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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



Displaying 10211 - 10220 of 16510
Interpretations Date
 search results table

ID: nht70-2.54

Open

DATE: 10/28/70

FROM: AUTHOR UNAVAILABLE; Rodolfo A. Diaz; NHTSA

TO: TVR Engineering Ltd.

TITLE: FMVSR INTERPRETATION

TEXT: This is in response to your letter of October 14, 1970, to the Director of the National Highway Safety Bureau forwarding information sheets on the TVR Vixen. I am enclosing copies of the Bureau's Consumer Information Regulations (49 CFR Part 575). The substantive provisions, @ 575.101 on vehicle stopping distance, @ 575.102 on tire reserve load, and @ 575.106 on acceleration and passing ability, require the furnishing of specific information in a format which is in the form set out in the regulations. The information sheets which you have provided fall short of these requirements in both form and substance. For example, @ 575.101 requires furnishing information on the minimum stopping distance, expressed in feet, for the particular vehicle, from a particular speed, at specified loads, with the braking system in a specified condition. The information provided by you in this regard is incomplete, and is not in the form specified. In addition, the regulations require the information to describe and be valid for each of the vehicles with which it is provided.

Please study the enclosed regulations carefully and forward to us complying consumer information within the near future. Let us know if you need further assistance.

ENCLOSURES

ID: nht70-2.6

Open

DATE: 04/30/70

FROM: AUTHOR UNAVAILABLE; R. A. Diaz; NHTSA

TO: Tradewind Industries, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of April 15, 1970, concerning the location requirements for lamps and reflectors as specified in Federal Motor Vehicle Safety Standard No. 108.

In answer to your first question, intermediate side marker lamps and intermediate side reflex reflectors are not required on trucks that are 60 inches or more in overall width and less than 30 feet in overall length.

In answer to your second question, front clearance lamps are not required on the truck body, provided the clearance lamps on the truck cab indicate the left and right extreme edges of the vehicle. For the vehicle shown on your drawing no. 130003A, it would appear that clearance lamps must be mounted on the truck body to provide an indication of the extreme edges of the vehicle. With clearance lamps on the body, duplicate lamps would not be required on the cab.

In answer to your third question, Table II of Standard No. 108 specifies that intermediate side marker lamps and reflectors be located at or near the midpoint between the forward and(Illegible Word) side marker lamps or reflectors, respectively. For side marker lamps the mounting height above the road surface is "not less than 15 inches." For side reflex reflectors the mounting height is "not less than 15 inches nor more than 60 inches." With this flexibility in mounting requirements, we are not aware of any truck body designs that would require installation of these devices "on the upper edges of the sides" of the truck bodies. Again, intermediate side marker lamps and reflectors are not required on vehicles that are less than 30 feet in overall length.

Removable sides (stakes) of farm and commercial stake-type bodies are not considered to be a permanent part of the vehicle.

Therefore, lamps and reflectors mounted on the platform bed of the body will meet the location requirements of Standard No. 108.

The alternative locations of lamps and reflectors on farm grain trucks and dump trucks, as suggested by your Drawing No. 130003A, are in conformance with Standard No. 108, except for location of front and rear clearance lamps. If such vehicles have permanent sides, the clearance lamps should be mounted "as near as practicable to the upper left and right extreme edges of the vehicle." The wording "as near as practicable" was purposely chosen to provide the vehicle manufacturer with a degree of flexibility in mounting clearance lamps on special purpose vehicles to insure that these lights will not be obscured or otherwise rendered ineffective in operation. Since certain vehicles may be covered with tarpaulins, this requirement may be met by mounting the clearance lamps as high as practicable and yet allow space for the use of tarpaulins,

Your concern for assuring compliance with the requirements of Standard No. 108 is greatly appreciated.

ID: nht70-2.7

Open

DATE: 05/01/70

FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA

TO: Pullman Incorporated

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of April 14, in which you question the legality of the State of California's enforcement of a State motor vehicle safety standard which is reportedly not identical to the Federal standard (No. 108) concerning the same aspect of performance. Your question arises from the failure, thus far, of the California Highway Patrol to approve as a clearance lamp a light installed on the rear of a Pullman flat bed trailer that is certified as complying with Federal Standard No. 108; Lamps, Reflective Devices and Associated Equipment.

Once a Federal motor vehicle safety standard has become effective, section 103(d) of the National Traffic and Motor Vehicle Safety Act of 1966 ("the Act") prohibits any State from having

"With respect to any motor vehicle or item of motor vehicle equipment any safety standard applicable to the same aspect of performance of such vehicle or item of equipment which is not identical to the Federal standard."

While the Act thus limits the nature of the standards which a State may issue, it does not preempt the authority of a State to enforce, by reasonable procedures, standards not prohibited by that section.

It is not clear from your letter and its enclosures whether you are objecting to the State requirement of submitting the lamp in question for approval, or are claiming that the State has unjustifies refused to approve the lamp. If you will clarify this question, we will be pleased to give the matter further consideration.

ID: nht70-2.8

Open

DATE: 05/05/70

FROM: AUTHOR UNAVAILABLE; R. A. Diaz; NHTSA

TO: D. F. Clausen

TITLE: FMVSS INTERPRETATION

TEXT: Your postcard of March 9, 1970, to the Chicago Regional Office of the Interstate Commerce Commission has been forwarded to this office by Mr. F. B. Farrell, Regional Administrator for Region 4, Federal Highway Administration. In your card, you request a copy of I.C.C. requirements for a camping trailer you intend to build.

The I.C.C. regulations concerning equipment for trailers are now administered by the Bureau of Motor Carrier Safety, Federal Highway Administration, Department of Transportation. These regulations apply only to vehicles used in interstate commerce for commercial purposes. If you intend to build a camping trailer for your personal use, these regulations would not be applicable to it. Should this not be the case, however, I am enclosing a copy of these requirements for your information.

Federal motor vehicle safety standards, which are issued by the National Highway Safety Bureau pursuant to National Traffic and Motor Vehicle Safety Act of 1966, do apply to manufacturers of camping trailers which will be towed on public highways. At present, the only Federal standard applicable to trailers is Standard No. 108, "Lamps Reflective Devices and Associated Equipment", and your trailer must conform to its requirements. I enclose a copy of this standard as amended, and a copy of the above mentioned Act.

I suggest you also consult state and local authorities for possible other requirements which they may impose on trailers. If I may be of further assistance, please contact me.

ENCLOSURES

ID: nht70-2.9

Open

DATE: 05/13/70

FROM: AUTHOR UNAVAILABLE; Rodolfo A. Diaz; NHTSA

TO: Department of California Highway Patrol

TITLE: FMVSS INTERPRETATION

TEXT: Thank you for your letter of March 2, 1970, petitioning for amendments to Federal motor vehicle safety standard No. 205-Glazing Materials. I apologize for the delay in this response to your petition.

The first amendment you propose would require each manufacturer to mark each piece of glazing material with his name, the model number and "AS" classification. A manufacturer electing the certification alternative now in S3.4 must provide the same information you request, except that a code number is substituted for the manufacturer's name. In this connection, the Director of the National Highway Safety Bureau is considering the issuance of a notice of proposed rule making which would require all manufacturers of glazing materials to adopt the certification method in S3.4. Consequently, while we are not granting your petition on identification requirements, we are actively considering your suggestions for future rule making.

The second amendment you propose would add to the standard a definition of "area requisite for driving visibility." Subsequent to the writing of your letter, the Director issued an advance notice of proposed rule making concerning a new standard, Direct Fields of View. In this notice, a copy of which is enclosed for your convenience, the Director announced that he was

considering the establishment of performance requirements for (1) direct fields of view outside the vehicle in all directions to provide adequate visibility for the driver from specified eye reference loci; (2) light transmission characteristics (including maximum

levels of tinting) of vehicle glazing materials; and (3) shade band boundaries of vehicle glazing materials. (Emphasis added)

Requirements developed with regard to items (3) and (3) would supercede provisions regarding shade band boundaries and tinting in standard No. 205. If this new standard is issued, it will deal with the problem which you mention.

We would welcome any additional comments you may have on these matters.

ENCLOSURES

ID: nht71-1.1

Open

DATE: 05/19/71

FROM: AUTHOR UNAVAILABLE; R. L. carter; NHTSA

TO: SAAB-Scania of America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your petition of March 12, 1971, for amendment of Motor Vehicle Safety Standard No. 101, Control Location, Identification, and Illustration.

You petitioned that the abbreviation for the defroster control identification be changed from "DEF" to "DEFR." In the preamble to the reconsideration and amendment of Standard No. 101, (36 F.R. 8269, May 4, 1971), a copy of which I enclose, this agency noted that additional identifying words or symbols are permissible if they do not conflict with the required or permissible words and symbols set out in Standard No. 101. In our opinion your use of "DEFR" would create no conflict.

You also petitioned that certain controls located below the drivers E point and available to all passengers be exempted from the control identification illumination requirement. The recent amendment to Standard No. 101 no longer requires illumination of all heating and air conditioning controls, but only those that direct air directly upon the windshield. We believe this may be responsive to your petition.

Finally, you asked that we define our position on bilingual control identification. Identification in a language other than English is permissible, in the

language of the preamble to the recent amendment, "as long as the additional words . . . do not conflict with the required words . . ."

We hope this answers your questions.

Sincerely,

ATTACH.

March 12, 1971

Docket Room National Highway Traffic Safety Administration

Our Reference: T. Needell

Reference: Petition for Rulemaking to Amend Federal Motor Vehicle Safety Standard 101 "Control Location, Identification and Illumination" Effective January 1, 1972 and September 1, 1972.

Gentlemen: Under the provision of Sub-part 553.31 of Sections 103 and 119 of The National Traffic and Motor Vehicle Safety Act of 1966, SAAB-Scania of America, Incorporated hereby petition that Federal Motor Vehicle Safety Standard 101 be amended as outlined below for the reasons included herein.

I - Table 1 "Control Identification and Illumination" list the acceptable abbreviation for a windshield wiping system control as "WIPE". Table 1 list the acceptable abbreviation for a windshield washing system control as "WASH". Both of these abbreviations contain 4 letters. However, Table 1 list the allowable abbreviation for a windshield defrosting system control as "DEF". (3 letters).

It is our opinion that some form of consistency is in order within Table I. Accordingly, we petition to change Column 2 of Table 1 to read so that the abbreviation "DEFR" (4 letters) is noted as an acceptable abbreviation for a windshield defrosting system control.

We believe that this abbreviation is completely concise as to its meaning. This Company has for several years used the abbreviation "DEFR" to identify the windshield defrosting controls of its products. To change the tooling necessary to bring this particular control into conformity with Column 2 of Table I would cause this Company to charge the customer an additional sum in excess of the list price of the vehicle. This, we feel, considering the above circumstances, is unfair to the purchaser.

II - Table I "Control Identification and Illumination" requires that all windshield Defrosting and Defogging Systems and heating and air conditioning controls be permissibly identified and illuminated. Table I makes no provision for the exclusion of rear passenger controls from this requirement.

This Company manufactures a vehicle offering sophisticated rear passenger-oriented controls, which are console mounted at the right side of the driver in approximate alignment with and just below the seated driver's 'H' point. These controls were primarily designed with the comfort of the rear passenger in mind and were so located to be accessible to any passenger in the vehicle.

Since these controls were so located, they, of course, are readily accessible to the driver, as well as rear passengers. SAAB has purposely located these controls to be placed so that the driver is capable of operating such without disturbing his vision. We feel the illumination of such controls will unnecessarily and dangerously burden the driver, by subconsciously attracting his vision to their location, while he performs relative adjustment.

Accordingly, we strongly appeal for amendment of Table I to so read that such rear passenger-oriented controls are not subject to the requirements of F.M.V.S.S. 101.

III - Nowhere, in the recent amendment to F.M.V.S.S. 101, do we note where it is unacceptable for control identification to appear in a bilingual (combination English/non-English) form. Although it is quite apparent which abbreviations or words or combination of abbreviations or words and symbols are permissible, nowhere can we find where bilingual identification is non-permissible.

Because the Administration's position on this subject is not defined within F.M.V.S.S. 101, many manufacturers may retool existing controls to bilingually conform to the requirements of this Standard. If in the event a manufacturer did bilingually retool his controls, it would be an extreme hardship on a smaller manufacturer if the Administration were to amend F.M.V.S.S. 101 so not to allow bilingual compliance in the future.

Accordingly, we ask that the Administration clearly define its position on bilingual identification in the content of F.M.V.S.S. 101. In so asking, we strongly urge that the Administration allow the use of bilingual controls for compliance with F.M.V.S.S. 101. The reasoning behind this request is evident. Immense financial burden will confront the small manufacturer forced to tool two individual sets of controls for the English and non-English speaking markets.

We ask that the Administration give this petition for rulemaking to amend Federal Motor Vehicle Safety Standard 101 very careful consideration. In view of the urgency involving the tooling now in progress for model year 1972, we feel that all you can do to expedite such amendment will be beneficial to the manufacturer.

Very truly yours,

SAAB-SCANIA OF AMERICA, INC.

Donald W. Taylor Product Technique Section Manager

cc: R. T. Millet/President, SAAB-Scania of America, Inc.; H. Gustavsson/BT; N. Gustavsson/BTS; B. Ilhage/BTE; L. Nilsson/BTSL; D. Schwentker/Consul A.I.A.

ID: nht71-1.10

Open

DATE: 06/04/71

FROM: AUTHOR UNAVAILABLE; R. L. Carter; NHTSA

TO: Voevodsky Associates, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of May 19 concerning installation by vehicle manufacturers of your Cyberlite system as original equipment on motor vehicles.

You ask two questions:

"(1) Is the installation . . . of the Voevodsky-Cyberlite System . . . permissible under Motor Vehicle safety Standard No. 108?"

"(2) If the installation . . . is permissible . . . does a state have the authority to (a) require the system, (b) permit the system, or (c) prohibit the system.

Section 103 (d) of the National Traffic and Motor Vehicle Safety Act of 1966 in effect permits the States to regulate any aspect of performance that is not covered by a Federal motor vehicle safety standard. As discussed in your meeting with NHTSA representatives on May 13, Standard No. 108 permits the installation of additional lighting equipment that does not impair the effectiveness of the required lighting equipment. It does not appear that the Cyberlite system, with the performance characteristics and location on the vehicle as you have described it, would impair the effectiveness of other vehicle lamps, and its installation is considered permissible under Standard No. 108. Since Standard No. 108 does not prescribe requirements for this aspect of performance, the States are free to require, permit, or prohibit the use of your warning system.

Sincerely,

VOEVODSKY ASSOCIATES, INC.

May 19, 1971

Laurance R. Schneider National Highway Traffic Safety Agency

Dear Mr. Schneider:

On 13 May 1971 I met with Richard Dyson, Lewis Owen, and Mike Esposito and on 14 May 1971 I met with Robert H. Cannon, Jr. As a result of these meetings I was directed to write to you for an opinion from the National Highway Traffic Safety Agency on the following legal questions.

(1) Is the installation on motor vehicles of the Voevodsky-Cyberlite System as described in the submission under Docket No. 69-19; Notice 1, permissible under Motor Vehicle Safety Standard No. 108?

(2) If the installation on motor vehicles of the Voevodsky Cyberlite System is permissable under Motor Vehicle Safety Standard No. 108, does a state have the authority to (a) require the system, (b) permit the system, or (c) prohibit the system?

The Voevodsky - Cyberlite System is an intervehicular deceleration warning communications system in which a red or amber warning light is center mounted on the rear of the leading vehicle at the same height as existing stop lights to communicate a component of deceleration initiated by the driver of the leading vehicle to the driver of a following vehicle. A device for measuring the deceleration of the leading vehicle is rigidly attached to this vehicle. The warning light is pulsed in a controlled fashion at a rate which varies exponentially with a component of deceleration. This component of decelaration will take into account the intensity of break action, the deceleration caused by all other frictional forces including aerodynamic, which vary from vehicle to vehicle and lastly, the deceleration caused by the component of gravitational forces parallel to the slope of the road. The exponential variation compensates for the neural response of the following driver to the pulsed coded light. The "on" time per cycle of the light pulse is also shortened with increasing frequency rate to provide a redundant warning. In practice, the maximum delay time for the driver in the following vehicle to obtain the knowledge of the degree of deceleration of the lead vehicle is 1/2 second while the deceleration is minimum; and the minimum delay time is approximately 1/14 second when the deceleration is maximum, thereby defining the band width of the information system. A 50% increase in frequency of the light pulses from 1.0 pulses per second to 7.6 pulses per second for each 0.1 "g" increase in deceleration from 0 to 0.5 g's provides the desired exponential relationship and the 50% duty cycle provides the necessary information band width.

Sincerely yours,

Dr. John Voevodsky

cc: Robert H. Cannon,

Richard Dyson;

Mike Esposito;

Lewis Owen

ID: nht71-1.11

Open

DATE: 03/29/71

FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA

TO: American Motors Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This is in reply to your letter of March 12, 1971, to Mr. Lewis C. Owen of this office concerning an interpretation on your lens assembly, SF-3610703.

Federal Motor Vehicle Safety Standard No. 108 requires a minimum effective projected illuminated area for Class A turn signal lamps of 12 square inches on motor vehicles other than passenger cars and motorcycles. The subject lens assembly used in a turn signal lamp assembly with the opaque ornament does not appear to meet the 12 square inches minimum requirement. The calculations for the area, as determined by the method contained in our October 28, 1970, letter to Mr. E. W. Bernitt, were based on measurements of the ornament, because the detail dimensions were not supplied.

The backup lamp design you discussed in a telephone conversation with Mr. Owen also apparently does not meet the requirements of FMVSS No. 108. If you would like an interpretation on this backup lamp, please furnish information on the design similar to that supplied with the subject letter.

ID: nht71-1.12

Open

DATE: FEBRUARY 23, 1971

FROM: AUTHOR UNAVAILABLE; L. R. Schneider; NHTSA

TO: E. W. Kintner, Esq.

TITLE: FMVSS INTERPRETATION

TEXT: Re: Petition for Rulemaking - Proposed Amendment of S4.5.6, Federal Motor Vehicle Safety Standard 109, As Revised, October 31, 1970.

This is in response to the petition for rulemaking of January 19 submitted on behalf of your client, Ideal Corporation, for an amendment of S4.5.6 of Federal Motor Vehicle Safety Standard No. 10, Lamps, Reflective Dev cos, and Associated Equipment, 35 F.R. 16840.

It is our understanding, based upon the meeting held on February 2 between representatives of your firm, Ideal Corporation, and NHSTA, that you client wishes to continue its established marketing practice of selling variable load flashers in the after market and of advertising these flashers as "all purpose" flashers. We understand further that variable load flashers frequently are purchased as replacements for fixed load flashers. When a variable load flasher is installed as a replacement for an original equipment fixed load flasher, it does not provide the outage indication required by S4.5.6. Your client therefore questions whether, under these circumstances, it could properly certify compliance with Standard No. 10 when the standard becomes applicable to replacement equipment.

The amendment proposed in the petition would add the following sentence to S4.5.6:

"Variable load flashers are permitted as replacement equipment by Standard 10 for any vehicle contemplated by Paragraph S2 herein, where such devices shall operate in accordance with Tables I and III, as applicable."

In our view Standard No. 108 permits your client to continue its practice and to properly certify compliance. S2 states in pertinent part that the standard applies to "lamps, reflective devices, and associated equipment for replacement of like equipment on vehicles to which this standard applies." This means that equipment must comply with applicable requirements regardless of whether it is used as original or replacement equipment. For example, original and replacement variable load flashers must both meet the appropriate requirements of SAE Standard J570b, "Automotive Turn Signal Flashers," October 1). It is not intended that a variable load flasher used as replacement for a fixed load flasher must provide the outage indication required by S4.5.6 for vehicles originally equipped with a fixed load flasher.

Although there presently is no legal prohibition on the advertising and sale of variable load flashers, we believe that your client should, in the interest of safety, either market variable load flashers only as replacements for like items or call prospective purchasers' attention to the fact that the flashers do not provide an outage indication. While the owner of a vehicle originally equipped with a fixed load flasher should be free to balance the merits of a fixed load flasher (such as the outage indication) with those of a variable load flasher (such as the continuing flash), he should not be misled as to the characteristics of each type, including the one with which his vehicle was originally equipped.

Please advise us within 10 days of the date of this letter if you wish to pursue this petition further; otherwise we shall consider the petition withdrawn.

ID: nht71-1.13

Open

DATE: 06/14/71

FROM: AUTHOR UNAVAILABLE; E. T. Driver; NHTSA

TO: Toyota Motor Co., Ltd.

TITLE: FMVSS INTERPRETATION

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.