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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 10111 - 10120 of 16510
Interpretations Date
 search results table

ID: nht94-4.5

Open

TYPE: INTERPRETATION-NHTSA

DATE: August 18, 1994

FROM: H. Kristie Jones -- President, P.J.'s Fabrication Inc., Stanfield, OR

TO: John Womack -- Acting Chief Counsel, NHTSA

TITLE: NONE

ATTACHMT: Attached to 10/05/94 letter from Philip R. Recht to H. Kristie Jones (A42; std. 115)

TEXT: P.J.'s Fabrication Inc. is a trailer manufacturing business. We are a new company and need assistance with rules and regulations regarding VIN numbers.

We have contracted with Coulson Commander Trailers, Boise, Idaho to build trailers under Coulson's name. As the manufacturer, P.J.'s accepts responsibility for warranty work and quality control to meet DOT specifications. My question, who issues the VIN number and Certificate of Origin?

I called Dorothy Nacomma on 8-18-94, she has informed me that P.J.'s Fabrication will issue the VIN number, but suggested I write to you for written confirmation of such.

At your earliest convenience, could you possibly sent us this confirmation.

Your time and consideration in this matter is greatly appreciated.

ID: nht94-4.50

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 13, 1994

FROM: Antonio Salvetti

TO: Chief Counsel, NHTSA

TITLE: None

ATTACHMT: ATTACHED TO LETTER DATED 12/29/94 FROM PHILIP R. RECHT/JOHN WOMACK TO ANTONIO SALVETTI (A42; PART 567)

TEXT: I am very interested in buying a new vehicle manufactured by Advanced Generation Motors Inc. called the AGM "PLAYA" which is based on a Geo Metro/Suzuki Swift unit.

The conversion consists on taking out all doors of the hatchback, cutting the roof and redesigning the vehicle in fiberglass as far as it was explained to me. The Playa has no doors and comes with a full enclosure in canvas.

My questions are:

1) Is this vehicle approved to be on the streets? 2) How do I know that they comply with all the safety requirements? 3) How are they responsible for any vehicles problems? 4) Are there any other requirements beside safety to meet?

Thank you in advanced for the information.

ID: nht94-4.51

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 14, 1994

FROM: Recht, R. Philip -- Chief Counsel, NHTSA

TO: Larson, Victor P. E. -- Cryenco, Inc. (COLORADO)

TITLE: NONE

ATTACHMT: Attached To A Letter Dated 5/17/94 From Victor Larson To John Womack (OCC 9984)

TEXT: This responds to your FAX of May 17, 1994, with reference to the application of conspicuity material to the sides of cryogenic tank trailers.

You point out that the only side mounting surface for striping that is perpendicular to the road is at the center of the tank, approximately 90 inches above the road surface. You ask for confirmation of your interpretation that conspicuity material can be placed at this location "if that is the only available mounting area" and that it is not necessary to add additional structure for the sole purpose of providing a lower vertical mounting surface.

We confirm your understanding. Standard No. 108 specified an original mounting height for conspicuity material as close as practicable to 1.25 m. However, in a notice published on October 6, 1993, NHTSA amended the requirement to "as close as practicab le to not less than 375 mm and not more than 1525 mm above the road surface." The practicability qualification allows manufacturers to choose a location for conspicuity treatment that is outside the specified range to avoid body modifications that might otherwise be required to mount the material within the specified range.

The manufacturers of conspicuity material certify its performance in a vertical plane. Trailer manufacturers should mount the material in a vertical plane or as close to a vertical plane as the trailer shape offers, in order to achieve the full conspicu ity benefits of the material. In the case of your tank trailer without a suitable vertical surface below the belt line of the tank, reflective material at a belt line that is 90 inches above the road surface would be considered to have been mounted as c lose as practicable to the upper specification of the height range (1.525 m). As NHTSA observed when it adopted the original mounting height specification with its practicability provision, flexibility in the vertical location of conspicuity material is necessary for compliance of some tank trailers. However, it should not be overlooked that other types of tank trailers may have vertical surfaces on the frame, fenders, or other equipment well suited for conspicuity material.

You inform us that some trailers have rear and midship cabinets that could be used, in conjunction with the belt line location, to provide a location for striping, although this would result in a non-aligned striping pattern. With respect to trailers eq uipped with cabinets, you asked whether compliance would be satisfied if only the belt-line location is used. The answer is yes, provided that the requirement of paragraph S5.7.1.4.2(a) is met, i.e., which provides that "the strip need not be continuous as long as not less than half of the length of the trailer is covered and the spaces are distributed as evenly as practicable." Since the strip need not be continuous, this would allow discontinuities in a strip mounted at 90 inches in which the cabinet s were not used.

Your final question is the required orientation of striping for conspicuity; some of your customers have requested placement of material at a downward angle of approximately 30 degrees to accommodate their graphics better. The standard does not explicit ly address the issue of orientation. However, as noted in response to your first question, trailer manufacturers should mount conspicuity material in a vertical plane, or as nearly thereto as the trailer shape allows, so that the full conspicuity benefi ts of the material may be realized. If there is no available vertical surface on which the material can be mounted, we urge that a wider stripe of conspicuity material be used to provide the minimum required performance at the installed downward angle. The manufacturer of the conspicuity material which you use should be able to determine whether an increase in the width of the striping would allow the material mounted at or near the downward angle that your customer prefers to provide performance comp arable to a narrower strip mounted in a vertical plane.

ID: nht94-4.52

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 14, 1994

FROM: Recht, Philip R. -- Chief Counsel, NHTSA

TO: Kover, Joe

TITLE: NONE

ATTACHMT: Attached To A Letter Dated 7/25/94 From Joe Kover To Jere Medlin (OCC 10216)

TEXT: This responds to your letter of July 25, 1994, to Jere Medlin of this agency. You have presented several questions regarding an electric circuit that you have designed for use in motor vehicles, and which you call a Light Control Unit (LCU).

The LCU automatically turns off the headlamps and tail and parking lamps when the ignition is turned off if the lamps have been activated. The LCU also automatically turns on the headlamps and the tail and parking lamps whenever the windshield wipers ar e turned on. If the LCU fails when the lights are on, a Light Bus Monitor will automatically restore them.

You have the following questions:

"Would a motor vehicle operator be in violation of the federal motor vehicle safety standards by maintaining both the head and tail/park lights on during the hours of daylight?"

No. The Federal motor vehicle safety standards do not tell an owner when it is or is not permissible to use safety equipment.

"Does the LCU meet the federal motor vehicle safety standards? Could the LCU be integrated into the light system of new production vehicles or currently registered vehicles;"

The Federal motor vehicle safety standard on lighting, Standard No. 108, does not apply to supplementary lighting devices such as the LCU. The LCU is permissible on new vehicles provided it does not impair the effectiveness of lighting equipment require d by the standard. We do not see that it has this effect. It is permissible to be installed on currently registered vehicles by manufacturers, distributors, dealers or motor vehicle repair businesses provided that it does not make inoperable any part i nstalled in accordance with a Federal motor vehicle safety standard. We do not see that the LCU has this effect either.

You have also told us that the LCU may be used to operate lamps as Daytime Running Lamps (DRLs) by maintaining the light switch in the on position when the wiper switch has been turned off. One feature of this function is that the LCU "allows the operat or to turn off either the head lights only or both the head lights and tail/park lights via the light switch." Your question is "If the operator should elect to employ the LCU as a DRL unit does it meet the federal motor vehicle safety standards?" Under Standard No. 108, a DRL system is a system of any pair of lamps on the front of a vehicle (other than parking lamps or fog lamps) that is automatically activated and that is automatically deactivated when the operator places the headlamp control in the on position. Further, DRLs can be lower beam headlamps operated at full voltage. Assuming that the LCU turns the lower beam headlamps on rather than the upper beam ones, your system would function as a DRL meeting the requirements of Standard No. 108 when the lower beam headlamps are automatically activated by the windshield wipers and deactivated by turning off the ignition. However, the feature that allows the headlamps to be turned off manually (whether or not simultaneously turning off the p arking lamps and taillamps) is not part of a DRL system as specified by Standard No. 108.

Your final request is that we "include the federal specifications for electronic devices." We are unsure what you mean by this as we have no "specifications for electronic devices." I enclose a copy of S5.5.11 of Standard No. 108, the DRL specifications.

(ENCLOSURE OMITTED.)

ID: nht94-4.53

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 14, 1994

FROM: Randal Busick -- President, Vehicle Science Corporation

TO: Mary Versailles, Esq. -- Office of the Chief Counsel, NHTSA

TITLE: Re: Request for interpretation of FMVSS 208 S7.1.2

ATTACHMT: Attached to 1/5/95 letter from Philip R. Recht to Randal Busick (A43; Std. 208; Std. 210)

TEXT: Dear Ms Versailles:

This is to request a clarification of FMVSS 208 S7.1.2. More specifically, would a seat belt system as shown on the attached drawing be in compliance with S7.1.2 as a so-called "semi-integrated" seat belt?

As shown on the drawing, the inboard lower FMVSS 210 anchorage, n1 is located on the seat frame and thus, as the seat moves fore and aft, the system allows a minimum of two seat belt adjustment positions and the distance between the two extreme adjustmen t positions of the system is more than 5 cm.

n1 The belt which holds the buckle is attached to this inboard anchorage.

We look forward to your response. If you have any questions, kindly contact the undersigned.

Sincerely

Enclosure

(Drawing omitted.)

ID: nht94-4.54

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 18, 1994

FROM: Roger W. Cole -- Vice President, Sales, Twin Tire U.S.A., Inc.

TO: Walters Meyers, Esquire -- NHTSA

TITLE: None

ATTACHMT: ATTACHED TO LETTER DATED 12/7/94 FROM PHILIP R. RECHT TO ROGER W. COLE (A42; REDBOOK 4; STD. 109; PART 575.105

TEXT: It was a pleasure speaking with you this morning on the telephone.

To review our conversation, we are in the business of marketing and selling the Twin Tire system in the USA and abroad and are currently in discussions with various tire manufacturers. Most recently, our tires have been manufactured by Yokohama Rubber C orporation. These tires were manufactured as recently as 1991. All of these tires have a D.O.T. designation and a U.T.Q.G. designation. Yokohama has recently breached their contract to manufacture these tires under the premises of US regulations.

Please confirm in writing that once the tires have received the D.O.T. and U.T.Q.G. approvals and ratings which are molded on the exterior of the tire that they are legal to sell in the US.

I thank you very much and would appreciate a quick response as we are urgently in need of product.

ID: nht94-4.55

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 18, 1994

FROM: Jerry G. Sullivan, P.E. -- The Braun Corporation

TO: Mary Versailles -- NHTSA Office of Chief Council

TITLE: NONE

ATTACHMT: Attached to 1/9/95 letter from Philip R. Recht to Jerry G. Sullivan (A43; Std. 217)

TEXT: Dear Mary,

I am writing for a clarification to FMVSS 217. For non-school buses, GVWR less than 10,000 lbs, can the driver side front door area be used to help meet the unobstructed openings requirement? [Ref: 55.2.2(c) Doors]

I appreciate your assistance in this matter.

Sincerely

ID: nht94-4.56

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 21, 1994

FROM: Recht, Philip R. -- Chief Counsel, NHTSA

TO: Williams, Harry L., Jr. -- President, Willy Lights Inc.

TITLE: NONE

ATTACHMT: Attached To September, 1994 Letter From Harry L. Williams, Jr. To NHTSA Office Of The Chief (SIC) Counsel (OCC 10391)

TEXT: We have received your letter mailed on September 27, 1994, with respect to the permissibility under Federal law of your invention, Willy Lights. This product appears to consist of lights installed on wheel rims.

You enclosed a copy of a memorandum to you on this subject dated October 24, 1988, from Greg Novak, an engineer with the Nevada Division of the Federal Highway Administration. After consulting with members of this agency, Mr. Novak wrote you that there were no regulations that prohibited the use of lighted wheel rims but that they could not "interfere with any standard safety equipment on a vehicle." You have asked whether this interpretation remains valid, and, if the lamps are not prohibited, the col or permissible for the lamps.

You have not provided a detailed description of your device, such as the amount of illumination provided by the lights. Mr. Novak's advice that there are "no regulations prohibiting the use of lighted wheel rims" must be qualified. There are no Federal regulations that specifically prohibit the sale and installation of lighted wheel rims, but there may be regulations governing the use of lighted wheel rims issued by the individual States. We have no knowledge of State laws on this matter and suggest that you write for an opinion to the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203.

Federal Motor Vehicle Safety Standard No. 108 Lamps, Reflective Devices and Associated Equipment establishes the requirements for original lighting equipment for motor vehicles. Standard No. 108, in effect, prohibits the installation of supplementary li ghting equipment such as Willy Lights before the initial sale of a vehicle if it impairs the effectiveness of the equipment required by Standard No. 108. Thus, if Willy Lights were sufficiently bright to mask in whole or in part the side marker lamps an d reflectors and any lamps mounted on the front and rear that wrap around the sides, Standard No. 108 would prohibit their installation. The seller (dealer) of the new vehicle has the responsibility of ensuring that the vehicle remains in compliance wit h Standard No. 108 when it installs supplementary lighting equipment, that is to say, the responsibility of determining whether or not impairment exists. This agency does not question such determinations unless they appear clearly wrong.

There is a similar prohibition for supplementary lighting equipment installed after the initial sale of a vehicle. When Willy Lights are installed by a manufacturer, dealer, distributor, or motor vehicle repair business, they must not make inoperative a ny of Standard No. 108's required equipment. With respect to Willy Lights, we would regard the question of making inoperative as equivalent to the question of impairing effectiveness. If it is concluded that Willy Lights do not impair new vehicle equip ment, then one can conclude that its installation on a used vehicle will not have an operative effect on 108's equipment. However, the States retain the right to say whether or not Willy Lights may be used within their borders.

The color of the lamps may also be important in any determination of impairment or inoperability. Under Standard No. 108, required side marking equipment at or near the front of a vehicle must be amber in color, and red at or near the rear. To lessen th e chance of confusion in a driver approaching from the side who may never have seen lighted wheel rims, we believe that it would be preferable to follow Standard No. 108's color code. Use of different colors, such as white or green, could cause momentar y confusion in the eyes of an approaching driver, leading to the conclusion that the required side lighting equipment has been impaired or made partially inoperative by Willy Lights.

ID: nht94-4.57

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 21, 1994

FROM: Donald Orlando -- Orlando World Industries

TO: Ed Glancy

TITLE: NONE

ATTACHMT: Attached to 1/5/95 from Philip Recht to Donald Orlando (A43; Std. 208; Std. 209)

TEXT: Dear Ed:

As per our telephone conversation on the "SEAT BELT BUDDY" which has been invented and developed to popularize the wearing of seat belts for children. The device is a stuffed toy [ILLEGIBLE WORDS] the center of the animal where you insert the seat belt t hrough and then into the automobile buckle.

If you have any questions please don't hesitate to call me at (914) 428-2871 or you can reach my associate [ILLEGIBLE WORDS] at (914) 686-0141

Thanking you in advance for your prompt attention to this matter.

Sincerely Yours,

ID: nht94-4.58

Open

TYPE: INTERPRETATION-NHTSA

DATE: October 21, 1994

FROM: Scott E. Peters -- Director, Regulations & Compliance, U.S. Electricar

TO: Phil Recht -- Chief Counsel, NHTSA

TITLE: Interpretation Regarding Tire Loads for Electric Vehicles

ATTACHMT: ATTACHED TO 2/13/95 LETTER FROM PHIL RECHT TO SCOTT E. PETERS (STD. 110)

TEXT: U.S. Electricar is a California corporation which manufactures electric vehicles, including the Electricar Pickup (converted Chevrolet S-10) and the Electricar Sedan (converted GEO Prizm). The Electricar Pickup is fully FMVSS certified while the Electri car Sedan is currently built under NHTSA temporary FMVSS exemption 92-3 for low-emission vehicles. We are aggressively pursuing development of the Sedan and expect to achieve full FMVSS certification within several months.

As you are aware, production electric vehicle development is fairly recent and most of the Federal Motor Vehicle Safety Standards were not written with electric vehicles in mind. We occassionally come across a Safety Standard provision which does not se em applicable to electric vehicles because of their special operating characteristics and limitations compared to traditional internal combustion powered vehicles. Section 4.4.2 of Standard No. 110 is such an example, and we believe this section is not relevant to our particular electric passenger car (the Electricar Sedan), with a speed and speed/endurance limitation substantially below almost any internal combustion powered passenger car.

The purpose of Standard No. 110 is to ensure proper tire selection in order to prevent tire overloading, and thus prevent tire failure. Section 4.2.1 requires that vehicle maximum load on each tire shall not be greater than the maximum tire load rating as specified in one of the tire industry publications listed in Standard No. 109. This section alone prevents tire overloading as long as high speed operation is not a factor.

Section 4.2.2 of Standard No. 110 states that the normal load on the tire shall not exceed the test load used in the high speed performance test specified in S5.5 of Standard No. 109. The test load is 88 percent of the tire's maximum load rating. As sp ecified in S5.5.4 of Standard No. 109, tires at this test load must operate at speeds of 75 mph for 30 minutes, 80 mph for 30 minutes and 85 mph for 30 minutes. It is our understanding that the purpose of Standard No. 110, S4.4.2 is to ensure against ti re failure due to prolonged operation at speeds in the range of 75 mph or higher.

It is our interpretation that Standard No. 110, S4.4.2 is not intended to apply to the Electricar Sedan and other electric passenger cars in which it is physically impossible to operate at high speeds for an extended duration. The Electricar Sedan is ba rely capable of reaching a speed of 75 mph, and could not maintain this speed for more than a few minutes due to the extremely high power requirements and limited energy stored on-board in the vehicle's batteries.

Electric vehicles are intended for use in urban areas with air quality problems and are not suitable for operation at prolonged freeway speeds because of their range limitations. To maximize range and reliability in the Electricar Sedan, the top speed i s limited by software in the vehicle's electronic power control unit. The drag limited speed (non-software governed) is also below most of the "high speed" figures cited in Standard 109, S5.5.4.

Optimizing tire size is an ongoing challenge in electric vehicle development. Because of the weight added in the electric conversion process, original tires must generally be replaced with larger tires which have a higher load capacity. Larger tires on c onverted electric vehicles have the disadvantages of increased rolling resistance and reduced tire clearance and turning radius compared to the original vehicle. Increased rolling resistance lowers the vehicle operating range, a factor which is critical in the acceptance of electric vehicles by both fleet users and the general public. Section 4.2.2 of Standard 110 is based on the load-carrying capacity of tires at high speeds and would require the use of tires which are larger than those needed for co mpliance with S4.2.1 and larger than we believe are required for the safe operation of an electric passenger car with limited speed and speed/endurance capability.

Would you please review Standard 110, S4.2.2 in light of the performance limitations of our electric passenger car and provide us with your interpretation as to the applicability of this section to the Electricar Sedan described above.

Please contact me if I can provide additional information for your consideration of our request.

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.