Skip to main content

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 11571 - 11580 of 16513
Interpretations Date
 search results table

ID: nht75-4.50

Open

DATE: 12/03/75

FROM: AUTHOR UNAVAILABLE; MaRK Schwimmer; NHTSA

TO: For Interpretation file

TITLE: FMVSR INTERPRETATION

TEXT: On December 1, 1975, I received a telephone call from Mr. Nakajima of Bridgestone Tire Co. (213-320-6030) concerning the meaning of the March 1, 1975, effective date of Standard No. 119. He wanted confirmation that tires, for vehicles other than passenger cars, that were manufactured before that date are not subject to the standard's labeling requirements. I explained that his understanding was correct, citing 49 CFR @ 571.7.

ID: nht75-4.6

Open

DATE: 09/11/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Strick Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your July 17, 1975, question whether a used running gear assembly can be combined with a new platform to qualify as a "repaired" trailer that would not have to conform to the requirements for air brake systems on newly-manufactured trailers (Standard No. 121, Air Brake Systems). I have enclosed an interpretive letter which should clarify this matter for you. Briefly, the answer is no, if the "platform" includes the main frame members.

You also asked whether the vehicle must conform to the safety standards if it is assembled for the manufacturer's own use or if it is leased to a third party. Section 108 (a) (1) (A) of the National Traffic and Motor Vehicle Safety Act (15 U.S.C 1397 (a) (1) (A)) prohibits not only the sale, but also the introduction or delivery for introduction in interstate commerce of vehicles which do not comply with all applicable safety standards in effect on the date of manufacture. Therefore the answer to your question is yes if the vehicle is ever operated on the public streets or highways.

SINCERELY,

STRICK CORP.

July 17, 1975

James C. Schultz, Esquire Chief Counsel U.S. Department of Transportation National Highway Traffic Safety Administration

Re: N40-30 (TWH)

Thank you very much for your letter of June 6, 1975 with regard to Standard #121, Air-Brake Systems. I would appreciate very much if you could let me know whether the NHTSA interpretations of the Standard would prohibit the utilization of a used running gear assembly with a new platform, on a platform trailer for our own use in our operations. In addition, we would appreciate advice as to whether or not the lease of such a vehicle to third parties would be prohibited.

Leonard Barkan Vice President and General Counsel

ID: nht75-4.7

Open

DATE: 12/05/75

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Blue Bird Body Company

TITLE: FMVSS INTERPRETATION

ID: nht75-4.8

Open

DATE: 05/02/75

FROM: AUTHOR UNAVAILABLE; J. C. Schultz; NHTSA

TO: General Motors Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This is in response to your letter of March 21, 1975, inquiring as to the effect of Federal Motor Vehicle Safety Standard No. 121 on Massachusetts and New Jersey State laws relating to air brake performance.

As you are aware, section 103(d) of the National Traffic and Motor Vehicle Safety Act of 1966 (15 U.S.C. 1392(d)) provides that no State or political subdivision of a State may promulgate or continue in effect standards applicable to an aspect of motor vehicle or motor vehicle equipment performance which is covered by a Federal motor vehicle safety standard, unless the standards are identical.

Standard No. 121 includes provisions relating to truck and bus brake performance, including requirements for stopping distances. A more restrictive State brake requirement than that specified in Standard 121 is voided by @ 103(d) since the Federal standard is intended to cover all aspects of air brake performance.

The Federal requirements must be regarded as conclusive with regard to service, emergency, and parking braking capabilities in order to maintain the uniformity necessary in a Federal regulatory scheme. This was affirmed in a recent decision rendered in a case brought by the Motorcycle Industry Council, Inc. against the State of California in the United States District Court for the Eastern District of California concerning the preemption of a California State requirement that motorcycle headlamps be wired to operate when the engine is running. The Court held that the California requirement is preempted by the Federal Motor Vehicle Safety Standard No. 108 since the National Highway Traffic Safety Administration intended to cover all aspects of performance directly involving motorcycle headlamps.

Therefore, requirements such as those described in your letter would be preempted by Standard 121 since the aspects of performance that would be affected are covered by the Federal standard. You should note that this discussion of State "requirements" only refers to rules of general applicability within a State or municipality. It does not refer to purchase specifications that may be imposed by any person or organization, including a State or municipality, with respect to vehicles purchased for the person or organization's own use. Such specifications are not limited by Federal law, and in the case of governmental bodies are specifically allowed by @ 103(d), although of course they cannot alter a manufacturer's duty to conform to Federal standards.

ID: nht75-4.9

Open

DATE: 05/20/75

FROM: AUTHOR UNAVAILABLE; R. B. Dyson; NHTSA

TO: Oshkosh Truck Corporation

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your April 1, 1975, request for confirmation that the emergency braking stopping distance requirements in S5.7.2.3 of Standard No. 121, Air brake systems, specify that, when stopped six times for each configuration of weight and speed specified in S5.3.1.1 on a road surface with a skid number of 75 (with a single failure introduced in the service brake system), the vehicle must stop at least once within the distances specified in Column 3 of Table II and no part of the vehicle must leave the 12-foot roadway. You also request confirmation that modulation of the service brake control during the stop is not prohibited.

With certain exceptions, the statements in your letter are correct. Your interpretation only sets out the basic stopping distance requirements for those vehicles which the manufacturer has chosen to make conform to S5.7.2 of the standard. Thus, your interpretation does not include any of the requirements of the emergency braking capability option found in S5.7.1. Additionally, your interpretation does not include the requirements for a truck-tractor at unloaded vehicle weight plus 500 pounds, or for the trucks and buses which qualify for the interim requirements of S5.7.2.3.1 and S5.7.2.3.2.

Section S5.7.2 does not prohibit modulation of the emergency braking capability, and modulation by means of the service brake control is therefore permissible.

YOURS TRULY,

April 1, 1975

Richard Dyson Acting Chief Counsel U.S. Dept. of Transportation National Highway Traffic Safety Admin.

Please review our interpretation of Sections 5.7.1 and 5.7.2 of FMVSS 121 which pertain to emergency brake system operation and performance.

Our interpretation is such that:

1) During an acceptable emergency braking stop, the stopping distance must not exceed the values specified in Column 3 of Table II and no part of the vehicle must leave the 12 foot roadway.

2) When stopped six times, for each combination of weight and speed specified in 5.3.1.1, with a skid number of 75, at least one acceptable emergency braking stop must occur.

3) During an emergency braking stop, the emergency braking system may be modulated. Modulation occurs by actuation of the service brake control.

OSHKOSH TRUCK CORPORATION

Danny J. Lanzdorf Supervising Engineer

ID: nht75-5.1

Open

DATE: 04/28/75

FROM: NOEL C. BUFE FOR JAMES B. GREGORY -- NHTSA

TO: Hendrickson Manufacturing Company

TITLE: FMVSR INTERPRETATION

TEXT: I am writing in response to your letter of March 25, 1975, in which you request advice as to whether you should establish gross axle weight ratings and gross vehicle weight ratings based on the 55 mph national speed limit or on the maximum attainable speed of the vehicle.

The Cross Axle Weight Rating (CAWR) and the Cross Vehicle Weight Rating (CVWR) are defined by the National Highway Traffic Safety Administration (NHTSA) as determinations made by the manufacturer. (49 CFR 3571.3). As a general matter NHTSA finds that the manufacturer is most familiar with the complexities of this product and is most qualified to assign these values.

Recently NHTSA has found it necessary to specify that CAWR's and CVWR's be calculated on the basis of highway speeds and not qualified by reduced speed ratings; our reasons for this action are contained in the enclosed letter. For purposes of CAWR-CVWR calculations, NHTSA will hencefort consider "highway speed" to be the 60 mph value used by the United States Tire and Rim Association in assigning unqualified ratings to their tires.

Therefore, your trucks and buses which are capable of speeds of 60 mph or more should be assigned ratings which reflect vehicle capabilities at 60 mph.

ID: nht75-5.10

Open

DATE: 05/30/75

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Bock & Jones

TITLE: FMVSR INTERPRETATION

TEXT: This is in response to your letter of May 2, 1975, inquiring about the existence of regulations governing the manufacture, design, and on-the-road operation of trailers used to transport fertilizer while hitched to a pickup truck.

The National Highway Traffic Safety Administration has the responsibility of promulgating safety standards that set minimum performance requirements for vehicles manufactured and/or sold in the United States. There are five motor vehicle safety standards that apply to trailers. These standards relate to trailer lighting, tires, and braking systems (Standard No. 106-74, Brake Hoses (49 CFR Part 571.106), Standard No. 108, Lamps, Reflective Devices and Associated Equipment (49 CFR Part 571.108), Standard No. 116, Motor Vehicle Brake Fluids (49 CFR Part 571.116), Standard No. 119, New Pneumatic Tires for Vehicles Other Than Passenger Cars (49 CFR Part 571.119), Standard No. 121, Air Brake Systems (49 CFR Part 571.121)).

There is no safety standard that applies to the towing of a trailer. The use of a safety chain to guard against release of the trailer may, however, be mandated by State law.

Yours truly,

ATTACH.

BOCK & JONES -- ATTORNEYS AT LAW

May 2, 1975

CERTIFIED MAIL -- RETURNED RECEIPT REQUESTED #466442

Legal Department -- Department of Transportation

Gentlemen:

I am involved in a lawsuit in which a large fertilizer manufacturer-distributor furnished a four wheel pull-type fertilizer applicator, constructed very similar to a normal trailer, and was used for transporting bulk fertilizer from the distribution point, on the public highways, pulled by a pickup truck, to farms, for fertilizer application.

The trailer hitch was of a standard type which coupled to a hole in the rear bumper of the pickup truck.

For some unknown reason, the clevis pin probably broke, the trailer became uncoupled from the pickup truck, and crossed the centerline of the public highway, killing the driver of the approaching vehicle.

The trailer did not have the standard type of commonly used safety chains, which are also usually attached to the pulling vehicle to avoid accidents if the trailer hitch becomes uncoupled.

Since becoming involved in this litigation, we have determined that this is not uncommon in the area, as apparently these clevis pins through use, jolts, etc., do fracture or break, but fortunately the other accidents in the area were not fatal to other people.

My purpose in writing to your department is to determine:

(1) Whether or not you issue any type of regulations covering the manufacture or design of such trailers?

(2) Whether or not you have any type of regulations that set minimum standards for such trailers or applicators to be pulled or used on public highways?

If your agency should not be involved in such, perhaps you could advise us of another regulatory agency that might have such regulations.

Thanking you for this information, we are

Sincerely yours,

By: Harold D. Jones

ID: nht75-5.11

Open

DATE: 07/21/75

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: FMC Corporation

TITLE: FMVSR INTERPRETATION

TEXT: This responds to FMC Corporation's June 23, 1975 request for clarification of a recent NHTSA proposal (40 FR 24915, June 11, 1975) to amend Standard No. 121, Air brake systems, to establish an exemption criterion for a vehicle that has an "unloaded vehicle weight that is not less than 95 percent of the vehicle GVWR [gross vehicle weight rating]". You ask whether a vehicle's "unloaded weight" means the GVWR, as established by adding the gross axle weight ratings (GAWR) of all axles, minus whatever portions of the vehicle are removed for highway travel.

The answer to your question is no. In light of the requirements for GVWR in Part 567.4 (Certification), unloaded vehicle weight will normally be the GVWR of a vehicle minus its rated cargo load and its assigned occupant weight (at least 150 lbs). The rated cargo load would not include the weight of portions of a vehicle which are essential to its specialized function but are removed in accordance with State regulation for transit purposes.

I would also note that the NHTSA definition of GVWR (49 CFR @ 571.3) does not require that the GVWR be the sum of the vehicle's GAWR's. Of course the GVWR must not exceed the sum of vehicle GAWR's.

With regard to your June 17, 1975, suggestion of a meeting with Mr. Larson, I would prefer first to have your view of these clarifications.

Yours Truly,

ATTACH.

June 23, 1975

Thomas Herlihy -- National Highway Safety Administration

Dear Mr. Herlihy:

This letter is a request for a legal interpretation of proposed revisions to 49CFR571.12153, Docket 75-16, Notice 01, Federal Register Vol. 40, No. 113 Wednesday, June 11, 1975.

My letter of June 16, 1975 to the Docket Section concerning the above is attached.

I would appreciate the interpretation as soon as possible to allow me time for an additional petition if it is required.

Very truly yours,

H. Ray Cozad -- Chief Engineer, FMC CORPORATION

ID: nht75-5.12

Open

DATE: 05/20/75

FROM: AUTHOR UNAVAILABLE; Richard B. Dyson; NHTSA

TO: Austrian Trade Delegation in the United States

TITLE: FMVSR INTERPRETATION

TEXT: This is in response to your letter of April 21, 1975, inquiring as to whether voltage regulators are of safety-related significance and therefore subject to the requirements of Public Law 93-492.

There are currently no motor vehicle safety standards regulating the performance of voltage regulators. However, under the National Traffic and Motor Vehicle Safety Act as amended (Pub. L. 93-492) the Secretary of Transportation is authorized to make a determination, in appropriate circumstances, that a motor vehicle or item of motor vehicle equipment contains a defect which relates to motor vehicle safety. If he finds that a safety-related defect exists, the manufacturer must notify purchasers of the hazard and recall and remedy the defective vehicles. Therefore, even though voltage regulators are not the subject of a safety standard, they still must be designed so as not to contain safety-related defects.

YOURS TRULY,

AUSTRIAN TRADE DELEGATION IN THE UNITED STATES

Richard D. Dyson Assistant Chief Counsel for Regulations Office of the Chief Counsel National Highway Traffic Safety Administration

April 21, 1975

Subject: Interpretation of Public Law 93-492

On April 3, we wrote to you on behalf of the Austrian company Uher AG of Vienna, a manufacturer of electrical automobile components, regarding your opinion as to whether voltage regulators for automobiles are of safety related significance and would therefore be affected by the requirements of Public Law 93-492.

We would very much appreciate your comments on this subject and thank you in advance for your kind assistance.

Harald Klug Deputy Trade Delegate

ID: nht75-5.13

Open

DATE: 06/26/75

FROM: AUTHOR UNAVAILABLE; Robert L. Carter; NHTSA

TO: Humanoid Systems

TITLE: FMVSR INTERPRETATION

TEXT: This is in response to your letter of May 30, 1975, to the Administrator.

Thank you for the offer to assist in the establishment of new specifications for dummy skin and flesh components. Any procurement of such services would be awarded by competitive procurement, and I hope your company will participate in any such competition when solicited.

The NHTSA issued Part 572, in the form of a large number of dummy design and material specifications supplemented by some calibrating component tests, in order to specify the vehicle performance requirements of certain crash-tent standards, such as standard No. 203, as precisely and objectively as possible. Dummies are not regulated items and not ends in themselves: as @ 572.3 states, the dummy specification "does not in itself impose duties or liabilities on any person." Thus, the dummy specification serves only as a means of informing the vehicle manufacturers how their vehicles must perform if and when tested by the government. There is no regulatory requirement either for "certification" of dummies or their "verification by an independent agency" or anyone else. It may be assumed that government testing will be carried out with dummies that conform to Part 572 as closely as possible. Vehicle manufacturers can ascertain that their vehicles will pass government tests by any means they choose. With this in view, it should be clear that any deviations from the Part 572 specifications are purely a matter of private negotiation and decision making between the dummy manufacturers and their customers, and no governmental "approvals" are possible or appropriate.

Any changes in Part 572 will of course be done through notice and opportunity for comment, and we expect and hope for your full participation in an administrative proceeding when it takes place.

SINCERELY,

June 27, 1975

James B. Gregory Administrator National Highway Traffic Safety Administration

This is to advise you that we have today sent to a Committee of the United States Senate various details concerning your policies as they affect our company.

We have discussed our situation with a number of prominent auto manufacturers which are coming to our support because they do not want to be confronted by a dummy industry in which we are not represented. They have given us considerable data to show that there are many precedents under which NHTSA has altered its rules to avoid giving unfair competitive advantage to any company or submitting another company to unfair competitive disadvantages. We have submitted the data which they have given us to our legal counsel with a view toward possibly taking legal action against your Agency.

I want to ask you to spare both parties the expense and the time involved in such an action by considering again the bald facts of this matter.

I alerted NHTSA in 1973 about the dangers inherent in the use of Nitrosan and was brushed off. In January, 1975, I notified NHTSA that the Dupont plant producing this material had exploded and would not resume its manufacture nor license its technology to any other company because of the numerous explosions which had occurred in the plants of Nitrosan users.

The response of NHTSA was to offer some suggestions for a substitute material and to inquire of the three dummy manufacturers as to their supplies of Nitrosan. Your own records disclose that ARL has a one-year supply, Sierra has enough material for 3 or 4 dummies, and we will exhause our own supply in 3 weeks. This spells creation of a dummy monopoly for ARL by NHTSA's failure to prepare a timely remedy.

In our own report to the Senate Committee, we have discussed the existence of two drawings of the dummy head, both stamped "NHTSA Release". Both drawings cannot be satisified in the same head. We have received no response to our several letters on the subject, dating back to two years ago, but we did receive information from other sources as to which drawing to follow. When I queried your people 2 or 3 months ago as to the status of these two drawings, I was told to "forget the GM drawing". This is to us a baseline as to your respect for "statutory" procedures.

In Part 572, we are dealing with a standard that is not a standard at all. There is little or no control of dummy kinematics, either by performance tests or by specification of some of the most critical determinants of such responses. We are dealing with a dummy where the neck cannot be assembled to the thorax if drawings are followed literally, where the drawings of 2 of the 6 ribs are indeterminate, where the pelvis cannot satisfy the molded weight requirement and the assembled weight requirement simultaneously, where the adbominal sac cannot both be molded to specification and pass your performance tests, and which generally can best be described as a mess. This is the background against which the legolisms of your agency should be weighed.

I have been told by Jim Hofferberth, that the only way we can use a substitute for Nitrosan is by the complete rule-making process which cannot possibly be carried through in less than 6 months, by which time our company will have been forced out of business. When viewed against the time frame, the disposition of the head matter, and the status of the Part 572 specifications, the treatment of this problem is patently unreasonable.

I spoke at length yesterday with Dick Dyson in your Legal Counsel's Office, and I was told that I was making a fuss about nothing, that the Part 572 had no legal standing any more, and that our inability to certify that we met the Part 572 requirements would have nothing to do with our sales of the dummy. I checked this out with the "Big 3" and found Dyson's remarks to be totally unfounded.

No one will buy our dummies if we cannot certify them, and we cannot certify them if the specifications call for a material which exists currently only in the plant of our competitor. If the situation were not so serious for our company, it would be an absurd comedy.

May we request that in the coming week you clear this matter up and permit us to continue to manufacture dummies, which, on balance, we know that we do better than anybody else.

HUMANOID SYSTEMS

Samuel W. Alderson

President

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.