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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 1341 - 1350 of 6047
Interpretations Date

ID: nht76-1.35

Open

DATE: 04/14/76

FROM: AUTHOR UNAVAILABLE; Francis Armstrong; NHTSA

TO: Bemperit of America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This confirms a telephone conversation between yourself and Mr. George Chifflett, a member of my staff, on March 12, 1976. In that conversation a telex from Semperit, Austria, was discussed and the following points were made:

1. Motor-driven cycles (mopeds) need not be equipped with tires conforming to Federal Motor Vehicle Safety Standard (FMVSS) No. 119, until September 1, 1976. Of course, if the tires were manufactured after March 1, 1975, they would have to conform (see paragraph S5.1.1 of FMVSS No. 120 and paragraph S3 of FMVSS No. 119, highlighted copies enclosed).

2. All tires manufactured after May 22, 1971, must be marked in accordance with Title 49, Code of Federal Regulations, Part 574 (49 CFR 574), Figure I (copy enclosed). Tires on mopeds being offered for sale must be marked accordingly. If branding would weaken the tire sidewall, replacement might be the only solution to the problem.

3. FMVSS No. 119, applies to all covered tires manufactured on or after March 1, 1975. It does not apply to tires in aftermarket inventory that were manufactured before that date.

4. "Federal Register Car [CFR] 393 Docket Number MC-56 Notice Number 75-19," pertains to a Bureau of Motor Carrier Safety regulation that applies to vehicles being used as interstate carriers. It does not apply to vehicles being manufactured or offered for sale. As stated before, vehicles manufactured on or after September 1, 1976, must be fitted with tires that meet FMVSS No. 109 or 119.

5. The post March 1975 labeling described in your telex does not meet the requirements of FMVSS No. 119.

(a) The symbol "DOT" must appear before the manufacturer's identification code number, as a certification that the tire complies with the standard. "TIRE" may appear elsewhere on the tire, but it is not required.

(b) The composition of the ply cord material must also appear.

(c) While the labeling "Maximum Speed 30 MPH" is not prohibited, the standard does not presently recognize a category of speed-restricted motorcycle tires. Moped tires are subject to the same performance requirements as other motorcycle tires, most notably, the high speed and endurance test requirements. An amendment on the subject is being considered, but no firm decision has been made.

ID: nht76-4.31

Open

DATE: 10/29/76

FROM: AUTHOR UNAVAILABLE; F. Berndt; NHTSA

TO: Truck Body and Equipment Association, Inc.

TITLE: FMVSS INTERPRETATION

TEXT: This responds to the Truck Body and Equipment Association's letter of September 14, 1976, inquiring as to the effect of Standard No. 121, Air Brake Systems, on State laws relating to air brake performance. You ask whether the Commonwealth of Massachusetts can impose requirements pertaining to parking brake release on trucks and buses which differ from provisions contained in the Federal standard.

I believe that the question you raised is identical to a question raised by the State of California, International Harvester Company, and White Motor Corporation in October 1974, prior to the effective dates of Standard No. 121. It was our opinion at that time that promulgation by a State of a more restrictive parking brake requirement providing for the installation of a release not specified in Standard No. 121 was prohibited by @ 103(d) of the National Traffic and Motor Vehicle Safety Act. A copy of that letter is enclosed for your information.

SINCERELY,

TRUCK BODY AND EQUIPMENT ASSOCIATION, INC.

September 14, 1976

Frank A. Berndt Office of Chief Counsel National Highway Traffic Safety Administration

The state of Massachusetts has established a law requiring an air brake equipped truck sold in that state, to have a system that differs from those presently designed and developed for FMVSS 121 compliance. The difference lies in the Massachusetts requirement that the air brake system be equipped with an additional air reservoir or "third tank" capable of supplying air to the spring set parking brakes in case of an air brake failure. (See Attachment # I).

At the present time, all new trucks equipped with air brakes are required by Department of Transportation through National Highway Traffic Safety Administration to be completed in accordance with the performance levels found in FMVSS 121. As a result, all new trucks have air systems that are capable of meeting the application and release times, system build up times and the spring brake modulation requirements found in FMVSS 121.

The Massachusetts law was instituted to provide an additional means by which the spring brakes may be released during emergency situations. This release requirement is already supplied on all new chassis produced today in compliance with FMVSS 121 by a mechanical means.

The Massachusetts law requires that the existing 121 system be repiped to accommodate the new third tank and emergency release circuit. Any modification to the complex 121 system increases the likelihood of system damage or the modification may cross connect the split air system thus defeating the intent of two separate brake systems.

The chances of a modified system failure seems more likely than a FMVSS 121 brake lock up on a railroad grade crossing.

In previous correspondence the National Highway Traffic Safety Administration Office of Chief Counsel, has indicated that a state can not set any motor vehicle safety standard that is in variance with an existing Federal Motor Vehicle Safety Standard. (See Attachment # II).

We at the Truck Body and Equipment Association feel that the Massachusetts requirement for a modified brake system is inconsistent with the requirements outlined in FMVSS 121 and would appreciate the National Highway Traffic Safety Administration's opinion of the legality of this state regulation.

Byron A. Crampton Manager of Engineering Services

ATTACHMENTS

The Commonwealth of Massachusetts Registry of Motor Vehicles

August 13, 1976

Dear Sir:

In reply to your inquiry as to brake requirements on commercial vehicle chassis, I am enclosing a copy of that portion of Massachusetts law in regards to brakes.

If a vehicle is equipped with air brakes and the parking or emergency brake portion of the brake system is a spring loaded brake, Massachusetts requires a third air tank and there must be a check valve between your main source (wet/dry tank or tanks) of supply and the third tank.

Under emergency conditions when there is a loss of the service brake, the spring loaded brake is automatically applied. To move the vehicle would require the winding down to release the spring loaded brake. Our requirement of a third tank allows 4 to 6 quick release operations so that the vehicle can be safely moved out of traffic, a roadway, a railroad crossing or an intersection.

Any vehicle equipped with air brakes and a spring loaded parking/emergency brake must be equipped with the third tank for registration and operation in Massachusetts. If we find a vehicle is not so equipped (third tank) we will not permit it to be registered. If it has been registered, statutory law allows the Registrar of Motor Vehicles to suspend the registration. No consideration is given relative to the reinstatement of the suspended registration until the brake system is in compliance and examined by an inspector from this department.

I hope this information will be of some help to you.

Charles V. Mulhern Supervisor Vehicle Inspection Branch

provisions of this section shall be punished by a fine of not less than ten nor more than one hundred dollars.

@ 7. Brakes, Lights and Other Equipment

[MASSACHUSETTS REGULATION OMITTED]

March 21, 1975

Chief Counsel NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION

Recently several members of the Truck Body and Equipment Association have raised questions concerning state versus federal motor vehicle lighting requirements.

The vehicle in question is a multipurpose passenger vehicle less than eighty (80) inches wide, equipped with a raised roof.

Our question is as follow: Can a state require a motor vehicle to be equipped with lights not required under FMVSS #1007

Thanking you in advance for your help, I am,

Byron Crampton Manager of Engineering Services

ID: 04-008470drn

Open

    N. Martin Stringer, Esq.
    McKinney & Stringer
    Corporate Tower
    101 North Robinson, Suite 1300
    Oklahoma City, OK 73102-5510

    Dear Mr. Stringer:

    This responds to the two letters you sent us dated November 2, 2004, concerning the Federal motor vehicle safety standards (FMVSSs) applicable to school buses that have been promulgated by the National Highway Traffic Safety Administration (NHTSA). One of your letters relates to how State definitions of school vehicles affect NHTSAs requirements to sell certified school buses. The other asks about the permissibility of reclining seat backs on school buses.

    You state that the Oklahoma Legislature has created a new category of buses, known as "auxiliary transportation equipment", to be used for transporting students "to and from extracurricular activities, but does not include transportation equipment used for transporting students from their homes to school and from school to their homes". You explain that the legislators and members of the school board believe that the legislation enables school districts to purchase and use "traditional charter-type buses, as well as 10+ passenger vans" for extracurricular activities. You explain that state officials believe that buses (new and used) for extracurricular activities are "exempt from the FMVSSs for school buses". You ask in the one letter: "Under FMVSS, can Oklahoma school districts purchase and use new traditional charter-type buses and/or [used] 10+ passenger vans for use in transporting school children to and from extracurricular activities?" You also ask the same question with regard to used buses.

    As you are aware, on July 31, 2003 (68 FEDREG 44892), NHTSA published its final rule creating the multifunction school activity bus (MFSAB) as a school bus category. The MFSAB was established for use in transporting children on trips other than those between home and school. The final rule took effect on September 2, 2003, but manufacturers have had the option of complying with the new rule as of July 31, 2003. As school buses, MFSABs must meet all FMVSSs applicable to school buses except for S5.1.4 of FMVSS No. 108, Lamps, reflective devices, and associated equipment, and FMVSS No. 131, School bus pedestrian safety devices.

    New Buses

    We do not regulate which vehicles school districts must purchase, nor do we mandate which must be used. However, we regulate the manufacture and sale of new vehicles. A person may not sell or lease a new "school bus" (as defined under NHTSAs regulations) unless it complies with, and is certified as complying with, all FMVSS applicable to school buses, regardless of how the vehicle would be characterized under State law.

    NHTSAs statute at 49 U.S.C. 30112(a) requires any person selling a new vehicle to sell a vehicle that meets all applicable standards. Accordingly, persons selling a new "school bus" must sell a vehicle that meets the FMVSSs applicable to school buses. 49 U.S.C. 30125 defines a "school bus" as any vehicle that is designed for carrying a driver and more than 10 passengers and which, NHTSA decides, is likely to be "used significantly" to transport "preprimary, primary, and secondary" students to or from school or related events. (NHTSA has consistently interpreted "related events" to include school-sponsored field trips and athletic events.)This definition was enacted as part of a comprehensive effort by Congress to increase school bus safety. By regulation, the capacity threshold for school buses corresponds to that of buses vehicles designed for carrying more than ten (10) persons.

    Our "school bus" definition determines which new vehicles sold or leased by dealers are required under Federal law to meet the Federal motor vehicle safety standards for school buses. If a State has a different school bus definition, that definition determines the applicability of State "use" requirements for school buses, but it has no effect on the Federal requirement on dealers to sell school buses that comply with the applicable FMVSS. Thus, Oklahomas defining a school bus as "auxiliary transportation equipment" does not affect the obligation of dealers selling the new vehicle for extracurricular transportation to sell a certified school bus. If a dealer sold new "auxiliary transportation equipment" to a school district that did not meet the FMVSSs for school buses when it should have under our requirements, the dealer would be subject to Federal penalties under the statute.

    Used Buses

    As explained below, we do not regulate the sale of used vehicles. Under Federal law, dealers or other persons may sell a used bus (e.g. , a charter bus or used 10+ passenger van) to a school district for the transportation of students even though the vehicle is not certified to Federal school bus safety standards.

    NHTSAs requirement to sell vehicles that meet applicable safety standards does not apply to the sale of a motor vehicle "after the first purchase of the vehicle in good faith other than for resale" (see 49 U.S.C. 30112(b)(1)). Nonetheless, because school buses are one of the safest forms of transportation in this country, we recommend that all buses that are used to transport school children be certified as meeting NHTSAs school bus safety standards.

    That view is shared by the National Transportation Safety Board (NTSB). At a June 8, 1999, public meeting, the NTSB issued the enclosed abstract of a special investigative report on nonconforming buses. The NTSB issued the report after investigating four crashes in 1998 and 1999 in which 9 people were killed and 36 injured when riding in "nonconforming buses". NTSB defines "nonconforming bus" as a "bus that does not meet the FMVSSs specific to school buses". Most of the victims, including eight of the fatalities, were children.

    Reclining Seat Backs

    You wish to know whether FMVSS No. 222 prohibits school bus seats from reclining. The answer is no. However, the school bus with such seats must meet all applicable FMVSS No. 222 requirements.

    I hope this information is helpful. If you have any further questions, please feel free to contact Dorothy Nakama at 202-366-2992.

    Sincerely,

    Jacqueline Glassman
    Chief Counsel

    Enclosures
    ref:VSA
    d.1/7/05

2005

ID: 17168.wkm

Open

Mr. Roy Hinz
Marketing Resources
Tire Pressure Control International, Ltd.
15803-121 A Avenue
Edmonton, Alberta, Canada T5V 1B1

Dear Mr. Hinz:

Please pardon the delay in responding to your letter addressed to Walter Myers of my staff in which you asked for "U.S. federal approval" of your REDLINE-ELTEK Tire Pressure Control (TPC) System. Please be advised that this agency cannot give Federal approval of motor vehicles and motor vehicle equipment, as explained below.

You stated that TPC International, a Canada-based company, manufactures and distributes the TPC system in Canada, New Zealand, and Australia. You now want to enter the U.S. market. You stated that your TPC system integrates with the vehicle's existing compressed air supply system. It has five component assemblies: a computer in the cab that lets the driver change pressures and warns of any problems; air priority valves that protect the air brake system; control air valves; air lines to and from the control valves; and axle-end rotary hardware that transmits air into and out of the tires even while the tires are rotating. If the driver wants to open the inflate control valve, air is provided from the wet tank into the TPC system. Air can be exhausted from the tires through the deflate valves. Priority switches ensure that air is available for tire inflation only when air brake pressure in the system is above a safe level, typically 90 psi. A computer continuously monitors tire pressure, thus inflating, deflating, or maintaining a pre-selected tire pressure. The system monitors vehicle speed and if the vehicle is going too fast and risking tire damage, the system warns the driver to slow down or choose another mode. If the driver ignores the warnings, the system is programmed to automatically select a mode more suitable for higher speeds. You indicated an intent to make your system available both as original equipment on new vehicles and as aftermarket add-ons, and asked how individual states within the U.S. would view our Federal recommendations.

By way of background information, Chapter 301 of Title 49, U.S. Code (hereinafter "Safety Act") authorizes this agency to issue Federal motor vehicle safety standards (FMVSS) applicable to new motor vehicles and new items of motor vehicle equipment. The Safety Act establishes a self-certification system in which vehicle and equipment manufacturers certify that their products comply with all applicable FMVSSs. This agency enforces the FMVSSs after the fact by purchasing vehicles and equipment at retail and testing them for compliance with the standards. If the vehicles or equipment pass, no further action is taken. If they do not pass, or if the manufacturer or the National Highway Traffic Safety Administration (NHTSA) determines that a noncompliance or defect exists, the manufacturer must notify purchasers of its product and remedy the problem at no expense to the customer. This responsibility would be borne by the vehicle manufacturer in cases in which your TPC system is installed as original equipment on a new vehicle. If the TPC system is marketed in the U.S. as an aftermarket item, the notification and remedy responsibilities would be borne by the TPC system manufacturer, which is defined to include the importer of equipment produced outside the United States. Any manufacturer that fails to provide notification of or remedy for a noncompliance or defect may be subject to substantial civil penalties.

Because of the self-certification system established by the Safety Act, this agency cannot approve, disapprove, endorse, or give assurances of compliance of your TPC system prior to its introduction into the U.S. retail market. If your TPC system is installed as original equipment on a new vehicle, the vehicle manufacturer is responsible for certifying that the vehicle complies with all applicable FMVSSs with the device installed. If the TPC system is installed on a used vehicle by a manufacturer, distributor, dealer, or motor vehicle repair business, that person or business is prohibited from making inoperative any device or element of design that was originally installed on or in the vehicle pursuant to any FMVSS.

We do not have an FMVSS applicable to a system such as the TPC system. However, FMVSS No. 121, Air brake systems (49 Code of Federal Regulations (CFR) 571.121) (copy enclosed) specifies performance and equipment requirements for braking systems on motor vehicles that are equipped with air brake systems. That standard does not prohibit the use of air pressure from the brake air supply to operate other items of equipment, but doing so could affect the vehicle's compliance with the brake standard.

The hoses connected to the TPC system could be subject to FMVSS No. 106, Brake hoses (49 CFR 571.106) (copy enclosed). Such hoses would be subject to the standard if they transmit or contain the air pressure used to apply force to a vehicle's brakes, or stated another way, if a failure of the hose would result in a loss of air pressure in the brake system. If this were the case, the hoses are "brake hoses" and must comply with FMVSS No. 106. If a check valve or other device is used so that the braking system is not affected by a leakage failure in your TPC system, then the hose would not be considered to contain or transmit brake air pressure and would not be required to comply with FMVSS No. 106.

With respect to your question about how the various states would view Federal recommendations, the Safety Act provides that states and political subdivisions thereof may specify a motor vehicle safety standard only if that standard is identical to the Federal standard. In other words, the FMVSSs preempt any state motor vehicle safety requirements that address the same aspects of motor vehicle performance, except that the U.S. and state governments may require a higher standard of performance on vehicles or equipment procured for their own use, such as school buses.

In addition to the requirements discussed above, should you market your TPC system in the U.S., you would be required by 49 CFR Part 566 (copy enclosed) to submit to NHTSA your name, address, and a brief description of the item or items of equipment that you manufacture. This requirement applies to the information from foreign manufacturers of covered equipment (any vehicle or item of equipment, except tires, to which an FMVSS applies) supplying its products to a domestic or foreign vehicle manufacturer selling its vehicles in the U.S. (See enclosed copy of NHTSA letter to Mr. Virve Airola, dated May 31, 1990).

Finally, if you market your TPC system in the U.S., you would be required by 49 CFR Part 551, Subpart D (copy enclosed) to designate a permanent resident of the U.S. as your resident agent for the service of legal process. Such agent can be a person, a firm, or a domestic corporation. Subsection 551.45(b) specifies the form and contents of the designation. However, you would not be required to designate a resident agent if you only supplied your TPC system to a foreign vehicle manufacturer, even if that foreign manufacturer installed your TPC system in vehicles manufactured for sale in the U.S.

Finally, for your additional information, I am enclosing two fact sheets entitled Information for New Manufacturers of Motor Vehicles and Motor Vehicle Equipment, and Where to Obtain NHTSA's Safety Standards and Regulations.

We are forwarding your letter with its enclosed product overview to the U. S. Federal Highway Administration for its review. That agency issues the Federal Motor Carrier Safety Regulations which establish safety standards applicable to vehicles-in-use in interstate commerce.

I hope this information is helpful to you. Should you have any further questions or need additional information, feel free to contact Mr. Myers at this address at (202) 366-2992, or by fax at (202) 366-3820.

Sincerely,
John Womack
Acting Chief Counsel
Enclosures
Ref:106#121
d.4/29/98

1998

ID: 008938drn

Open

    Randy Dukek, Coordinator of Transportation
    Department of Transportation
    Independent School District 196
    15180 Canada Avenue
    Rosemount, MN 55068-1758

    Dear Mr. Dukek:

    This responds to your November 20, 2003, letter and subsequent telephone conversation with Ms. Dorothy Nakama of my staff about Federal Motor Vehicle Safety Standard (FMVSS) No. 217, Bus emergency exits and window retention and release. You ask whether a school bus that provides more emergency exits than those required by FMVSS No. 217 can be modified to provide just the exits required by the Federal standard. Our answer is such modification is not prohibited by our requirements.

    You state a concern about buses that have removable seating to accommodate wheel chairs. When placed in certain positions, a wheelchair may block a window exit. To avoid blocking a window exit in school buses that have more window emergency exits than are required by FMVSS No. 217, you wish to know whether your school district can replace the optional extra emergency exit windows with non-emergency exit windows and remove all "exit" markings. [1]

    The relevant National Highway Traffic Safety Administration (NHTSA) statutory provision is 49 U.S.C. Section 30122, "Making safety devices and elements inoperative," which states in part:

    (b) Prohibition. A manufacturer, distributor, dealer, or motor vehicle repair business [2] may not knowingly make inoperative any part of a device or element of design installed on or in a motor vehicle or motor vehicle equipment in compliance with an applicable motor vehicle safety standard .

    Section 30122 prohibits a manufacturer, distributor, dealer, or motor vehicle repair business from removing or making inoperative a window emergency exit that was installed to assure compliance with FMVSS No. 217. Because the emergency exits you want to remove were not installed to enable the vehicles to meet FMVSS No. 217, an entity listed in Section 30122 is not prohibited from removing them, provided that the school buses continue to meet FMVSS No. 217 after the modification.

    You informed Ms. Nakama that the school district itself might be modifying its own vehicles. The make inoperative provision does not apply to vehicle owners modifying their own vehicles. However, we encourage your school district to ensure that after any changes, the school buses continue to meet all school bus FMVSSs.

    We recommend that you check with State officials as to whether there are any Minnesota state requirements applying to the modification of the school buses. For further information, we suggest you contact Minnesotas State Director of Pupil Transportation:

    Captain Ken Urquhart
    Minnesota State Director of Pupil Transportation
    Department of Public Safety
    1110 Centere Pointe Curve, Suite 410
    Mondota Heights, MN 55120
    Telephone: (651) 405-6180.

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

    Sincerely,

    Jacqueline Glassman
    Chief Counsel

    ref:217
    d.1/22/04




    [1] On April 19, 2002 (67 FR 19343, DOT Docket No. NHTSA-99-5157), NHTSA published a final rule amending FMVSS No. 217 that, among other matters, specifies a "DO NOT BLOCK" label to be placed directly above or beneath each emergency door or emergency exit (including windows). The final rule is slated to take effect on April 21, 2004. The agency is considering three petitions for reconsideration of this final rule.

    [2] Defined at 49 U.S.C. Section 30122(a) as "a person holding itself out to the public to repair for compensation a motor vehicle or motor vehicle equipment."

2004

ID: 07-005414--13 Feb 08--sa

Open

Mr. Kiminori Hyodo

Deputy General Manager, Regulation & Certification

Koito Manufacturing Co., Ltd.

4-8-3, Takanawa

Minato-Ku Tokyo

Japan

Dear Mr. Hyodo:

This is in response to your letter, in which you asked about the origin of the required visibility angle in Figure 20 of Federal motor vehicle safety standard (FMVSS) No. 108, Lamps, Reflective Devices, and Associated Equipment. Specifically, you ask whether the origin of the visibility angle for FMVSS No. 108, Figure 20 is identical to that described in Economic Commission for Europe (ECE) R.48, i.e., the intersection of the axis of reference with the exterior lens of the lighting device. As discussed below, our answer is no. It is our opinion that the referenced Society of Automotive Engineers (SAE) standard (SAE J575e) makes clear that the photometric measurement is made at a distance between the light source of the lighting device and the point of measurement specified for the lighting device, and in the case of the filament light sources you have provided as examples, the light source of the device is the filament itself. Thus, the measurement is made from the filament center, and not from the exterior lens.

By way of background, the National Highway Traffic Safety Administration (NHTSA) is authorized to issue FMVSSs that set performance requirements for new motor vehicles and items of motor vehicle equipment (see 49 U.S.C. Chapter 301). NHTSA does not provide approvals of motor vehicles or motor vehicle equipment.  Instead, manufacturers are required to self-certify that their products conform to all applicable safety standards that are in effect on the date of manufacture. NHTSA selects a sampling of new vehicles and equipment each year to determine their compliance with applicable FMVSSs.  If our testing or examination reveals an apparent noncompliance, we may require the manufacturer to remedy the noncompliance, and may initiate an enforcement proceeding if necessary to ensure that the manufacturer takes appropriate action.



Our August 11, 2004 Final Rule (2004 Final Rule) amended the visibility requirements of FMVSS No. 108 and consolidated all the visibility requirements in a new paragraph, S5.3.2. 69 Fed. Reg. 48805. As you pointed out in your letter, S5.3.2(b)(2) states that [w]hen a vehicle is equipped with any lamp listed in Figure 20 of this standard, each such lamp must provide a luminous intensity not less than specified in Figure 20 in any direction throughout the pattern defined by the corner points specified in Figure 20 for each such lamp. The luminous intensity must be measured in accordance with the photometry test requirements of the applicable SAE Standards and Recommended Practices incorporated by reference or sub-referenced in this standard. As you further pointed out in your letter, SAE J575e (Tests for Motor Vehicle Lighting Devices and Components) is incorporated by reference in FMVSS No. 108, and states that the photometric measurement shall be made at a distance between the light source and the point of measurement specified for the lighting device. SAE J575e goes on to define the V axis as the line formed by the intersection of a vertical plane through the light source of the device This indicates that the light source is the origin of the beam in a lighting device, or, in the devices you gave as illustrative examples in your letter, the filament center.

Moreover, while the 2004 Final Rule sought to improve compatibility of our lighting requirements with those of the [ECE], the new geometric visibility requirements you seek clarification on did not entirely harmonize FMVSS No. 108 with ECE R.48. In the 2004 Final Rule, the agency recognized that one of the many ways ECE R.48 visibility requirements differed from FMVSS No. 108 requirements was that ECE R.48 contains a definition for angles of geometric visibility, whereas the specifications for lighting tests in FMVSS No. 108 are all in SAE J575e, which is incorporated by reference. 69 Fed. Reg. 48805, 48806. In your letter, you suggest that since the new luminous intensity method Figure (Figure 20) was introduced to increase compatibility with ECE, the origin of the visibility angle for Figure 20 is identical to that described in ECE R.48. We disagree. Since NHTSA declined to adopt ECE R.48s definition of angles of geometric visibility in the 2004 Final Rule, we effectively retained the photometry measurements as specified in SAE J575e. Accordingly, we believe that the angles of measurement required in Figure 20 are to be measured from the light source of the lighting device, and in the lighting devices you have provided as illustrative examples, the measurement should be made from the filament center.

If you have any further questions, please do not hesitate to contact Sarah Alves of my staff at (202) 366-2992.

Sincerely yours,

Anthony M. Cooke

Chief Counsel

ref:108

d.4/17/08

2008

ID: 1985-01.2

Open

TYPE: INTERPRETATION-NHTSA

DATE: 01/02/85

FROM: AUTHOR UNAVAILABLE; Frank Berndt; NHTSA

TO: B. Henderson -- Automobile Importers of America, Inc.

TITLE: FMVSS INTERPRETATION

TEXT:

Mr. B. Henderson Automobile Importers of America, Inc. 1735 Jefferson Davis Highway, Suite 1002 Arlington, VA 22202

This responds to your letter of November 8, 1984, asking numerous questions concerning Standards No. 208, 209 and 210. The answer to your questions, numbered as presented in the attachment to your letter, are as follows:

1.) S.7.4.4 of Standard No. 208 sets requirements concerning access to the latchplate on the outboard side of a seat. The purpose of the requirement is to make safety belts more convenient to operate by requiring the latchplate to be accessible. You asked, in effect, whether the requirements of S7.4.4 also applies to an inboard mounted buckle located between the seat and a console. The answer is no. An inboard mounted buckle, however, must comply with the requirements of S7.4.6.

2.) You asked what is the meaning of the terms "comfort clip and window-shade" in section 7.4.2 of Standard No. 208. The terms refer to elements of a safety belt system which are used to relieve tension in the torso portion of a Type 2 lap-shoulder belt. A comfort clip is a device which attaches to the belt and can be positioned by an occupant to introduce and maintain slack in the belt system by physically preventing the belt slack from being taken up by the belt's retractor. The term window-shade refers to a type of device in a safety belt retractor which allows an occupant to introduce and maintain slack in the belt once it has been adjusted around the occupant.

3.) You asked if it is considered, "Action", if the driver hangs the webbing of an automatic belt on a manual convenience hook. An automatic belt must provide protection by means that require no action by the vehicle occupants. Manual vehicle convenience hooks used with an automatic belt system must comply with S 7.4.1 of the Standard, which requires a convenience hook to automatically release under specified conditions.

4.) You asked if it is mandatory to use 7/16-20 UNF 2A or 1/2-13 UNC-2A bolts for automatic belt mounting hardware. The answer is no. Automatic belts meeting the frontal crash protection requirements of Standard No. 208 are not required to meet all of the requirements of Standard No. 209. The enclosed interpretation letter of August 7, 1981, to Volkswagen more fully explains the application of Standard No. 209 to automatic belts.

5.) You asked if the retractor of a rear lap belt is a 2 point mounting type, are both points considered to be anchorage points? You also asked if both points must be within the range specified in S 4.3.1.1 of Standard No. 210.

Standard No. 210 defines an anchorage as "provision for transferring seat belt assembly loads to the vehicle structure." If by a two point mounting you mean a retractor that has two means for transferring the belt loads to the vehicle structures, then both points are anchorages and must conform to Standard No. 210. The range specified in S4.3.1.1. is measured from the seating reference point to the point of contact of the webbing with its attachment hardware. It does not require the anchorage points to be within that range.

6.) Finally, you asked what is the definition of the term "most upright position" used in S 4.3.2.1 of Standard No. 210. In referring to the "most upright position" of the seat back, the agency means the seat back adjustment position which most closely approximates a vertical position.

I hope this information is of assistance to you.

Sincerely,

Frank Berndt Chief Counsel

Enclosure

November 8, 1984

Office of Chief Counsel NOA-30 National Highway Traffic Safety Administration 400 Seventh Street, S.W. Washington, DC 20590

Dear Sir or Madam:

Please provide a written interpretation of the following question:

FMVSSS 210, Section 4.3.2. requires that the seat back be "in its most upright position". Please define the phrase "in its most upright position".

Also please provide answers for the questions on the attached page.

Thank you for your prompt reply.

Automobile Importers of America, Inc.

B. Henderson

BH:js Attachments

QUESTIONS ON FMVSS 208, 209, 210.

1. FMVSS 208 S.7.4.4. states "the side of the vehicle interior to allow unhindered transit of the test block defined in Figure 4 of this standard to the latch plate or buckle......"

Does it mean that the whole buckle should be in the test block area as illustrated in Fig. A below?

What if the only push-button of the buckle fall in that test block area as illustrated in Fig. B below?

"INSERT"

Figure A Figure B

2. What is the meaning of comfort clip and window-shade? (in FMVSS 208 S.7.4.2)

3. Is it considered to be 'Action' if the driver hangs the webbing on the hook of the passive belt with manual convenience hook?

(New regulation FMVSS 208 5.4.1.2.1.1)

4. Is it mandatory to use 7/16-20 UNF-2A or 1/2-13 UNC-21 for the passive belt mounting hardware? (FMVSS 209 S.4.1(f)).

5. If the retractor or reel of the rear lap belt is 2 point mounting type, are both points considered to be anchorage points? Should both points be in the range defined in the FMVSS 210 S.4.3.1.1?

6. What is the definition of 'most upright position' of seat back in the FMVSS 210 S.4.3.2.1?

ID: nht94-8.19

Open

DATE: February 11, 1994

FROM: Jerry L. Steffy -- Triumph Designs, Ltd.

TO: Taylor Vinson -- NHTSA

TITLE: None

ATTACHMT: Attached to letter dated 3/16/94 from John Womack to Jerry L. Steffy (A42; Std. 108; Part 555)

TEXT:

Since I faxed you with my question regarding FMVSS 108 and ECE Reg. 20, I received Part 555 of 49 CFR from Luke Loy.

555.5 implies that we could apply for an exemption from FMVSS 108 for this headlamp since there exists "an equivalent overall level of motor vehicle safety." This is of course, if NHTSA recognizes the worthiness of the testing under ECE Reg. 20.

This exemption would only be for the first model year as afterwards we will change to a headlamp already FMVSS 108.

Can you please confirm for the if this is a route we can employ in this instance?

Best regards.

2-10-94 fax from J.L. Steffy to Taylor Vinson:

Dear Taylor:

Luke Loy suggested that I contact you with a specific query I have. Recently, in Canada, we were able to use ECE Reg. 20 in lieu of FMVSS 108 for a particular headlamp system use. Is it possible to substitute ECE 20 for FMVSS 108 in the states in some instances? Of course the majority of our suppliers fulfill testing according to FMVSS 108 however, there are individual exceptions. Some cases may require significant investment in order to have individual cases comply, so it is important to know.

Best regards

ID: 08-003191--zero voltage safe--24 Sept 08 rsy

Open

Kenneth N. Weinstein, Esq.

Mayer Brown LLP

1909 K Street, NW

Washington, DC 20006-1101

Dear Mr. Weinstein:

This responds to your letter requesting an interpretation of Federal motor vehicle safety standard (FMVSS) No. 305, Electric-powered vehicles; electrolyte spillage and electrical shock protection. Specifically, you asked that we confirm that a vehicle will be deemed to be in compliance with S5.3 of FMVSS No. 305 if there is no measurable voltage following the crash tests specified in S6 of the standard. Based on the information you have provided and the analysis below, we agree that where there is no measurable voltage following the crash tests, the vehicle will have passed S5.3 of the standard.

Paragraph S5.3 of FMVSS No. 305, Electrical isolation, currently states that Electrical isolation between the battery system and the vehicle electricity-conducting structure after each test must not be less than 500 ohms/volt. The electrical isolation test procedure, specified in S7.6 of FMVSS No. 305, requires that two voltage measurements be taken after the vehicle is crash-tested: the first measurement (V1) must be taken between the negative side of the propulsion battery and the vehicle chassis, and the second measurement (V2) must be taken between the positive side of the propulsion battery and the vehicle chassis. Electrical isolation is then determined by means of an equation: if V1 is greater than or equal to V2, the equation is:

Ri = Ro (1 + V2/V1 ) [(V1-V1)/V1]

where Ri is electrical isolation, Ro is a known resistance, and V1 is the voltage measured between the negative side of the propulsion battery and the vehicle chassis after the known resistance Ro is inserted between the negative side of the propulsion battery and the vehicle chassis.



If V2 is greater than V1, the equation for measuring electrical isolation is:

Ri = Ro (1 + V1/V2) [(V2-V2)/V2]

where Ri and Ro are the same as above, and V2 is the voltage measured between the positive side of the propulsion battery and the vehicle chassis after the known resistance Ro is inserted between the positive side of the propulsion battery and the vehicle chassis.

These equations are relevant to your question because they both require one voltage measurement to be divided by another. As your letter states, many current electric vehicle designs use electrical contactors to disconnect high voltage sources from the vehicles propulsion system in the event of a crash or other loss of isolation. If the high voltage source is immediately disconnected, there would be no voltage to measure. If there is no voltage to measure, a value of zero could end up in the denominator of an equation used to determine electrical isolation. Mathematically, a value of zero in the denominator of a fraction results in an undefined value, which has no meaning and cannot be used, in this case, to actually calculate electrical isolation. Thus, technically speaking, the equations in S7.6 could not be used to certify compliance with FMVSS No. 305s electrical isolation requirement.[1]

We have decided that a sensible and simple approach is warranted in response to the issue you raise. We do not believe that the mathematically impossible must be a bar against a certification of compliance in this situation. Accordingly, we will interpret FMVSS No. 305 such that a voltage reading of zero will constitute compliance with the electrical isolation requirement.[2]

I hope this information is helpful. If you have any further questions, please do not hesitate to contact Rebecca Yoon of my staff at (202) 366-2992.

Sincerely yours,

Anthony M. Cooke

Chief Counsel

ref:305

d.11/20/08




[1] NHTSA is currently involved in rulemaking to revise FMVSS No. 305 to allow other ways of determining electrical safety besides electrical isolation, including a requirement that the voltage between the vehicle chassis and the high voltage source be less than 60 VDC or 30 VAC. See notice of proposed rulemaking, 72 FR 57260 (Oct. 9, 2007). As your letter states, this would allow a manufacturer to certify compliance with FMVSS No. 305s requirements if the vehicle achieved a zero post-crash voltage. However, that new requirement has not yet been finalized.

[2] One could also point out that, mathematically, as your voltage measurement gets smaller and smaller (in other words, as your denominator approaches zero), your isolation becomes infinite. An electrical isolation approaching infinity is clearly greater than or equal to 500 ohms/volt, even if it cannot be defined mathematically.

2008

ID: GF007705

Open

    [ ]

    Dear Mr. [ ]:

    This responds to your letter of October 7, 2003, regarding certain trailer lighting requirements. You intend to install a set of two lamps at the top rear corners of the trailer. The outer-most lamp would have a dual function of a clearance lamp, and an "auxiliary" turn signal lamp. The horizontally adjacent (inboard) lamp would function as an "auxiliary" stop lamp and, possibly, as a second clearance lamp. [1] You ask whether such a lamp configuration is permissible under Federal Motor Vehicle Safety Standard (FMVSS) No. 108. Further, you are aware that FMVSS No. 108 limits the number of rear identification lamps to three. You ask at what horizontal distance from these identification lamps would supplemental lamps be deemed "auxiliary" and not a part of this identification lamp cluster.

    Before I address your questions, I note that you requested confidential treatment for the identity of your company and for yourself. I agree to keep your name and the name of your company confidential. All information in bold brackets [      ] will be kept confidential from the public. Your incoming interpretation request will be redacted before being made publicly available.

    By way of background, the National Highway Traffic Safety Administration (NHTSA) does not provide approvals of motor vehicles or motor vehicle equipment. Under 49 U.S.C. Chapter 301, manufacturers are required to certify that their vehicles and equipment meet applicable requirements.

    With respect to your first question, the dual function "auxiliary" lamps described in you letter are permissible under FMVSS No. 108 with certain limitations. First, Table II of FMVSS No. 108 requires that the rear clearance lamps be red. Accordingly, the outer-most clearance lamp (that will also function as a turn signal lamp) must be red. Second, the stop lamp that is adjacent to the clearance/turn signal lamp, cannot also function as an additional clearance lamp, because Table II of FMVSS No. 108 requires that clearance lamps indicate the overall width of the vehicle. Accordingly, only the outer-most turn signal lamp can function as a clearance lamp, because it is the outermost lamp that indicates the overall width of the vehicle. We note, however, that it would be permissible for the adjacent inboard lamp to have a dual function of an auxiliary stop lamp and an auxiliary tail lamp.

    In response to your second question, Table II of FMVSS No. 108 provides precise guidance for the location of the five lamps that are required at the top rear of the trailer. Specifically, Table II requires that the three identification lamps be located as close as practicable to the top and center of the trailer, spaced between 6 and 12 inches apart. Similarly, Table II requires that the two clearance lamps be located as close as practicable to the top of the trailer and as close to the edges as would be necessary to indicate the overall width of the trailer.

    While the location of auxiliary lighting on the top rear of the trailer is not regulated by FMVSS No. 108, S5.1.3 of the standard does prohibit installation of lamps that would impair the effectiveness of required lighting. Therefore, your auxiliary lamps must be located far enough away from the three identification lamps, that they do not impair their effectiveness. In a recent interpretation letter, the agency stated that the function of this three-lamp identification cluster is to indicate the presence of a large vehicle in the roadway. The agency has long maintained that highway traffic safety is enhanced by the familiarity of drivers with established lighting schemes, which facilitates their ability to instantly recognize the meaning the lamps convey and respond accordingly. Therefore, any auxiliary lighting on the top rear of the trailer must be located such that it would not interfere or be confused with the three-lamp identification cluster.

    After studying your diagrams, it appears that your auxiliary lamps would not impair the effectiveness of the required three-lamp identification cluster. The three-lamp identification cluster is located at the top center of the trailer. By contrast, your two auxiliary lights are located toward the edges of the trailer, adjacent to the clearance lamps. Thus, your rear lighting configuration would be permissible under FMVSS No. 108. [2]

    I hope you find this information helpful. If you need further assistance, please contact George Feygin of my staff at this address or at (202) 366-2992.

    Sincerely,

    Jacqueline Glassman
    Chief Counsel

    Enclosures
    ref:108
    d.1/21/04




    [1] You have enclosed drawings and a description of two versions of a rear lighting configuration. In one of the two versions, the lamps adjacent to the outer-most turn signal supplemental lamp also functions as a second clearance lamp.

    [2] You may also want to review our Interpretive Rule on the proper location of identification lamps and clearance lamps, which NHTSA published on April 5, 1999 (64 FR 16358). A copy is attached.

2004

Request an Interpretation

You may email your request to Interpretations.NHTSA@dot.gov or send your request in hard copy to:

The Chief Counsel
National Highway Traffic Safety Administration, W41-326
U.S. Department of Transportation
1200 New Jersey Avenue SE
Washington, DC 20590

If you want to talk to someone at NHTSA about what a request for interpretation should include, call the Office of the Chief Counsel at 202-366-2992.

Please note that NHTSA’s response will be made available in this online database, and that the incoming interpretation request may also be made publicly available.

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