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: nht92-8.42OpenDATE: February 28, 1992 FROM: Stephen E. Selander -- Attorney, GM Legal Staff TO: Paul Jackson Rice -- Office of the Chief Counsel, NHTSA TITLE: Re: General Motors Corporation; FMVSS 114; Request for Interpretation ATTACHMT: Attached to letter dated 5/22/92 from Paul J. Rice to Stephen E. Selander (A39; Std. 114) TEXT: General Motors Corporation (GM) is designing an electronic key locking ignition system which we would like to offer for sale in the near future. GM believes that this system meets the requirements of Federal Motor Vehicle Safety Standard (FMVSS) 114 without using a conventional mechanical key. In view of the novelty of this approach, GM would like to have the concurrence of the NHTSA with our opinion. FMVSS 114 S.3 Definitions includes the following definition of a "Key": Key includes any other device designed and constructed to provide a method for operating a locking system which is designed and constructed to be operated by that device. An electronic "Key" is consistent with the preamble to the Final Rule - FMVSS 114 (33 Fed.Reg. 6472 (1968)) where the following appears at the top of the middle column: The term "key" is defined so as to include methods of activating the locking system other than the commonly accepted concept of a key. This electronic key locking system would be operated by a key (an electronic code) entered and removed by the operator. When the key is entered into the locking system by the operator, a match is made with an electronic code stored in the system's memory. This match is analogous to the tumblers of a conventional lock cylinder matching the cut of a conventional key. When a correct key match occurs, the person could then move the locking system out of the lock position to other positions such as accessory, off, on, or start, in order to activate the vehicle's engine, motor, or accessories. With the locking system out of the lock position, the transmission can be shifted out of the "PARK" position in order to operate the vehicle. The transmission shift lever must be returned to the "PARK" position in order to place the locking system back into the lock position. Placement of the locking system back into the lock position by the operator would automatically cause removal of the key from the system. At that time, re-entry of the correct key (electronic code) would be necessary to operate the vehicle.
SUMMARY A key locking system, using an electronic key code other than a conventional mechanical key, has been developed which, GM believes, will meet the requirements of FMVSS 114. However, GM requests the concurrence of the NHTSA regarding the definition of "Key" so that design work can continue and the system can be offered to the public in a timely manner. If helpful, we would be pleased to demonstrate an example of the system under development. If the agency has any questions or requires additional information, please contact me on (313) 974-1704. |
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ID: nht92-8.43OpenDATE: February 27, 1992 FROM: Kevin J. Stoll -- Technical Advisor, Russell Products Incorporated TO: Taylor Vinson -- Legal Counsel FMVSS - 108, NHTSA COPYEE: Thomas L. Russell TITLE: None ATTACHMT: Attached to letter dated 4/27/92 from Paul J. Rice to Kevin J. Stoll (A39; Std. 108) TEXT: My purpose for writing you today is that the "Office of Rulemaking" stated to me that I should address my questions directly to you via letter. Russell Products is a multi-line distributor to the recreational vehicle and van conversion industry. We are currently selling third brake lights to the van and R.V. industry. We also are familiar with the standards that are in effect for all vehicles that are manufactured in our industry. However, the purpose for this letter is that I am currently designing a third brake light for the truck cap and truck camper vehicles. Listed below are a few questions that I have not been able to find rulings on. I would appreciate any help or insight that you may have in obtaining the answers to these questions. 1. Are the LED (light emitting diode) being used for third brake light legal? If so, what are the specifications so that they can be used as a third brake light? 2. a. Where are the truck manufacturers ie. GM, Ford, Dodge locating the third brake fight on pickup trucks? b. What effect will this have on truck cap manufacturers and the dealer responsibility to the consumer? c. Can the dealer wire directly to the existing third brake light harness used to light up the factory third brake light? 3. a. We have a customer that would like to mount a flush mounted third brake light in the rear glass window of a truck cap. This window is used also as the rear access door to get to the truck bed from the outside of the truck. b. This would allow the third brake light to be moveable and not stationary. If a consumer would have an object in the bed of the truck with the window in the open position, allowing for the third brake light to be left in an upward position and no longer viewed from the rear. Would this application be approved? 4. Could you please enter Russell Products, Inc. on your mailing lists for all future updated mailings on third brake lights passed or discussed at all committee meetings.
If you have any questions or would require additional information, please don't hesitate to call me at 1-800-545-5620. I appreciate your help in advance. |
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ID: nht92-8.44OpenDATE: February 25, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Phil Gray -- Inventor, Westech U.S.A. Inc. TITLE: None ATTACHMT: Attached to letter dated 1/13/92 from Phil Gray to Paul Jackson Rice (OCC 6925) TEXT: This responds to your letter asking how the laws and regulations administered by this agency would apply to a product you have invented. The device is a flexible plastic stalk that reroutes the shoulder belt to improve the shoulder belt fit for children that have outgrown child safety seats. I am pleased to have this chance to explain our laws and regulations to you. The National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1381 et seq.; the Safety Act) authorizes this agency to issue motor vehicle safety standards for new motor vehicles and new items of motor vehicle equipment. We have exercised this authority to establish Standard No. 208, Occupant Crash Protection (49 CFR S571.208). This standard requires new motor vehicles to be equipped with safety belts and requires that those belts meet specified fit and comfort requirements, as set forth in S7 of the standard. However, Standard No. 208 does not apply to aftermarket items that seek to alter belt fit and/or comfort. Hence, your company is not required to certify that this product complies with Standard No. 208 before offering the product for sale. In addition, you are not required to get some sort of "approval" from this agency before offering this product for sale. NHTSA has no authority to "approve" motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the Safety Act establishes a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. As stated above, this product is not subject to any safety standard, so your company does not have to make any certification. Although none of our safety standards directly apply to this product, there are several provisions in the Safety Act that are relevant. Manufacturers of motor vehicle equipment such as your belt positioning device are subject to the requirements in sections 151-159 of the Safety Act (15 U.S.C. 1411-1419) concerning the recall and remedy of products with defects related to motor vehicle safety. Your letter indicated that you were aware of this responsibility and your company would carry out any necessary recalls if problems should become apparent with this device when it is used by the public. In addition, use of your product could be affected by section 108(a)(2)(A) of the Safety Act (15 U.S.C. 1397(a)(2)(A)). That section prohibits manufacturer, distributors, dealers, and repair shops from knowingly "rendering inoperative," in whole or in part, any device or element of design installed on or in a vehicle in compliance with an applicable safety standard. There are two elements of design in a vehicle that might be "rendered inoperative" by the use of your company's belt positioning device. One is the occupant protection afforded by belts that meet the specified fit and comfort requirements. The other element of design that could be rendered inoperative by the use of your belt positioning device is the burn resistance required by Standard No. 302, Flammability of Interior Materials (49 CFR S571.302). The materials used in the interior of vehicles, including the seat belts, seat backs and cushions, trim panels, and headliner must comply with the burn resistance requirements of Standard No. 302 to reduce deaths and injuries in the event of a fire in the vehicle's interior. If your belt positioning device renders inoperative the belt fit and comfort requirements specified in Standard No. 208 or does not comply with burn resistance requirements, it could not be installed in a vehicle by any manufacturer, distributor, dealer, or repair shop. I have enclosed a general information sheet for new manufacturers that gives a thumbnail sketch of NHTSA's regulations and provides information on how to obtain copies of those regulations. I hope that this information is helpful. If you have any further questions or need some additional information, please feel free to contact Steve Kratzke of my staff at this address or by telephone at (202) 366-2992. Attachments NHTSA information sheets, dated September, 1985 entitled: Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment, and Where to Obtain Motor Vehicle Safety Standards and Regulations (Text of attachment omitted)
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ID: nht92-8.45OpenDATE: February 25, 1992 FROM: L. Louis Raring -- Raring & Lipoff TO: Jack Rice -- Chief Counsel, NHTSA TITLE: Re: Motorcycle Helmet Law; Federal Motor Vehicle Safety Standard No. 218 ATTACHMT: Attached to letter dated 5/6/92 from Paul J. Rice to L. Louis Raring (A39; Std. 218) TEXT: Our office represents numerous clients who are involved with the recently-enacted motorcycle helmet law in California which requires compliance with Federal Motor Vehicle Safety Standard No. 218. We have been asked to give advice to manufacturers of helmets, potential manufacturers of helmets and individuals who are receiving tickets for wearing improper helmets. I have had discussions with Ron Engle, Division Chief for Safety Counter measures at the Department of Transportation, John Lee, Chief Engineer, and Cathy Demeter in the General Law Division. It is my understanding that the Department of Transportation does not approve helmets but is more of a policing organization which tests and recalls helmets on a random basis. No one has been able to direct me to any policy documents, such as rules and regulations in the Federal Register, which would outline just what the Department of Transportation does regarding Standard No. 218. There is a popular misconception in California among drivers, enforcement officers and manufacturers that the Department of Transportation actually approves helmets. It is my understanding in talking to people within DOT that DOT does not approve helmets and this is left strictly to the manufacturer to certify. We are requesting a letter from your office outlining what DOT's policy is and its involvement with Federal Standard No. 218. We would appreciate any reference to any rules or regulations we can look up and copies of any policy statements which will help us to document what DOT's position is regarding approval of helmets under Standard No. 218. If you have any questions, please give me a call. We anxiously await your response to this request. |
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ID: nht92-8.46OpenDATE: February 24, 1992 FROM: Neil Friedkin -- Attorney at Law TO: Erica Z. Jones -- Chief Counsel, NHTSA TITLE: Re: Fred Levinson Productions v. Sports Imports Inc. and Coachbuilders Ltd. ATTACHMT: Attached to letter dated 4/13/92 from Paul J. Rice to Neil Friedkin (A39; S 108 (a)(1)(A); S 108 (a)(2)(A); S 108 (b)(1); Part 567) TEXT: I am the attorney for Fred Levinson Productions Inc. ("FLP"). In August of 1986, FLP leased a 1986 Mercedes 560 LEC from Sports Leasing. As part of the lease, Coachbuilders Ltd converted the vehicle from hardtop to convertible. The vehicle identification Number is WDBCA45D3GA270730. Mr. Levinson is in litigation concerning the vehicle. In part, he alleges Coachbuilders did not RECERTIFY the vehicle after conversion and that the conversion did not conform with the standards of the Safety Act. In the past, I have written to your office concerning what rules would be applicable to the conversion and whether Coachbuilders would have been required to recertify the vehicle. I also asked if any complaints had been made against Coachbuilders. In response, you were kind enough to provide me with certain rules and regulations and with opinion letters you had issued in the past (copies of which are enclosed) on similar inquiries. I am writing to you now to see if you can provide a similar opinion letter addressed to my client and the conversion of this Mercedes hardtop to convertible. If this is possible, or if you require further information, please contact me. |
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ID: nht92-8.47OpenDATE: February 21, 1992 FROM: Masashi Maekawa -- Director, Technical Division, Ichikoh Industries, Ltd. TO: Paul Jackson Rice -- Chief Counsel, NHTSA TITLE: Re: Request for the interpretation of photometric output requirements for tail/stop lamps on passenger cars ATTACHMT: Attached to letter dated 4/10/92 from Paul Jackson Rice to Masashi Maekawa (A39; Std. 108) TEXT: Thank you for your answering letter dated Dec. 18, 1991 to our questions concerning the interpretation of photometer output requirements for tail/stop lamps on passenger cars dated Nov. 27, 1991. We had some questions as follows regarding positions stated in the letter from NHTSA. 1. NHTSA stated in the letter dated Dec. 18, 1991 as follows; " It is not possible to consider the two adjacent lamps as one lamp for purpose of measuring the minimum photometrics required under standard No. 108." But another letter from NHTSA dated June 28, 1985 addressed to Mazda (North America), Inc. stated as follows; " We also discuss the implications of a stop lamp and tail lamp constructed so that a portion is fixed to the body of the vehicle adjacent to the decklid opening and the remaining portion is mounted on the outboard area of the decklid. Compliance of a vehicle is determined with respect to its normal driving position, that is to say, with the tailgate, hatch, or decklid closed." We realized the noticeable difference between those two letters. We have been designing and testing lamps until now according to the interpretation dated June 28, 1985. 2. As the interpretation of the testing method concerning photometer output requirements of lamps mounted onto both the moving vehicle part and the rigid vehicle part is not written in FMVSS No. 108, we have been designing those lamps to comply with photometer output requirements by using both lamps mounted onto the moving vehicle part (Lamp-B) and the rigid vehicle part (Lamp-A), in accordance with the sentence "The device shall be mounted in its normal operating position." of J (Photometry) of SAE J575e incorporated in FMVSS No. 108. For the reason mentioned above, we would like to ask whether your stance concerning the interpretation of those lamps has been changed or not. Kindly let us know your opinion concerning the above matters. |
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ID: nht92-8.48OpenDATE: February 19, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: James Hansen -- Model E Concepts TITLE: None ATTACHMT: Attached to letter dated 12/20/91 from James C. Hansen to Office of the Chief Council, NHTSA (OCC 6832) TEXT: This responds to your letter inquiring about the applicability of National Highway Traffic Safety Administration (NHTSA) regulations to the alteration of previously certified new and used motor vehicles. You stated that your company is considering the alteration of motor vehicles to a hybrid version of an electric powered vehicle. In altering the current vehicles, your company would remove the internal combustion engine and associated components (including the transmission on some vehicles) and replace them with an electric battery. To accommodate the added weight, you would change the suspension and brake systems and add aluminum beams to the vehicle; however, your company does not plan to cut or otherwise change the vehicle's original unibody structure. You indicated that you believe NHTSA's regulations would only require your company to affix to the vehicle an additional label stating its modified gross vehicle weight rating (GVWR) and gross axle weight rating (GAWR). I welcome this opportunity to explain our regulations to you. Some background information on Federal motor vehicle safety laws and regulations may be helpful. As you are aware our agency is authorized under the National Traffic and Motor Vehicle Safety Act (15 U.S.C. S1381 et seq.; Safety Act), to issue safety standards applicable to new motor vehicles and certain items of motor vehicle equipment. NHTSA however does not approve motor vehicles or motor vehicle equipment, nor do we endorse any commercial products. Instead, the Safety Act establishes a "self-certification" process under which each manufacturer is responsible for certifying that its products meet all applicable safety standards. The answer to your question depends upon whether the vehicles your company modifies are new (that is, the vehicles have not yet been sold to the first retail purchaser) or used (vehicles that have already been sold to and used by the first retail purchaser). With respect to your company's modifications of new vehicles, your company would be an "alterer" for the purposes of NHTSA's laws and regulations. 49 CFR S567.7 requires an alterer of a new vehicle to supplement the original manufacturer's certification label, which must remain on the vehicle, by affixing an additional label. This label added by the alterer must state that the vehicle as altered continues to comply with all applicable safety standards. The added label must set forth the alterer's name and the date of the alterations. In addition, if after alteration, the vehicle classification or the vehicle's GVWR or GAWR differs from the information shown on the original certification label, then the alterer's label must reflect this new information. Your letter suggests that you believe your company must simply add a label showing the modified GVWR and GAWR of these vehicles. That is not entirely correct. Your company must also certify that the altered vehicle continues to comply with all applicable safety standards. An alterer must have some independent basis for this certification. This does not however mean that an alterer must conduct crash testing, even with respect to standards that include dynamic test requirements. Certifications of continuing compliance for altered vehicles may be based on, among other things, engineering analyses, computer simulations, actual testing, or instructions for alteration voluntarily provided by the original vehicle manufacturer in a "body builder's guide." It may be difficult for your company to certify that the hybrid electric-powered vehicles your company produces will continue to comply with Standards No. 204, Steering Control Rearward Displacement No. 208, Occupant Crash Protection, and the other crashworthiness safety standards that measure compliance during or after a 30 miles per hour rigid barrier crash test. The difficulty would arise because the weight your company would add to the vehicles during the alteration may result in more overall deformation of the vehicle during the crash test. To address these potential difficulties for electric vehicles, NHTSA published an advance notice of proposed rulemaking on whether and how the agency should modify its safety standards to account for electric vehicles. This advance notice was published on December 27, 1991 (56 FR 67038; copy enclosed). The comment period for this notice closes on March 27, 1992. Your company may wish to respond to our request for comments on this subject. Different requirements apply if you modify used vehicles. In that case, the requirements in S567.7 would not apply, because that regulation applies only to motor vehicles before the first retail purchase of the vehicle. Hence, your company is not required to affix an alterer's label to those used vehicles you convert into hybrid electric vehicles. Instead, the relevant requirements are set forth in S108 (a)(2)(A) of the Safety Act. That section of Federal law 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 motor vehicle or item of motor vehicle equipment in compliance with an applicable Federal motor vehicle safety standard. For your information, I have also enclosed a general information sheet for new manufacturers that gives a thumbnail sketch of the relevant NHTSA regulations and explains how to get copies of those regulations. I hope this information is helpful. If you have any further questions or need some additional information on this subject, feel free to contact Marvin Shaw of my staff at this address or by telephone at (202) 366-2992. |
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ID: nht92-8.49OpenDATE: February 19, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Richard W. Balsama, Esq. TITLE: None TEXT: In response to your inquiry concerning the applicability of the Federal motor vehicle safety standards to new motor vehicles and motor vehicle equipment offered for sale in the territories of the United States, I refer you to the definition of "State" in section 102 of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1391): (8) "State" includes each of the several States, the District of Columbia, the Commonwealth of Puerto Rico, Guam, the Virgin Islands, the Canal Zone, and American Samoa. Section 108 of the Act (15 U.S.C. 1397) in turn provides that a new motor vehicle or item of motor vehicle equipment may not be offered for sale in the United States unless it conforms to all applicable Federal motor vehicle safety standards. Based on these provisions, the answer to your inquiry is that the vehicles and equipment in question must conform to the standards. |
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ID: nht92-8.5OpenDATE: April 3, 1992 FROM: Frank J. Sonzala -- Senior Vice President, International Transquip Industries, Inc. TO: Paul Jackson Rice -- Chief Counsel, NHTSA TITLE: Re: Single Service Diaphragm Failure Test per FMVSS 121 ATTACHMT: Attached to letter dated 6/1/92 from Paul J. Rice to Frank J. Sonzala (A39; Std. 121); Also attached to letter dated 5/20/92 from Frederick H. Grubbe to Phil Gramm (A39; Std. 121); Also attached to letter dated 4/3/92 from Frank J. Sonzala to Phil Gramm (OCC 7206) TEXT: Under the current FMVSS 121 regulation, a diaphragm has been ruled as not being part of a brake chamber housing. The current regulation amendment, which is effective December 9, 1991, states: In S5.6.6.2 and S5.6.6.3, the test sequence for S5.6.6.1 is as follows: The engine is turned off. Any single leakage type failure in any other brake system of a part designed to contain compressed air or brake fluid (excluding failure of a component of a brake chamber housing, but including failure of any brake chamber diaphragm that is part of any other brake system, including a diaphragm which is common to the parking brake system and any other brake system) is then introduced in the brake system. An application actuation of the parking brake control is then made. Thirty seconds after such actuation, a release actuation of the parking brake control is made. Thirty seconds after the release actuation, a final application actuation of the parking brake control is made. During this particular test, it is assumed that the diaphragm has been failed. However, there is no determination as to what constitutes a failed diaphragm. ITI's testing and years of experience have shown that a hole in a diaphragm starts as a small tear, a wear point between the push rod plate and the diaphragm. By design, the diaphragm has a scrim of layered material interwoven and sandwiched between two pieces of neoprene or rubber. As the rubber or neoprene wears, a part of the surface wears away, and the scrim material, made of a nylon glass woven material will start to be exposed. This woven material is a rip-stop design which does not allow the diaphragm to rip quickly or cultivate further tearing. Once the rip-stop has been worn by the push rod plate to an 1/8" hole, then any subsequent parking brake application in the ITI system, after such an 1/8" hole, will cause the brake chambers to apply, hold the proper grade as per FMVSS 121, and not be able to release. Original equipment manufacturers generally do not recognize that an 1/8" hole is sufficient to call a diaphragm failed. ITI has tested diaphragms extensively for their tear proclivities, and those test results are found in Exhibit C, attached. In the ITI system, a hole as small as 1/8" in the diaphragm is detected and the brakes are automatically held in a mechanically locked position by the first parking application after the hole is created. In a spring brake system, a hole in a service diaphragm on the service side of a spring type parking brake goes physically undetected, so that a hole in a spring brake diaphragm can be ripped at 1/8" to 1/2" to 1" and beyond. This design fault in spring brake systems allows vehicles to be on the highway without proper service brake applications. A soft or weak brake may not even be noticeable to a driver at low air pressure applications. But in the need for a hard application such as in a panic stop, this service diaphragm can be ripped too far, causing the vehicle to go beyond a safe stopping mode. In the case of the ITI Air Brake System, the system incorporates a constant air check of every component that is designed to hold compressed air. If a component that is designed to hold compressed air has failed, and specifically if a diaphragm has failed, it is detected at the moment of its failure. In the case of the diaphragm, a hole of approximately 1/8" would still allow the brake to be applied, therefore meeting the sequence testing. But an 1/8" hole will not allow the mechanical locking piston to release, therefore holding the retardation force through the second phase of this test sequence. Because the retardation force is being held, the brake remains applied through all phases of the test procedure. By design, the ITI Air Brake chamber cannot develop over 1/8" hole in its parking or service diaphragm. This particular chamber uses one diaphragm to accomplish both tasks. In a demonstration done at the National Highway Traffic Safety Administration's offices on October 31, 1991, a failed diaphragm with an 1/8" hole was shown to the following parties: Blaine Laubis, Richard Carter, George Entwistle, Scott Schadle, and Larry Minor. The demonstration showed clearly that the brakes can be applied with adequate air pressure and mechanically locked. Because the system senses the failure, the chamber cannot be released from that park position, and it will remain applied in a safe failure mode. The demonstration was done because many of the original equipment manufacturers with whom we wish to do business have a problem with the testing sequence of the failed diaphragm, and we hoped that NHTSA would be able to clarify the test procedure and the failed diaphragm parameters. The problems with S5.6.6.1 are as follows: #1 The size of the failure hole in a diaphragm has not been defined. #2 The common position of the failure hole in the diaphragm has not been defined. International Transquip Industries has designed a fail safe mode into their non-spring brake type brake actuator that prevents any vehicle from being put on the road with a hole in the diaphragm greater than 1/8". This design is far superior to the spring brake systems that are now in use on our highways. A hole in a parking diaphragm in a spring brake system may begin or start while the vehicle is in motion. Once that hole starts, air pressure will allow the spring to creep on, possibly causing fires, possibly causing jackknifes, possibly causing a moving vehicle accident. This cannot happen with the ITI Air Brake System. ITI's system prevents spring brake accidents such as the one reported in Docket Part 571 (amended) Docket 87-04 Notice 6 (copy of which is enclosed - Exhibit A). ITI requires a ruling that will state that an 1/8" hole in a service system diaphragm constitutes a failed diaphragm for the purposes of the test sequence in S5.6.6.3, and that the hole must be placed on the service diaphragm within 1 inch of where the push rod plate meets the diaphragm. A drawing accompanies this letter showing the common area where these failures tend to occur. (Exhibit B). A hole much larger than 1/8" or placed anywhere else in the diaphragm would not constitute a realistic and valid test. Additionally, in the ITI Air Brake System, the hole in the diaphragm can only be put into the system after the system is fully aired up to 100 psi with all brakes released. The diaphragm must be taken out of the chamber and reinserted with a 1/8" hole for the test procedure as outlined in S5.6.6.3. It should be borne in mind that the OEM test for all components is performed on new vehicles and all items are to pass a performance test to meet the regulations as outlined in FMVSS 121. It takes up to two million applications for a hole to wear into a diaphragm and therefore the failed diaphragm test under FMVSS 121 does not seem realistically justified. (We recommend that the diaphragm in a brake chamber should be considered a brake chamber component that does not require a separate test under FMVSS 121. If a torn diaphragm is to be tested, then the suggested test and size and placement of the diaphragm tear should be as stated in the previous paragraphs. Our questions, therefore, for interpretation are: 1. Should a torn diaphragm be considered during a FMVSS 121 test, and if so, should the parameters as requested by ITI of 1/8" tear at one inch from the push rod plate area be used by OEMs for compliance testing? 2. Should other broken components such as heavy parking springs, brake shoes, lining and drums be part of the OEMs FMVSS 121 test requirements, based on the premise that a torn diaphragm should be tested? Your prompt and positive response to these questions will prevent further loss of revenue to our company. Because of the ambiguity of the test procedure, and comments made by NHTSA personnel to OEM inquiries that refer to larger diaphragm failures as "being possible", International Transquip Industries, Inc. has lost hundreds of thousands of dollars in sales to major customers. Attachments Exhibit A. Letter dated 3/26/90 from Bob Brinton, owner, Friction Advisory Service, to NHTSA regarding Docket Revision Part 571 (Amended) - Docket #87-04 Notice 6. Exhibit B. Drawing. Exhibit C. Summary of Diaphragm Test Results. (Text of attachments omitted.) |
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ID: nht92-8.50OpenDATE: February 18, 1992 FROM: Paul Jackson Rice -- Chief Counsel, NHTSA TO: Russell J. Eisert COPYEE: American International Conversions TITLE: None ATTACHMT: Attached to letter dated 10/25/91 from Russell J. Eisert to Steve Kratze (OCC 6617) TEXT: This responds to your letter of October 25, 1991, requesting a waiver from the requirements of the Federal motor vehicle safety standards so that you can purchase a new vehicle that has been modified to allow you to operate the vehicle from your wheelchair. The safety requirements for new light trucks and vans were upgraded as of September 1, 1991. Light trucks and vans manufactured on or after that date must be capable of providing occupant crash protection to belted front seat occupants when the vehicle is crash tested at 30 miles per hour (mph) into a concrete barrier. A vehicle that provides this crash protection will increase the safety of vehicle occupants. As a result of this new requirement, this agency has recently received a number of phone calls and letters, from both van converters and individuals like yourself, suggesting that the new light truck and van requirement will, in effect, prohibit van converters from modifying vehicles to accommodate the special needs of persons in wheelchairs. The agency also received a petition asking for an amendment to the light truck and van crash test requirement in Standard No. 208 "to eliminate requirements that inadvertently discriminate against individuals with disabilities including individuals who use wheelchairs." On January 9, 1992, this agency granted that petition. You should understand that the granting of a petition for rulemaking signifies that the agency believes a further review of the issues raised in the petition appears to have merit, but it is not a determination that the light truck and van crash test requirement should be amended. Any determination to amend the crash test requirement would be made in the course of a rulemaking proceeding, in accordance with statutory criteria. By addressing the issue comprehensively, in response to this petition for rulemaking, instead of in a piecemeal fashion, in response to each of the individual requests, NHTSA will be able to ensure that the resulting requirement offers persons in wheelchairs the best possible safety protection. However, we are aware that you and others need more immediate relief than rulemaking can offer. To afford more immediate relief, we announced in a January 21, 1992 letter to Representative Porter Goss that this agency will not conduct any crash testing under Standard No. 208 of vehicles modified for operation by persons with disabilities while this rulemaking is pending. We have also notified the van converter mentioned in your letter of rulemaking action is pending. With regard to your request for a waiver to have the rear seats in the van you will purchase moved rearward of the side door, the agency is not aware of any reason that would prevent a van converter from making this modification in such a way that the rear seats would continue to comply with all applicable safety standards after they were moved. There is, therefore, no need for us to grant such a waiver. If you have any further questions or need some additional information, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992. |
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.