NHTSA Interpretation File Search
Overview
NHTSA's Chief Counsel interprets the statutes that the agency administers and the standards and regulations that it issues. Members of the public may submit requests for interpretation, and the Chief Counsel will respond with a letter of interpretation. These interpretation letters look at the particular facts presented in the question and explain the agency’s opinion on how the law applies given those facts. These letters of interpretation are guidance documents. They do not have the force and effect of law and are not meant to bind the public in any way. They are intended only to provide information to the public regarding existing requirements under the law or agency policies.
Understanding NHTSA’s Online Interpretation Files
NHTSA makes its letters of interpretation available to the public on this webpage.
An interpretation letter represents the opinion of the Chief Counsel based on the facts of individual cases at the time the letter was written. While these letters may be helpful in determining how the agency might answer a question that another person has if that question is similar to a previously considered question, do not assume that a prior interpretation will necessarily apply to your situation.
- Your facts may be sufficiently different from those presented in prior interpretations, such that the agency's answer to you might be different from the answer in the prior interpretation letter;
- Your situation may be completely new to the agency and not addressed in an existing interpretation letter;
- The agency's safety standards or regulations may have changed since the prior interpretation letter was written so that the agency's prior interpretation no longer applies; or
- Some combination of the above, or other, factors.
Searching NHTSA’s Online Interpretation Files
Before beginning a search, it’s important to understand how this online search works. Below we provide some examples of searches you can run. In some cases, the search results may include words similar to what you searched because it utilizes a fuzzy search algorithm.
Single word search
Example: car
Result: Any document containing that word.
Multiple word search
Example: car seat requirements
Result: Any document containing any of these words.
Connector word search
Example: car AND seat AND requirements
Result: Any document containing all of these words.
Note: Search operators such as AND or OR must be in all capital letters.
Phrase in double quotes
Example: "headlamp function"
Result: Any document with that phrase.
Conjunctive search
Example: functionally AND minima
Result: Any document with both of those words.
Wildcard
Example: headl*
Result: Any document with a word beginning with those letters (e.g., headlamp, headlight, headlamps).
Example: no*compl*
Result: Any document beginning with the letters “no” followed by the letters “compl” (e.g., noncompliance, non-complying).
Not
Example: headlamp NOT crash
Result: Any document containing the word “headlamp” and not the word “crash.”
Complex searches
You can combine search operators to write more targeted searches.
Note: The database does not currently support phrase searches with wildcards (e.g., “make* inoperative”).
Example: Headl* AND (supplement* OR auxiliary OR impair*)
Result: Any document containing words that are variants of “headlamp” (headlamp, headlights, etc.) and also containing a variant of “supplement” (supplement, supplemental, etc.) or “impair” (impair, impairment, etc.) or the word “auxiliary.”
Search Tool
NHTSA's Interpretation Files Search
Interpretations | Date |
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ID: nht79-2.21OpenDATE: 08/31/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Halliburton Services TITLE: FMVSS INTERPRETATION TEXT: Mr. Ron Bechtel Halliburton Services Drawer 1431 Duncan, Oklahoma 73533 Dear Mr. Bechtel: This is in response to your letter of May 1, 1979, requesting an interpretation of the definition of "incomplete vehicle" contained in Federal Motor Vehicle Safety Standard No. 115, and in confirmation of your subsequent telephone conversations with Mr. Schwartz of my office. The term "incomplete vehicle" is defined in S3 of the standard to mean "an assemblage consisting, as a minimum, of frame and chassis structure, power train, steering system, suspension system, and braking system, to the extent that those systems are to be part of the completed vehicle, that requires further manufacturing operations, other than the addition of readily attachable components, such as mirrors or tire and rim assemblies, or minor finishing operations such as painting, to become a completed trailer." You are correct in saying that most of the components listed in the definition are not meant to be part of a trailer. Consequently, an incomplete trailer would consist of only those components, such as a frame, listed in the definition which are meant to be part of the completed trailer. The outfitting of an incomplete trailer for a specific purpose would not be sufficient to make Halliburton Services responsible for assigning the vehicle identification number. Sincerely, Frank Berndt Chief Counsel (405) 251-3565 May 1, 1979 RB-90-79 Office of Chief Council National Highway Traffic Safety Administration 400 7th Street, S.W. Washington, D.C. 20590 Dear Sir: VIN Standards I would like to request an interpretation as to the definition of an "incomplete vehicle" in regard to trailers. The definition as contained in S571.115(s)(3) is only applicable to powered vehicles as the stated minimum requirements are not relative to trailers. Very truly yours, Ron Bechtel RB:im |
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ID: nht79-2.22OpenDATE: 09/28/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: PACCAR, Inc. TITLE: FMVSS INTERPRETATION TEXT: Mr. Mark K. McDonald PACCAR, Inc. Business Center Building P. O. BOX 1518 Bellevue, Washington 98009 Dear Mr. McDonald: This is in response to your letter of May 22, 1979, concerning Federal Motor Vehicle Safety Standard No. 115, and in confirmation of your telephone conversation with Mr. Schwartz of my office. You have asked whether a manufacturer must designate a vehicle an "incomplete vehicle" if, although it is shipped in an incomplete form, its completed type is known. The "incomplete vehicle" type was established to deal with situations where the manufacturer did not know what the vehicle's final type would be when it assigned the VIN. If the final form the vehicle will take is known to the manufacturer, it may identify that type in the VIN, or it may designate it as an incomplete vehicle. The agency would prefer, however, that the final type be indicated. There is no requirement that use of a particular vehicle type designation for VIN purposes be consistent with any other documentation regarding shipment or sale of vehicles manufactured in more than one stage, except that the actual VIN must be used where it appears on the documentation. For example, a vehicle may be designated an incomplete vehicle for the purposes of the NHTSA certification requirements and a truck for the purposes of the VIN requirements. You have also asked the agency to confirm that engine horsepower need not be directly or indirectly decipherable from the VIN. This is essentially correct. "Engine type" is defined in S3 of the standard to mean a power source with defined characteristics such as fuel utilized, number of cylinders, displacement and net brake horsepower. Thus, encoding an engine manufacturer's basic model number would be sufficient. There remains, however, a question as to the point at which two engines with the same characteristics except for horsepower become two different engines. The agency intends to resolve this question in a notice in the Federal Register. Sincerely, Frank Berndt Chief Counsel May 22, 1979 Mr. Fred Swartz National Highway Traffic Safety Administration 400 Seventh Street, S.W. Washington, D.C. 20590 Dear Fred: To follow up our phone conversation of today, PACCAR will proceed to formulate its VIN code in compliance with FMVSS 115 under these assumptions: 1. Incomplete Vehicle Type: It is our understanding that this designation is to be used at the manufacturer's discretion when designation of a complete vehicle type would not be practical. There are no circumstances which require that the manufacturer use the incomplete vehicle type designation. Moreover, there is no requirement that use of the incomplete vehicle designation be consistent with any other documentation regarding shipment or sale of vehicles manufactured in more than one stage. 2. Horsepower Rating: There is no requirement that engine horsepower be either directly or indirectly decipherable from the VIN. Horsepower may be used as one characteristic by which engines are classified. A complete and acceptable method of classification would be to encode as a separate classification each basic model number as specified by the engine manufacturer. I am requesting that you send written acknowledgement that the above assumptions are proper interpretations of FMVSS 115. Thank you. Sincerely, Mark K. McDonald MKM:ed |
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ID: nht79-2.23OpenDATE: 10/25/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Blue Bird Body Co. TITLE: FMVSS INTERPRETATION TEXT: Mr. W. G. Milby Manager, Engineering Services Blue Bird Body Company P.O. Box 937 Fort Valley, Georgia 31030 Dear Mr. Milby: This is in response to your letter of March 29, 1979, requesting an interpretation of Federal Motor Vehicle Safety Standard No. 115 (49 CFR 571.115). We are sorry for the delay in responding. You wish to know whether the "body number" that Blue Bird Body Company assigns to its school buses will satisfy the requirement of S4.5.3.3 that the last six characters of the Vehicle Identification Number (VIN) represent the production sequence of the vehicle. Your concern arises from the fact that the "body number" does not indicate the true numerical sequence of manufacture. As explained in Notice 5 (43 FR 36448) and Notice 6 (43 FR 52246) the production sequence represents the "number sequentially assigned by the manufacturer in the production process" (S4.5.3.3), rather than the numerical sequence of actual manufacture. Consequently, the Blue Bird body number may be used as the production sequence number since the "body numbers" are sequentially assigned when purchase orders for the buses are received. Sincerely, Frank Berndt Chief Counsel March 29, 1979 Mr Joseph L. Levin, Jr. Chief Counsel National Highway Traffic Safety Administration Washington D.C. 20590 Reference: 1. FMVSS 115 Vehicle Identification Number Amendment dated March 27, 1979 2. Telephone conversation by Bob DuMond with Nelson Erickson, NHTSA on March 13, 1979 Dear Mr. Levin: I am writing with reference to section S 4.5.3.3 of the above Federal Standard and seek your approval of our interpretation of the term "production sequence number" contained within this section. As a manufacturer of a forward control type of school bus, Blue Bird Body Company will be required to develop a VIN (Vehicle Identification Number) as referenced in the Federal Standard. Blue Bird assigns a body number to each vehicle as soon as a purchase order is accepted. This unique number forever establishes the identity of each vehicle. All pertinent body and chassis information can be determined by knowing this number. Body and chassis service numbers are set up for the customer use in handling service problems. These numbers indicate exact production sequence of the separate body and chassis. Also, our Federal Certification records establish the day that the vehicle was certified. However, permanent files can be accessed at any time by using any of these numbers for information relative to each unique vehicle. Our plan is to reduce error in the VIN by having the number computer generated. All pertinent information required by FMVSS 115 will be carried in our computer files. Because the body number is the earliest number assigned to the vehicle, Blue Bird would seek to use this number as the "production sequence number". However, due to early assignment of this number, sometimes six months prior to production, this body number will not indicate true numerical sequence. However, the importance of the value of this particular number as identified by NHTSA for recall campaign, etc. would ideally be the one for Blue Bird to use. Therefore, I seek your approval of the use of the Blue Bird Body Company "body number" as the "production sequence number." I am looking forward to your favorable response. Thank you. Very truly yours, W. G. Milby Manager, Engineering Services WGM:oct cc: VIN Committee |
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ID: nht79-2.24OpenDATE: 10/24/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Toyo Kogyo Co., Ltd. TITLE: FMVSS INTERPRETATION TEXT: Mr. Kei Matsui Toyo Kogyo Co. Ltd. P.O. Box 18, Hiroshima 730-91 Japan Mr. Matsui: This is in response to your letter of May 11, 1979, requesting the National Highway Traffic Safety Administration's (NHTSA) views on whether the inclusion of optional equipment on certain Mazda models would be sufficient to create a number of different series within that model. Section 4.5.2 of Federal Motor Vehicle Safety Standard No. 115 (Vehicle Identification Number) states that the second section of the vehicle identification number for passenger cars shall be decipherable into the vehicle's line, series, body type, engine type, and restraint system type. "Line" is defined as "a name which a manufacturer applies to a family of vehicles which have a degree of commonality in construction, such as body, chassis or cab type." "Series" is defined as "a name which a manufacturer applies to a subdivision of 'line', denoting price, size, or weight identification, and which is utilized by the manufacturer for marketing purposes." Based on the facts presented, it is apparent that models equipped with different optional equipment could each be designed a "series" if Mazda desired. Nonetheless, the definition of "series" makes clear that the responsibility for applying and utilizing the "series" designation rests initially with the manufacturer. If the difference between the potential series are superficial and a manufacturer chooses not to designate separate series for marketing reasons because of the superficiality, the agency will not require such a designation. Sincerely, Frank Berndt Chief Counsel May 11, 1979 Our Ref. No. RDE-79-8 Chief Counsel National Highway Traffic Safety Administration 400 Seventh Street SW. Washington, D.C. 20590 U. S. A. Dear Sir: Subject: Question on Interpretation of FMVSS No. 115 "Vehicle Identification Number" Docket No. 1-22, Notice 8 We are now developing a system to comply with the requirements of FMVSS No. 115 published in the March 22, 1979 Federal Register. As shown in the attached tables, our vehicles are advertized and sold under the designations given according to their specifications. For example, the Mazda GLC has the designations of "Basic", "Custom", "Decore Package" and "Sports". Although these designations are utilized for the purpose of sales, they have been only given according to the level of the optional parts installed. Therefore, we think that these designations do not correspond to "Series" stipulated in S3 "Definition". We would like to confirm whether our interpretation is correct or not. We would appreciate your reviewing our above request and advising us of your comment at your earlist convenience. Sincerely yours, Kei Matsui Manager Development Administration Division |
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ID: nht79-2.25OpenDATE: 10/22/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Carolina International, Inc. TITLE: FMVSS INTERPRETATION TEXT: Mr. John W. Howard, III Product Engineering Manager Carolina International, Inc. 1 Hurstbourne Park, Suite 703 Louisville, Kentucky 40222 Dear Mr. Howard: This is in response to your letter of June 19, 1979, and in confirmation of your telephone conversation with Mr. Schwartz of my office. The VIN format you forwarded with your letter is essentially correct. There are, however, several aspects of it which should be modified. They will be discussed as numbered in your letter. It is important to point out at the outset that Standard 115 requires Carolina International Inc. to assign a VIN to only those vehicles for which it is the first stage manufacturer, in this case trailers. Ford and General Motors will be assigning a VIN to those vehicles for which it is the first stage manufacturer, even though Carolina is the final stage manufacturer. I. World Identification Numbers. The first three characters of the VIN designate the manufacturer, make, and type of vehicle. While Carolina is the final stage manufacturer for several types of vehicles, it is the first stage manufacturer for only one type. Consequently, one manufacturer identifer is sufficient. As the Agency has contracted with the Society of Automotive Engineers (SAE) to act as its agent in assigning these Identification codes (see enclosed notice), you should communicate with the SAE if your identifier was not assigned by it. II. Vehicle Description Section (VDS). Your proposed coding for the VDS is satisfactory, except that it encodes data relating to vehicles produced by other manufacturers who would, as explained above, assign the VIN for those vehicles. III. Check Digit. The mathematical values assigned to the alphabetic characters are not correct. Please consult Table IV in Notice 8 (44 PR 17489, March 22, 1979) which I have enclosed. IV. Vehicle Indicator Section. The format utilized in this section is correct, except that the series of trailer must be indicated in the Vehicle Descriptor Section. Perhaps this can be encoded where you previously intended to indicate chassis type (2.4). I hope this information has been helpful. Please write or call Mr. Schwartz of my office at 202-426-1834 should you have any additional questions. Sincerely, Frank Berndt Chief Counsel Enclosure June 19, 1979 Mr. Frederick Schwartz, Jr. Office of the Chief Counsel National Highway Traffic Safety Administration 400 7th Street, S.W. Washington, D.C. 20590 RE: Federal Motor Vehicle Safety Standard No. 115, Vehicle Identification No. Dear Mr. Schwartz: Per our telephone conversation last week, and pursuant to the above referenced standard, attached please find an outline of Carolina International, Inc.'s proposed method to meet the above referenced standard. Please review, and return an approved copy to me for our files. Should you have any questions, or need additional information, please call.
Sincerely, John W. Howard, III Product Engineering Manager JWH/nhs Encl. |
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ID: nht79-2.26OpenDATE: 12/07/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Mack Trucks, Inc. TITLE: FMVSS INTERPRETATION TEXT: December 7, 1979 Mr. Thomas F. Brown Executive Engineer Mack Trucks, Inc. P.O. Box 1761 Allentown, Pennyslvania 18105 Dear Mr. Brown: I apologize for the delay in responding to your letter of June 26, 1979, questioning an opinion contained in our December 12, 1978, letter to you regarding the requirements of Federal Motor Vehicle Safety Standard No. 120. Our letter stated that your company should stamp the words "not applicable", or words of similar import, in any spaces on your certification label which are for axles not present on the vehicle to which the label is affixed. You responded that the blank spaces on the label would not be confusing, and that the likelihood of a discrepancy between the vehicle and the label is very remote. Our letter did not address the question of the wrong label accidentally being affixed to a vehicle. Such an occurrence would mean that the vehicle would not comply with the requirements of Standard No. 120, and it could not legally be sold in the United States. Hence, any questions about a discrepancy between the information appearing on the label and the vehicle are beyond the scope of this reply. S5.3 of Standard No. 120 requires that the labeling information specified in S5.3.1 - S5.3.3 appear in the format shown in the truck example following S5.3. As explained in the December 12 letter, minor variations on what is set forth in the truck example are permitted, but only if those minor variations do not change or obscure the meaning of the label. Minor variations consist of slight differences in punctuation or a substitution of words for a punctuation mark. The purpose of the labeling requirement is to clearly convey to the user of the vehicle the information specified in Standard No. 120. Leaving blank spaces for axles which do not exist on the particular vehicle being labeled does not, upon reconsideration, change or obscure the meaning of the label. Nor is it reasonable to assume that blank spaces will confuse the average reader of the label, when those blank spaces correspond to axles not present on the vehicle. Therefore, I am hereby withdrawing the statement in our previous letter that Mack Trucks should stamp "not applicable" or words of similar import on certification labels for axles not present on the vehicle being labeled. It would be more accurate, however, to insert these words and it would be a simple matter to do so at the same time the other variable information is applied to the label form. Sincerely, Frank Berndt Chief Counsel June 26, 1979 Chief Counsel National Highway Traffic Safety Administration U.S. Department of Transportation 400 Seventh Street, S.W. Washington, D.C. 20590 Dear Sir: Subject: Vehicle Certification Label/FMVSS 120 Ref: NOA-30 On January 5, 1979, we sent the attached letter to Mr. Joseph J. Levin, Jr., who was Chief Counsel at that time. As of this date, we have not received a reply to this letter. The letter concerns the blank spaces present in the FMVSS 120 portion of our Vehicle Certification Label which Mr. Levin felt were confusing. We do not feel that they could be confusing. Please review both Mr. Levin's attached letter and our response to his letter and advise us of your findings. Very truly yours, MACK TRUCKS, INC. Thomas F. Brown Executive Engineer- Vehicle Regulations and Standards vy Attach. January 5, 1979 Mr. Joseph J. Levin, Jr., Chief Counsel National Highway Traffic Safety Administration U.S. Department of Transportation 400 Seventh Street, S.W. Washington, D.C. 20590 Dear Mr. Levin: SUBJECT: Vehicle Certification Label Ref: NOA-30 In your letter of December 12, 1978, you noted the following: "The label enclosed with your letter shows spaces to provide information for the front, rear, and three intermediate axles. When this label is used on vehicles with fewer than five axles, you should stamp 'Not applicable', or words of similar import, in the spaces provided for axles which do not exist on the particular vehicle which is being labelled. Without this indication, the label could be confusing and so would fail to clearly provide the required information for that vehicle. An indication of nonapplicability would alert the reader to that fact." Mack Trucks, Inc. does not understand how one (1) to three (3) blank axle/tire/rim spaces could be confusing since the label is affixed to the vehicle. If, for some reason, the number of axles on the vehicle does not agree with the number represented on the label, obviously, something is wrong. Whether there are "blank spaces" or "not applicable spaces" is of little consequence. The likelihood of a discrepancy between the label and the vehicle is very remote. Please note the GAWR requirement on the label was effective January 1, 1972. We have used the "FRONT, 1ST INT., 2ND INT., 3RD INIT., REAR AXLE" format with blank spaces since that date (7 years). We are not aware of any problems associated with this format. Therefore, we would appreciate an explanation of how blank spaces could be confusing under the outlined circumstances. Very truly yours, MACK TRUCKS, INC. T. P. Brown Executive Engineer- Vehicle Regulations and Standards vy bcc: Messrs. L. F. Donnelly S. Robson C. D. Trexler |
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ID: nht79-2.27OpenDATE: 10/30/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Bendix Corporation TITLE: FMVSS INTERPRETATION TEXT: October 30, 1979 NOA-30 Mr. R. W. Hildebrandt Group Director-Engineering Bendix Corporation 901 Cleveland Street Elyria, Ohio 44035 Dear Mr. Hildebrandt: This responds to your September 20, 1979, letter asking the National Highway Traffic Safety Administration (NHTSA) to give you written confirmation that your tandem axle trailer brake system complies with Standard No. 121, Air Brake Systems. The NHTSA does not provide advance determinations of compliance with the agency's safety standards. It is the manufacturer's responsibility to test for and certify the compliance of its vehicles or equipment. The agency cannot always tell by diagrams and word descriptions whether a system will or will not comply with applicable safety standards. Compliance of a braking system, such as yours, can only be determined when tested on a completed vehicle. Our technical staff has reviewed the diagrams and the letter that you submitted. In their opinion, your system appears to comply with the requirements of the standard. However, this is merely an opinion based upon your submission and does not bind the agency in any way should your device fail any compliance tests conducted by the agency. Sincerely, Frank Berndt Chief Counsel Office of Chief Counsel National Highway Traffic Safety Adm. 400 Seventh Street, S.W. Washington, D.C. 20590 Sept. 20, 1979 Subject: Request for Confirmation - FMVSS 121 Gentlemen: A customer of The Bendix Corporation, Heavy Vehicle Systems Group (Bendix), has requested that Bendix obtain written confirmation from the National Highway Traffic Safety Administration (NHTSA) that the two reservoir tandem axle trailer brake system (Bendix System) shown and described herein, meets the requirements of Section S5.2.1.1 and S5.2.1.2 of Federal Motor Vehicle Safety Standard 121 - Air Brake Systems. Previous Bendix studies concluded that based on the interpretation given by the NHTSA letter of January 22, 1976, to Wagner Electric Corporation (copy attached) the Bendix System is in compliance with these reservoir requirements. The design objectives for the Bendix System were safety, performance, reliability, simplicity, and economy of cost and space. Two years of production installations of this Bendix System have proven that the design objectives have been met. The Bendix System (Figure 1), utilizes two service reservoirs for normal service braking and reserves sufficient air pressure in one or the other to provide the required spring brake release in the event of a failure to a reservoir. The major component of the Bendix System is the SR-4 Spring Brake Control Valve (Figure 2) whose operational functions are as described herein. SYSTEM CHARGING Trailer supply line air pressure enters the SR-4 valve at the trailer supply port, actuates the control piston, opens the spring brake inlet/exhaust valve and flows into the cavity under the pressure protection piston. When the air builds to a pressure of aproximately 55 psi, the pressure protection inlet valve opens and the air pressure flows past Check Valve "A" and into the rear service reservoir and PR-3 Pressure Protection Valve and then past Check Valve "B" and through the open spring brake inlet/exhaust valve and into the spring brake units. Air pressure is prevented from passing into the front service reservoir by Check Valve "C". When the pressure in the PR-3 valve reaches approximately 60 si the PR-3 inlet valve opens and the air pressure flows past the PR-3 check valve and into the front service reservoir. Both reservoirs and all the spring brake units can now be charged to full system pressure and parking brakes will be released. NORMAL OPERATION Service Brakes Trailer service brakes are controlled by application and release of pressure in the trailer service line connected to the control port of the relay valve. Air pressure consumed from the front reservoir is replenished from the rear reservoir and the trailer supply line via the open PR-3 Pressure Protection Valve. The combined volume of front and rear reservoirs is at least 8 times the volume of all the service chambers at maximum travel. Since the rear reservoir is in communication with the front reservoir via the open PR-3 Pressure Protection Valve during normal operation (system supply pressure in excess of 60 psi) that total service reservoir volume of the system is in compliance with the requirements of S5.2.1.2. Parking Brakes Trailer parking brakes are controlled by application and release of air pressure in the trailer supply line. Loss of supply line pressure due to trailer breakaway, leakage or operation of tractor valving causes the pressure protection valve to close and deactuates the control piston, which closes the spring brake inlet/exhaust valve and vents the air pressure in the spring brake units via the SR-4 exhaust port; thereby causing application of all trailer parking brakes. Reapplication of air pressure in the tractor supply line reactuates the control piston, opens the spring brake inlet/exhaust valve and pressurizes the spring brake units with the air pressure contained in both reservoirs; thereby releasing all trailer parking brakes. SERVICE FAILURES Failure of Rear Reservoir System With a failure in the rear reservoir full air pressure is retained in front reservoir due to the check valve in the PR-3 Pressure Protection Valve and Check Valve "B". Pressure in trailer supply line is maintained at approximately 55 psi due to closing of the pressure protection inlet valve. The reduced trailer supply line pressure actuates the low pressure warning on the tractor alerting the driver to a system failure. The trailer parking brakes do not automatically apply because the trailer supply pressure keeps the control piston actuated and front reservoir pressure is maintained in the spring brake units. In this failure mode, trailer braking is provided by service brake applications on both axles using the air pressure retained in the front reservoir, or by a manual parking brake application on both axles, releaseable by the air pressure retained in the front reservoir. Failure of Front Reservoir System With a failure in the front reservoir, approximately 55 psi air pressure is retained in rear reservoir due to closing of the PR-3 Pressure Protection Valve and Check Valve 'C'. Pressure in trailer supply line is maintained at approximately 55 psi due to closing of the pressure protection inlet valve. The reduced trailer supply line pressure actuates the low pressure warning on the tractor alerting the driver of a system failure. The trailer parking brakes do not automatically apply because the trailer supply pressure keeps the control piston actuated and full pressure is maintained in the spring brake units. In this failure mode, trailer braking is provided by a manual parking brake application on both axles, releaseable by the air pressure retained in the rear reservoir. Air pressure in rear reservoir is rechargeable to approximately 60 psi from the trailer supply line pressure. With respect to the foregoing service failures in the front and rear reservoir systems, the failure modes depict system functions after the reservoirs have been pressurized to 90 psi air pressure and the respective reservoir pressure has been vented to atmosphere to simulate an extreme failure in a service brake system. In summary, the Bendix Two Reservoir Tandem Axle Trailer Brake System, with its four wheel non-automatic "back-up" braking on tandem axle trailers under conditions of a trailer service system failure, complies with the noted reservoir requirements of FMVSS 121 and provides the safety, performance and economy of cost and space objectives necessary for acceptance by the industry. Bendix hereby respectfully requests from the NHTSA written confirmation similar to that issued to the Wagner Electric Corporation that the Bendix System complies with the requirements of Sections S5.2.1.1 and S5.2.1.2 of FMVSS 121. We would be pleased to discuss this system in more detail at your convenience. Very truly yours, R. W. Hildebrandt Group Director-Engineering RWH:ep Attachments |
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ID: nht79-2.28OpenDATE: 09/11/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Dixson, Inc. TITLE: FMVSS INTERPRETATION TEXT: NOA-30 Mr. Clay Lansdown Chief Engineer H. D. Instrument Division Dixson, Inc. P. O. Box 1949 Grand Junction, Colorado 81501 Dear Mr. Lansdown: This is in response to your letter of August 8, 1979, asking whether construction, mining and agricultural machinery must comply with the requirements of Federal Motor Vehicle Safety Standard No. 127. In order for a vehicle to fall within the ambit of Standard 127 or any other safety standard it must be a motor vehicle. Section 103(3) of the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1381 et seq.) defines a motor vehicle as any vehicle drawn or driven by mechanical power manufactured primarily for use on the public streets, roads, and highways, except any vehicle operated exclusively on a rail or rails. Thus, a motor vehicle is a vehicle which the manufacturer expects will use the public highways as part of its intended function. There are two exceptions to the above rule that permit certain vehicles to use the highways without being considered motor vehicles. Agricultural equipment that is strictly used in farm fields and only incidentally uses the roads adjacent to those fields has been excepted from the definition of motor vehicle. However, not all agricultural equipment is excepted from the definition of motor vehicle. A piece of agricultural equipment, like any other vehicle, that uses the public streets and roads not adjacent to the fields on a necessary and recurring basis would be considered to be a motor vehicle and must meet the requirements of Standard 127 and the other safety standards.
The agency has further excepted certain vehicles from the definition of motor vehicle despite frequent highway use. Some maintenance and construction equipment whose maximum speed does not exceed 20 miles per hour and whose abnormal configuration distinquishes them from the traffic flow are not considered motor vehicles. I suggest that you contact the manufacturers to whom you are selling your equipment. It is their responsibility initially for determining whether use on the public highways is part of the vehicles' intended function. The enclosed information sheet should be helpful in making that determination. Sincerely, Frank Berndt Chief Counsel Enclosure August 7, 1979 National Highway Traffic Administration United States Department of Transportation Docket No. 76-06 Speedometer-Odometers 400 Seventh Street S. W. Washington, D. C. 20590 Dear Sir, Our product line includes electronic speedometer-odometers. A significant portion of the units we manufacture are sold to manufacturers of construction, mining, and agricultural machinery. I am not sure if S3 of Standard 127 defines vehicles of the type listed above. These vehicles do on occasion, travel on highways, and in some cases are used to repair and build highways. The speedometers in these vehicles rarely, if ever, have markings above 40 MPH I wish to know if these vehicles are defined by S3 of Standard 127 in order to determine if the speedometers are required to meet S4.1.1 and S4.1.3 of Standard 127. Sincerely, DIXSON, INC. Clay Lansdown Chief Engineer aH. D. Instrument Division CL/ms |
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ID: nht79-2.29OpenDATE: 11/08/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Veeder-Root Company TITLE: FMVSS INTERPRETATION TEXT: NOA-30 Mr. Alan L. Sinder Manager Vehicle Products Group Veeder-Root Company Hartford, Connecticut 06102 Dear Mr. Sinder: This is in response to your letter of August 21, 1979, asking whether Federal Motor Vehicle Safety Standard No. 127, Speed-ometers and Odometers, applies to your product, the Veeder-Root 7-Day Tachograph, and whether the odometer provisions of the standard would apply if your product were installed in vehicles with gross vehicle weight ratings (GVWR) of less than 16,000 pounds. You also asked whether a tachograph installed in a school bus as a replacement for the speedometer and marked with speeds from 0 to 50 mph on both the dial and on the inside chart would comply with Safety Standard 127. Section 4.1.1 of Safety Standard 127 requires that "each motor vehicle shall have a speedometer that meets the requirements . . ." of the standard. Section 4.2.1 requires that "each motor vehicle with a gross vehicle weight rating of 16,000 pounds or less shall have an odometer that meets the requirements . . ." of the standard. Therefore a tachograph installed in lieu of the speedometer and odometer in a new vehicle with a gross vehicle weight rating of 16,000 pounds or less must meet both the speedometer and the odometer requirements of Safety Standard 127. If the new vehicle in which the tachograph were installed had a gross vehicle weight rating greater than 16,000 pounds the speedometer requirements of Safety Standard 127 would apply but the odometer requirements would not. If the tachograph were installed in a new vehicle as a supplement to an existing speedometer and odometer which meet the requirements of Safety Standard 127, the provisions of Safety Standard No. 127 would not apply to the tachograph. Section 4.1.4 of Safety Standard 127 provides that: No speedometer shall have graduations or numerical values for speeds greater than 140 km/h and 85 mph and shall not otherwise indicate such speeds. Although this section specifies the maximum speed indication which may appear on the dial of a speedometer, it does not prohibit the use of a lower maximum speed indication. Section 4.1.5 of the standard provides that "each speedometer shall include the numeral '55' in the mph scale." However, this provision assumes that the speedmmeter dial will have calibrations for speeds in excess of 55 mph. If the speedometer dial will not include calibrations for speeds of 55 mph and above, then there is no requirement that the numeral 55 be included in the mph scale. This follows from the rationale on which Safety Standard 127 is based, which is to reduce the temptation for drivers to test the top speeds of their vehicles and to induce greater compliance with the national maximum speed limit of 55 mph. I hope that you will find this response helpful and have not been greatly inconvenienced by our delay in sending it to you. Sincerely, Frank Berndt Chief Counsel August 21, 1979 Ms. Kathleen DeMeter Office of Legal Counsel National Highway Traffic Safety Administration Room 5219 400 7th Street, So. West Washington, D. C. 20591 Dear Ms. DeMeter: Mr. Kevin Cavey of the Office of Crash Avoidance suggested that I write you seeking a legal opinion concerning the coverage of FMVSS-127 in regards to Tachographs. The enclosed literature describes our products. The Tachograph sometimes is used by itself and sometimes in conjunction with the existing speedometer. I would like to know if 127 is applicable to these products and whether the odometer sections of 127 would apply if these units were installed on vehicles of less than 16,000 pounds GVW. We are currently working with a School Bus Authority whose installations specify a unit whose dial face shows from 0 to 50 MPH. It is probable that this unit would replace the current speedometer. Must the Tachograph face show from 0 to 85 MPH with 55 highlighted or can this School District specification stand as written ( 0 to 50 MPH on a dial and 0 to 50 on the inside chart)? The specifications also call for road speed - electro mechanical engine - governors permanently set at 45 MPH maximum. I would appreciate your response as soon as possible as the specification for this School District requirements are in the process of being finalized. Please do not hesitate to call me if you have any questions. Very truly yours, VEEDER-ROOT COMPANY Alan L. Sinder Manager Vehicle Products Group ALS/gsb Enclosure |
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ID: nht79-2.3OpenDATE: 08/30/79 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: Freedman Seating Company TITLE: FMVSS INTERPRETATION ATTACHMT: Attached to 8/16/88 letter to Glenn L. Duncan from Erika Z. Jones (Redbook A32; Std. 207); Letter dated 4/28/77 to Gordon P. Cress from Frank A. Berndt (Std. 210); Letter dated 2/1/88 to Erika Z. Jones from Glenn L. Duncan; Letter dated 11/16/97 to Erika Z. Jones from Glenn L. Dunn (OCC 1278) TEXT: This responds to your recent letter asking how much deflection or deformation of seat belt anchorages is allowed under the requirements of Safety Standard No. 210, for anchorages that are attached to or are a part of revolving pedestal seats. You mention cases in which seat bases deflect so much that the seat touches the floor before the forces required by the standard are attained. As noted in your letter, paragraph S4.2.3 of Safety Standard No. 210 specifies that permanent deformation or rupture of a seat belt anchorage or its surrounding area is not considered to be a failure, if the required force is sustained for the specified time. Likewise, the agency has stated in the past that the force requirements of Safety Standard No. 207, Seating Systems, allow some deformation of the seats during the force test, provided structural integrity of the seats is maintained. Although Safety Standard No. 210 would allow some deformation of the seat base for anchorages that are part of pedestal seats, the structural integrity of the seats would have to be maintained during the force test. Further, you should note that Safety Standard No. 207 requires the forces for testing seats and the forces required by Safety Standard No. 210 to be applied simultaneously for seats that have belt assemblies attached to them. Thus, the pedestal seats discussed in your letter would have to maintain their structural integrity when subjected to the combined forces required by both standards. The agency Would not consider pedestal seats to be in compliance with these requirements, if the seats are displaced to an extent that the agency determines occupant safety is threatened. I hope this letter has clarified the agency's position regarding the force requirements of both Safety Standard No. 210 and Safety Standard No. 207. SINCERELY, FREEDMAN SEATING COMPANY June 22, 1979 Office of Vehicle Safety Standards National Highway Traffic Safety Administration Dear Sirs: This letter is a request for clarification of Federal Motor Vehicle Safety Standard No. 210. As a seat manufacturer and supplier for the Recreational Vehicle Industry, we have developed products which are intended for use in a variety of vehicles, and therefore must certify their compliance with Motor Vehicle Safety Standards when installed in these vehicles. It has become common practice for seating companies as ourselves to test certain "seating systems" on laboratory test equipment, rather than in each vehicle, and certify that the "seating system" complies with applicable Motor Vehicle Safety Standards when installed properly. In the case of revolving seat pedestals which are designed to be "seat belt anchorages" (by definition, the provision for transferring seat belt assembly loads to the vehicle structure) this laboratory testing raises certain questions relative to interpretation of MVSS No. 210. Per MVSS 210, "permanent deformation or rupture of a seat belt anchorage or its surrounding area is not considered to be a failure, if the required force is sustained for the specified time." Since no limitations are set for seat belt anchorage deflection, many seat manufacturers have ignored this aspect totally, and tested seat bases (seat belt anchorages) to force requirements only. In some cases, the seat bases deflect so much that the front edge of the seat is touching the floor before the required force is eventually attained. (See enclosed photographs.) While it would appear obvious that these bases are not in compliance with MVSS 210 for driver application, since the seat back would have impacted the steering wheel prior to the required force being attained, (the steering column is sustaining part of the force) the bases appear to be in compliance with MVSS 210 when installed at a location in a vehicle where there is nothing to obstruct free movement of the seat. Our request at this time is that the Department of Transportation supply us with its interpretation of MVSS 210 to the extent that it would consider seat bases of this type in compliance or not in compliance with the standard. Secondly, with respect to the intent of the safety standards, it would appear that future consideration should be given to setting deflection limitations in Motor Vehicle Safety Standards 207 and 210. If the "seating system" or "seat belt anchorage" is able to sustain required forces only after the occupant has impacted the steering wheel or windshield, it appears that we have met a safety standard without providing the intended safety. Your prompt attention to this matter will be appreciated. Robert J. Wahls Chief Engineer ENC. Kenco Builds Stress Machine A new stress test machine for van and motorhome seat bases has been designed and built by Kenco Engineering, Middlebury, Indiana, to meet the specifications required by the Department of Transportation (D.O.T.). The machine operates hydraulically and can exert 8,000 pounds of pull. The seat base pictured above has sustained 6,750 pounds, well over the D.O.T. requirement of 5,000 pounds for 10 seconds. Kenco will use the machine for testing seat bases, tire carriers and other products which undergo stress in use. (Graphics omitted) (Graphics omitted) |
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.