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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.”

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NHTSA's Interpretation Files Search



Displaying 12421 - 12430 of 16490
Interpretations Date

ID: nht92-9.49

Open

DATE: January 16, 1992

FROM: Steve Ross -- Future Visions, Ltd.

TO: NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 3/2/92 from Paul Jackson Rice to Steve Ross (A39; VSA 108(a)(2)(A))

TEXT:

Please supply me with the appropriate DOT Vehicle Safety Standards that would apply to my Truck-Car Auto-Theft Device. The device is described in the attached sheets; schematic of installation is also included. The device is designed to prevent the theft of a vehicle, by blocking the flow of hydraulic fluid, so the vehicle cannot be steered. There are three means with which prevent unintended driving while steering is locked. The device originally was designed for all size trucks and may mow be (proposed) to use in automobiles.

Please provide me with a most complete "interpretation" of the US-DOT Safety Standards Re: Steering Systems and my device.

If you should have any questions please call or Fax. I would be most appreciative if I could have a rapid determination.

Attachment

Description of Hydraulic Steering Lock (Text and graphics omitted)

ID: nht79-4.14

Open

DATE: 06/15/79

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: Subaru of America Inc.

TITLE: FMVSR INTERPRETATION

TEXT: This is in response to your letter of May 23, 1979, addressed to Ms. Eileen T. Leahy of my staff, in which you provide further information in support of your earlier request for this agency's opinion as to whether a 1980 4WD Hatchback Sedan to be imported by Subaru of America can be classified as a multi-purpose passenger vehicle (MPV).

As I stated to you in my letter of May 31, 1979, the fact that a vehicle is equipped with four-wheel drive is not, in itself, sufficient to qualify the vehicle as an MPV, as that term is defined in 49 CFR @ 571.3. Your second letter lists six other features of the 1980 hatchback sedan which you state are designed to permit occasional off-road use. The additional features you describe are: a ground clearance of 8.07 inches, or 1.57 inches higher than a similar 2WD vehicle; adjusting devices to permit an additional 0.78 inches of ground clearance front and rear; an engine under-cover to protect the engine from rocks and other debris; a clutch cover to prevent entry of dust and sand; bumper overriders to protect front and rear bumpers; and a tubular guard in front of the air dam for protection from rocks and other debris.

The ground clearance you describe exceeds that specified in the definition of automobiles "capable of off-highway operation" contained in the fuel economy regulations (49 CFR @ 523.5 (b)(2)(iv)). In addition, the other features you describe appear to be designed to protect various parts of the vehicle from damage from rocks, sand and other types of debris that are more likely to be encountered in off-road driving. Therefore, all of the items you mention can be considered "'special features for occasional off-road operation" when determining the proper classification of the vehicle for purposes of compliance with Federal Motor Vehicle Safety Standards.

Since the vehicle as you have described it in your letters has several features in addition to four-wheel drive that make it suitable for occasional off-road use, it is the agency's opinion that the 4WD Hatchback Sedan would qualify as a multipurpose passenger vehicle.

SINCERELY,

May 23, 1979

Eileen Leahy Office of Chief Counsel U.S. Dept. of Transportation National Highway Traffic Safety Adm.

Re: 1980 4WD HB Sedan MPV

Dear Ms. Leahy: On April 23rd, our letter No. 056-79C requested your office's opinion regarding MPV classification of this carline. Based upon our recent telephone conversation, we provide the following list of special features, which in addition to four-wheel drive, will permit this vehicle to be operated for occasional off-road use.

1. The ground clearance is 8.07 inches which is 1.57 inches higher than a similar 2WD vehicle.

2. It is equipped with adjusting device(s) to further increase the ground clearance, both front and rear by an additional 0.78 inches.

3. An engine undercover is installed to protect the engine from rocks and other debris.

4. A special clutch cover is provided to prevent the invasion of dust and sand.

5. Bumper overriders are provided on front and rear bumpers to protect bumpers.

6. A tubular guard is placed in front of the air dam for protection from rocks and other debris.

Should you have any questions, please contact this office.

John Cordner Technical Assistant Product Compliance

ID: 7813

Open

Lawrence A. Beyer, Esq.
674 Lake Road
Webster, N.Y. 14580

Dear Mr. Beyer:

This responds to your FAX of September 22, 1992, to Taylor Vinson of this Office with reference to your request to become a Registered Importer ("RI"). We interpret your letter as seeking an opinion on your eligibility to submit an application to become an RI under 49 CFR 592.

Because of your representation of RIs, you are familiar with the record keeping mechanisms and other regulatory requirements of this agency. Your intent is to perform modifications on those Canadian vehicles which require only minor modifications, and you have a 3-car garage, tools including pneumatics, and storage space. You would have in your employ several people qualified to perform the modifications required. You are aware that, in promulgating Part 592, NHTSA specificaly rejected a proposal to allow RIs to designate agents to perform conformance work, thus you would not accept vehicles requiring major modifications, but would refer those to the other RIs.

Section 592.5 sets forth the requirements for registration as an RI. According to paragraph 592.5(a), "any person" may file an application. An application must contain the information specified by the subparagraphs of paragraph (a). We note no restrictions upon who is eligible to apply for RI status. We therefore see no legal impediment to your submitting an application under section 592.5.

The Office of Vehicle Safety Compliance (OVSC) has the authority to grant or deny applications for RI status. Your application must, therefore, contain arguments sufficient to convince OVSC of your ability to perform the limited modifications that you contemplate. We advise you, therefore, to set out with specificity in your application the Federal motor vehicle safety standards for which you have the capability to conform vehicles, and the standards for which you have not. We would like to make clear that, in the event a vehicle requires major modifications, our regulations would not allow you to bring the vehicle into partial conformance before transfering the vehicle to another RI for to complete the conformance process. An RI must certify the conformance work to NHTSA, and paragraph 592.6(e) requires the RI's certification to state that "it is the person legally responsible for bringing the vehicle into conformity." We interpret that as meaning that the certifier itself performed all the conformance work and did not resort to an agent.

Sincerely,

Paul Jackson Rice Chief Counsel

ref:592 d:11/24/92

1992

ID: nht94-4.85

Open

TYPE: INTERPRETATION-NHTSA

DATE: November 18, 1994

FROM: Harry C. Gough, P. E., Automotive Engineering, Professional Specialist, State of Connecticut, Department of Motor Vehicles

TO: Chief Counsel, NHTSA

TITLE: NONE

ATTACHMT: ATTACHED TO 3/16/95 LETTER FROM PHILIP RECHT TO HARRY GOUGH (A43; STD. 217); ALSO ATTACHED TO 7/7/93 AND 3/28/94 LETTERS FROM JOHN WOMACK TO THOMAS D. TURNER

TEXT: Dear Sir:

I am writing on behalf of the State of Connecticut Department of Motor Vehicles. We are requesting a written opinion or interpretation regarding the meaning of the phrase "outlined around it's outside perimeter" as used in FMVSS # 217 S5.5.3, Subsection( c). The term is used in regard to retroreflective tape required to identify emergency exits on school buses. The reason for the request is that a State requirement on the color of school buses requires the rear bumper to be black. One school bus manuf acturer supplied buses with the bottom piece of retroreflective tape required for the rear emergency exit installed on the rear bumper. While discussing options regarding relocation of the bottom piece of tape we were told that installation on the botto m of the door itself (not the opening) was not viable since it would not comply with FMVSS # 217 language. Subsequently a number of new school buses from a different manufacturer which were required to have their emergency exits marked were noted to hav e the tape on the door itself rather than on the edges of the opening.

When the door itself is outlined, the tape is not visible when the door is fully opened. When the edges of the opening for the door are outlined then only the hinge side of the tape is not visible. If only the bottom section of the door outline were on the door itself then both the bottom and hinge side would not be visible when the door is opened.

The ultimate question is; Does the language in FMVSS # 217 allow the required retroreflective tape marking around an emergency exit door to be installed on the door itself?

While I realize your office very busy with such interpretations. I would appreciate a response at your earliest convenience. If there are any additional questions or information required, please feel free to have your office call me at (203) 566-8754.

Thank you in advance for your attention to this matter.

ID: nht92-2.7

Open

DATE: 11/24/92

FROM: PAUL JACKSON RICE -- CHIEF COUNSEL, NHTSA

TO: LAWRENCE A. BEYER -- ESQ.

ATTACHMT: ATTACHED TO LETTER DATED 9-22-92 FROM LAWRENCE A. BEYER TO Z. TAYLOR VINSON (OCC 7813)

TEXT: This responds to your FAX of September 22, 1992, to Taylor Vinson of this Office with reference to your request to become a Registered Importer ("RI"). We interpret your letter as seeking an opinion on your eligibility to submit an application to become an RI under 49 CFR 592.

Because of your representation of RIs, you are familiar with the record keeping mechanisms and other regulatory requirements of this agency. Your intent is to perform modifications on those Canadian vehicles which require only minor modifications, and you have a 3-car garage, tools including pneumatics, and storage space. You would have in your employ several people qualified to perform the modifications requires. You are aware that, in prmmulgating Part 592, NHTSA specificaly rejected a proposal to allow RIs to designate agents to perform conformance work, thus you would not accept vehicles requiring major modifications, but would refer those to the other RIs.

Section 592.5 sets forth the requirements for registration as an RI. According to paragraph 592.5(a), "any person" may file an application. An application must contain the information specified by the subparagraphs of paragraph (a). We note no restrictions upon who is eligible to apply for RI status. We therefore see no legal impediment to your submitting an application under section 592.5.

The Office of Vehicle Safety Compliance (OVSC) has the authority to grant or deny applications for RI status. Your application must, therefore, contain arguments sufficient to convince OVSC of your ability to perform the limited modifications that you contemplate. We advise you, therefore, to set out with specificity in your application the Federal motor vehicle safety standards for which you have the capability to conform vehicles, and the standards for which you have not.

We would like to make clear that, in the event a vehicle requires major modifications, our regulations would not allow you to bring the vehicle into partial conformance before transfering the vehicle to another RI for to complete the conformance process. An RI must certify the conformance work to NHTSA, and paragraph 592.6(e) requires the RI's certification to state that "it is the person legally responsible for bringing the vehicle into conformity." We interpret that as meaning that the certifier itself performed all the conformance work and did not resort to an agent.

ID: nht92-1.24

Open

DATE: 12/14/92

FROM: PAUL JACKSON RICE -- CHIEF COUNSEL, NHTSA

TO: MICHAEL J. MOTZKIN -- PIONEER PLUMBING

ATTACHMT: ATTACHED TO LETTER DATED 10-14-92 FROM MICHAEL J. MOTZKIN TO PAUL J. RICE (OCC 7871)

TEXT: This responds to your letter of October 14, 1992 regarding Federal requirements pertaining to brake specifications. In particular you asked whether there are any regulations requiring automotive brake drums and rotors not to be milled beyond manufacturer specifications, and whether manufacturers are required to stamp their specifications on brake drums and rotors. I am pleased to have this opportunity to explain our law and regulations for you.

The National Traffic and Motor Vehicle Safety Act of 1966 (Safety Act) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards for new motor vehicles and new motor vehicle equipment. All motor vehicles and items of motor vehicle equipment manufactured or imported for sale in the United States must comply with all applicable safety standards. This agency does not provide approvals of motor vehicles or motor vehicle equipment. Under the Safety Act, the manufacturer is responsible for certifying that its motor vehicles or equipment meet applicable standards.

NHTSA has issued a number of safety standards which specify performance requirements for new motor vehicle brake systems and certain new brake equipment. The standards do not require manufacturers to stamp specifications on drums or rotors, although it is common practice for manufacturers to do so.

The Federal motor vehicle safety standards do not apply to a motor vehicle after its first sale to a consumer. However, manufacturers, distributors, dealers, or motor vehicle repair businesses modifying a used vehicle are prohibited by section 108(a)(2)(A) of the Safety Act from knowingly rendering inoperative any safety device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with a safety standard. The milling or turning of brake drums and rotors is typically performed during the course of repairing a used vehicle with worn brakes. We do not believe that the "render inoperative" provision would ordinarily be relevant to such a situation.

The states may regulate the repair of motor vehicles. We suggest you investigate the laws of Arizona to see whether they affect your situation.

I hope this information is been helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact David Elias of my staff at this address or by telephone at (202) 366-2992.

ID: 7871

Open

Mr. Michael J. Motzkin
Pioneer Plumbing
Post Office Box 35833
Tucson, AZ 85740-5833

Dear Mr. Motzkin:

This responds to your letter of October 14, 1992 regarding Federal requirements pertaining to brake specifications. In particular you asked whether there are any regulations requiring automotive brake drums and rotors not to be milled beyond manufacturer specifications, and whether manufacturers are required to stamp their specifications on brake drums and rotors. I am pleased to have this opportunity to explain our law and regulations for you.

The National Traffic and Motor Vehicle Safety Act of 1966 (Safety Act) authorizes the National Highway Traffic Safety Administration (NHTSA) to issue Federal motor vehicle safety standards for new motor vehicles and new motor vehicle equipment. All motor vehicles and items of motor vehicle equipment manufactured or imported for sale in the United States must comply with all applicable safety standards. This agency does not provide approvals of motor vehicles or motor vehicle equipment. Under the Safety Act, the manufacturer is responsible for certifying that its motor vehicles or equipment meet applicable standards.

NHTSA has issued a number of safety standards which specify performance requirements for new motor vehicle brake systems and certain new brake equipment. The standards do not require manufacturers to stamp specifications on drums or rotors, although it is common practice for manufacturers to do so.

The Federal motor vehicle safety standards do not apply to a motor vehicle after its first sale to a consumer. However, manufacturers, distributors, dealers, or motor vehicle repair businesses modifying a used vehicle are prohibited by section 108(a)(2)(A) of the Safety Act from knowingly rendering inoperative any safety device or element of design installed on or in a motor vehicle or item of motor vehicle equipment in compliance with a safety standard. The milling or turning of brake drums and rotors is typically performed during the course of repairing a used vehicle with worn brakes. We do not believe that the "render inoperative" provision would ordinarily be relevant to such a situation.

The states may regulate the repair of motor vehicles. We suggest you investigate the laws of Arizona to see whether they affect your situation.

I hope this information is been helpful. If you have any further questions about NHTSA's safety standards, please feel free to contact David Elias of my staff at this address or by telephone at (202) 366-2992.

Sincerely,

Paul Jackson Rice Chief Counsel ref:105 d.12/14/92

1992

ID: nht91-3.4

Open

DATE: March 29, 1991

FROM: Paul Jackson Rice -- Chief Counsel, NHTSA

TO: Rueben K. Brown -- Product Engineer, Crane Carrier Company

TITLE: None

ATTACHMT: Attached to letter dated 3-12-91 from Rueben K. Brown to Chief Counsel, Office of Chief Counsel, NHTSA (OCC 5815)

TEXT:

This responds to your letter of March 12, 1991 requesting an interpreta- tion of the applicability of the spike stop requirement in Standard No. 105 to school buses with GVWR greater than 10,000 lbs. While school buses are required by S5.1 to be capable of meeting the requirements of S5.1.1 through S5.1.6, the spike stop requirement in S5.1.6 is only applicable to vehicles with a GVWR of 10,000 lbs. or less. Therefore, school buses with a GVWR greater than 10,000 lbs are not required to be capable of meeting the spike stop requirement.

I hope this information has been helpful. If you have further questions, please contact Mary Versailles of my staff at this address or by telephone at (202) 366-2992.

ID: nht94-3.84

Open

TYPE: INTERPRETATION-NHTSA

DATE: August 1, 1994

FROM: Richard Quigley -- Special Consultant, Ill Eagle Helmet Company

TO: John Womack -- Acting Chief Counsel, NHTSA

TITLE: None

ATTACHMT: Attachment dated 8/18/94: Letter from John Womack to Richard Quigley (Std. 218)

TEXT: I have reviewed your letter of July 15, 1994, and have come to some conclusions regarding your apparent confusion concerning the "DOT" symbol I sent to you for your approval, and your subsequent emphatic rejection of same.

Let me see if I understand. You are rejecting my "D" on the basis that the computer bitmapped the letter "D" in transmission to your fax machine, so the right side, therefore, had the appearance of "jagged lines at the top and bottom of the letter th at meet in a straight line parallel to the line that forms the left side of the 'D'"; and our letter "O" on the basis that our letter "O" was not a letter "O", but rather just a circle - or a symbol resembling a circle. Have I got that?

I thought everybody had seen "The letter 'O'" segment of Sesame Street: "To make the letter 'O', (just) draw a circle." Big Bird wouldn't lie.

From that lesson, and/or a little common sense, a common person would be led to conclude that sometimes a circle is just a circle, and sometimes its the letter "O". But, our letter "O" isn't a letter "O", its just a circle . . . right? How does that work?

I think you may have been confused by the fact that I had superimposed the name of our company -- "THE ILL EAGLE HELMET COMPANY" -- inconspicuously around the surface of the letter "O", and had placed our unimposing logo in the center of same. How el se could you have been led to the mistake of believing that our letter "O" was just a circle?

So, here is a another version (this time with the bitmapped "D" smoothed out) for you to show around the office. Ask your people if they read it to say "DOT"? The surveys we have taken (our tests) indicate that virtually everybody sees our version o f a "DOT" sticker for just what it is, a "DOT" sticker.

So, other than the problem with our letter "D" (now corrected), and the fact that you were mistaken about our letter "O", do you have any remaining objections to our use of this sticker on helmets that we have certified as being in compliance with FMV SS 218?

If not, we will proceed on the basis that your silence means consent, and thank you for your response.

ID: nht80-1.13

Open

DATE: 02/08/80

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Motor Coach Industries

TITLE: FMVSS INTERPRETATION

TEXT: This responds to your December 11, 1979, letter asking whether you would be permitted to install a valve in your braking system that would prevent air from reaching the front axle brakes when your vehicle is in reverse. You want to make such a modification to prevent brake chatter when your vehicle is in reverse and question whether such a modification would comply with the requirements of Standard No. 121, Air Brake Systems.

Sections S5.3.3 and S5.3.4 of the standard establish brake actuation and release times. In an interpretation of those sections (July 23, 1976), the agency stated that the air pressures of 60 psi and 95 psi were only benchmarks, and that the agency would use either of those values or 70 percent of the maximum pressure in the brake chamber, whichever is lower. You state that this interpretation allows you to install a valve, because the maximum air pressure reaching the front brake chamber when the vehicle is in the reverse gear would be 0 and 70 percent of 0 is 0. Therefore, you suggest that your vehicle would pass the tests in these two sections if tested at 0 psi.

The intent of the July 23 interpretation of the sections was to provide flexibility of designs that incorporate lower air pressures than originally contemplated by the air brake standard. The interpretation was not intended as a device to escape from compliance with the air brake standard by creating a situation where front brakes would be rendered inoperative. Accordingly, the agency limits its July 23, 1976, interpretation to those instances where air brakes are receiving air pressure and are performing as designed to stop the vehicle. Using this limitation on our July 23 interpretation, the NHTSA concludes that your new brake design would violate the standard and, therefore, will not permit the use of the valve that you recommend.

The brake chatter that you refer to in your letter appears to be a problem that occurs only in your vehicles. We have not been made aware of similar problems affecting other manufacturer's vehicles. Accordingly, we must assume that something in your design is creating the chatter problem. We suggest that you alter your brake design in a way that eliminates the chatter problem while maintaining the vehicle's compliance with the air brake standard.

SINCERELY,

December 11, 1979

National Highway Traffic Safety Agency Chief Consul

SUBJECT: REQUEST FOR INTERPRETATION -- STANDARD #121

Gentlemen: We are manufacturers of the MC-9 Crusader Intercity bus. Some of our operators, have experienced a brake chatter, from the front axle, when the coach is in reverse. This does not affect brake performance, but can be annoying to the passengers. As this situation only occurs when the coach is backing up, we question if a value can be inserted into the braking system, to stop the air from the front axle, only when the transmission is in reverse. This control would be automatic, and could not be controlled by the driver (except by shifting into "reverse").

We question if this modification will affect the compliance to Standard #121. Specifically, we are looking at Section S5.3.3 and S5.3.4 which covers apply and Release times. Also, we refer to Mr. Frank Berndt's letter to White Motor Corporation (copy enclosed), which refers to 70% of the maximum air pressure at the brake chamber. In our proposal, this could mean 70% of zero.

We would appreciate your comments on this proposal.

MOTOR COACH INDUSTRIES

Ted J. Szkolinicki, Supervisor Mechanical Engineering

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.

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