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: aiam3769OpenGreg Kreshel, P.E., V.P. Production, Alloy Trailers, Inc., P.O. Box 19208, Spokane, WA 99219; Greg Kreshel P.E. V.P. Production Alloy Trailers Inc. P.O. Box 19208 Spokane WA 99219; Dear Mr. Kreshel: This is in reply to your letter of October 25, 1983, to Mr. Vinson o my staff, in which you question the practice by Fruehauf of replacing upper rear identification lamps with reflectors, on certain trailers. You asked if it were possible that the manufacturer would say that the header was too narrow for a light to fit.; I enclose a copy of an interpretation this office furnished Fruehau and the State of Wisconsin on June 18, 1981, which will clarify this issue. In summary, Fruehauf demonstrated to us the impracticability of mounting the identification lamps at the top of a vehicle of this configuration (principally because of the vulnerability of the wiring). At the time, Fruehauf expressed its concern about conspicuity of its vehicles and assured us that it would investigate ways to improve it in future production. Apparently it decided that adding reflectors at the top, at the body edges and towards the middle where the doors open, was the most satisfactory way to enhance conspicuity, given the design of the vehicle.; Thank you for your interest in this question. Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4556OpenMr. Wayne Ivie Manager, Vehicle Support Service Section Oregon Department of Transportation 1905 Lana Avenue NE Salem, OR 97314; Mr. Wayne Ivie Manager Vehicle Support Service Section Oregon Department of Transportation 1905 Lana Avenue NE Salem OR 97314; "Dear Mr. Ivie: This responds to your letter seeking information abou the labeling requirements in Standard No. 218, Motorcycle Helmets (49 CFR 571.218). You noted that Oregon recently enacted a mandatory helmet use law which adopted Standard No. 218 as the minimum standard for helmets. You correctly noted that section S5.6.1 of Standard No. 218 requires subject motorcycle helmets to be permanently and legibly labeled with specified information, including the symbol 'DOT' as a certification that the helmet complies with Standard No. 218. However, you stated that you have received reports that the labeling required by Standard No. 218 is not present on many helmets, either because it has fallen off or been removed by someone. You said that there is often no other identification of the manufacturer or brand name on the helmet. Accordingly, it is not possible for the owner of a helmet without the Standard 218 label present to contact a dealer or manufacturer for information about the helmet. You then asked several questions about the labeling requirements set forth in Standard No. 218. Before answering your specific questions, I would like to provide some general background information on Standard No. 218. Prior to October 3, 1988, Standard No. 218 applied only to helmets that could be placed on the size C headform. The helmet manufacturers estimated that approximately 90 percent of all motorcycle helmets were subject to Standard No. 218, because they could be placed on the size C headform. However, helmets manufactured before October 3, 1988 that could not be placed on the size C headform (these were typically smaller sizes of helmets) were not subject to Standard No. 218. Hence, manufacturers of helmets that could not be placed on the size C headform were not required by Standard No. 218 or any of our other regulations to label any information on these helmets. In fact, manufacturers could not label the DOT certification symbol on those helmets that were not subject to Standard No. 218. See the enclosed December 4, 1987 letter to Mr. Hoppe for more information on this subject. We published a final rule on April 6, 1988 that extended the requirements of Standard No. 218 to all motorcycle helmet sizes (53 FR 11280). This rule became effective on October 3, 1988. Accordingly, all motorcycle helmets manufactured on or after October 3, 1988 are subject to Standard No. 218 and must be labeled in accordance with the requirements of S5.6 of that standard. With this background, your question can be answered as follows. For the approximately 10 percent of helmets manufactured before October 3, 1988 that could not be placed on the size C headform, Standard No. 218 did not apply to them, so there was no requirement for any information to be labeled on these helmets. Any such helmets would not display a 'DOT sticker' because they were not required or permitted to display such a sticker when they were new, not because the sticker 'fell off' or was removed. However, Standard No. 218 applied to approximately 90 percent of all helmets manufactured before October 3, 1988 and applies to every motorcycle helmet manufactured on or after that date. For those helmets, S5.6.1 of Standard No. 218 requires that: 'Each helmet shall be permanently and legibly labeled . . .' with the manufacturers name or identification, the precise model designation, the size, the month and year of manufacture, the DOT certification mark, and warning instructions. (emphasis added) In an October 16, 1973 letter to the Cycraft Co., NHTSA stated that the requirement that helmets be permanently labeled prohibits the use of labels that can be removed easily by hand without tools or chemicals. You stated that you have heard of two reasons why helmets that originally had a DOT certification label would no longer have such a label. One of the reasons was that the affixed label was a 'sticker' and it 'fell off.' Standard No. 218 permits manufacturers to label the required information on the helmet by means of a 'sticker,' provided that the label is permanent and legible and contains all the information required by S5.6. A 'sticker' that falls off the helmet would not appear to be permanent within the meaning of Standard No. 218, so this would be an apparent noncompliance with the standard. If you have any evidence that 'stickers' are falling off helmets, please forward that information to our Office of Vehicle Safety Compliance at this address, and we will take appropriate actions. The second reason that you have heard for helmets no longer having the labeling required by Standard No. 218 is that someone removed the label to paint the helmet and failed to put the label back on the helmet. Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C 1397(a)(2)(A)) prohibits any manufacturer, distributor, dealer, or repair business from 'knowingly render ing inoperative any device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard.' In this case, the label on motorcycle helmets is a device or element of design installed on the helmet in compliance with Standard No. 218. If a manufacturer, distributor, dealer, or repair business removed that label and failed to put it back on the helmet, then those entities would be rendering the label inoperative, in violation of Federal law. Again, if you have any evidence that violations of Federal law have occurred in your State, please forward that evidence to our Office of Vehicle Safety Compliance and we will take appropriate actions. Please note that Federal law does not prohibit the helmet's owner or any other person that is not a manufacturer, distributor, dealer, or repair business from removing the label from motorcycle helmets. Thus, the owner of a motorcycle helmet is permitted to remove the label from his or her helmet for any reason without violating any provision of Federal law. The individual States are free to establish requirements for motorcycle helmets used in their State, and could prohibit an owner from removing the label. You suggested that the problem of missing labels could be solved if this agency were to require that the DOT symbol be embossed on or in the helmet. NHTSA considered and rejected this suggestion 15 years ago when it established Standard No. 218. In the August 20, 1973 preamble to the final rule that established FMVSS 218, we said: With respect to providing important safety information in the form of labeling, one comment recommended that, due to possible label deterioration, both the manufacturer's identification and the helmet model designation should be permanently marked by etching, branding, stamping, embossing, or molding on the exterior of the helmet shell or on a permanently attached component so as to be visible when the helmet is in use. The NHTSA has determined that the practical effect of this recommendation is accomplished by requiring each helmet to be permanently and legibly labeled. The method to be used to permanently and legibly affix a label for each helmet is therefore left to the discretion of the manufacturer. (38 FR 22391) You finally asked if other jurisdictions have informed NHTSA of similar problems and sought suggestions on methods to resolve the situation where an apparently undamaged helmet would be in compliance with the standard except that it is not properly labeled. As noted above, approximately 10 percent of the motorcycle helmets manufactured before October 3, 1988 were not subject to Standard No. 218 and were not required to be labeled. To my knowledge, no other jurisdictions have informed this agency of problems akin to those raised in your letter aside from more general questions about labeling. I hope this information is helpful. If you have any further questions or need some more information on this subject, please do not hesitate to contact Mr. Marvin Shaw of my staff at this address, or by telephone at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel Enclosure"; |
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ID: aiam3293OpenMr. William G. Milby, Manager, Engineering Services Department, Blue Bird Body Company, P.O. Box 937, Fort Valley, GA 31030; Mr. William G. Milby Manager Engineering Services Department Blue Bird Body Company P.O. Box 937 Fort Valley GA 31030; Dear Mr. Milby:#This responds to your letter of January 16, 1980, i which you asked a number of questions pertaining to Federal Motor Vehicle Safety Standard No. 101-80, *Controls and Displays*. The answers to your questions are presented below and are numbered to correspond with the numbering of the questions in your letter.#1. Section 5.2.1 provides that where Table 1 of Standard 101-80 shows both a symbol and identifying words or abbreviations for a particular control, use of the symbol is mandatory and use of the words or abbreviations is optional.#2. When a manufacturer identifies a control with both the symbol shown in Table 1, Column 3, and the identifying words or abbreviations shown in Table 1, Column 2, only the symbol is subject to the illumination requirements of Section S5.3. That section states that with certain exceptions (i.e., foot operated controls or hand operated controls mounted upon the floor, floor console or steering column or in the windshield header area) 'the identification required by S5.2.1 or S5.2.2 of any control listed in column 1 of Table 1 and accompanied by the word 'yes' in the corresponding space in column 4 shall be capable of being illuminated whenever the headlights are actuated.' Since this section refers only to the identification required by Safety Standard 101-80, it does not apply to identification which is optional under the standard.#3., 4., 5., 6., 7., 8. In questions designated by these numbers, you asked whether the following controls are subject to the identification and illumination requirements of Standard 101-80:#>>>(a) a driver comfort fan which is not a part of the windshield or rear window defrosting and defogging system or the heating and air conditioning system,#(b) hot water flow valves for heaters which are opened in winter and then closed again in summer,#(c) heater fresh air control valves used to control the ratio of fresh to recirculated air entering the heater,#(d) driver's side window defroster control,#(e) driver's fresh air vent control,#(f) fan control for an optional driver's heater which directs air at the driver's feet.<<<#Section 5 of Standard 101-80 states that each vehicle that is subject to the standard and is manufactured with any control listed in Section 5.1 or in column 1 of Table 1 must comply with the requirements of Standard 101-80 regarding the location, identification and illumination of such control. Of the controls listed above, those lettered (a), (d) and (e) are not listed in either of these locations and thus are not subject to these requirements. Items (b), (c) and (f) are part of a heating or air conditioning system indicated in column 1 of Table 1 and is therefore subject to the location and identification requirements of Standard 101-80. However, the fan control, which directs air at the driver's feet, is not subject to the illumination requirements, since section 5.3.1 states, 'control identification for a heating and air conditioning system need not be illuminated if the system does not direct air directly upon windshield.' Likewise, if the hot water flow valves and fresh air control valves are 'mounted upon the floor, floor console or steering column, or in the windshield header area,' then section 5.3.1 does not require them to be illuminated.#9. In your question 9, you asked whether the penultimate line in Table 2 concerning malfunctions in antilocks applies only to vehicles equipped with air brakes and whether the last line concerning brake system malfunctions applies only to vehicles equipped with hydraulic brakes.#The penultimate line of Table 2 applies to all vehicles less than 10,000 pounds GVWR which are equipped with an antilock system, regardless of whether they are air or hydraulic brake equipped vehicles. The agency included the reference to Standard 105, *Hydraulic Brake Systems*, to indicate that section 5.3 of that standard permits a manufacturer to use either a yellow or red warning light depending on whether there is a separate indicator that only warns of antilock failure or there is an indicator which warns of antilock and other brake system failures.#The last line of Table 2 concerning the telltale for brake system malfunction applies to all vehicles equipped with this type of telltale regardless of the type of brake system. The agency included the reference to Standard 105 since section 5.3 of that standard specifies other requirements that brake system malfunction indicators used in hydraulic brake systems must meet.#10. This agency has never established specific size requirements for the identification symbols specified in Tables 1 and 2 of Standard 101-80. Sections 5.2.1 and 6 only require that such symbols be visible to a driver restrained by crash protection equipment.#11. None of the display requirements of Table II of Standard 101-80 apply to vehicles with a GVWR exceeding 10,000 pounds. Displays included in such vehicles in accordance with other standards are subject only to the provisions of those standards.#12. Section 5.3.1 provides that the illumination requirements of Standard 101-80 do not apply to hand operated controls mounted on the steering column. Accordingly, they are not applicable to a hazard control mounted on the steering column.#13. If the clearance lamps are controlled with the headlamp switch, Table 1, footnote 2, of the standard provides that the only identification required is the headlamp switch symbol.#14. Standard 101-80, section 5.2.1, states that controls must be identified with the symbol indicated in Table 1 and that such identification shall be placed on or adjacent to the control. The agency has previously indicated that manufacturers could use a symbol that is a minor deviation from the required symbol, as long as the symbol used substantially resembles that specified in the standard (43 FR 27541, June 26, 1978). Thus, if the wiper symbol you want to use is only a minor deviation and substantially resembles the required wiper symbol, you may use it.#15. You enclosed in your letter a blueprint showing a bank of switches which control multispeed fans and asked whether the identification shown in the print would comply with the requirements of Standard 101-80. Since the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391) requires manufacturers to certify their compliance with all applicable Federal motor vehicle safety standards, this agency does not approve products. However, from our understanding of the information you have provided, it appears that the identification you propose to use for fan controls would comply with Standard 101-80. This opinion is based on the fact that your blueprint shows use of the fan symbol in accord with section 5.2.1 and identification of each function of the fan switch in accord with section 5.2.2.#16. With respect to air conditioning systems:#>>>(1) Section 5.3.1 does not require illumination of the control identification if the system does not direct air directly upon the windshield.#(2) Table 1 and section 5.2.1 require the fan symbol to be used to identify the fan for an air conditioning system,#(3) If the air conditioning system control regulates temperature over a quantitative range, the extreme positions must be identified in accord with 5.2.2.<<<#17. With respect to vehicles over 10,000 pounds GVWR, the requirements of Standard 101-80 concerning telltales used to indicate high engine coolant temperature or low engine oil pressure are inapplicable. With respect to vehicles less than 10,000 pounds GVWR, these requirements are applicable. In a letter to Ford Motor Company (copy enclosed), this agency stated that use of the engine symbol which Ford proposed for identification of such telltales would comply with the requirements of Standard 101-80.#Sincerely, Frank Berndt, Chief Counsel; |
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ID: aiam1304OpenMrs. Joan Norton, 7741 Stilwell Road, Jacksonville, FL 32205; Mrs. Joan Norton 7741 Stilwell Road Jacksonville FL 32205; Dear Mrs. Norton: I appreciate your taking the time to bring to our attention possibl odometer tampering by Southside American, Inc., of Jacksonville, Florida.; The Motor Vehicle Information and Cost Savings Act prohibits odomete tampering and provides a remedy in the form of a civil action to be brought by a defrauded party. If it's possible to find the person who bought the car - a search that will probably require the assistance of the state motor vehicle department - he should be advised of the apparent error in the odometer. If he decides to pursue his remedy under the Act, he may have to rely heavily on your testimony, particularly if the oil sticker has been removed.; Although a private civil action is the principal remedy under the Act the Federal government has auxiliary authority to enjoin violations of the Act. You can assist us in the exercise of this authority by forwarding the enclosed copy of this letter to your local consumer affairs office. If they encounter additional instances of apparent violation by Southside, or by other dealers, we would consider the possibility of seeking an injunction.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam3339OpenMr. F. E. Stephens, Williamsen Truck Equipment Corporation, 1925 W. Indiana Avenue, P.O. Box 30426, Salt Lake City, Utah 84125; Mr. F. E. Stephens Williamsen Truck Equipment Corporation 1925 W. Indiana Avenue P.O. Box 30426 Salt Lake City Utah 84125; Dear Mr. Stephens: This is in response to your letter forwarding your firm's vehicl identification numbering system and requesting confirmation that it complies with Federal Motor Vehicle Safety Standard No. 115, *Vehicle Identification Number*.; The National Highway Traffic Safety Administration does not giv advance approval of a manufacturer's compliance with motor vehicle safety standards or regulations, as it is the manufacturer's responsibility under the National Traffic and Motor Vehicle Safety Act to ensure that its vehicles comply with the applicable safety standards. However, my office has reviewed your proposed system. Based on our understanding of the information which you have provided, your system apparently complies with Standard No. 115.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam4106OpenMr. I. Levy, B.P.T. Leisure International Ltd., 3/4 Portland Street, London, W1N 5AG, ENGLAND; Mr. I. Levy B.P.T. Leisure International Ltd. 3/4 Portland Street London W1N 5AG ENGLAND; Dear Mr. Levy: Thank you for your letter of January 14, 1986, concerning the effect o our regulations on a product you may export to the United States. I hope the following discussion answers your questions.; The product, which you call a 'Klunk- Klip' safety belt comfort device consists of a plastic device which attaches to the upper torso belt anchorage. A belt user can then pull the webbing through the open wedge and close the wedge to introduce slack into the shoulder portion of the belt.; As background information, let me explain that the agency does not hav the authority to approve or endorse items of motor vehicle equipment, such as your device. We do have the authority to issue Federal Motor Vehicle Safety Standards that set performance requirements for motor vehicles and items of motor vehicle equipment. Manufacturers of vehicles or equipment covered by our standards must certify that their product complies with all of the applicable standards.; Your particular aftermarket product is not covered by any of our safet belt or other standards. However, as a manufacturer of an item of motor vehicle equipment, you do have certain responsibilities concerning possible safety-related defects you or the agency discover in your product. Those responsibilities are set out in sections 151-160 of the National Traffic and Motor Vehicle Safety Act. I have enclosed an information sheet on our defect and other regulations for your review.; If you have any further questions, please let me know. Sincerely, Erika Z. Jones, Chief Counsel |
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ID: aiam2178OpenMr. John Evans, Wenke, Burge, and Taylor, 1055 N. Main St., Suite 801, Santa Ana, CA 92701; Mr. John Evans Wenke Burge and Taylor 1055 N. Main St. Suite 801 Santa Ana CA 92701; Dear Mr. Evans: I am writing in response to questions you raised in a January 7, 1976 telephone conversation with Mark Schwimmer of this office concerning the determinations of Gross Vehicle Weight Rating (GVWR) and Gross Axle Weight Rating (GAWR) for a boat trailer.; >>>GVWR is defined as: the value specified by the manufacturer as the loaded weight of single vehicle. (49 CFR 571.3).<<<; One constraint on this specification is found in the Certificatio regulation, which requires that the GVWR be; >>>not less than the sum of the unloaded vehicle weight, rated carg load, and 150 pounds times the vehicle's designated seating capacity ... . (49 CFR 567.4(g)(3))<<<; 'Rated cargo load' is not defined. If a manufacturer does not provide cargo load rating to dealers or consumers, the NHTSA expects his determination of GVWR to reflect a good faith evaluation of the vehicle's load carrying capacity. In the case of a boat trailer, this evaluation should be made with the assumption that the trailer is attached to a towing vehicle and should include that portion of the trailer's load that is carried by the towing vehicle.; >>>GAWR, on the other hand, is defined as: the value specified by the vehicle manufacturer as the load varyin capacity of a single axle system, as measured at the tire-ground interfaces.<<<; The GAWR of a boat trailer's axle system could thus be less than th GVWR, because some of the trailer's load would be carried by the towing vehicle. However, the NHTSA would consider a boat trailer with a GAWR that is less than the actual load on its axle system, when loaded to its GVWR and attached to a towing vehicle, to contain a safety-related defect, which is subject to the notification and remedy requirements of the National Traffic and Motor Vehicle Safety Act of 1966.; The NHTSA expects to issue, in the near future, Federal Motor Vehicl Safety Standard No. 120, *Tire and rim selection for vehicles other than passenger cars* (49 CFR 571.120). Until the effective date of that standard, however, we will continue to consider a vehicle with tires insufficient for its gross axle weight ratings to contain a safety-related defect.; Yours truly, Richard B. Dyson, Assistant Chief Counsel |
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ID: aiam0145OpenMr. W.J. Sears, Vice President, Rubber Manufacturers Association, 1346 Connecticut Avenue, N.W., Washington, D.C. 20036; Mr. W.J. Sears Vice President Rubber Manufacturers Association 1346 Connecticut Avenue N.W. Washington D.C. 20036; Dear Mr. Sears: This letter reaffirms the position of the National Highway Safet Bureau with respect to the handling of petitions for the addition of new tires as stated in recent telephone discussions with members of the Office of Standards on Accident Avoidance.; It was related during these discussions that further action on th petition of November 13, 1968, requesting the addition of the C78-13 tire size designation to Table I-J of the Appendix A of Standard No. 109 cannot be taken until the information indicating compliance with Federal Motor Vehicle Safety Standard No. 110 is received covering the desired test rim width. The Standards are directed at total motor vehicle safety: accordingly, they are just as applicable to replacement tires as to tires intended for new motor vehicles and the guidelines for addition of new tire size designations and new alternative rims to Standards No. 109 and No. 110 as published in the *Federal Register* of October 5, 1968, therefore apply.; The question of a precedence having been established by the addition o the 5 1/2JJ alternative rim to Table I of the appendix to Standard No. 110, without supporting date, in the case of the C70-15 tire size designation has been raised by your organisation. Our records indicate that your request for the addition of this tire size was based on the petition of August 19, 1968. This Action was well in advance of the procedural guidelines established on October 5, 1968. Although this test rim was added to Table I of the appendix A of Standard No. 110, without test date, the National Highway Safety Bureau believes that a safety hazard could exist if this tire and rim combination is not compatible. We Would, therefore, appreciate test information certifying compliance with the requirements of Standard No. 110 by the 5 1/2JJ rim and the C70-15 tire size combination.; Our records indicate that you have submitted petitions dated July 1 and August 29, 1968, requesting the addition of twelve additional alternative rim sizes to Table I of Appendix A of Standard No. 110. To date, data indicating compliance with Standards No. 109 and No. 110 has not been received and we have advised you in several telephone discussions that no action is contemplated until data is submitted.; In conclusion, We would like to reiterate that all future petitions fo additions to Standards No. 109 and No. 110 must be submitted in accordance with the guidelines published in the *Federal Register* on October 5, 1968. The Bureau makes no provisions or exceptions based on the ultimate use of tha(sic) tires. All new tires will be considered within the framework of these guidelines.; Sincerely, H.M. Jacklin, Jr. Acting Director, Motor Vehicle Safet Performance Service; |
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ID: aiam2482OpenMrs. Billie Reynolds, Executive Director, National School Transportation Association, Post Office Box 324, Fairfax, VA 22030; Mrs. Billie Reynolds Executive Director National School Transportation Association Post Office Box 324 Fairfax VA 22030; Dear Mrs. Reynolds: In reply to your letter to Fred Vetter of May 6, 1977, concerning th knee room required for passengers in a small school bus, I think it is essential for your members to understand that the terms 'Type I' and 'Type II' are meaningless in the context of the motor vehicle safety standards. There is a difference in the seat spacing requirements for large buses and small buses, but in deciding which spacing a particular bus must meet, the manufacturers must use the criteria of the standards under 49 CFR Part 571, and not the Type I/Type II distinction.; In dealing with the motor vehicle safety standards applicable to schoo buses, two criteria determine the applicability of various requirements: seating capacity and vehicle weight. The seating capacity of a vehicle determines whether a vehicle is to be considered a school bus. Under the definitions of bus and school bus in 49 CFR S571.3, the critical number of passengers is 10. If a motor vehicle is designed to carry 'more than 10 persons,' it is a bus. If a bus is sold 'for purposes that include carrying students to and from school or related events' it is a school bus. *All* school buses must conform to the applicable requirements of Motor Vehicle Safety Standard No. 222, *School Bus Passenger Seating and Crash Protection*.; Standard No. 222, however, makes the criterion of weight relevant i determining the spacing between seats. In a bus with a gross vehicle weight rating (GVWR) of more than 10,000 pounds, section 5.2 of the standard requires each passenger seat to have either a seat back or a restraining barrier within 20 inches of the 'seating reference point,' a design point that is roughly 5.2 inches forward of the seat back. Measured from the seat back, therefore, all school buses with GVWR's of more than 10,000 pounds must provide 'knee room' of not more than about 25.2 inches. School buses with GVWR's of 10,000 pounds or less do not have to meet the spacing requirements.; Any school buses that your members purchase will therefore have to mee the spacing requirements of Standard No. 222 if they weigh more than 10,000 pounds. This weight corresponds roughly to a bus with a seating capacity of 14-17 persons, so that *most* 'Type I' school buses would have to meet the spacing requirements, and *most* 'Type II' buses would not. Always keet in mind that it is the school bus's weight, not its seating capacity, that determines the applicability of the spacing requirement.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam5347OpenMr. Christopher S. Spencer Engineering 4100 Troy Road #206 Springfield, Ohio 45502; Mr. Christopher S. Spencer Engineering 4100 Troy Road #206 Springfield Ohio 45502; "This responds to your letter about the brake reservoir requirements o Federal Motor Vehicle Safety Standard No. 121, Air Brake Systems (49 CFR 571.121). I apologize for the delay in our response. You stated that you are developing a new reservoir design to improve reservoir volume without increasing the need for space. You asked how to test your reservoirs since you believe that '(t)he safety standard does not clarify the test criteria specifically how the reservoir is to be sealed.' By way of background information, the National Highway Traffic Safety Administration does not provide approvals of motor vehicles or motor vehicle equipment. Under the National Traffic and Motor Vehicle Safety Act, it is the responsibility of the manufacturer to ensure that its vehicles and equipment meet applicable requirements. The following represents our opinion based on the facts provided in your letter. Standard No. 121 establishes performance and equipment requirements for braking systems on vehicles equipped with air brakes. The standard's reservoir requirements for trucks and buses are set forth in section S5.1.2. That section requires these vehicles to be equipped with one or more service reservoir systems that meet specified performance requirements. Section S5.1.2.2 specifies the following: Each reservoir shall be capable of withstanding an internal hydrostatic pressure of five times the compressor cutout pressure or 500 psi, whichever is greater, for 10 minutes. The purpose of this requirement is to ensure that an air brake system reservoir has a minimum level of structural integrity. NHTSA has long interpreted the term 'withstand' to require that there be no rupture or permanent circumferential deformation of the reservoir exceeding one percent. At one point, the agency issued an interpretation concluding that the term 'withstand' meant that a reservoir can deform only slightly and must contain the applied pressure with only a limited pressure drop at any time during the test. However, NHTSA later withdrew that interpretation because it inadvertently increased the severity of the requirement. See 42 FR 64630, December 27, 1977, and 43 FR 9149, March 6, 1978. You asked about this requirement in connection with a reservoir design that includes a bushing on the inside of an endcap. A weld is placed around the bushing. You describe two different procedures you have used to seal the reservoir. In what you describe as 'Test Criteria 1,' a socket head plug is put into the bushing with 3 full wraps of tape. With this first method, you state that as the pressure is applied to the reservoir, the endcap starts to expand out. The bushing stretches with the endcap, and as the bushing stretches the threads are pulled away from the plug. The plug must therefore be retightened several times before the required pressure is reached. In your 'Test Criteria 2,' you state that a rubber grommet or washer is placed on the inside of the bushing and forced to expand to seal the bushings from the inside. You stated that this method checks the weld but removes the threads from the test. With the second method, you state that there was no failure at over five times the working pressure. While Standard No. 121 does not specify a particular test procedure for this requirement, the language of S5.1.2.2 makes it clear that a reservoir must 'withstand' for 10 minutes a condition where the reservoir is pressurized at the specified level. Therefore, in conducting a compliance test, NHTSA would pressurize a reservoir to the specified level. This would necessitate sealing the reservoir. In considering how a particular reservoir would be sealed, it is important to bear in mind that the purpose of the test is to evaluate the reservoir's structural integrity and ability to withstand pressurization. I can offer you the following comments on the two alternative test methods you described. The first method (Test Criteria 1) would appear to evaluate a reservoir's ability to withstand pressurization. The threaded plug would appear to reasonably approximate how the reservoir would be sealed in an actual use situation. I note that the mere fact that the plug needs to be tightened during the test to achieve the specified level of pressure would not indicate a failure but would simply reflect minor air leakage around the plug. The second method (Test Criteria 2) would not fully evaluate a reservoir's ability to withstand pressurization, since it would, as you recognized, remove the threads from the test, thereby creating an artificial seal. It is our opinion that a reservoir would not be capable of 'withstanding' the specified hydrostatic internal pressure if the threads failed under such pressurization. This would represent a structural failure equivalent to a rupture. 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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Request an Interpretation
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The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590
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