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: aiam4946OpenThomas A. Gerke, Esq. Smith, Gill, Fisher & Butts 1200 Main St., Suite 3500 Kansas City, MO 64105-2152; Thomas A. Gerke Esq. Smith Gill Fisher & Butts 1200 Main St. Suite 3500 Kansas City MO 64105-2152; "Dear Mr. Gerke: This responds to your December 23, 1991 lette concerning Safety Standard 107, Reflecting Surfaces. You asked us to confirm the interpretation of the standard set forth in my September 3, 1991 letter to Mr. Thomas Steinhagen. The interpretation is correct. My letter to Mr. Steinhagen was about the applicability of Standard 107 to a replacement windshield wiper arm and blade, a type of motor vehicle equipment that your client, Rally Manufacturing, seeks to sell. You state that Rally ceased producing certain windshield wiper arms and blades after NHTSA's Enforcement office notified Rally that it appeared the products did not meet the requirements of Standard 107. My letter to Mr. Steinhagen clarified the requirements of Standard 107 and the Vehicle Safety Act. I emphasized the following points in the letter: 1. Standard 107 applies to new motor vehicles, and not to items of motor vehicle equipment, such as a replacement wiper arm and blade. Replacement wiper arms and blades may be sold to consumers without violating Federal law, even if the component does not conform to the requirements of Standard 107. 2. Section 108(a)(2)(A) of the Safety Act prohibits any manufacturer, distributor, dealer or motor vehicle repair business from 'rendering inoperative' any device or element of design installed in or on a vehicle in compliance with an applicable safety standard. If a person in the aforementioned categories installed a wiper arm and blade that did not conform to the requirements of Standard 107, the person would violate 108(a)(2)(A). 3. The prohibition of 108(a)(2)(A) does not apply to individual vehicle owners who alter their own vehicles. Thus, individual owners may install any item of motor vehicle equipment regardless of its effect on compliance with Federal motor vehicle safety standards. However, NHTSA encourages vehicle owners not to tamper with vehicle safety equipment if the modification would degrade the safety of the vehicle. 4. Regardless of whether Standard 107 applies to the replacement arm and blade, the device is subject to the requirements in 151-159 of the Safety Act concerning the recall and remedy of products with safety defects. If the manufacturer or NHTSA determines that a safety-related defect exists either in an arm and blade that conforms to Standard 107 or in one that does not, the manufacturer must notify purchasers of the product and remedy the problem free of charge. In your letter, you specifically ask about the sale of a replacement wiper blade 'by a wholesaler/distributor to retail stores and other similar customers without any installation service by the wholesaler/distributor.' The sale is not prohibited by Standard 107 or 108(a)(2)(A). However, the retail store or 'other similar customer' would be considered a dealer under 102(7) of the Safety Act, and thus subject to the 'render inoperative' prohibition of 108(a)(2)(A). While the dealer may sell the replacement blade, the dealer would be prohibited from installing it on a motor vehicle. I regret any confusion resulting from NHTSA's letters to your client. If you have further questions, please do not hesitate to contact my office. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam5654OpenFred H. Pritzker, Esq. Pritzker & Meyer, P.A. Suite 1275 Peavey Building 730 Second Avenue South Minneapolis, Minnesota 55402; Fred H. Pritzker Esq. Pritzker & Meyer P.A. Suite 1275 Peavey Building 730 Second Avenue South Minneapolis Minnesota 55402; "Dear Mr. Pritzker: This concerns your August 29, 1995 letter about th replacement of a rear seat in a 1993 GEO Tracker with a speaker box. In response to your request that we speak with you about the issues raised in that letter, Mr. Edward Glancy of my staff spoke with you by telephone. In that conversation, you requested a written opinion. Our opinion is set forth below. According to your letter, the son of the Tracker owner took the vehicle to the local outlet of a national electronics 'super store' to upgrade the vehicle's automobile stereo equipment. An employee of that store removed the rear seat and replaced it with a speaker box. As part of this process, the female portion of the seat belt buckle was removed. You stated that the speaker box has a ledge not unlike a bench-type seat, the speaker box was strong enough for a person to sit on, and was carpeted. You represent a person who was sitting on this speaker box when the vehicle was involved in a serious collision, and believe that the electronics company violated the 'make inoperative' provision of Federal law, 49 U.S.C. 30122(b). As Mr. Glancy explained to you by telephone, NHTSA cannot make a determination as to whether a company violated the 'make inoperative' provision outside a compliance proceeding. I can, however, provide general information on how this provision applies in such a situation. By way of background information, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue Federal motor vehicle safety standards applicable to the manufacture and sale of new motor vehicles and items of motor vehicle equipment. NHTSA has exercised this authority to establish Federal Motor Vehicle Safety Standard No. 208, Occupant Crash Protection (49 CFR 571.208), which specifies performance requirements for the protection of vehicle occupants in crashes. Standard No. 208 required model year 1993 passenger cars and other light vehicles to have a Type 2 (lap/shoulder) seat belt assembly at each forward-facing rear outboard designated seating position, and either a Type 1 (lap) or Type 2 seat belt assembly at all other rear designated seating positions. NHTSA's safety standards apply only to new motor vehicles and new motor vehicle equipment. However, section 30122(b) applies in the case of used as well as new vehicles. That section reads as follows: A manufacturer, distributor, dealer, or motor vehicle repair business may not knowingly make inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable safety standard prescribed under this chapter unless the manufacturer, distributor, dealer, or repair business reasonably believes the vehicle or equipment will not be used (except for testing or a similar purpose during maintenance or repair) when the device or element is inoperative. I can offer the following thoughts concerning how section 30122(b) would apply in the context of a manufacturer, distributor, dealer or motor vehicle repair business removing rear seat belts. First, electronics companies which install stereo equipment in motor vehicles are subject to section 30122(b), given the broad language 'manufacturer, distributor, dealer or motor vehicle repair business.' Second, some specific examples will illustrate how answering the question of whether a particular action makes inoperative a device installed in compliance with a Federal safety standard depends on the underlying factual circumstances. As noted above, under Standard No. 208, seat belts were required to be installed at the rear designated seating positions in the Tracker. The definition of 'designated seating position,' set forth in 49 CFR 571.3, reads as follows: Designated seating position means any plan view location capable of accommodating a person at least as large as a 5th percentile female, if the overall seat configuration and design and vehicle design is such that the position is likely to be used as a seating position while the vehicle is in motion, except for auxiliary seating accommodations such as temporary or folding jump seats. . . . The simple removal of rear seat belts from designated seating positions, without other modifications to a vehicle, would obviously make inoperative a device, i.e., seat belts, installed in compliance with Standard No. 208. Similarly, the removal of rear seat belts, coupled with replacing the rear seat with another rear seat, would make the seat belts inoperative (assuming the rear seat belts were not replaced). However, if rear seat belts were removed as part of permanently converting a passenger van to a cargo van by removing the rear seat, the removal of the seat belts would not make inoperative a device installed in compliance with a safety standard. This is because Standard No. 208 would not have required rear seat belts in the absence of rear designated seating positions. Your letter raises the question of whether a speaker box of the type installed by the electronics company would be considered to provide designated seating positions. I have enclosed a copy of the final rule establishing the designated seating position definition (44 FR 23229, April 19, 1979). As discussed in that notice, any position likely to be used while the vehicle is in motion will be considered a designated seating position. The notice includes several discussions which are relevant to the issue of whether a position is likely to be used while the vehicle is in motion. Included is a discussion that a manufacturer would not be responsible for abusive or unorthodox use of a particular position. If you have further questions, please feel free to call Mr. Glancy at (202) 366-2992. Sincerely, Samuel J. Dubbin Chief Counsel Enclosure"; |
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ID: aiam2191OpenHonorable Robin Beard, Member of Congress, 710 North Garden Street, Columbia, TN 38401; Honorable Robin Beard Member of Congress 710 North Garden Street Columbia TN 38401; Dear Mr. Beard: This responds to your January 29, 1976, question whether an owner of vehicle manufactured to comply with Standard No. 121, *Air Brake Systems, may legally disconnect portions of the brake system after a vehicle has been delivered for use in his business.; Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safet Act (15 U.S.C. S 1397(a)(2)(A)) prohibits, with one exception, knowing disconnection of safety components by manufacturers, distributors, dealers, or repair businesses. Thus, there is no prohibition on disconnection by an owner of his own vehicle's system under the Traffic Safety Act. However, State statutes, or the regulations of the Bureau of Motor Carrier Safety may prohibit disconnection. In any case, the NHTSA urges that owners not disconnect safety devices without consultation with the vehicle manufacturer with regard to the safest configuration of the vehicle.; Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam2484OpenMr. P. J. Sandblade, Philsco Products Company, Inc., Post Office Box 317, Larned, KS 67550; Mr. P. J. Sandblade Philsco Products Company Inc. Post Office Box 317 Larned KS 67550; Dear Mr. Sandblade: This is in response to your December 27, 1976, letter concerning th effect of Federal Motor Vehicle Safety Standard No. 301-75, Fuel System Integrity, on the auxiliary fuel tanks that you manufacture for pick-up trucks. The question you have asked was addressed in my November 10, 1976, letter to Mr. Charles Atkinson. It does not appear that you are in danger of going out of the auxiliary tank business.; A copy of that letter is enclosed for your convenience. Sincerely, Frank Berndt, Acting Chief Counsel |
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ID: aiam5341OpenMr. Robert L. Montgomery Safety Manager Leprino Transportation Division Leprino Foods P.O. Box 17989 Denver, CO 80217-0989; Mr. Robert L. Montgomery Safety Manager Leprino Transportation Division Leprino Foods P.O. Box 17989 Denver CO 80217-0989; Dear Mr. Montgomery: This replies to your letter of March 9, 1994, t the Regional Office of the Federal Highway Administration (FHWA). You have questions regarding the trailer conspicuity requirements of Federal Motor Vehicle Safety Standard No. 108, a regulation of the National Highway Traffic Safety Administration. You have enclosed photos of two rear end treatments. In Photo; 1, the conspicuity treatment is applied 'on the doors at a height of 5 inches which is approximately 6 inches higher than the 1.25 meters (50 inches) dictated.' The conspicuity treatment appears to extend the full width of the vehicle. In Photo; 2, the reflectorized material is located '4 inches less than the 1.2 meters (50 inches) dictated.' In this configuration, the conspicuity treatment has been relocated to a position between the rear lighting units so that it no longer extends the full width of the vehicle. Photo; 1 represents the trailer as received from the manufacturer. Photo 2 represents the modifications you wish to make to the trailer. Yo have asked whether the configuration depicted in Photo; "2 complies with Standard No. 108. The manufacturer of the trailer ha certified its compliance with all applicable Federal motor vehicle safety standards, including the conspicuity treatment location requirements of Standard No. 108. Paragraph S5.7.1.4.1(a) specifies that the material be located 'as close to the extreme edges as practicable.' The relocation you contemplate would place the material where it is not as close to the extreme edges of the trailer as it originally was. This would create a noncompliance with Standard No. 108. Section 108(a)(2)(A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C. 1397(a)(20(A)) (the Act) prohibits any manufacturer, dealer, distributor, or motor vehicle repair business from knowingly rendering inoperative, in whole or in part, any device or element of design installed in accordance with a Federal motor vehicle safety standard. The prohibition, however, does not apply to the vehicle owner. This means that Leprino Foods and its employees are not themselves prohibited by the Act from modifying your trailers to the configuration depicted in Photo"; 2. It does mean that a 'manufacturer, dealer, distributor, or moto vehicle repair business' cannot perform this work for you. We surmise that your trailers are subject to the jurisdiction of the FHWA when they are operated in interstate commerce. FHWA regulations require your trailer to be equipped to conform to Standard No. 108. Thus, if you modify your trailers so that they no longer conform to the rear location requirements of Standard No. 108, you would be in violation of the regulations of that agency. This is to advise you that the FHWA has concurred in this interpretation to you. Either mounting height location is permitted. Originally, Standard No. 108 did specify a mounting height for rear conspicuity material that was 'as close as practicable to 1.25 meters above the road surface.' However, the agency amended this paragraph on October 6, 1993, to adopt a height range of 'as close as practicable to not less than 375 mm and not more than 1525 mm above the road surface.' This is the equivalent of 15 to 60 inches above the road surface. Therefore, the mounting heights of 46 and 56 inches shown in your two photos is in accordance with the revised requirement. Finally, we note your comment that the diagram in the Federal Register 'failed to consider the bumper bar area and the light assemblies that are actually on a van.' The requirements that must be adhered to are found in the text of Standard No. 108, Figure 30 is meant only as a general guide as to the placement of the conspicuity material. Obviously, it cannot depict the exact rear configuration of all van trailers. Sincerely, John Womack Acting Chief Counsel; |
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ID: aiam0143OpenHector J. Rosso, Esquire, 141 North Arrowhead, San Bernardino, California 92401; Hector J. Rosso Esquire 141 North Arrowhead San Bernardino California 92401; Dear Mr. Rosso: This is in response to your letter of February 14, 1969, in which yo seek information concerning possible overloading of Seiberling 8.25-20 ten ply rating truck tires manufactured in approximately 1963.; The Federal Highway Administration has issued a Federal motor vehicl safety standard for passenger car tires manufactured after January 1, 1968 requiring them to meet certain tests when loaded to prescribed weights. (49 C.F.R. S371.21 Standard 109). Performance requirements for truck tires are presently under consideration. Comments have been received in response to an Advance Notice of Proposed Rule Making on this matter but regulations have not as yet been issued.; The Bureau of Motor Carrier Safety regulates the safety and operatio of interstate motor carriers. Its regulation regarding tires (49 C.F.R. S393.75) is not relevant to your inquiry.; One fruitful source of information may be the Tire and Rim Associatio Yearbook. This publication provides data on tires and suggests standards for tire load limits. It is published by the Tire and Rim Association, Inc., Comand Building, 34N. Hawkins Avenue, Akron, Ohio 44313.; I hope this information will be of value to you. Sincerely, Robert M. O'Mahoney, Assistant Chief Counsel fo Regulations(sic); |
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ID: aiam4803OpenMr. Danny Pugh Engineering Manager Utilimaster Corporation 65266 State Rd. 19 P.O. Box 585 Wakarusa, IN 46573; Mr. Danny Pugh Engineering Manager Utilimaster Corporation 65266 State Rd. 19 P.O. Box 585 Wakarusa IN 46573; "Dear Mr. Pugh: This responds to your letter seeking an interpretatio of Standard No. 208, Occupant Crash Protection (49 CFR 571.208). More specifically, you asked about the requirements for safety belts at the various seating positions in vehicles with a gross vehicle weight rating under 10,000 pounds that you called 'van conversions.' You first asked whether a 'van conversion' would be classified as a passenger car, truck, or multipurpose passenger vehicle. Vehicles commonly called 'vans' may be classed in four different vehicle categories (set forth at 49 CFR 571.3) for the purposes of our safety standards, depending on the configuration of the particular 'van.' Most cargo vans are classified as 'trucks' under our safety standards, because those vehicles are 'designed primarily for the transportation of property or special purpose equipment.' Most passenger vans are classified as 'multipurpose passenger vehicles,' because they do not meet the definition of a 'truck', but are 'constructed on a truck chassis.' Those vans that have eleven or more designated seating positions are classified as 'buses,' because they are 'designed for carrying more than 10 persons. Finally, one minivan (the Nissan Axxess) was certified by its manufacturer as a 'passenger car,' because it was 'designed for carrying 10 persons or less.' Additionally, the National Traffic and Motor Vehicle Safety Act places the responsibility for classifying a particular vehicle in the first instance on the vehicle's manufacturer. For this reason, NHTSA does not approve or endorse any vehicle classification before the manufacturer itself has classified a particular vehicle. NHTSA may reexamine the manufacturer's classification in the course of any enforcement actions. If you are interested in the appropriate classification for a particular van conversion, we will offer our tentative opinion if you will provide us with detailed information on the van conversion in which you are interested. You next asked on what date safety belts were required in 'van conversions,' what type of safety belts, and at what locations those belts were required. As explained above, we do not class vehicles as 'van conversions' for the purposes of our safety standards. If the vans were classed as passenger cars, passenger cars manufactured on or after January 1, 1968 were required to have lap/shoulder safety belts at the front outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position in the car. Beginning December 11, 1989, passenger cars were required to have lap/shoulder safety belts at both front and rear outboard seating positions, with either lap/shoulder or lap-only safety belts at every other seating position. Since September l, l989, all passenger cars are required to be equipped with automatic crash protection for outboard front-seat occupants. Multipurpose passenger vehicles and trucks with a gross vehicle weight rating of 10,000 pounds or less manufactured on or after July 1, 1971 were required to have lap/shoulder safety belts at the front outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position in the vehicle. Beginning September 1, 1991, vans classified as multipurpose passenger vehicles or trucks (other than motor homes) must have lap/shoulder belts at both front and rear outboard seating positions, with either lap or lap/shoulder belts at all other seating positions. Motor homes manufactured on or after September 1, 1991 will continue to be required to have lap/shoulder belts at front outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position. In addition, effective September l, l99l vans must meet dynamic crash test injury criteria for the front outboard seating positions. If the vans were classed as buses, buses manufactured on or after July 1, 1971 were required to be equipped with either a lap/shoulder or a lap-only safety belt at the driver's seating position. Beginning September 1, 1991, buses with a gross vehicle weight rating of 10,000 pounds or less (except school buses) must be equipped with lap/shoulder belts at all front and rear outboard seating positions and either lap/shoulder or lap-only safety belts at every other seating position. Also, the agency has proposed extending the automatic crash protection requirements mentioned above to these other vehicle classifications. I hope this information is useful. If you have any further questions or need some additional information on this subject, please contact Steve Kratzke of my staff at this address or by telephone at (202) 366-2992. Sincerely, Paul Jackson Rice Chief Counsel"; |
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ID: aiam0513OpenMr. Thomas S. Pieratt, Jr., Executive Secretary, Truck Equipment & Body, Distributors Association, 602 Main Street, Cincinnati, OH 45202; Mr. Thomas S. Pieratt Jr. Executive Secretary Truck Equipment & Body Distributors Association 602 Main Street Cincinnati OH 45202; Dear Mr. Pieratt: This is in reply to your letter of November 5, 1971 regarding the Tir Identification and Record Keeping Regulation (49 C.F.R. 574). The questions raised in your letter are repeated below with our answers immediately following each question.; 1. Section 574.9 of the above states that anyone who leases a vehicl equipped with new tires for more than 60 days is classified as a tire dealer, and shall meet the requirements specified in Section 574.8. Under the above, what would be the 'tire dealer's' responsibility if the customer exchanged these tires, without the knowledge of the leasor (sic), and what should the leasor (sic) do re: compliance if the vehicle is returned and he notices that a substitution had been made?; >>>Under these circumstances the leasor (sic) would only be responsibl for the new tires that were on the vehicle when leased to his customer. It would be the responsibility of the tire dealer selling the replacement tires to the leasee (sic) of your vehicle to record the pertinent tire information and forward it to the manufacturer of the tires.<<<; 2. A company buys a truck as a 'demonstrator' for its own use, bu prior to the actual 'use' of the vehicle, it is sold under a new title. If the seller of the demonstrator advises the local truck dealer of this sale (to include the customer data), has he satisfied all of his responsibilities under Part 574?; >>>Under these circumstances the person who buys a truck and does no use it, but instead sells it, is considered a vehicle dealer selling a new truck. It would be your responsibility to assure that the dealer who originally sold you the truck notifies the vehicle manufacturer that the vehicle changed hands.<<<; 3. A leasor (sic) takes a vehicle back after a 12-month lease. Afte reconditioning it, he leases it to a different customer. The tires were still in good condition and were not removed. Under these circumstances, does the leasor (sic) have any responsibility to notify the vehicle manufacturer that the vehicle is now in different hands?; >>>Under these conditions the leasor (sic) would be in the sam position as a vehicle dealer selling a used vehicle with used tires and the reporting requirements would not apply.<<<; 4. It is our interpretation that under the provision of Part 574, th only time that a final stage manufacturer would be required to maintain tire records would be if he becomes the vehicle manufacturer and places new tires onto a vehicle for the first time. (This would be in the case of adding a tandem axle requiring additional tires, or the actual manufacture of a trailer to which he installed the tires.) Is this correct?; >>>Your understanding is not correct. The final stage manufacturer i required to maintain or have maintained for him a record of tires on or in each vehicle he ships to a motor vehicle distributor or dealer, and maintain or have maintained for him a record of the name and address of the first purchaser for purposes other than resale of each vehicle equipped with such tires.; For your information, attached is a letter sent to major chassi manufacturers dealing with this subject for cases where the final stage manufacturer does not deal with the purchaser of the completed vehicle. The replies received from the chassis manufacturers have been, for the most part, cooperative.<<<; a. In the case of a manufactured vehicle, we interpret section 574.9 t mean that the records kept for three years need not conform with any special format, so long as the customer name and address is evident, and the customer can be contacted by the manufacturer in the event that the tire manufacturer initiated a recall campaign which included the group of tires placed on that vehicle. Is this a correct assumption?; >>>Your understanding is correct, however the requirements for vehicl manufacturers are found in 574.10, not 574.9.<<<; Sincerely, David Schmeltzer, Assistant Chief Counsel |
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ID: aiam4550OpenMr. J. E. Carr Product Safety & Environmental Control Caterpillar Inc. Peoria, IL 61629; Mr. J. E. Carr Product Safety & Environmental Control Caterpillar Inc. Peoria IL 61629; "Dear Mr. Carr: This letter responds to your inquiry of April 29, 1988 asking this agency for an interpretation of Standard 124, Accelerator Control Systems, as it applies to the components of a diesel truck engine and accelerator control components described in your letter. I apologize for the delay in this response. With your letter, you provided diagrams of three different accelerator control systems and fuel metering devices for a diesel engine. The first system (Type I in your letter) was a purely mechanical system. In this system, the linkage from the accelerator pedal connects to a mechanical governor. This governor is a device that responds to pedal displacement, and causes a rack to move, thereby controlling the flow of fuel from fuel injector pumps into the engine cylinders. The second and third systems described in your letter operate through an electrical-mechanical sequence. In the second system (Type II in your letter), mechanical linkage from the accelerator pedal connects to an electronic pedal position sensor. When the vehicle operator puts pressure on the accelerator pedal, this sensor converts that movement into an electrical signal. The electrical impulse travels through a wire to an engine control module (ECM). The ECM interprets pedal position and engine speed from the sensor impulse, and determines how much fuel must go to the engine cylinders either to maintain or reduce speed in consequence of pedal movement. In turn, the ECM sends a signal to a motor which moves a fuel rack to control the flow of fuel from the injector pumps into the engine cylinders. In the system you call Type III, the ECM sends a signal directly to individual fuel injector pumps without the intervention of a rack. Otherwise, Type II and III are the same. On October 28, 1988, at the agency's invitation, you met with us to further explain the background information for this request and why Caterpillar believes that particular components were included in either the accelerator control system or the fuel metering device. During the course of that meeting, you agreed with us that Caterpillar's principal concern was not whether any particular component was part of the accelerator control system or the fuel metering device. Instead, you were concerned with the requirement that the throttle 'shall return to idle' under specified conditions. You explained that your ECM is designed to shut off the engine, rather than return the throttle to idle, during many failure modes. We conclude that the requirement that the throttle 'return to idle' is satisfied by a system that shuts off the engine in the specified circumstances. As S2 of Standard 124 makes clear, the purpose of the standard is to prevent runaway vehicles when certain malfunctions occur in the accelerator control system. If such malfunctions do occur, the standard ensures that the engine will not continue at a high speed, but will return to idle, so that the driver can safely brake the vehicle and get it off the road. In both the Type II and III systems referred to in your letter, the agency understands that a failure in the ECM circuitry, or a failure of the components that respond to the ECM, will either return the throttle to idle or shut down the engine. Either of these results would serve the purpose of Standard 124. Therefore, we interpret the phrase 'return to idle' to be satisfied by returning to idle or going beyond that throttle position to shut off the engine. Accordingly, based on the information you have provided, it appears that your Type II and III systems would comply with Standard 124 regardless of whether the ECM and other components are considered part of the acclerator control system or the fuel metering device. I hope you find this information helpful. If you have further questions, please call Joan F. Tilghman of my staff at (202) 366-2992. Sincerely, Erika Z. Jones Chief Counsel"; |
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ID: aiam3295OpenMr. Martin D. Davis, Meon, Inc., 221-18 Merrick Boulevard, Springfield Gardens, NY 11413; Mr. Martin D. Davis Meon Inc. 221-18 Merrick Boulevard Springfield Gardens NY 11413; Dear Mr. Davis: This is in response to your letter of May 12, 1980, requestin interpretation of paragraph (c)(2)(iii) of the Uniform Tire Quality Grading Standards (49 CFR S 575.104). That paragraph provides that to qualify as a limited production tire a tire cannot have been listed as a vehicle manufacturer's recommended tire size designation for a new motor vehicle produced in or imported into the United States in quantities greater than 10,000 during the preceding calendar year. You ask whether a tire meets this requirement if its size is recommended for use on several new vehicles, none of which is produced in quantities greater than 10,000 yearly, but which in the aggregate account for annual production in excess of 10,000 vehicles.; Paragraph (c)(2)(iii) refers to '*a* vehicle manufacturer's recommende tire size designation (emphasis added)' and '*a* new motor vehicle (emphasis added)', indicating that the 10,000 vehicle limitation refers to the production or importation of a particular vehicle model, rather than the total of all models for which the tire size is recommended. Thus, if a tire's size is recommended for use on several vehicle models, none of which is produced in or imported into the United States in quantities greater 10,000 during the calendar year preceding the year of the tire's manufacture, the tire would meet the criterion of paragraph (c)(2)(iii).; Sincerely, Frank Berndt, Chief Counsel |
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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.