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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 13751 - 13760 of 16510
Interpretations Date
 search results table

ID: nht93-4.30

ID: nht93-4.31

Open

DATE: June 11, 1993

FROM: Howard M. Smolkin -- Acting Administrator, U.S. Department of Transportation, NHTSA

TO: Laura J. Platter

COPYEE: Barbara A. Mikulski -- United States Senate

TITLE: None

ATTACHMT: Attached to letter dated 5-21-93 from Carl W. Vogt to Howard Smolkin (OCC 8692)

TEXT: This responds to your letter to Senator Barbara Mikulski about the Federal government's classification of minivans for safety purposes. You were concerned that classifying minivans as trucks rather than passenger vehicles would permit these vehicles to be equipped with fewer safety features.

Congress has authorized this agency, the National Highway Traffic Safety Administration (NHTSA), to issue Federal motor vehicle safety standards that are applicable to new motor vehicles and items of motor vehicle equipment. In the last few years, NHTSA has extended nearly all the passenger car safety standards to cover light trucks and multipurpose passenger vehicles (MPVs). (Minivans are typically considered to be MPVs under our safety standards.)

The only significant safety requirement for passenger cars that the agency has not extended to light trucks and MPVs is dynamic side impact protection. This is a new requirement that is being phased in for passenger cars beginning this September. NHTSA is currently in rulemaking to consider whether the dynamic side impact protection requirements should be extended to light trucks and MPV's, and published an advance notice of proposed rulemaking on this subject in June 1992.

I hope this information is helpful to you.

ID: nht93-4.32

Open

DATE: June 13, 1993

FROM: Charlie McBay -- Chief Engineer, Barrett Trailers, Inc.

TO: Office of Chief Counsel, NHTSA

TITLE: Conspicuity

ATTACHMT: Attached to letter dated 7-14-93 from John Womack to Charlie McBay (A41; Std. 108)

TEXT:

This letter asks that the Office of Chief Counsel review the enclosed drawings (Model 80MP6-DD & GNXS-207) for compliance of the upcoming conspicuity treatment.

As you can see, both models have "outside post" design and air gaps that run through the sides and rear of the trailer. Air gap quantity and locations vary with different designs.

2" red and white alternating pattern used on sides and rear. 2" white on upper rear corners.

Note: Location of side material as close to 4ft. off the ground as possible. In the center the location stays on the bottom rail (due to air gaps) and ranges from 14" to 20" off the ground.

Reflector material to be a 14" strip placed in center of each opening between side post. This length meets the 50% coverage requirements.

Note that post spacing throughout the length of the trailer is not the same. Evenly distributed material will be in most areas, but breaks between material vary. Will this suffice for evenly distributed? Also, if we have an area where a minimum 12" strip will not fit, can we install smaller material or must this area stay blank?

Note that white strips in upper rear corners do not meet. Must white be touching or can there be a gap between the strips? Our design makes it near impossible to make a nice continuous square corner. Installation of the white corners is also closer than 3" from red top rail lights. Is there any tolerance on the 3" dimensions? One full width red and white strip on rear of trailer on both models as close to 4ft. off the ground as possible.

Enclosed are drawings of proposed installation as close as we can get to meeting the requirements outlined. (The yellow hi-lited areas represent reflective Material)

I would welcome any comments and ask that our installation have your approval.

Attachments omitted:

Drawing of Model 80MP6-DD and drawing of GNXS-207.

ID: nht93-4.33

Open

DATE: June 14, 1993

FROM: Kenneth E. Ross -- C.P.A.

TO: Consumer Coordinator, NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 8/13/93 (est) from John Womack to Kenneth E. Ross (A41; Std. 108; Std. 111)

TEXT:

We will soon be introducing a new consumer product which attaches to the back window of an automobile. We believe it is small enough not to block the driver's rear view.

Can you tell us:

1) are there any NHTSA rules, standards, guidelines or opinions on the subject? 2) do you have any studies of state or local laws on the subject?

ID: nht93-4.34

Open

DATE: June 15, 1993

FROM: John Womack -- Acting Chief Counsel, U.S. Department of Transportation, NHTSA

TO: Edward F. Conway, Jr. -- Assistant General Counsel, Recreation Vehicle Industry Association

TITLE: None

ATTACHMT: Attached to letter dated 5-19-93 from Edward F. Conway, Jr. to John Womack.

TEXT: We have received your letter of May 19, 1993, asking for an interpretation of Motor Vehicle Safety Standard No. 108.

You are concerned with an opinion that the agency expressed when it published the rule requiring center highmounted stoplamps (CHMSLs) on trucks whose overall width is less than 80 inches and whose GVWR is 10,000 pounds or less that are manufactured on and after September 1, 1993 (56 FR 16015). NHTSA pointed out that installation of an aftermarket slide-in camper by a manufacturer, dealer, distributor, or motor vehicle repair business might "render inoperative" the CHMSL within the meaning of the prohibition of 15 U.S.C. 1397(a)(2)(A) if it obscured the original equipment CHMSL.

You have apprised us that a number of your manufacturer members produce slide-in campers that are more than 80 inches wide that obscure CHMSLs. When these campers are installed on trucks that are 80 inches or less in overall width, you argue that "(a) CHMSL is NOT required on that pickup truck because its overall width is now MORE THAN 80 inches". You ask that we concur in your conclusions that these campers may lawfully be installed by a person other than a vehicle owner, and that these campers themselves are not required to be equipped with a CHMSL.

We are pleased to inform you that we concur with your conclusions under the conditions to be discussed. Virtually all modifications of vehicles in use by persons other than the owner are subject to the "render inoperative" prohibition. Over the years, we have informed prospective modifiers that we do not interpret the prohibition to require continued compliance to all Federal motor vehicle safety standards (FMVSS) that originally applied to the vehicle to be modified if the modifications contemplated will result in a change in the applicability of the original FMVSS. For example, if a 1990 passenger car is changed from a closed car to an open one, it need no longer meet all FMVSS that applied to closed vehicles manufactured in 1990. However, at the end of the modification process, it must meet all FMVSS that applied to convertibles in that year.

In our opinion, the same principle applies in the fact situation you have outlined. A pickup truck with an overall width of 80 inches or more is not required to have a CHMSL, but it is required to be equipped with clearance and identification lamps. The descriptive literature that you enclosed on "hardside" and "folding" campers shows that each camper is equipped with clearance and identification lamps, so that the lighting equipment requirements for wide trucks will be met when the campers are installed. Therefore, if a camper whose overall width is 80 inches or more is equipped with clearance and identification lamps, it is not required to be equipped with a CHMSL, and its

installation by a person other than the vehicle owner will not be a violation of 15 U.S.C. 1397(a)(2)(A) even if the CHMSL on the pickup carrying the camper is obscured.

ID: nht93-4.35

Open

DATE: June 17, 1993

FROM: John Womack -- Acting Chief Counsel, U.S. Department of Transportation, NHTSA; Signature by Kenneth N. Weinstein

TO: Dennis Platt -- Sergeant, Program Supervisor, Vehicle Safety & Equipment Section, Utah Highway Patrol

TITLE: None

ATTACHMT: Attached to letter dated 4-20-93 from Dennis Platt to Marvin Shaw (OCC 8577)

TEXT: This responds to your letter requesting an interpretation of the labeling requirements of Standard No. 205, GLAZING MATERIALS (49 CFR S571.205) for glazing used in school buses and heavy trucks. You explained that along with the information required by Standard No. 205, the windshields in your jurisdiction are being replaced with glass that is marked with "16 CFR 1201 CAT II." You asked whether it is permissible to mark replacement windshields with both the AS1 marking required by Standard No. 205 and "16 CFR 1201 CAT II." As explained below, it would be permissible for glazing to be marked with this additional information.

Under the authority of the National Traffic and Motor Vehicle Safety Act, NHTSA has issued Standard No. 205, GLAZING MATERIALS, which establishes marking and certification requirements for manufacturers and distributors of glazing materials. A replacement windshield would be required to be marked with the following information in accordance with section 6 of the American National Standard (ANS) Z26: (1) the words "American National Standard" or the characters "AS," (2) a number identifying the item of glazing, (3) a model number assigned by the manufacturer that identifies the type of construction of the glazing material, and (4) the manufacturer's distinctive designation or trademark. In addition, the replacement windshield would be required to be marked with the symbol "DOT" and a manufacturer's code mark assigned by this agency.

With respect to additional information not required by the Standard, the agency's longstanding policy is that an item of glazing is permitted to be marked with additional information provided that the additional marking does not obscure or confuse the meaning of the required information.

The purpose of the marking -- 16 CFR 1201 CAT II -- is to inform a glazing purchaser that the glazing may be used for architectural applications. Thus, such information would serve a different purpose than our marking requirements.

It is our opinion that marking glazing with the information about its use for architectural applications would not cause confusion with respect to the markings required by Standard No. 205, nor raise other concerns with respect to our marking requirements. We believe that the additional marking would not interfere with an individual's understanding that the glazing is certified for motor vehicle applications.

You express concern that glass designed for architectural purposes (e.g., for shower stall doors) might not be appropriate for motor vehicles. Glazing cannot be certified to Standard No. 205 unless it meets all requirements of that standard. Glazing certified to Standard No. 205 has the appropriate

performance characteristics to be installed in motor vehicles, even if the glazing was also designed for architectural purposes.

I hope you find this information helpful. If you have any other questions, please contact Mr. Marvin Shaw of my staff at (202) 366-2992.

ID: nht93-4.36

Open

DATE: June 17, 1993

FROM: Han Dinh -- Project Manager, Delivery & Customer Services Equipment Engineering, Research and Development, United States Postal Service

TO: Steven P. Wood -- Office of Chief Counsil (Counsel), Rule Making Division

TITLE: ANSI/AGA NGV2 Standard

ATTACHMT: Attached to letter dated 8/16/93 from John Womack to Han Dinh (A41; Part 303)

TEXT:

The U.S. Postal Service is in the process of converting our postal fleet to operate on alternative fuel; mainly compressed natural gas, as it is required by the Clean Air Act and Energy Policy Act.

As a background, The U.S. Department of Transportation (DOT) has a standard for the fuel tanks that are all-steel and all-aluminum pressure vessels, as well as vessels which are reinforced with composite. Since the standard was not intended for vehicular fuel tank usage, the cylinder makers have to obtain approval of exemption from Title 49 of the Code of Federal Regulation.

In the past, we required the manufacturers of the cylinders to obtain DOT exemption (i.e., Press Steel Tank Company has DOT-E-8965 or SCI Company has DOT-E-8725) so they can be considered as a supplier.

The American Gas Association, with help from industry, has generated a standard called NGV2, which is referenced by the National Fire Protection Agency Standard NFPA-52 as an acceptable standard and has also been adopted by the American National Standards Institute (ANSI). The National Highway Traffic Safety Administration (NHTSA), a branch of DOT, is in the process of NGV2 review.

This brings us to the point of our concern. The Brunswick Composite Tank Company has informed us that they have just passed the NGV2 standard; and we believe they are the only company with this claim. In the near future, we are planning to release an RFP for converting 1400 vehicles to compressed natural gas. We would like to ask your office for a recommendation as to which standard we should require (DOT exemption cylinder or NGV2 cylinder). Your guidance in this matter would help us a great deal. If you have any questions, please contact me at (703) 641-7138 or Chris Nikpora at (703) 641-7416. We would appreciate it very much if you could respond to us before July 1, 1993.

ID: nht93-4.37

Open

DATE: June 17, 1993

FROM: James N. Doan -- Counsel-Operations, Eaton Corporation

TO: John Womack -- Acting Chief Counsel, NHTSA

COPYEE: P. M. Menig

TITLE: INTERPRETATION OF FMVSS 101

ATTACHMT: Attached to letter dated 9/21/93 from John Womack to James N. Doan (A41; Std. 101)

TEXT:

Eaton Corporation manufactures and sells transmissions for heavy duty (MVMA Class 6-8) trucks. This is to request an interpretation of Federal Motor Vehicle Safety Standard Number 101, Controls and Displays (49 CFR 571.101) regarding an enhancement being considered to the mechanical controls situated at the top of the transmission shift lever for such vehicles. Specifically the issue is the necessity of illuminating a control for automated vehicle speed (cruise control) mounted on the transmission shift lever.

Presently we offer up to two pneumatic control switches for controlling an auxiliary transmission mounted integrally with the main transmission. Examples of the controls mounted on the lever in the cab of the truck are shown in Figure 1. We are considering augmenting this control with three electrical switches mounted in a housing integral with what we call the "skirt." The skirt is the plastic extending downward from the knob that covers the metal parts of the valve and creates a more aesthetically pleasing appearance. Figure 2 shows the proposed skirt with the addition of two rocker switches. One controls cruise on/off (mounted on the side face) and the other controls cruise set/resume and accelerate/coast (mounted on the slanted top face). Figure 3 shows the proposed skirt with the addition of a rotary electrical switch for controlling an engine retarder or brake. This switch has an off position and up to three levels of retardation. Extreme care has been taken to make these controls readily accessible to the driver such that they can be operated without the driver having to remove his eyes from the road. We expect the cruise switches to be used during certain shifting maneuvers, especially on long upgrades where the driver will manipulate the switches to achieve cruise control in the next lower numerical gear ratio. This is consistent with how the driver presently operates the two pneumatic switches, completely by feel. We have chosen two separate planes for the switches (side face and slanted top face) to aid the driver in differentiating the switches. Furthermore, we have put the engine brake switch on yet another face to further aid operation by feel/position. With electronically controlled engines in trucks, we expect the engine brake switch will be put in one position and left there. On/off operation will then be handled by interrupts from other switches in the cab, especially the service brake switch.

"Cut out" of the cruise control and engine brake by other cab mounted switches is an important consideration. Figure 4 is a spreadsheet of intended operation of electronic engine controls for trucks for 1994 and beyond. Note that the service brake and the clutch pedal switches can cause the engine control to cease regulating engine and vehicle speed. In any emergency situation, one of these switches is likely to be activated, stopping the cruise control mode of operation.

It would be difficult and costly to illuminate the automated vehicle speed switches. We believe that these controls are "hand operated controls mounted upon the floor ... (or) floor console" and do not require illumination as specified in S 5.3.1 of FMVSS 101. They are mounted on a shift lever, mounted on the floor next to the operator and within easy reach. We would appreciate confirmation of this interpretation.

Please let me know if you have any questions or require any further information.

(Graphics omitted.)

ID: nht93-4.38

Open

DATE: June 18, 1993

FROM: John Womack -- Acting Chief Counsel, U.S. Department of Transportation, NHTSA; Signature by Ken Weinstein

TO: Bob Jones -- Director of Engineering, Independent Mobility Systems, Inc.

TITLE: None

ATTACHMT: Attached to letter dated 4-29-93 from Bob Jones to Mary Versailles.

TEXT: This responds to your letter of April 29 1993, addressed to Mary Versailles of this office, requesting information on the proper testing of your raised-roof minivan for compliance with Federal Motor Vehicle Safety Standard (FMVSS) 220, SCHOOL BUS ROLLOVER PROTECTION.

You correctly stated in your letter that the school bus rollover protection requirements of FMVSS 220 do not apply to minivans. You explained, however, that many states and/or localities require compliance with FMVSS 220 for vehicles equipped to transport the handicapped, and you asked how properly to test your raised-roof minivan for compliance with FMVSS 220.

Since the requirements you referred to are state or local requirements, this agency cannot comment on them. You should contact the states or localities concerned to find out what their expectations are in that regard.

I hope this information will be of assistance to you.

ID: nht93-4.39

Open

DATE: June 19, 1993

FROM: Ray M. Miyamoto

TO: Public Community Strategy, NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 7/29/93 from John Womack to Ray M. Miyamoto (A41; Std. 208)

TEXT:

I would like to know if I can have my own business retrofitting older cars with air bags. I would like to be subject to the same rules and regulations as men who service brakes. I would emphasize in my advertising and all literature that seat belts should also be worn (just as the NHTSA emphasizes).

I would optionally retrofit cars of the same make and model, but would consider others if the retrofitting was not to complex or costly. There should be a way (and I'm sure there is) to pre-test each retrofit by deploying and (restuffing) or refitting the air bag and retrofitted equipment for about 20 to 50 deployments. That is, to trigger the sensors without any damage to the vehicle. Possibly I could test each retrofit by applying the same PSI that it would take to deploy it. (There is body and fender and/or construction equipment that can apply the same PSI as in a crash to test air bags.) Liability should be limited to replacement. Only in cases of poor workmanship, and/or gross incompatibility between the retrofit and the car, and/or negligence should I or any other retrofit serviceman be subject to liability.

Such retrofits would be a boon to the drivers of many older vehicles who don't have the funds or means to afford newer air bag equipped cars.

Also, in regard to testing, the bumper of the newer air bag equipped car could be retrofitted to the older vehicle if this would ease the deployment of the air bag in a normal manner (through the sensors) if the older car's bumper was found to block the sensors in any way or make it more difficult for air bag deployment.

There should be room for some compromise here. I don't think it is technically impossible to retrofit older cars with air bags. (And it is technically feasible.) Moreover, to deny people with older cars the right to have air bags, would mean injury and more needless deaths on our highways.

There should be a way for retrofit business (once government approval is given) to be tested by state or local auto safety inspection stations. It is not technically impossible to refit an air bag after a crash by replacing any or all of the following:

1) the air bag 2) sensors 3) wires and terminals 4) deployment canisters or cylinders 4) steering column 5) bumper 6) any other parts, such as a computer, and/or a motor(s).

If brakes can be tested, why not air bags? If an ABS can be tested, why not air bags? To give approval to retrofit businesses would break the monopoly new car manufacturers have on air bags and would lower prices on air bags, not to mention the thousands of lives saved as a result of the greater availability of air bags.

The opposition I have encountered regarding retrofitting of air bags has been without any logical basis. But I am open to any factual, logical and safe argument.

PS J.C. Whitney has a retrofit kit for anti-lock braking systems. So why not a kit for air bags? (as long as they're tested and inspected the ways I mentioned earlier). Moreover, how do you, the NHTSA and the new car manufacturers know that every air bag installed in a new car is safe? By pre-testing and/or inspecting, right? Retrofitting could be done in the SAME way.

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.