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 10331 - 10340 of 16510
Interpretations Date
 search results table

ID: nht94-3.68

Open

TYPE: INTERPRETATION-NHTSA

DATE: July 14, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: James H. Shuff -- President, Freedom Trailers

TITLE: NONE

ATTACHMT: Attached to letter dated 2/9/94 from James H. Shuff to NHTSA Chief Counsel (OCC-9666)

TEXT: This responds to your letter asking whether tires and wheel rims used with your "park model travel trailers" are subject to Federal Motor Vehicle Safety Standard (FMVSS) No. 120, Tire selection and rims for motor vehicles other than passenger cars. As ex plained below, the answer is no, because your travel trailers are not motor vehicles.

Your letter provided the following information about your "trailers." The trailers are intended for recreational use, rather than for year round living. Each unit is a maximum of 400 sq. ft., and may be as wide as 12 feet. You state that after your trai lers are constructed, they "will be towed to their campsite and set up," where they may be used for "winter camping in the year round parks." Once your trailers are set up, you would reuse the tires and rims.

By way of background, 49 U.S.C. @ 30101 et seq. authorizes NHTSA to regulate new motor vehicles and motor vehicle equipment, including tires and rims. Standard No. 120, and all of our safety standards, apply only to vehicles that are "motor vehicles," w ithin the meaning of the statute. The term "motor vehicle" is defined at 49 U.S.C. @ 30102(a)(6) as:

"motor, vehicle" means a vehicle driven or drawn by mechanical power and manufactured primarily for use on public streets, roads, and highways, but does not include a vehicle operated only on a rail line.

We have determined that your "trailers" are not motor vehicles based on two examinations. First, while the characteristics of your trailers are not entirely clear in your letter (our repeated attempts to reach you by telephone have been unsuccessful), i t appears that your trailers could be considered "mobile homes." Mobile homes are regulated by the U.S. Department of Housing and Urban Development (HUD), and

2

are not "motor vehicles" subject to regulation by NHTSA. Accordingly, tire and rim selection for mobile homes is not subject to Standard No. 120 or any other NHTSA regulation. For information about mobile homes, you can contact the Assistant Secretary for Housing-Federal Housing Commissioner, U.S. Department of Housing and Urban Development, 451 7th St., SW, Washington, DC 20410.

Second, even if your "trailer" is not a mobile home, it does not meet the Safety Act definition of a "motor vehicle." We have interpreted the definition as follows. Vehicles designed and sold solely for off-road use are not considered motor vehicles, ev en though they may be operationally capable of highway travel. Vehicles, such as mobile construction equipment, that use the public roads only to travel between job sites and which typically spend extended periods of time at a single job site, are not c onsidered motor vehicles. In such cases, the use of the public roads is incidental, not the primary purpose for which the vehicle was manufactured.

On the other hand, if a vehicle is readily usable on the public roads and is in fact used on the public roads by a substantial number of owners, NHTSA has found the vehicle to be a motor vehicle. This finding was made with respect to dune buggies and re gardless of the manufacturer's stated intent regarding the terrain on which the vehicles were to be operated.

Based on your description, it appears that, analogous to mobile construction equipment, the on-road use of your travel trailers appears to be incidental and not the primary purpose for which they are manufactured. Therefore, your trailers are not subjec t to Standard No. 120's requirements for tire selection and rims. Please note that this conclusion is based solely on the facts presented in your letter. We may reexamine this conclusion if additional information becomes available that would warrant a reexamination.

I hope that this information is helpful. If you have any questions, please contact Dorothy Nakama of my staff at this address or at (202) 366-2992.

ID: nht94-3.69

Open

TYPE: INTERPRETATION-NHTSA

DATE: July 14, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Reidar Brekke -- Market Analyst, Norwegian Trade Council

TITLE: NONE

ATTACHMT: Attached to letter dated 6/15/94 from Reidar Brekke to NHTSA Chief Council (OCC-10095)

TEXT: This responds to your letter asking about the legality of "Belly Safe," a device to alter the positioning of vehicle lap and shoulder belts, for the advertised purposes of improving the fit of the belts on pregnant women. As described in the material yo u enclosed, two long straps attached to the "Belly Safe" are attached around the back of the seat. The occupant then sits on the "Belly Safe," attaches the safety belt, brings two straps from the "Belly Safe" up between the legs, and attaches the lap be lt through the velcro on those straps.

The following discussion explains the effect of our regulations on such products and concerns NHTSA has about this specific product.

By way of background information, this agency has the authority to issue safety standards applicable to new motor vehicles and new items of motor vehicle equipment. This agency does not have a safety standard that directly applies to belt positioning de vices. Our safety standards for "Occupant Crash Protection," (Standard No. 208) and "Seat Belt Assembly Anchorages" (Standard No. 210) apply to new, completed vehicles. In addition, our safety standard for "Seat Belt Assemblies" (Standard No. 209) appl ies to new seat belt assemblies. Because the "Belly Safe" is neither installed as part of a completed vehicle nor as part of a seat belt assembly, none of these regulations apply to the device.

While none of these standards apply to the "Belly Safe," the manufacturer of the product is subject to federal requirements concerning the recall and remedy of products with defects related to motor vehicle safety (49 U.S.C. 30118-30121). The agency does not determine the existence of defects except in the context of a defect proceeding. In addition, while it is unlikely that the "Belly Safe" would be installed by a motor vehicle manufacturer,

2

distributor, dealer or repair business, 49 U.S.C. 30122 prohibits those businesses from installing the device if the installation "makes inoperative" compliance with any safety standard.

NHTSA is concerned that the "Belly Safe" could be used in a way that adversely affects crash forces on the occupant. Standard No. 208 includes requirements that have the effect of ensuring that the lap and shoulder belts distribute the crash forces to t he occupant's skeletal structure, a part of the body that can better withstand the forces. For example, Standard No. 208 requires the shoulder belt and the lap belt to intersect off of the abdominal area. The "Belly Safe" places an object between the l egs of the occupant. This change in the distribution of crash forces could have serious safety implications for the wearer of the belt.

There are other concerns about the "Belly Safe." The realigning of the lap belt through the "Belly Safe" could increase the amount of webbing in the belt system. If the straps which attach around the back of the seat or the Velcro holding the lap belt a re unable to withstand the forces of a crash, there would be excessive slack in the lap belt. Slack in the lap belt would increase the risk of the occupant sliding under the lap belt (submarining) and slack in the belt system generally introduces higher crash forces, both of which would increase the risk of injury. In addition, should a non-pregnant occupant use the "Belly Safe," the device could do more harm than good.

I have enclosed a consumer information sheet titled "Pregnancy: Protecting Your Unborn Child in a Car." This sheet explains that the lap belt should be placed low, across the hips and over the upper things. If a woman takes the time to adjust the belt a s recommended (an action also needed to install the "Belly Safe"), NHTSA is unaware of any need for a device to keep the lap belt in this position.

I hope you find this information helpful. If you have any other questions, please contact Mary Versailles of my staff at this address or by phone at (202) 366-2992.

ID: nht94-3.7

Open

TYPE: INTERPRETATION-NHTSA

DATE: May 25, 1994

FROM: George W. Sudenga, Johnson, Sudenga, Latham & Peglow

TO: Marvin Shaw -- Attorney at Law, NHTSA

TITLE: Neil Rowe

ATTACHMT: Attached to letter dated 7/1/94 from John Womack to George W. Sudenga (A42; STD. 106) and letter dated 5/18/94 from John Womack to Neil Rowe.

TEXT: I represent Neil Rowe who has corresponded with you historically concerning his "Glad Grip". I visited with you via telephone communication on May 12, 1994 and am happy to report that a response has come from the NHTSA, Mr. John Womack.

By way of reference I am enclosing a reproduced copy of the letter to Neil dated May 18, 1994.

The contents of the letter, unfortunately, are vague to both myself and Mr. Rowe. We would like to market the Glad Grip, both as an improvement to the present system of hooking up airlines, and ultimately for use in new equipment. We would like appro val of NHTSA in advance of major marketing efforts. If possible, I would like to impose on you and the engineering offices and receive suggestions as to additional testing that might be provided with positive results that when forwarded to NHTSA would r esult in advance approval. Please help.

Enclosure

ID: nht94-3.70

Open

TYPE: INTERPRETATION-NHTSA

DATE: July 14, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Eric T. Stewart -- Engineering Manager, Mid Bus Inc.

TITLE: NONE

ATTACHMT: Attached to letter dated 5/26/94 from Eric T. Stewart to NHTSA Office of Chief Counsel (OCC-10049)

TEXT: This responds to your letter of May 26, 1994, asking whether the daylight opening of a door located to the left of the driver's seat can "be used in the calculations of required emergency exit area if it meets the performance requirements of Standard No. 217," Bus Emergency Exits and Window Retention and Release. The vehicle on which the door is installed has a capacity of 48 children or 40 adults and a gross vehicle weight rating (GVWR) of more than 10,000 pounds (4,536 kilograms).

During a June 27, 1994 phone conversation with Mary Versailles of my staff, you explained that you anticipate producing these vehicles as both buses and school buses. Accordingly, I will address the question separately for each of these vehicle types. As explained below, provided that the exit meets all the performance requirements for a side door exit, it may be possible to apply the area of such a door to the emergency exit area requirements for either type of bus.

Non-School Bus

The emergency exit requirements for non-school buses with a GVWR of more than 10,000 pounds are found in S5.2 of Standard No. 217. That section requires non-school buses to have "unobstructed openings for emergency exit which collectively amount, in tot al inches, to at least 67 times the number of designated seating positions on the bus." That section further requires at least 40 percent of the areas for emergency exit to be on each side of the bus and limits the amount that can be credited for each ex it to 536 square inches. If the door otherwise meets the emergency exit performance requirements, nothing in Standard No. 217 would prohibit counting the door as an emergency exit. Therefore, if the 40 percent distribution requirements are met, the

2

unobstructed area of a door to the left of a driver on a non-school bus can be credited, up to a maximum credit of 536 square inches.

School Bus

The emergency exit requirements for school buses with a GVWR of more than 10,000 pounds are found in S5.2.3 of Standard No. 217. That section states "(t)he area in square centimeters of the unobstructed openings for emergency exit shall collectively amo unt to at least 432 times the number of designated seating positions in the bus." All school buses are required to have either a rear emergency door exit or a side emergency door exit and a rear push-out emergency window. To determine if additional emer gency exits are required, the area of "daylight opening" of the front service door and those required emergency exits is subtracted from the total area required.

The formulas in S5.2.3 for subtracting the front service door and the required emergency exits refer to the "size of the available front service door opening" (emphasis added). We interpret this language as allowing the subtraction of the "daylight open ing" of a single front service door. The drawings you faxed on July 12, 1994 indicate that the vehicle has a front service door to the right of the driver in addition to the door to the left of the driver. Since the daylight opening of only one front s ervice door can be credited, the daylight opening of the door to the left of the driver cannot be credited as a front service door.

If additional emergency exits are required, they must be added in the following order:

1) Left side emergency exit door near the mid-point of the passenger compartment (if the vehicle has a rear door exit) or right side emergency exit door (if the vehicle has a side door exit and rear push-out window);

2) emergency roof exit;

3) any combination of side emergency exit doors, emergency roof exits, or emergency window exits.

Since the door to the left of the driver is not credited as the front service door, the only opportunity for crediting the area would be under the third level above. The door could not qualify for category (1), above, because a left side emergency door must be located near the mid-point of the passenger compartment.

3

I hope you find this information helpful. If you have any other questions, please contact Mary Versailles at this address or by phone at (202) 366-2992.

ID: nht94-3.71

Open

TYPE: Interpretation-NHTSA

DATE: July 15, 1994

FROM: Guy Dorleans -- Legal Compliance Department, Valeo Vision (France)

TO: Office of Chief Council, NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 8/31/94 from John Womack to Guy Dorleans (A42; Std. 108)

TEXT:

I am inquiring for information and assistance with the interpretation of Section 571.108 of the Federal Traffic Code. The attached sketch shows the front end of a vehicle which incorporates the following features:

Lamp A is a highbeam contributor with one monofilament light source. The wiring of the vehicle dies not allow this lamp to be lit alone in highbeam mode. Lamp A is 150 mm high, between level 750 and level 600 above the ground.

Lamp B is the lowbeam with one monofilament light source. Its light emitting area is 50 mm high, between level 650 and 700.

Lamp C is a combination of parking lamp and turn signal.

In highbeam mode, both filaments A and B are energized simultaneously and table 17a of FMVSS 108 is then fulfilled.

Lamp D is a foglamp.

As an alternative to the above description, we would like to know whether it is permissible to sell new cars in the United States with the foglamp replaced by an auxiliary driving beam. In this case, all three A, B and D filaments would be permanently e nergized together in high beam mode and table 17a of FMVSS 108 is then fulfilled. Lamp D alone, when tested in a laboratory, would satisfy the photometric requirements of SAE J581 June 89.

In another variant, two or three filaments could be switched on in highbeam mode depending on the position of a switch on the instrument panel, at the discretion of the driver. Whatever the position of the switch, table 17a of FMVSS 108 shall be fulfill ed. Would this be permissible?

Thank you in advance for your cooperation.

Graphics omitted.

ID: nht94-3.72

Open

TYPE: INTERPRETATION-NHTSA

DATE: July 15, 1994

FROM: Thomas L. Wright, Coordinator, Technical Support, State of New Jersey, Dept. of Law and Public Safety

TO: Robert Hellmuth -- Office of Vehicle Safety Compliance, NHTSA

TITLE: None

ATTACHMT: ATTACHED TO LETTER DATED 10/27/94 FROM PHILIP R. RECHT TO THOMAS L. WRIGHT (A42; STD. 108; REDBOOK 2)

TEXT: The New Jersey Division of Motor Vehicles performs a periodic safety inspection on all gasoline powered vehicles. Part of this inspection includes a check of the headlights. I am writing to request an opinion on the application of brush guards installe d forward of headlight units on Range Rover all-terrain vehicle models. The units are depicted installed in new car brochures supplied by the Range Rover dealerships.

I would appreciate a determination as to whether this device placed across the headlight face is a violation of Part 108.

Please respond to me by writing to New Jersey Division of Motor Vehicles, CN 177, Trenton, New Jersey 08666. Thank you for your attention to this matter.

ID: nht94-3.73

Open

TYPE: INTERPRETATION-NHTSA

DATE: July 18, 1994

FROM: Federico Trombi -- Chief Homologation Engineer, Bugatti Automobiles

TO: Taylor Vinson, Esq. -- Office of the Chief Counsel, NHTSA

TITLE: Additional Request for Interpretation of FMVSS 108

ATTACHMT: Attached to letter dated 7/28/94 from John Womack to Lance Tunick (Std. 108)

TEXT: Dear Mr. Vinson:

This letter requests an additional opinion from NHTSA as to whether a second anticipated version of the Bugatti EB 110 headlamp would be in compliance with Federal Motor Vehicle Safety Standard (FMVSS) 108.

This letter is in addition to the Bugatti interpretation request of July 8, 1994, and it is not in lieu thereof. We therefore request that NHTSA respond to both requests. However, we ask that NHTSA not delay the response to either this or the July 8 request because a response to the other may not be ready. Thus, when a response to one is ready, kindly provide it to us, without waiting for the other to be completed. Thereafter, when the other response is prepared, please provide it in a separate l etter. Thank you.

The second version of the proposed Bugatti headlighting system, that is the subject of this letter, would consist of two headlamps. In each headlamp:

The low beam would be provided by a gas discharge unit; and

The high beam would be provided by one "irreplaceable bulb" unit, or such unit together with the gas discharge unit. (In the alternative, instead of an "irreplaceable bulb unit, Bugatti may use a second gas discharge unit.)

The headlamp "box" would be an indivisible entity that would be treated as an exchange unit, and all internal screws would be sealed to prevent removal. The gas discharge unit's bulb, receptacle, reflector, ballast, etc. would be an indivisible unit. The "irreplaceable bulb" unit would be a replaceable bulb unit with an H-1 bulb of approximately 100 watts and the unit would be modified so that the bulb is NOT replaceable. All problems with

2

the headlamp box would therefore be remedied by the replacement of the entire box, which can then be remanufactured at the factory.

As described above, the headlamp would be an integral beam headlighting system provided for in FMVSS 108, S7.4. More specifically, the Bugatti integral beam headlighting system would be comprised of two headlamps that comply with S7.4 (a)(2) and the photometric requirements of either (a)(2)(i) or (a)(2)(ii).

The Bugatti headlamp would have the low beam gas discharge unit mounted towards the center of the box (as in the diagram provided to NHTSA) and the "irreplaceable bulb unit" would be mounted inboard of the gas discharge unit.

Outboard of the low beam gas discharge unit, Bugatti may install either a replaceable bulb fog lamp or driving lamp that is not regulated under FMVSS 108.

Bugatti believes that the above headlighting arrangement is permissible under FMVSS 108. Table IV requires that the low beams be mounted "as far apart as practicable". The reason that the gas discharge unit cannot be mounted any farther outboard tha n as proposed is that, because of the design of the Bugatti EB110 body, there simply is not sufficient room (Bugatti's previously submitted attachment shows that if the gas discharge unit were mounted further outboard, it would conflict with the wheel ar ch).

Moreover, the headlamp would be in conformity with S7.4(b) as the lamp would have 2 light sources and the lower beam would be provided by the most outboard light source (as far as FMVSS 108 is concerned -- the fog or driving lamp would be disregarded) , and the upper beam would be provided by either the most inboard light source or both the gas discharge and irreplaceable bulb light sources.

Is the above-described headlighting system permissible?

We urgently need as swift a response as possible in order to proceed with production. Kindly contact the following with any questions and the response:

Mr. Lance Tunick

1919 Mt. Zion Drive

Golden CO 80401

tel. 303 279 0203

fax 303 279 9339

Thank you.

ID: nht94-3.74

Open

TYPE: INTERPRETATION-NHTSA

DATE: July 19, 1994

FROM: P. Binder -- ITT Automotive Europe GmbH

TO: John Womack -- Office of Chief Counsel, NHTSA

TITLE: NONE

ATTACHMT: Attached to letter dated 8/2/94 from John Womack to P. Binder (Std. 108)

TEXT: Dear Mr. Womack,

Thank you for your reply of June 21, 1994.

To my regret I was forced to realize that I had made a mistake. My fax of April 28, 1994 should be referred to tail lamps.

Lighting System:

[ILLUSTRATION OMITTED - SEE ORIGINAL SOURCE]

1. With regard to the tail lamps I interpret FMVSS 108 and SAE J 585e, Sept. 77 as follows:

- This Lighting System is a multiple lamp arrangement, therefore the combination of taillamp 1 and taillamp 2 has to be used to meet the photometric requirements for 2 lighted sections (SAE J 585e; 3.1 and Table 1).

2

- Visibility will be judged with tailgate closed. Only taillamp 2 mounted on the tailgate will meet the requirements for an unobstructed projected illuminated area of 12,5 cm' measured at 45 deg inboard. This is in accordance with SAE J 585e; Par. 4.

Is my interpretation o.k.?

2. Some general questions:

- Are there regulations, which lamps has to be mounted on the body and which lamps are allowed on the tailgate?

Is there a regulation to take an approval test in an authorized test laboratory (e.g. ETL)?

- Which US-Authority has to be informed about this test?

- How long is this test valid?

- After which period has this test to be repeated?

Excuse my thoughtlessness. Please reply as soon as possible by fax (Fax-No.: Germany - 7142 - 73 28 95). Thank you very much in advance.

ID: nht94-3.75

Open

TYPE: Interpretation-NHTSA

DATE: July 19, 1994

FROM: Richard Kreutziger -- Executive Director, New York School Bus Distributors Assn. (Penn Yan, NY)

TO: John Womack -- Acting Chief Counsel, NHTSA

ATTACHMT: Attached to letter dated 8/26/94 from John Womack to Richard Kreutziger (A42; Std. 217(2))

TEXT:

As a liaison and so termed "answer man" for the NYS School Bus Distributors, a question has arisen relating to vehicles (school buses) less than 4,356 kilograms - and pupil capacity - because of special use - handicapped and other - having a passenger se ating capacity ranging from as low as two (2) to as much as sixteen (16) seated or wheelchair positions in combination.

The direct question - do these vehicles - less than 4,356 kilograms, have to be equipped with the retroreflective tape as depicted in S5.5.3 (c) "school bus"?

The question really arises in the fact that - in most other instances where GVWR is depicted as a related factor - unless there is a GVWR related factor for a lesser capacity the lesser capacity is not required or mandated to meet the same factors as the stated GVWR. (See S5.4.2.1 of the amended FMVSS 217

Any response to the "question" will be greatly appreciated, by myself and the membership of the association.

ID: nht94-3.76

Open

TYPE: INTERPRETATION-NHTSA

DATE: July 20, 1994

FROM: John Womack -- Acting Chief Counsel, NHTSA

TO: Samson Helfgott -- Esq., Helfgott & Karas, P.C.

TITLE: Your Ref. No.: 12.065

ATTACHMT: Attached to letter dated 7/1/94 from Samson Helfgott to Paul Jackson Rice (OCC-10165), letter dated 3/30/89 from Erika Z. Jones to Samson Helfgott, and letter dated 9/17/90 from Paul Jackson Rice to Samson Helfgott

TEXT: We have received your letter of July 1, 1994, to Paul Jackson Rice, former chief counsel of this agency, on behalf of your client Harold Caine, with respect to whether a certain supplementary lighting system would be permissible under Federal Motor Vehic le Safety Standard No. 108. You have enclosed copies of two previous letters that this Office has sent you on other supplementary lighting systems developed by Mr. Caine.

You state that "Mr. Caine is considering the possibility of utilizing [a] combination of red and amber lighting arrangement to be placed along the side of trucks and other vehicles." Since you later ask "whether the presence of the red and amber lights o n the sides of the vehicle would be permissible under Standard No. 108", we interpret this as meaning that the red and amber lamps would be in addition to those red and amber lamps that are presently required on the sides of vehicles (the side market lam ps) by Standard No. 108. However, your letter fails to state the number and candela of the lamps, and how they would be arrayed along the side of the vehicle.

As we understand it, during normal vehicle operation, the amber side lamps of the system would be activated. When the brake pedal is applied, the amber lamps are extinguished and the required stop lamps and red side lamps of the system would be activate d. As you know from previous correspondence, supplementary lighting equipment is prohibited only if it impairs the effectiveness of lighting equipment that is required by Standard No. 108. Standard No. 108 specifies that front and intermediate side mar ker lamps (those at or near the midpoint of the length) shall be amber, and that rear ones shall be red. If, in the Caine system, the amber supplementary lamps are mounted to the front of the vehicle side and the red supplementary lamps to the rear of t he

2

vehicle side (i.e., amber from front to and including the midpoint; red, after the midpoint to the rear), we do not see that the supplementary system would have an impairing effect upon the stop lamps or rear side market lamps and reflectors. If, howeve r, the system consists of alternating red and amber lamps displayed along the side of the vehicle, then the potential for confusion as to orientation of the trailer could result, impairing the effectiveness of the color code of the required side market l amps. We assume that the candela of the lamps in the Caine system is no greater than that permitted for the side marker lamps that are required by Standard No 108, but if the candela is greater, that would also create the potential for impairment if the array alternates red and amber lamps.

You have also asked "whether there are any prohibitions that might prevent utilization of this structure on the sides of the vehicles." We know of none, however, it is possible that some States might have laws that would affect this. As we are unable to advise you on State law, we suggest that you write for an opinion to the American Association of Motor Vehicle Administrators, 4600 Wilson Boulevard, Arlington, Va. 22203.

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.