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 |
|---|---|
ID: aiam2449OpenMr. Byron Crampton, Truck Body and Equipment Association, 5530 Wisconsin Ave., Suite 1220, Washington, DC 20015; Mr. Byron Crampton Truck Body and Equipment Association 5530 Wisconsin Ave. Suite 1220 Washington DC 20015; Dear Mr. Crampton: This responds to the Truck Body and Equipment Association's November 8 1976, question whether any provision of Standard No. 120, *Tire Selection and Rims for Motor Vehicles Other than Passenger Cars*, prohibits the certification of a vehicle following the addition of an axle system (typically known as a 'tag' or 'pusher' axle) that is not equipped with tires or rims at the time of sale and delivery to the first purchaser for purposes other than resale.; The answer to your question is no. The requirement of S5.1.1 that '. . each vehicle equipped with pneumatic tires for highway service shall be equipped with tires that meet specified requirements . . . ' prohibits the installation of tires that do not meet certain performance requirements, but it is not a requirement that tires be fitted to every axle of a vehicle prior to certification and sale.; I would like to point out that S 567.4(g)(4) of Part 567 *Certification*, requires that a gross axle weight rating be assigned to each axle system. Section S5.1.2 of Standard No. 120 specifies that the GAWR be not more than the sum of the maximum load ratings of the tires fitted to the axle in question. While the agency interprets Standard No. 120 to permit the assignment of a GAWR on the basis of tires listed on the certification plate for that GAWR, the assignment of an arbitrarily high (or low) GAWR for purposes such as avoiding a Federal motor vehicle safety standard (such as Standard No. 121, *Air Brake Systems*), would constitute a violation of S108(a)(1)(D) of the National Traffic and Motor Vehicle Safety Act:; >>>S108(a)(1) No person shall (A) . . . (c) (sic) Fail to issue a certificate required by section 114 of thi title, or issue a certificate to the effect that a motor vehicle or item of motor vehicle equipment conforms to all applicable Federal motor vehicle safety standards, if such person in the exercise of due care has reason to know that such certification is false or misleading in a material respect.<<<; Sincerely, Frank A. Berndt, Acting Chief Counsel |
|
ID: aiam4964OpenHerrn. Westermann u. Schmidt Hella KG Hueck & Co. Rixbecker Stra e 75 Postfach 2840 4780 Lippstadt Germany; Herrn. Westermann u. Schmidt Hella KG Hueck & Co. Rixbecker Stra e 75 Postfach 2840 4780 Lippstadt Germany; "Gentlemen: This responds to your FAX of December 9, 1991, to Richar Van Iderstine of this agency. You ask for a definition of two and four headlamp systems, stating that formerly 'this definition was done under para. S4.1.1.36, but today there only remains figure 26, which explains the application of photometric requirements with respect to the bulb or bulb combination used.' You have enclosed sketches of three replaceable bulb headlighting systems and ask for confirmation that each is a two or four headlamp system under Standard No. 108. Standard No. 108 has never contained a specific definition of two or four lamp headlamp systems. Paragraph S4.1.1.36 impliedly defined these systems for headlamps incorporating replaceable bulbs by specifying requirements for the upper and lower beams of headlamp systems consisting of two or four lamps, each containing one or two standardized replaceable light sources. When Standard No. 108 was amended to delete S4.1.1.36, these provisions became part of new paragraph S7.5 Replaceable Bulb Headlamp System. Figure 26 Table of Photometric Requirements was added to illustrate photometric requirements for headlighting systems that use combinations of replaceable bulbs listed in S7.6 Standardized Replaceable Light Sources, and as the systems are described in S7.5. The understanding expressed in your drawings of replaceable bulb headlamp systems is correct. A 4-lamp system is one in which each lamp contains one light source, usually HB3 or HB4 light source for a total of two HB3 and HB4 light sources per system. A 2-lamp system is one in which each lamp typically contains a single dual filament light source such as HB1 or HB5, and achieves both a lower beam and an upper beam, alternatively, each lamp may contain two light sources, typically one HB3 and one HB4 light source, each with individual reflectors, but together with a common housing and lens. This lamp achieves both a lower and an upper beam. Sincerely, Paul Jackson Rice Chief Counsel"; |
|
ID: aiam3608OpenMr. Jerome N. Sonosky, Mr. Mark S. McConnell, Hogan & Hartson, 815 Connecticut Avenue, Washington, DC 20006; Mr. Jerome N. Sonosky Mr. Mark S. McConnell Hogan & Hartson 815 Connecticut Avenue Washington DC 20006; Dear Messrs. Sonosky and McConnell: This is in further response to your letter concerning the applicatio of several Federal Motor Vehicle Safety Standards to mopeds. You asked whether Standard No. 108 and Standard No. 127 would preempt States statutes or regulations on the same subjects.; Your specific question on Standard No. 127 was whether section 3 of th standard, which excluded mopeds from the coverage of the standard, would preempt State laws that require all motor vehicles operated on the highways to be equipped with a speedometer. Subsequent to your letter, the agency rescinded Standard No. 127 (47 FR 7250). In rescinding the standard, the agency stated that it recognized that there is a nexus between having a speedometer and motor vehicle safety. Based on available information, however, the agency concluded that the specific requirements of the standard concerning the markings on a speedometer, such as the highlighting of the numeral '55', were not yielding and could not be expected to yield significant safety benefits. Because the marking requirements were not yielding safety benefits, the agency stated that it intended that other levels of government be preempted from establishing similar requirements. In preempting States from establishing marking requirements, the agency did not intend to preempt States from enforcing laws or regulations which only require the presence of a speedometer and do not set marking requirements for the speedometer.; Your final question concerned section 4.1.1.26 of Standard No. 108 which exempts motor-driven cycles whose speed attainable in one mile is 30 mph or less from the requirement that motor vehicles be equipped with turn signal lamps. You asked if that provision preempts State laws to the extent they require all motor vehicles to be equipped with turn signal lamps. The answer is yes.; In adopting section 4.1.1.26, the agency specifically addressed th issue of what turn signal requirements are necessary and appropriate for mopeds. The agency determined that the speed and weight characteristics of mopeds made the problems associated with hand signaling less significant than they are for larger motorcycles. The agency concluded that exempting mopeds from the turn signal requirement would ease the burden of compliance for moped manufacturers without jeopardizing safety. Since Standard No. 108 specifically addresses the issue of what turn signal requirements are applicable to mopeds, States are preempted from establishing or enforcing a safety standard on that aspect of performance that is not identical to the Federal standard.; If you have any further questions, please let me know. Sincerely, Frank Berndt, Chief Counsel |
|
ID: aiam1635OpenMr. W. M. Griffith, Secretary, Canadian Truck Trailer Manufacturers Association, P.O. Box 294, Kleinburg, Ontario, Canada; Mr. W. M. Griffith Secretary Canadian Truck Trailer Manufacturers Association P.O. Box 294 Kleinburg Ontario Canada; Dear Mr. Griffith: This responds to your October 11, 1974, request for an interpretatio of the application of Standard No. 121, *Air brake systems*, to Canadian-made truck trailers manufactured in Canada following the effective date of the standard and subsequently used in inter-country commerce.; I have enclosed a copy of a letter on this subject to th representative of another Canadian manufacturer, which should answer your question. Please write again if you have further questions.; Yours truly, Richard B. Dyson, Acting Chief Counsel |
|
ID: aiam0927OpenMr. Evan Hammond, Manager-Central Engineering, Trailmobile, 4453 34th Street, Cincinnati, OH 45209; Mr. Evan Hammond Manager-Central Engineering Trailmobile 4453 34th Street Cincinnati OH 45209; Dear Mr. Hammond: This is in reply to your letter of November 3, 1972, in which you as whether a Certification label, a drawing (33-1-78) of which you enclose, will meet both the requirements of the Certification regulations (49 CFR Part 567) and those of proposed Motor Vehicle Safety Standard No. 120, 'Tire and Rim Selection and Rim Performance' (36 F.R. 142730). In our conversation of November 28, 1972, you asked two additional questions--first, whether GAWR for trailers could be expressed as a single figure when the ratings for each axle are identical, and second, as followed up by your letter of November 30, what is the appropriate method for determine GVWR for a semitrailer having a 'sliding-bogie' axle.; The Certification label you have submitted would conform to th requirements of Part 567, and proposed Standard No. 120 if 'rim size' is moved from its location following GAWR and GVWR to the bottom of the label, in proximity to the 'maximum rim load rating.' The Certification regulation does not require rim size to be specified, and rim size would therefore have to appear after the information required by that regulation. The requirements of proposed Standard No. 120 are tentative only, as you must know, and manufacturers should not make permanent plans regarding them until a final rule is issued.; The NHTSA position with respect to GAWR being expressed as one figur when identical axles are involved is that such a method is not consistent with the Certification regulation. Each axle must be listed separately on the Certification label regardless of whether its rating is identical to that of other axles. We have no record of any oral statement to the contrary, and if one was made, as you seem to recall, we regret that it was in error. With respect to specifying GVWR for trailers having sliding-bogie axles, the NHTSA position is that a manufacturer is free to assume the axle to be in either position. If the manufacturer wishes to indicate at which position the rating is based, he may do so on the label, following all required information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam4437OpenMr. Doug Cole National Van Conversion Association, Inc. 2 West Main St., Suite 2 Greenfield, IN 46140; Mr. Doug Cole National Van Conversion Association Inc. 2 West Main St. Suite 2 Greenfield IN 46140; "Dear Mr. Cole: This responds to your letter asking about the tes procedures of Federal Motor Vehicle Safety Standard No. 302, Flammability of Interior Materials. I regret the delay in responding. In your letter, you explained that the National Van Conversion Association (NVCA) gathers samples of materials used for vehicle floor coverings, seat covers, etc., in van conversions to determine the compliance of the material with Standard No. 302. In your test program, you have found that many samples do not appear to comply. You said that a closer look at the conditions under which these samples were tested revealed that use of support wires affected whether many materials passed or failed the standard's test. You ask for clarification as to when support wires are used in Standard No. 302 testing. The conditions and procedures under which Standard No. 302 compliance testing is conducted using support wires are stated in paragraphs S5.1.3 and S5.3(a) of the standard. Basically, these two paragraphs specify, respectively, that support wires are used: (1) when testing a specimen 'that softens and bends at the flaming end so as to cause erratic burning,' to keep the specimen horizontal, and (2) when testing a specimen that has an available width of not more than 2 inches, to position and mount the specimen on the U-shaped frames used in the test. Standard No. 302 makes no provision for using the wires other than in these two situations. The agency follows the test procedure specified in Standard No. 302 when testing vehicles for compliance with the requirements of the standard. The agency uses heat-resistant wires as specified in S5.1.3 when there is a reasonable expectation that a test specimen will bend or curl while burning. NHTSA bases its determination about the likelihood of bending or curling on observations made in previously-conducted compliance tests of the specimen, or on the agency's knowledge of or testing experience with materials similar to a test specimen. I would like to point out that manufacturers are not required by Standard No. 302 to test the flammability of their vehicles in only the manner specified in the standard. The standard only sets the procedure that the agency will use in its compliance testing. Thus, a manufacturer is not required to use wires only with specimens that are anticipated to bend or curl, or that are too small to fit in the test frame without wires. However, manufacturers must exercise due care in making their certification of compliance that their product will meet the standard's requirements when tested by the agency according to the specified procedures of the standard. Whether a manufacturer meets that due care standard when using heat-resistant wires in situations other than those described in Standard No. 302 is a matter that can be determined only in the context of an enforcement proceeding. Please contact us if you have any further questions. Sincerely, Erika Z. Jones Chief Counsel /"; |
|
ID: aiam3258OpenMr. J. W. Lawrence, Manager, Reliability & Government Standards, White Motor Corporation, 35129 Curtis Boulevard, Eastlake, OH 44094; Mr. J. W. Lawrence Manager Reliability & Government Standards White Motor Corporation 35129 Curtis Boulevard Eastlake OH 44094; Dear Mr. Lawrence:#This responds to your letter of January 15, 1980 which requested an interpretation of Federal Motor Vehicle Safety Standard No. 101, *Controls and Displays*. You described a control to be included in heavy duty truck tractors which would operate the cab marker lights and some of the trailer lamps and asked whether Safety Standard 101 would permit labeling of the control with the words 'marker lamps.'#We have concluded, for the reasons stated below, that Safety Standard 101 would not permit the control to be labeled in the fashion you suggest. However, it would permit labeling of the control with the symbol for clearance lamps designated therein accompanied by the words 'Clearance Lamps' or the abbreviation 'Cl Lps' and by the words 'marker lamps.'#With respect to vehicles including trucks with gross vehicle weight ratings exceeding 10,000 pounds manufactured before September 1, 1980, S4 of Safety Standard 101 permits manufacturers to comply with its requirements or with those of Safety Standard 101-80. S4.2.1 of Safety Standard 101 requires that a control which operates clearance lamps, identification lamps and/or side marker lamps be identified with the words 'Clearance Lamps' or the abbreviations 'Cl Lps' as shown in Table I Column 2 of the standard. In addition, S4.2.1 provides that such a control may also be identified by one of the symbols for clearance lamps shown in Columns 3 and 4 of Table I. (See Table I, Footnote 3.) S5.2.1 of Safety Standard 101-80 requires that such a control be labeled with the symbol for clearance lamps shown in Column 3 of Table I of the standard. However, this symbol may be accompanied by the word or abbreviation shown in Column 2 (i.e., Clearance Lamps or Cl Lps) and additional words or symbols may be used at the manufacturer's discretion for the purpose of clarity. (See Table I, Footnote 3.) The requirements of Safety Standard No. 101-80 will become mandatory and will supercede those of Safety Standard 101 for all vehicles to which it applies which are manufactured on or after September 1, 1980.#According to your product description, the control which you propose to label with the words 'marker lamps' would operate some of the trailer lamps and the cab marker lamps which also serve as clearance lamps. Thus, the control would be considered to operate clearance lamps and marker lamps and would be subject to the provisions of Safety Standard 101, Table I, Footnote 3. Accordingly, on vehicles manufactured *before* to September 1, 1980, the control you propose either must be identified in one of the following methods:#>>>1. with the words 'CLEARANCE LAMPS' or the abbreviations 'CL LPS', or#2. with the words or abbreviations shown in method number 1 above accompanied by the symbol shown in Column 3 of Table I or by the symbol shown in Column 4, Table I, of Safety Standard No. 101, or#3. with the symbol for clearance lamps shown in Column 3, Table I, of Safety Standard 101-80, or#4. with the symbol noted in method number 3 above accompanied by the words 'clearance lamps' or the abbreviations 'Cl Lps' as shown in Column 2 of Table I of Safety Standard 101-80, or#5. with the symbol and the words or abbreviations noted in method number 4 above accompanied by any additional clarifying words or symbols the manufacturer may choose.<<<#If the control you have proposed is included in vehicles manufactured on or after September 1, 1980, it must be identified as indicated in method number 3 above and may be identified as indicated in method number 4 or 5 above. Use of method number 5 above would permit use of the words 'marker lamps' in addition to the required symbol and the words 'Clearance Lamps' or the abbreviation 'Cl Lps.'#I hope that you will find this response helpful and have not been inconvenienced by our delay in sending it to you.#Sincerely, Frank Berndt, Chief Counsel; |
|
ID: aiam1265OpenMr. Gene J. Shapiro, The Temple Building, Suite 707, Seventy-seven West Washington Street, Chicago, IL 60602; Mr. Gene J. Shapiro The Temple Building Suite 707 Seventy-seven West Washington Street Chicago IL 60602; Dear Mr. Shapiro: This is in reply to your letter of August 28, 1973, concerning Federa Motor Vehicle Safety Standard No. 218, 'Motorcycle Helmets.' You request information regarding the American National Standards Institute (ANSI) Standard Z90.1, and all existing State standards or regulations requiring the use of headgear by motorcyclists.; First, it appears you may be under the impression the Z90.1 standar and its revisions were issued by the Federal Government. This is not the case. Although the requirements of Federal Motor Vehicle Safety Standard No. 218 are largely, though not entirely, based on the Z90.1-1971 Standard published by the American National Standards Institute, the Institute is a private organization neither sponsored nor supported by the Federal Government. You will have to write to the ANSI if you want any information concerning the Z90.1 standard and its revisions.; You may obtain the existing State standards or regulations requirin the use of headgear by motorcyclists from the Department of Motor Vehicles in each State, respectively. However, it may interest you to know that any State or local requirements for the design or performance of motorcycle helmets, that have a bearing on safety, will have to be identical to the requirements of the Federal standard when the Federal standard goes into effect.; A copy of Standard No. 218 and a copy of the National Traffic and Moto Vehicle Safety Act of 1966, are enclosed for your information.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
|
ID: aiam4067OpenMr. Benjamin R. Jackson, Executive Director, Automobile Importers Compliance Association, 1607 New Hampshire Avenue, N.W., Washington, DC 20009; Mr. Benjamin R. Jackson Executive Director Automobile Importers Compliance Association 1607 New Hampshire Avenue N.W. Washington DC 20009; Dear Mr. Jackson: This responds to your letter requesting an interpretation of 49 CF Part 541, *Federal Motor Vehicle Theft Prevention Standard*. Specifically, you noted that section 541.5(d)(2)(iii) requires the original equipment parts on vehicles subject to the theft prevention standard to have the required markings entirely within the target area specified for the part by the original manufacturer of the vehicle. You stated that it was possible that target areas specified by the original manufacturer might be suitable for marking by means of labels, but not suitable for marking by means of inscription. If this situation were to occur, you asked if Part 541 could be interpreted to permit manufacturers that must mark by means of inscription to place those markings outside the target area designated by the original manufacturer. Part 541 cannot be so interpreted.; In the case of inscribed markings, S541.5(d)(2)(iii) specifies that th required markings shall be 'placed entirely within the target area specified by the original manufacturer for that part.' This requirement applies to *all* markings inscribed for the purposes of Part 541, whether done by an original manufacturer or a direct importer.; The policy bases underlying this requirement were explained at lengt in the preamble to the final rule establishing Part 541. *See* 50 FR 43166, at 43172, October 24, 1985. First, it is important that all parts be marked in the same target area so that investigators will know exactly where to look on a part for the required marking. The investigator would be alerted to possible suspicious activity if the marking were outside the target area. Second, the different target areas for original equipment and replacement parts marking are intended to ensure that there will be an adequate separation between the areas where the different types of parts will be marked. This will ensure that a thief cannot obliterate an original equipment part marking and affix a counterfeit replacement part marking directly over the area where the original equipment part marking was located.; Both of these purposes would be undercut if original manufacturers an direct importers were allowed to designate different target areas for marking vehicles in the same line. Accordingly, Part 541 explicitly requires only one target area for the required marking on each part of a covered line.; We do not believe that your concern about inscribing markings on curve surfaces is well- founded. The agency knows of a number of means of inscribing numbers on curved surfaces that would permit direct importers to mark those surfaces within the $15 cost limit set forth in section 604(a)(2) of the Cost Savings Act.; Sincerely, Erika Z. Jones, Chief Counsel |
|
ID: aiam4572OpenThe Honorable Howard Wolpe U.S. House of Representatives Washington, D.C. 20515; The Honorable Howard Wolpe U.S. House of Representatives Washington D.C. 20515; "Dear Mr. Wolpe: Thank you for your letter to former Secretary Burnle on behalf of your constituent, Mr. Dennis Furr of Lansing, Michigan. I've been asked to respond to your letter since the National Highway Traffic Safety Administration (NHTSA) is responsible for administering Federal programs relating to school bus safety. Mr. Furr is concerned about the potential safety problems that may result if school bus seats are being overloaded. In particular, Mr. Furr asks whether NHTSA's Highway Safety Program Guideline (HSPG) No. 17, Pupil Transportation Safety (23 CFR /1204.4), is consistent with Federal Motor Vehicle Safety Standard (FMVSS) No. 222, School Bus Passenger Seating and Crash Protection (49 CFR /571.222), with regard to seating specifications. Mr. Furr is particularly interested in how manufacturers are calculating the number of seating positions on a bench seat. I am pleased to address your constituent's concerns. Before I begin, I want to note that we have answered a number of similar inquiries from Mr. Furr in past years. We have two sets of 'regulations' for school buses. The first, issued under the Vehicle Safety Act, includes our motor vehicle safety standards which apply to the manufacture and sale of new school buses. Compliance with these standards is mandatory for new vehicle manufacturers, and is enforced by this agency with civil penalties. FMVSS No. 222, with which your constituent is concerned, is one such safety standard. The second set of 'regulations,' or guidelines, for school buses was issued under the Highway Safety Act. Guidelines issued under this Act are not mandatory for the states, rather, they are recommended practices. Highway Safety Program Guideline No. 17, to which Mr. Furr frequently refers in his letter, consists of recommendations to the States for operating their school buses and pertains to Federal funding of State highway safety programs. Both FMVSS No. 222 and Guideline No. 17 contain specifications for school bus seating. Paragraph S4.1 of FMVSS No. 222 states: 'The number of seating positions considered to be in a bench seat is expressed by the symbol W, and calculated as the bench width in inches divided by 15 and rounded to the nearest whole number.' The guideline for seating accommodations in HSPG 17 states: Seating should be provided that will permit each occupant to sit in a seat in a plan view lateral location, intended by the manufacturers to provide seating accommodation for a person at least as large as a 5th percentile adult female, as defined in 49 CFR 571.3. Mr. Furr appears to see a conflict between the formula used in calculating the forces to be applied to the seats of large school buses under FMVSS No. 222, on the one hand, and the use by States and manufacturers of 13-inch seating positions for rating the capacity of a 39-inch seat, on the other hand. I believe that Mr. Furr's belief in the existence of a conflict rests on a misunderstanding. We view Standard No. 222 and HSPG 17 as complementary, not inconsistent. HSPG 17 reflects NHTSA's belief that all school bus passengers should be seated in the interest of safety. To that end, the guideline provides that there should be a seating position for each passenger and that the position should be at least large enough to accommodate a 5th percentile adult female. The hip width (sitting) of a 5th percentile adult female is 12.8 inches. The figure '15' in FMVSS No. 222's compliance formula is not a minimum requirement for the width of a seating position. It is the number which is used to establish the number of designated seating positions and ensures that the forces applied to the seat during compliance tests are reasonable reflections of the crash forces that would be involved in a real-world crash. It is also the number which ensures that the width of the smallest seat is approximately equal to the hip width of the 5th percentile female. That is consistent with HSPG 17 which provides that seating positions shall be at least large enough for a 5th percentile female. Use of the figure '15' in the FMVSS No. 222 formula results in a minimum seating position width of 12.67 inches (for a 38-inch wide seat.) That is only slightly smaller than the 12.8 inch hip width of the 5th percentile female. For a 39-inch wide seat, the single position width is 13 inches, which is slightly larger than the hip width of a 5th percentile female. It should be remembered, however, that the number of seating positions derived from the FMVSS No. 222 formula is not meant to be a measure of the absolute capacity of the bus for all size occupants. We recognize that, in practice, school buses transport a tremendously wide variety of student sizes. For example, a bus that may be capable of easily accommodating 65 preschool or elementary students may be capable of carrying only 43 high school students. When the bus is used to transport students of widely varying ages and sizes, reasonable accommodations may vary between those values. The decision on how many passengers may be comfortably and safely accommodated, therefore, is a decision that must be reached by the bus operator, in light of the ages and sizes of passengers involved. NHTSA does not have the authority under either the Highway Safety Act or Vehicle Safety Act to regulate how States use school buses. Therefore, NHTSA could not preclude a State from carrying more passengers on a bench seat than there are designated seating positions. However, this agency agrees with Mr. Furr that a student should not sit on a seat unless the student can sit fully on the seat instead of sitting only partially on the seat and thus only being partially protected by the compartmentalization. We believe that Mr. Furr's concerns as they apply to public schools would be best addressed by his working with the local school board and state officials. Mr. Furr is also concerned about a reference in our occupant crash protection standard (No. 208) to a 95th-percentile adult male occupant size. He asks why FMVSS No. 222 uses a 15-inch seat dimension, when FMVSS No. 208 references the 95th-percentile adult male occupant size in specifying occupant sizes which safety belts must adjust to fit. Both FMVSS No. 208 and FMVSS No. 222 are directed at providing occupant crash protection. Both of these standards set forth comprehensive requirements that are directed at protecting occupants likely to be inside a vehicle in a crash. With regard to school buses, the agency determined that the crash protection requirements should be developed taking into account the full size range of passengers typically riding on school buses. If we designed the force and deflection (energy-absorbing) characteristics of the seats for the 95th percentile males, the seats may be too stiff for a small child. Finally, Mr. Furr asks whether, when voluntarily installing safety belts on large school buses, States are violating Federal law by using S4.1 of FMVSS No. 222 in determining how many positions (and belts) there are on a bench seat. The answer is no. FMVSS No. 222 requires safety belts only for the passenger positions of small (10,000 pounds or less GVWR) school buses. Under S5 of the standard, belts on a small school bus bench seat are installed at 'W' seating positions, as determined under S4.1. If a State wishes to order belts on its new large school bus and to use the same method for determining the number of belts to be installed, the State may do so. I hope this information is helpful. If you have any further questions, please do not hesitate to contact me. Sincerely, Diane K. Steed"; |
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.