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
| Interpretations | Date |
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ID: nht88-1.96OpenTYPE: INTERPRETATION-NHTSA DATE: APRIL 14, 1988 FROM: C. DIANNE BLACK -- ENGINEERING MANAGER, JAGUAR TO: ERIKA Z. JONES -- CHIEF COUNSEL, NHTSA TITLE: FMVSS 108, HEADLAMP LEVELLING SYSTEMS ATTACHMT: MEMO DATED 8-1-88, TO C. DIANNE BLACK, FROM ERIKA Z. JONES, STD 108 TEXT: Thank you for your letter of February 1, 1988 which discussed our June and October 1987 letters regarding a headlamp levelling system for our US models. We have reviewed your letter, and we have decided that we should go one step further and provide a drawing of the switch, showing its location on the steering column shroud and to perhaps better describe its operation. To reiterate from our October 17, 1987 letter, the switch has three positions - zero = driver only or driver plus front passenger or driver plus front and rear passengers one = driver plus passengers plus maximum trunk load two = driver plus maximum load in trunk The switch/lamp motor system is limited to the above three positions and intermediate settings are not possible. The switch is not a rheostat but rather a 'master/slave' unit. The switch is illuminated by turning on the headlamps and it cannot be turne d off. Headlamp alignment is adjustable only in the zero position. We believe that full description in the owner handbook, and the fully visible illuminated switch will enhance owner familiarity with the system and the system can be used to enhance headlighting performance. We hope this will further clarify the system and allay your concerns over our headlamp levelling system and its operation. Feel free to contact me should you have further questions. Headlamp Dipped-Beam Levelling Control Driver's-Eye View (On Left Steering Column Shroud) |
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ID: 1982-2.2OpenDATE: 04/07/82 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: D. L. Robertson TITLE: FMVSS INTERPRETATION TEXT: This is in reply to your letter of September 9, 1977, regarding a letter from your constituent, Mr. Larry Gabor, Chairman of the Huntington Consumer Protection Board, concerning the safety of vehicle seats which do not lock in fore-and-aft adjustment position. As we explained to Mr. Gabor in our letter of August 18, 1977 (copy enclosed), we have a Federal motor vehicle safety standard which is designed to prevent this situation. The standard regulates vehicles at initial sale, but does not cover inadvertent failure or premature wear-out situations. We do have authority to investigate such situations, however, to determine if grounds exist for conduct of a safety related defect "recall campaign." We are forwarding a copy of Mr. Gabor's letter to our Office of Defects Investigation to alert them of this situation. Our previous letter urged Mr. Gabor to furnish them the pertinent details on this matter. Only then can they investigate properly. SINCERELY, TOWN OF HUNTINGTON LONG ISLAND, NEW YORK (Illegible Word) PROTECTION BOARD July 25, 1977 Congressman Jerome Ambro This Office is concerned about a particular aspect of automobile safety; the construction of the adjustable driver seat is what concerns us. Based on an incident that occurred in our Town recently, it would appear that it is possible for a driver seat not to look into position but to actually slide back and forth depending on the motion of the driver, or the car, or both. The incident that brought this to our attention was a driver, short in stature, actually unable to reach the brakes or the steering wheel of her car because the seat slid backward during acceleration. The driver of the car in this case was seriously injured. We feel that this may be a significant hazzard and that some fail-safe system ought to be developed. Please advise us of your thinking and experience on this subject. Larry Gabor Chairman |
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ID: 1982-2.28OpenDATE: 08/01/82 FROM: AUTHOR UNAVAILABLE; Diane K. Steed; NHTSA TO: Larry Pressler; U.S. Senate TITLE: FMVSS INTERPRETATION TEXT: Dear Senator Pressler: This responds to your July 23, 1982, letter enclosing correspondence from your constituent, Mr. Clyde Pritchard. Mr. Pritchard questioned the applicability of the National Highway Traffic Safety Administration's Standard No. 121, AirBrakes, to certain "heavy hauler trailers." He also questioned a portion of that standard that indicated that manufacturers of some vehicles may comply with the standard or, alternatively, with Part 393.43 of the regulations of the Bureau of Motor Carrier Safety (BMCS). Only some types of heavy hauler trailers must comply with Standard No. 121. The applicability section of the standard states that a vehicle with a width in excess of 102 inches or a heavy hauler trailer with a gross vehicle weight rating (GVWR) in excess of 120,000 pounds need not comply with any of the requirements. Therefore, any vehicle designed by Mr. Pritchard falling within these categories would be excepted from the standard. A heavy hauler trailer with a width less than 102 inches and a GVWR less than 120,000 must comply with the standard. Mr. Pritchard appears most interested in the specific requirements for parking brakes on heavy hauler trailers. Paragraph S5.6 of Standard No. 121 states that heavy hauler trailers shall comply with the requirements of Standard No. 121 for parking brakes or, alternatively, with BMCS regulation 393.43 for breakaway. Accordingly, the manufacturer of such a vehicle has the option of complying with either provision; parking brakes under Standard No. 121 or the breakaway and emergency braking section of the BMCS regulation. The citation in Standard No. 121 to BMCS regulation 393.43 is correct. The agency did not intend to permit optional compliance with BMCS regulation 393.41 as suggested by Mr. Pritchard. That regulation does not require separate brakes on trailers which the agency has always deemed necessary. I hope this clarifies the air brake issue for your constituent. Please contact me if you need additional information. Diane K. Steed Administrator |
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ID: 1982-2.36OpenDATE: 08/10/82 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Nissan Motor Co. Ltd. TITLE: FMVSS INTERPRETATION TEXT:
Mr. Shizuo Suzuki Nissan Motor Co., Ltd. Suite 707 1919 Pennsylvania Avenue, N.W. Washington, D.C. 20037
Dear Mr. Suzuki:
This is to follow-up on your conversation with Stephen Oesch of my staff concerning the armrest requirement of Standard No. 201, Occupant Protection in Interior Impact. Your specific question concerned the application of section 5.3.1(c) of the standard to an armrest attached to a door. The inboard side of the armrest consists of two vertical surfaces, an upper one and a lower one. The upper surface extends 3 mm closer to the center of the vehicle than does the lower surface. You stated that the two surfaces when viewed in side elevation, i.e., from the vantage point of the door latch or door hinges, together provide more than 2 inches of vertical height within the pelvic impact area. You also asked if section 5.3.1(c) set any limits on the material used for armrests. Section 5.3.1(c) of the standard provides that:
Along not less than 2 continuous inches of its length, the armrest shall, when measured vertically in side elevation, provide at least 2 inches of coverage within the pelvic impact area.
Section 5.3.1(c) does not set any radius of curvature or height limitation on armrest surfaces. The only requirement is that the armrest provides at least 2 inches of coverage within the pelvic impact area. Section 5.3.1(c) also does no specify any limits on the materials that may be used in an armrest. Obviously, such surfaces must be designed carefully to ensure that the armrest does no concentrate potentially harmful forces on an occupant striking the armrest.
If you have any further questions please let me know. Sincerely,
Original Signed By Frank Berndt Chief Counsel |
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ID: 1983-2.2OpenTYPE: INTERPRETATION-NHTSA DATE: 05/06/83 EST FROM: FRANK BERNDT -- CHIEF COUNSEL, NHTSA TO: F. MICHAEL PETLER -- HEAD, ADMINISTRATION, GOVERNMENT RELATIONS DEPARTMENT, SUZUKI MOTOR TITLE: NOA-30 ATTACHMT: MEMO DATED 4-20-83, REQUEST FOR INTERPRETATION FMVSS NO. 210; SEAT BELT ASSEMBLY ANCHORAGES TEXT: This responds to your recent letter requesting information concerning the requirements for seat belt anchorages in passenger cars under Safety Standard No. 210. Specifically, you ask whether only Type 1 seat belt anchorages are required in rear seating positions in passenger cars. The answer to your question is no. Under paragraph S4.1.1 of standard 210, Type 2 seat belt anchorages (for combination lap and shoulder belts) are required as follows: at each front and rear forward-facing outboard designated seating position in passenger cars other than convertibles; and at each front forward-facing outboard designated seating position in vehicles other than passenger cars where Type 2 belts are required by Safety Standard No. 208. All other seating positions in both passenger cars and other vehicles may be equipped with anchorages for either Type 2 belts or Type 1 belts (lap belts). Safety Standard No. 208, Occupant Crash Protection, requires Type 2 belts only in front outboard designated seating positions in passenger cars, but passenger cars still must be equipped with anchorages for Type 2 belts in rear outboard designated seating positions. As to your reference to discussion of anchorages in the agency's November 2, 1981 denial notice to Toyo Kogyo (46 FR 54391), that discussion was misleading because it did not provide complete information or distinguish adequately between passenger cars and other types of vehicles. The agency intended to refer to the type of belts required by Safety Standard No. 208, i.e., Type 2 belts in front outboard designated seating positions and Type 1 belts in front center and all rear seating positions. I hope this has clarified any misunderstanding you may have had concerning the anchorage requirements. Please contact Hugh Oates of my staff if you have any further questions (202-426-2992). Sincerely, |
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ID: 1983-1.3OpenTYPE: INTERPRETATION-NHTSA DATE: 01/07/83 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Oshkosh Trucks -- Tom Dobbs TITLE: FMVSS INTERPRETATION TEXT: Mr. Tom Dobbs Oshkosh Trucks 2307 Oregon Street Oshkosh, Wisconsin 54901 Dear Mr. Dobbs: This responds to your recent telephone request asking whether Standard No. 121, Air Brake Systems, would prohibit the use of a hand control that would allow the vehicle operator to apply only the rear brakes if the driver so chooses. You question whether this can be proper in light of the requirement that vehicles be equipped with brakes that act on all wheels. Although the standard requires brakes acting on all wheels, nothing in the standard prohibits the type of hand control that you mention. For years, tractor-trailer combinations have been equipped with brakes acting on all wheels. Some of these combinations also have been equipped with hand controls that allow the operator to activate only the trailer brakes. It has been argued that in some instances this control can be used to reproduce beneficial results in combination vehicles. While we can see no beneficial results that could possibly be gained by the use of hand controls in trucks, such a control would not be prohibited by the standard. The standard simply requires a service brake system acting on all wheels. The trucks that you mentioned would still have this system, and therefore, would continue to comply with the standard. You should note that the agency does not encourage the use of such hand controls, particularly on trucks. This type of control provides a opportunity for vehicle operators to lessen the effectiveness of their braking systems. Should an operator use the hand control instead of the full service brakes in a stop and create an accident, there could be the potential for tort liability for both the operator that purchased vehicles with such systems and for the manufacturer who installed them knowing that they could lead to the easy missue of the braking system. We suggest that you contact your attorneys for further guidance in this area. Sincerely, Frank Berndt, Chief Counsel |
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ID: 1983-1.4OpenTYPE: INTERPRETATION-NHTSA DATE: 01/13/83 FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA TO: CONSUS INTERNATIONAL, INC TITLE: FMVSS INTERPRETATION TEXT:
NOA-30
Mr. Robert B. Wessel Consus International, Inc. P.O. Box 594 Port Jefferson Station, NY 11776
Dear Mr. Wessel:
This is in response to your December 1, 1982, letter regarding a warning device you plan to manufacture. The device is powered by 4 AA batteries, and has a light which can stay on continuously or can flash. You have asked whether the device complies with Federal Motor Vehicle Safety Standard 125.
Standard 125 applies to warning devices "without self-contained energy sources." The four batteries in your device which power the light would constitute such a source. Therefore, Standard 125 is inapplicable to your device.
If you have further questions on this matter, feel free to contact us.
Sincerely,
Frank Berndt Chief Counsel
December 1, 1982
National Highway Traffic Safety Administration Rm 5219 U.S. Dept. Of Transportation 400 7th Street S.W. Washington D.C. 20590 To Whom It May Concern;
Please review the enclosed sample and advise complience with your standard 125. The unit is made to work with four "AA" Batteries and has reflective as well as lighted capabilities.
The light can stay on, or in the flasher mode will blink, and is visible at great distances.
Thank you in advance for your early response as we are waiting your acknowledgement before our marketing push.
I remain Very truly yours;
Robert B. Wessel |
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ID: 1984-2.6OpenTYPE: INTERPRETATION-NHTSA DATE: 06/06/84 FROM: AUTHOR UNAVAILABLE; Z. Taylor Vinson; NHTSA TO: Memorandum - Interpretations file TITLE: FMVSS INTERPRETATION TEXT:
Subject: Standard No. 218 - "Rigid Projection"
From: Z. Taylor Vinson Senior Staff Attorney
To: Interpretations File
Paragraph S5.5 Projections of Motor Vehicle Safety Standard No. 218 states in pertinent part: "A helmet shall not have any rigid projections inside its shell." The term "rigid projections" does not appear to have been interpreted up to now.
The Office of Vehicle Safety Compliance has brought to our attention a type of helmet which has a lever inside the helmet, below the shield, by which the visor shield is released to open. It has also procured another type of helmet which comes equipped with a headset. Inside the helmet are two speakers, made of hard rubber, which fasten into the shell. Each speaker is roughly an inch in height. Its shape is odd, basically eliptical, and about 1 1/2 inches at its longest point. OVSC has asked whether the lever and the speakers are "rigid projections" prohibited by the standard. Assuming that the lever is made of either plastic or hard rubber, it would appear to be "rigid" in the sense of "unyielding," as are the speakers. The speakers do not lie flush with the shell or liner but just out an inch from their mounting points, and would appear to "project" in the normally understood sense of the word. The lever presumably also does not lie flush in the inner chin area of the helmet. Rigid projections are allowed on the exterior of a helmet provided that "they shall not protrude more than .19 inch" and "are limited to those required for operation of essential accessories." But neither the lever nor speakers could meet both criteria were they externally mounted, leading a fortiori to the conclusion that, internally mounted, they are prohibited.
OVSC says that motorcycle helmet headsets are illegal in at least 5 states. |
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ID: 1985-01.38OpenTYPE: INTERPRETATION-NHTSA DATE: 02/27/85 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Mr. H. Horiyoshi Mazda (North America), Inc. TITLE: FMVSS INTERPRETATION TEXT:
Mr. H. Horiyoshi Executive Vice President and General Manager Mazda (North America), Inc. 24402 Sinacola Court Farmington Hills, MI 48018
Dear Mr. Horiyoshi:
This is in reply to your letter of November 21, 1984, asking for an interpretation of Motor Vehicle Safety Standard No. 108 as it would apply to a contemplated parking lamp system.
Usually passenger cars are designed with two parking lamps, one on each side of the vehicle front. Mazda would have two such lamps on each vehicle side, each of the two lamps flanking the headlamp. You have asked whether, in determining the H-V axis, one takes the axis as the center of each lamp, or should one consider the pair a single device and place the H-V axis at the midpoint between them. Standard No. 108 requires passenger cars to be equipped with a minimum of two parking lamps, located "as far apart as practicable." Therefore, the outermost parking lamp, (the one located between the turn signal lamp and the headlamp) is the lamp that must meet the parking lamp requirements of Standard No. 108, and the H-V axis for purposes of compliance would be determined at the center of the lens of that lamp. Supplementary lighting equipment is permissible under Standard No. 108 and does not have to meet the standard's requirements, but it must not impair the effectiveness of the lighting equipment required by the standard (paragraph S4.1.3). Because of the difference in candela between parking lamps and headlamps, information available to us does not indicate that your supplementary parking lamp would have this effect, and consequently, the design would be permitted.
I hope that this answers your questions.
Sincerely,
Original Signed By Frank Berndt Chief Counsel |
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ID: 1985-01.8OpenTYPE: INTERPRETATION-NHTSA DATE: 01/08/85 FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA TO: Peter Kopanon, Director, Registry of Motor Vehicles, Boston, MA TITLE: FMVSS INTERPRETATION TEXT: Mr. Peter Kopanon, Director Registry of Motor Vehicles 100 Nashus Street Boston, Massachusetts 02114
This is in reply to your telephone call of August 1, 1984, requesting our opinion as to the applicability of Highway Safety Program Standard No. 17, Pupil Transportation Safety, 23 CFR 1204.4, to Massachusetts.
As I understand it, your call was prompted by our letter of May 14, 1984, to Mr. Paul Pakos, in which we ruled that a vehicle with a capacity of 8 or fewer persons would be a "Type II School Vehicle" under the standard if it were used to transport students to and from school. Your question is whether Massachusetts is required by law to adhere to this aspect of the standard.
Standard 17 is among the standards issued by this agency under authority of the Highway Safety Act of 1966, as amended, 23 U.S.C. 401-408. The Act provides that the States are to administer their highway safety programs in accordance with the standards. However, it also gives us the discretion not to insist that a State comply with every standard. We have employed this discretion to administer the highway safety program on the basis of mutual cooperation rather than by rigid enforcement of the standards.
In the case of Standard 17, we have worked with Massachusetts and all other States to improve the overall quality of pupil transportation, in keeping with the intent of the Standard. The results of our mutual efforts can be seen in the marked decline in serious school bus accidents during the last ten years. We intend to continue to follow this cooperative policy.
Let me know if you have further questions.
Sincerely, Frank Berndt Chief Counsel |
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.