen is to be clamped into a test fixture before the specimen is tested. If an item of glass-plastic glazing passes each of the 14 tests applicable to Item 14 glazing, including Test No. 26, with clamping, and complies with Standard No. 205's labeling and certification requirements, the prime glazing material manufacturer of the material may designate that item of glass-plastic glazing as Item 14 glazing. You were also correct in your understanding that Standard No. 205 permits Item 14 glazing to be used for passenger car glazing in any position except the windshield of convertibles. I hope this information is helpful. Please feel free to contact Dorothy Nakama of my staff at this address or by telephone at (202) 366-2992 if you have any further questions or need additional information. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0473OpenMr. Louis C. Lundstrom, Director, Automotive Safety Engineering, General Motors Technical Center, Warren, MI 48090; Mr. Louis C. Lundstrom Director Automotive Safety Engineering General Motors Technical Center Warren MI 48090; Dear Mr. Lundstrom: This is in response to your letter of October 19, 1971, in which yo asked whether the second and third options of Standard 208 require anthropomorphic test devices to be placed for the frontal crash tests only in the front designated seating positions, and not in the rear positions.; The answer is yes. The second and third options pose no requirement for testing that require dummies in the rear positions, hence dummies should be placed only in front positions. In the period from January 1, 1972 to August 15, 1973, they should in fact be placed only in the front outboard positions.; You also suggested that 'if Option 1 is used, a test device must be a each designated seating position.' This statement is true, in a strict sense. But the general requirements for the periods before August 15, 1975 (S4.1.1 and S4.1.2) explicitly allow the 'mixing' of options, so that if belts are provided for the rear seating positions they may be considered as fulfilling option two or three, without dummies positioned there for the crash tests. In other words, dummies must be positioned in the rear seating positions only if and when the manufacturer elects to fulfill option one for the rear positions.; Sincerely, Robert L. Carter, Acting Associate Administrator, Moto Vehicle Programs; |
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ID: aiam0166OpenMr. Francois Louis, Manager, Technical Standards Department, National Service and Parts Division, Renault, Incorporated, 100 Sylvan Avenue, Englewood Cliffs, NJ 07632; Mr. Francois Louis Manager Technical Standards Department National Service and Parts Division Renault Incorporated 100 Sylvan Avenue Englewood Cliffs NJ 07632; Dear Mr. Louis: Thank you for your letter of June 18, 1969, to the U.S. Department o Transportation, concerning your request for clarification of the visibility requirements of back up (sic) lamps as specified in Federal Motor Vehicle Safety Standard No. 108.; The visibility requirements for backup lamps on station wagons o similar type motor vehicles will be predicated on the normal driving, or closed tailgate, position. These lamps may therefore be mounted on the tailgate.; Sincerely, Charles A. Baker, Office of Standards on Accident Avoidance Motor Vehicle Safety Performance Service; |
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ID: aiam5364OpenMartin M. Sackoff, Ph.D. Executive Director of Laboratories International Testing Laboratories 578-582 Market Street Newark, NJ 07015-2913; Martin M. Sackoff Ph.D. Executive Director of Laboratories International Testing Laboratories 578-582 Market Street Newark NJ 07015-2913; "Dear Dr. Sackoff: This responds to your letter to this agency wit reference to Federal Motor Vehicle Safety Standard No. 109, New Pneumatic Tires. Your specific question addressed S4.2.2.4, Tire strength, which states: 'Each tire shall meet the requirements for minimum breaking energy specified in Table I when tested in accordance with S5.3.' You asked for an interpretation of the term 'breaking,' whether it means a blowout of the tire or the breaking of the tire caused by the plunger used in the test specified in the standard. The breaking energy test is a measure of the resistance of the tire to bruise or damage due to impact of the tire with road hazards. This agency tests such resistance in accordance with the procedures of S5.3, Tire strength, of the standard. In that test, a cylindrical steel plunger is forced perpendicularly into the tire rib at the rate of 2 inches per minute at five test points equally spaced around the circumference of the tire. The inch-pounds of force required to push the plunger into the tire is continuously monitored. As the plunger pushes into the tire, the resistance to the plunger force increases. That resistance requires ever-increasing force applied to the plunger to continue pushing it into the tire. Ultimately, one of two things will happen: 1. The plunger will push all the way to the rim, or 2. The tire cords, plies, innerliner, or other components of the tire will stretch, separate, crack or break so that the resistance pressure of the tire diminishes. The 'breaking' of the tire at that point does not require an actual blow-out although, obviously, a blow-out would constitute a 'breaking.' The plunger force is measured just prior to contact with the rim as in 1 above or just prior to the force reduction described in 2 above. The measured force is then combined with the penetration of the plunger into the tire as specified in S5.3.2.3 and S5.3.2.4 of the standard. The breaking energy value of the tire is then determined by computing the average of the values obtained at the five test locations on the tire. Table I, Appendix A of the standard specifies the minimum breaking energy of tires based on tire type, size, composition, and inflation pressure. I hope this information is helpful to you. Should you have any further questions or need any 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: aiam0536OpenJohann und Konen, 53 Bonn-Beuel 1, Rosenbach 32, Ortsteil Putzen, Germany; Johann und Konen 53 Bonn-Beuel 1 Rosenbach 32 Ortsteil Putzen Germany; Gentlemen: This is in reference to your letter of August 22, 1972, requestin information relative to Federal Motor Vehicle Safety Standard No. 125, 'Warning Devices.'; You state that the width of the reflex reflective material in th Warning Triangle you are concerned with is 1.6732 inches, and inquire whether it is permissible to utilize 'for manufacturing reasons' a non-reflective border around the reflective material which would increase the width of the red reflective section to 1.8504 inches.; Paragraph S5.2.2 of Standard 125 specifies that the width of each o the three sides of the triangular portion of the warning device shall be not less than 2 and not more than 3 inches wide, as depicted in Figure 1. If the required widths specified in S5.2.5 for the red reflex reflective and orange fluorescent materials are met, provision of non-reflective or non-fluorescent 'border' material is permitted, as long as the overall width requirements for the side of the triangle are also met.; I hope this answers your questions. Sincerely, E.T. Driver, Director, Office of Operating Systems, Moto Vehicle Programs; |
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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.