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: aiam3567OpenMr. J. Mack Shively, Grebe, Bross, Jensen & Peek, P.C., 1530 S.W. Taylor Street, Portland, OR 97205; Mr. J. Mack Shively Grebe Bross Jensen & Peek P.C. 1530 S.W. Taylor Street Portland OR 97205; Dear Mr. Shively: This is in response to your letter of May 11, requesting our views a to the applicability of vehicle identification number requirements and certification label requirements to a semi-trailer to be manufactured by Cranston Diversified Industries. This trailer would have three interchangeable sections.; You are correct in your interpretation of the manner in which ou requirements would be applied to the trailers in question. Only one vehicle identification number and one certification label are required. Affixing the label to the left side of the front section would be consistent with our regulations.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam5519OpenMr. Paul Pinoski Project Engineer SLP Engineering, Inc. 1501 Industrial Way North Toms River, NJ 08755; Mr. Paul Pinoski Project Engineer SLP Engineering Inc. 1501 Industrial Way North Toms River NJ 08755; "Dear Mr. Pinoski: This responds to your letter to me in which yo requested an interpretation of the term 'vehicle capacity weight,' as defined in Federal motor vehicle safety standard (FMVSS) No. 110, Tire selection and rims (49 CFR 571.110). I apologize for the delay in our response. FMVSS No. 110 applies to passenger cars. Section S4.3 of the standard requires a placard to be placed on the door of the glove compartment or other accessible place on which shall be displayed, among other things, the 'vehicle capacity weight.' This term is defined in S3 as meaning 'the rated cargo and luggage load plus 150 pounds times the vehicle's designated seating capacity.' You asked how to obtain the 'rated cargo and luggage load,' so that you can calculate vehicle capacity weight. The agency does not define the term 'rated cargo and luggage load' or otherwise regulate how that load is determined. The term simply refers to the vehicle manufacturer's determination of the cargo and luggage carrying capacity of the vehicle. The choice of methodology to be used in making that determination is left to the discretion of the vehicle manufacturer. From a safety standpoint, the important issue is the overall value specified by the vehicle manufacturer as the loaded weight of a vehicle. That value is also known as the gross vehicle weight rating (GVWR). The GVWR informs a vehicle owner how heavily he or she can load a vehicle. The only express regulatory limitation on the GVWR manufacturers may assign to their vehicles is set forth in 49 CFR 567.4(g)(3), which provides that the assigned GVWR 'shall not be less than the sum of the unloaded vehicle weight, rated cargo load, and 150 pounds times the vehicle's designated seating capacity.' (Emphasis added.) 'Rated cargo load' and 'rated cargo and luggage load' are interchangeable terms. I hope this information is helpful to you. Should you have further questions or need additional information, please feel free to contact Walter Myers of my staff at this address or at (202) 366-2992. Sincerely, Philip R. Recht Acting Chief Counsel Enclosure"; |
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ID: aiam2726OpenMr. Michael Flowers, Manager, Electric Products Division, General Engines Company, 591 Montana Boulevard, Jewell, N.J. 08080; Mr. Michael Flowers Manager Electric Products Division General Engines Company 591 Montana Boulevard Jewell N.J. 08080; Dear Mr. Flowers: This is in reply to your letter of November 4, 1977, asking for a interpretation of Federal Motor Vehicles Safety Standard No. 123 *Motorcycle Controls and Displays* as it applies to electricity-powered motor driven cycles that you manufacture.; "Paragraph S5.1 of Standard No. 123 requires each motorcycle to b equipped with a supplemental engine stop control. Your Electroped GX 2000 is operated through a 'uni-control lever' which, when released, turns off the power j source 'thereby acting as an automatic motor stop in the event of an accident.' Your Electroscooter is operated through a twist-grip throttle and when it is released 'the motor is completely off.' You have asked how S5.1 applies to your vehicles."; In our opinion, Standard No. 123 was not drafted wit electricity-powered motorcycles in mind. Unlike a motorcycle powered by an internal combustion engine, the driving force (i.e. current) of an electricity-powered motorcycle is terminated when the force control is released, and no supplemental engine stop control or 'emergency kill button' is required. In other words, S5.1 does not appear to be an appropriate requirements for an electricity-powered vehicle.; however, until Standard 123 can be amended appropriately your vehicle are required to be equipped with the supplemental engine stop control. In other instances where manufacturers have found conflicts between the safety standards and electricity-powered vehicles they have applied for a temporary exemption from such standards.; Work is in progress on your request to be exempted from Standard No 120, and by including your letter and this interpretation to it in the docket, we can include in the *Federal Register* notice a request to be exempted from S5.1 as well. Please confirm that this is acceptable to you.; Sincerely, Joseph J. Levin, Jr., Chief Counsel |
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ID: aiam3834OpenJohn R. Bailen, Esq., Bane, Allison, Saint & Ehlers, P.C., 200 West Front Street, Fifth Floor, Bloomington, IL 61701; John R. Bailen Esq. Bane Allison Saint & Ehlers P.C. 200 West Front Street Fifth Floor Bloomington IL 61701; Dear Mr. Bailen: This responds to your letter to this office asking about th requirements of Federal Motor Vehicle Safety Standard No. 213, *Child Restraint Systems* (49 CFR S571.213). Specifically, you represent a client who will be manufacturing seat covers which would be attached to the seat of the child restraint system. You stated that you had spoken with Mr. Radovich of our Rulemaking Division, and he had indicated his opinion that the only requirements to which these seat covers might be subject would be the flammability requirements. You asked if this is correct, and if any other requirements were applicable, noting a particular interest in whether any labeling requirements might apply to these seat covers. There are no labeling requirements promulgated by this agency applicable to those seat covers. Further, the flammability requirements incorporated in Standard No. 213 are applicable only if your client wishes to have those covers installed on child restraint systems by manufacturers, dealers, distributors, or repair shops.; Standard No. 213 specifies information which must appear on a labe affixed to each child restraint system. However, none of that information relates to the materials used in the seat covers. Hence, Standard No. 213 does not impose any labeling requirements which might be applicable to seat covers for child restraint systems.; Further, Standard No. 213 applies to child restraint systems prior t their first purchase in good faith for purposes other than resale, and not to aftermarket accessories for use with or on the child restraint system. Generally those aftermarket accessories may be added to the child restraint system, even if the addition of those accessories causes the child restraint to no longer comply with Standard No. 213, without violating the requirements of the standard.; This general rule is, however, limited by the application of th provisions of section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act, as amended (hereinafter 'the Safety Act', 15 U.S.C. 1397(a)(2)(A)). That section specifies: 'No manufacturer, distributor, dealer or motor vehicle repair business shall knowingly render inoperative...any device or element of design installed on or in...an item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard,....' Section S5.7 of Standard No. 213 requires that each material used in a child restraint system conform to the requirements of section S4 of Standard No. 302, *Flammability of Interior Materials* (49 CFR S571.302). If a party were to add a seat cover which did not meet the flammability requirements of Standard No. 302 to a child restraint which was previously certified as meeting those flammability requirements, that act would be interpreted by this agency as rendering inoperative the flammability resistance installed on the child restraint in compliance with an applicable Federal safety standard. If such an act were performed by a manufacturer, dealer, distributor, or repair business, it would be a violation of section 108(a)(2)(A) of the Safety Act, and such a violation would subject the offender to a civil penalty of $1,000 for each violation, as specified in section 109 of the Safety Act (15 U.S.C. 1398).; You should note that the prohibitions in section 108(a)(2)(A) of th Safety Act do not apply to a consumer who renders inoperative some element of design of the child restraint system, and therefore your client's seat cover need not satisfy the flammability requirements for child restraint systems if it is intended to be sold to and installed by consumers. You might wish to inform your client about potential liability under State and common law if the seat covers do not comply with those flammability requirements, in the event those seat covers catch fire.; You may also wish to inform your client about the potentia consequences of an item of motor vehicle equipment which is determined to contain a safety-related defect. Should these seat covers catch fire in situations where seat covers which comply with Standard No. 302 would not catch fire, the non-complying seat covers might well be found to contain a safety-related defect. Sections 151-154 of the Safety Act (15 U.S.C. 1411-1414) require that, when an item of motor vehicle equipment contains a safety-related defect, the manufacturer of the item must recall and repair or replace the defective equipment without charge to the purchaser.; If you have any further questions or need more information on thi subject, please feel free to contact me.; Sincerely, Frank Berndt, Chief Counsel |
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ID: aiam1809OpenMr. Harold D. Shall, Legal Counsel, Dana Corporation, P.O. Box 1000, Toledo, OH 43697; Mr. Harold D. Shall Legal Counsel Dana Corporation P.O. Box 1000 Toledo OH 43697; Dear Mr. Shall: This responds to Dana Corporation's January 1, 1975, question whethe the exception found in S5.3.1(a) and S5.3.2(a) of Standard No. 121, *Air brake systems*, which permits 'controlled lockup of wheels allowed by an antilock system' is available in the case of a wheel which is not 'sensed' by the antilock system through a wheel sensor. You indicate that a statement in our November 1, 1974, letter to Dana Corporation appears to permit the exception for wheels that are not equipped with a antilock valve and logic system.; The answer to this question is no. The statement in our November 12 1974, letter states that 'the manufacturer may choose the number of wheel speed sensors and logic modules that he includes in his antilock system.' This statement simply recognizes that the standard does not require an antilock system, and that the number of wheel speed sensors and logic modules in any antilock system employed by a manufacturer is also not specified.; The standard does require 'no lockup' of any wheel above 10 mph excep 'controlled lockup allowed by an antilock system.' It is clear that a manufacturer who wishes to make use of this exception must provide an antilock system and that it must control lockup at the wheel in question. We pointed out in our November 12, letter that an antilock system would not control lockup of a wheel unless a sensor located on that wheel signaled the logic module of the lockup condition. It would not be sufficient that an antilock system controlled the air available to the wheels' brake system without the ability to sense that wheel's lockup.; To summarize, a manufacturer may choose whether to utilize an antiloc system, and whether to equip each wheel with a sensor. However, a manufacturer must equip each wheel with a sensor in order to take advantage of the controlled lockup exception at that wheel.; Yours truly, James C. Schultz, Acting Chief Counsel |
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ID: aiam5149OpenMr. Marty D. Pope President Wheels 'R' Rollin, Inc. 6702 North Highway 66 Claremore, OK 74017; Mr. Marty D. Pope President Wheels 'R' Rollin Inc. 6702 North Highway 66 Claremore OK 74017; "Dear Mr. Pope: This responds to your February 18, 1993 letter t Walter Myers of this office. You stated in your letter and in telephone conversations with Mr. Myers that your firm obtains used wheels from salvage yards, mostly passenger car wheels, refurbishes them by sandblasting and refinishing them, then sells them to manufacturers of utility trailers. You asked how to 'bring the wheels manufactured before 1977 up to standards' (referring to Federal Motor Vehicle Safety Standard No. 120, Tire selection and rims for motor vehicles other than passenger cars), and whether it is possible to 'stamp the wheels previous to 1977 with a regulation code to approve their usability.' 'Wheels' refers to the wheel rim and the hub to which the rim is attached. By way of background information, the National Highway Traffic Safety Administration (NHTSA) is authorized by the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.) (Safety Act) to issue Federal motor vehicle safety standards (FMVSS's) for new motor vehicles (including trailers) and new items of motor vehicle equipment (including tires and wheels). The purpose of Standard 120 is to provide safe operational performance by ensuring that vehicles to which it applies are equipped with tires of adequate size and load rating and with rims of appropriate size and type designation. The standard applies to new trailers, and to rims manufactured on or after August 1, 1977. Violations of any of the standards are punishable by civil fines of up to $1,000 per violation, with a maximum fine of up to $800,000 for a related series of violations. You ask about our requirements for the rims of the wheels you refurbish. The answer depends on whether the rim is intended to be installed on a new trailer or intended as a replacement rim for a used trailer. If the rim is intended for a new trailer, the new trailer manufacturer must certify that the vehicle complies with Standard 120. Standard 120 establishes two requirements for the vehicle. First, S5.1.1 requires that the rims on a new trailer be listed by the manufacturer of the tires mounted on the trailer as suitable for use with those tires. Second, the rims on a new trailer must meet the rim marking requirements of S5.2 of Standard 120. Since the rims you refurbish were originally passenger car rims, they will not have the required markings, regardless of date of manufacture, because Standard 120 does not apply to passenger car rims. Therefore, trailer manufacturers may not install passenger car rims on new trailers unless those rims are marked in accordance with Standard 120. If the rim is intended as a replacement rim on a used trailer, different requirements apply. The rim marking requirements of S5.2 of Standard 120 apply only to new rims manufactured on or after August 1, 1977. Refurbished wheels sold for used trailers are considered used wheels instead of new wheels for purposes of Standard 120, and are thus not subject to the rim marking requirements of the standard. As pointed out above, however, a new or refurbished rim installed on a new trailer must meet the rim selection and marking requirements of Standard 120 (S5.1.1 and S5.2). Relatedly, you ask about marking a used rim with the information required by Standard 120 for new rims. Any rim, new or used, that is installed on a new vehicle must be marked with the 'regulation code' (i.e., the 'DOT' symbol constituting the manufacturer's certification of compliance with Standard 120) and the other information required by the standard. However, a rim manufactured prior to August 1, 1977, that is sold as a replacement rim must not be marked with the DOT symbol. NHTSA has long held that manufacturers may not show the DOT certification on items of motor vehicle equipment to which no Federal motor vehicle safety standard applies. The reason for that decision is that such a certification would be false and misleading to NHTSA and to consumers who might assume that the item was subject to and met a Federal safety standard. Thus, since Standard 120 does not apply to rims manufactured prior to August 1, 1977, such rims cannot now be marked with the DOT symbol. You should also be aware of two other provisions of the Safety Act. The first provision is 108(a)(2)(A), which provides that no manufacturer, distributor, dealer, or motor vehicle repair business may knowingly render inoperative, in whole or in part, any device or element of design installed on or in a new or used motor vehicle or item of motor vehicle equipment in compliance with an applicable FMVSS. This means that a person in these categories cannot remove the label information required by Standard 120 during the refurbishing process. Second, under 151-157 of the Safety Act, manufacturers of motor vehicles and items of motor vehicle equipment (e.g., wheel rims) are responsible for safety- related defects in their products. If a manufacturer or NHTSA determines that a safety-related defect exists, the manufacturer must notify purchasers of the product and remedy the problem free of charge. (This responsibility is borne by the vehicle manufacturer in cases in which a defective wheel rim is installed on a new vehicle by or with the express authorization of that vehicle manufacturer.) A refurbished rim that had been previously damaged (e.g., cracked, bent, or pitted) might not be capable of performing safely while in service. For your further information, I am enclosing a pamphlet issued by this agency entitled Federal Motor Vehicle Safety Standards and Regulations and a fact sheet entitled Where to Obtain NHTSA's Safety Standards and Regulations. The pamphlet briefly summarizes each of our Federal motor vehicle safety standards and the fact sheet advises where to obtain the full text of those standards and our other regulations. You may also find helpful the attached fact sheet entitled Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment. We also note that the Occupational Safety and Health Administration (OSHA) has a regulation on the refurbishing of damaged rim components. You can contact OSHA at (202) 219-7202, ATTN: Mr. Richard Sauger, for information about that regulation. I hope this information is will be of assistance to you. Should you have any further questions, please feel free to contact Mr. Myers at this address or at (202) 366-2992. Sincerely, John Womack Acting Chief Counsel Enclosures"; |
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ID: aiam2376OpenMr. Paul Atkinson, No. 13 Connell Dr., Little Rock, AR 72205; Mr. Paul Atkinson No. 13 Connell Dr. Little Rock AR 72205; Dear Mr. Atkinson: This is in response to your June 18, 1976, letter concerning th application of Federal Motor Vehicle Safety Standard No. 117, *Retreaded Pneumatic Tires*, to passenger car tires that are retreaded from bead to bead.; I understand that in this process, the labeling information molded o the sidewalls of the tire to be retreaded is buffed off prior to the application of new rubber. You have requested our assurance that 'it is permissible to do bead to bead retreading, removing the present labeling and remolding all the pertinent information on the tire.'; The requirements for casings to be used in retreading are set out i S5.2.3 of Standard No. 117:; >>>Each retreaded tire shall be manufactured with a casing that bears permanently molded at the time of its original manufacture into or onto the tire sidewall, each of the following:; (a) The symbol DOT, (b) The size of the tire, and (c) The actual number of plies or ply rating.<<< This section requires the above information to be present on the casin at the beginning of the retreading process, to ensure both that the carcass was originally manufactured to comply with Standard No. 109, *New Pneumatic Tires--Passenger Cars*, and that the retreader has reliable information on which to base the labeling of the completed tire. The section does not, however, require that this originally molded information be retained on the completed tire.; Certification and labeling requirements for completed retreaded tire are set out in S6 of the standard. The DOT symbol required by S6.1, however, is not a 'remolding' of the original DOT symbol (certifying compliance with Standard No. 109) that may have been buffed off. It is a new certification by the retreading party that his product complies with Standard No. 117. Further, this new DOT symbol must be followed by the letter 'R', as indicated in 49 CFR S 574.5, *Tire Identification and Recordkeeping*. 'Remolding' of the original DOT symbol is neither required nor permitted. Finally, the information required by S6.3 to appear on the completed tire is permitted, but not required, to so appear through retention of the original labeling.; In conclusion, bead- to-bead retreading is not prohibited by Standar No. 117, provided that the casings satisfy S5.2.3 at the beginning of the retreading process, and all other requirements of the standard are met.; Yours truly, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam2458OpenMr. Leon W. Steenbock, Engineering, FWD Corporation, Clintonville, WI 54929; Mr. Leon W. Steenbock Engineering FWD Corporation Clintonville WI 54929; Dear Mr. Steenbock: This responds to FWD Corporation's October 15, 1976, request to kno whether a truck that complies with the requirements of Standard No. 121, *Air Brake Systems*, would continue to comply after the addition of another parking brake system (hand-operated mechanical, operating on the driveline) or another service brake control (piped to either or both sides of a split system).; Standard No. 121's requirements for braking systems does not preclud the addition of an additional braking system. The agency would not consider the requirements of S5.6.4 to prohibit an additional parking brake control.; Standard No. 121 does not prohibit installation of more than on service brake control. The installation of a hand- operated control lever that your letter appears to describe would not of itself violate the standard's requirements. If the hand control were piped into both systems, however, a failure introduced into the control would probably result in violation of S5.7.1, which requires certain secondary braking performance following a single failure introduced into the service brake system.; Sincerely, Frank A. Berndt, Acting Chief Counsel |
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ID: aiam0465OpenMr. Edward W. Mentzer, Attorney and Assistant Secretary, Rex Chainbelt, Inc., P.O. Box 2022, Milwaukee, WI 53201; Mr. Edward W. Mentzer Attorney and Assistant Secretary Rex Chainbelt Inc. P.O. Box 2022 Milwaukee WI 53201; Dear Mr. Mentzer: This is in response to your letter of October 8, 1971, in which yo expressed concern over the implications of the gross axle and gross vehicle weight ratings to appear on certification labels, beginning January 1, 1972. You requested our assurance that 'the GVWR will not be interpreted so strictly as to make liable the manufacturer whose body, if loaded to its nominally rated capacity, would exceed the GVWR indicated on the certificate.'; The GVWR and GAWR values are, within limits, to be supplied by th vehicle manufacturer based on his own knowledge of the vehicle's capacity. In the amendment to the certification regulations published October 8, 1971 (36 F.R. 19593), a requirement was added that the GVWR figure 'shall not be less than the sum of unloaded vehicle weight, rated cargo load, and 150 pounds times the vehicle's designated seating capacity.' From the standpoint of the regulation itself, the only other limit on GVWR would be that it should not be more than the sum of the GAWR's (although it may be less), since otherwise the vehicle would obviously be supplied with axle systems inadequate for its carrying capacity.; Thus, the GVWR must not be less than a figure that reflects the ful 'rated cargo load' of the completed vehicle. Obversely, if you supply a rated cargo load, the weight of the vehicle when carrying that load must not exceed the GVWR. If you supply no rated cargo load, but only the volumetric capacity, the capacity would not on its face lead to a violation of the certification regulations, since as you note the specific weight of the material carried varies considerably.; You should be aware, however, that completing the vehicle so that it apparent carrying capacity exceeds the stated weight ratings may create some risks of liability beyond the certification regulations themselves. If, for example, the vehicle suffers a hazardous malfunction in use that can be traced to overloading of its axle systems, its manufacturer may be liable both under the defect provisions of the National Traffic and Motor Vehicle Safety Act (section 113, 15 U.S.C. 1402) and under common-law product liability doctrines. In such a case, the manufacturer of the incomplete vehicle might avoid liability, leaving it all on the final-stage manufacturer, by pointing out that the design of the vehicle as completed led the user to exceed the GVWR and GAWR furnished with the incomplete vehicle.; Sincerely, Lawrence R. Schneider, Acting Chief Counsel |
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ID: aiam4975OpenMr. Charles Danis Les Enterprises Track Test Inc. 4652 Avenue Victoria Montreal, Quebec H3W 2N1 Canada; Mr. Charles Danis Les Enterprises Track Test Inc. 4652 Avenue Victoria Montreal Quebec H3W 2N1 Canada; "Dear Mr. Danis: This responds to your letter about testing related t Federal motor vehicle safety standard No. 121, Air Brake Systems, (49 CFR 571.121). You explained that your company has recently conducted a compliance test on an articulated bus manufactured by MCI Greyhound Canada. According to your letter, the buses were tested using 28 psi for the brake actuation test and 40 psi for the brake release test. While these air pressures differ from the pressures specified in S5.3.3 and S5.3.4 for brake actuation and release times, you stated that MCI was relying on a July 23, 1976 interpretation issued by the agency to Mr. J.W. Lawrence of the White Motor Corporation that permitted such brake actuation and release pressures. We note that to be consistent with that interpretation, the maximum brake chamber pressure must have been 40 psi when the service reservoir pressure was at 100 psi. Your letter was not clear on that point. You asked whether this interpretation is still valid. As explained below, the answer is yes. In its inquiry to NHTSA, White Motor Corporation asked whether S5.3.3 and S5.3.4 of Standard No. 121 require minimum brake chamber actuation and release time pressures of 60 psi and 95 psi, respectively, or whether these air pressures are included in the sections only as 'bench marks' on which to base specifications for minimum actuation and release timing. In response, the agency's July 23, 1976 interpretation letter stated in relevant part that: Your understanding that S5.3.3 and S5.3.4 only specify the air pressures of 60 psi and 95 psi as the basis for timing requirements is correct. Neither value is intended as a requirement that the vehicle be designed to provide a certain level of brake chamber air pressure. The values were based on an understanding of the typical configuration of existing air brake systems at the time the final rule was issued. In response to your specific question, NHTSA's July 23, 1976 interpretation letter continues to be valid. I hope this information is helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel Enclosure"; |
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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.