NHTSA Interpretation File Search
Understanding NHTSA’s Online Interpretation Files
- 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
Example: functionally AND minima
Result: Any document with both of those words.
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Result: Any document containing the word “headlamp” and not the word “crash.”
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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.”
NHTSA's Interpretation Files Search
Pierre Villeneuve, Standard Technician
Dear Mr. Villeneuve:
This responds to your request for an interpretation of Federal Motor Vehicle Safety Standard No. 217, Bus emergency exits and window retention and release. Specifically, you wish to know "how many emergency exits" are needed on each side of a non-school bus over 4,536 kg (10,000 pounds) GVWR with "21 passengers" (not including the driver).
Standard No. 217 requirements applicable to the bus at issue are at S188.8.131.52 and S184.108.40.206, Buses with GVWR of more than 10,000 pounds. S220.127.116.11 requires that non-school buses provide unobstructed openings for emergency exits based on the number of "designated seating positions on the bus," a term which includes the drivers seat. Thus, the bus at issue has 22 designated seating positions.
Standard No. 217 does not specify the number or types (i.e., doors versus windows) of emergency exits that must be provided. However, the standard specifies the total area of the unobstructed openings for emergency exits that must be provided. For the bus at issue, S18.104.22.168 specifies that the unobstructed openings for emergency exits must amount to 9,504 square centimeters (cm) (432 cm x 22 designated seating positions). At least 3,801.6 cm (40 percent) of the total required area of unobstructed openings shall be provided on each side (i.e., the right side or left side) of a bus.
The following explains how the 9,504 cm is to be allocated among the right and left sides of the bus and the rear emergency exit.
Emergency exits on the right side of the bus You stated that there was only one door, opposite the drivers seat, for entrance and egress. If the front door meets Standard No. 217 emergency exit requirements, it can be considered an emergency exit. See June 30, 1988, letter to Mr. Terry K. Brock (copy enclosed): "As long as the front door meets all applicable requirements for emergency exits under Standard No. 217, the door can be considered as an emergency exit. " However, as specified in S22.214.171.124, regardless of its actual area, the front door cannot be credited with more than 3,458 cm of the total area requirement.
Subtracting the square centimeters of the front door (not to exceed 3,458 square centimeters) from 3,801.6 cm, the remainder (of the area representing the unobstructed openings for the right side emergency exit) may be allocated to a side exit such as a window. The combined unobstructed opening area for the front door and the right side emergency exit window must total at least 3,801.6 cm.
Emergency exits on the left side of the bus The combined unobstructed openings for emergency exits for the left side of the bus must also be at least 3,801.6 cm. The emergency exits may consist of a left side emergency door and an emergency exit window, or may consist of emergency exit windows only.
Rear emergency exits Although you did not ask about rear emergency exits, please note that the unobstructed opening for the rear emergency exit must total at least 1900.8 cm (9,504 cm (total unobstructed area) minus 3801.6 cm (right side) minus 3801.6 cm (left side)). S126.96.36.199 states that when the bus configuration precludes installation of an accessible rear exit (such as a rear exit door), a roof exit that meets the requirements of S5.3 through S5.5 when the bus is overturned on either side, with the occupant standing facing the exit, shall be provided in the rear half of the bus.
I hope this information is helpful. If you have any further questions, please feel free to contact Dorothy Nakama at this address or at (202) 366-2992.
Mr. Reginald Gray
Dear Mr. Gray:
This is in response to your letter in which you ask if selling custom seat belts would be affected by any Federal motor vehicle safety standards (FMVSS) issued by this agency. You state that you are interested in selling seat belts with various designs and logos on the seat belt webbing. However, it was unclear from your letter if the designs would be added to a vehicles existing belts or if custom belts would be manufactured to replace a vehicles existing belts. Each of these possibilities is addressed below.
I am pleased to have this opportunity to explain our statute and regulations. The National Highway Traffic Safety Administration (NHTSA) is authorized under the National Traffic and Motor Vehicle Safety Act (49 U.S.C. Chapter 301; Safety Act) to issue Federal motor vehicle safety standards that apply to the manufacture and sale of new motor vehicles and new items of motor vehicle equipment. 49 U.S.C. 30112(a) prohibits any person from manufacturing, introducing into commerce, selling, or importing any new motor vehicle or item of motor vehicle equipment unless the vehicle or the equipment is in conformity with all applicable safety standards and is certified as being in compliance.
NHTSA has issued four safety standards that may be relevant to your custom seat belts. The first is FMVSS No. 208, Occupant crash protection, which sets forth requirements for occupant protection at the various seating positions in vehicles. The second relevant standard is FMVSS No. 209, Seat belt assemblies, which sets forth strength, elongation, webbing width, durability, and other requirements for seat belt assemblies. The third relevant safety standard is FMVSS No. 210, Seat belt assembly anchorages, which establishes strength and location requirements for seat belt anchorages. The final relevant safety standard is Standard No. 302, Flammability of interior materials. This standard specifies burn resistance requirements for materials used in the occupant compartment of motor vehicles. FMVSS Nos. 208, 210, and 302 apply, with certain exceptions that are not relevant to your product, to vehicles and, not directly to items of equipment. FMVSS No. 209 applies to all seat belt assemblies regardless of whether the seat belts are originally installed in the vehicle or are installed after the vehicle has been purchased.
Because federal law operates differently depending on whether you manufacture, sell, or install the custom seat belts, I will discuss each possible scenario.
Manufacturer and Seller Requirements
The Safety Act states:
If you were to manufacture the custom seat belts, you would have to certify that the belts comply with FMVSS No. 209. As noted above, FMVSS No. 209 sets forth strength, elongation, webbing width, durability, and other requirements for seat belt assemblies. This standard applies to all seat belt assemblies for use in motor vehicles, regardless of whether the belts are installed as original equipment in a motor vehicle or sold as replacements. Hence, any seat belt sold for installation in an existing vehicle would have to comply with, and be certified as complying with, FMVSS No. 209.
If your product were not a seat belt, but a component to be attached or added to the seat belt, there would be no NHTSA standards directly applicable. However, if you were to manufacture such a product, we would urge you to evaluate carefully whether your product would in any way degrade the performance of vehicle safety belts. For example, you should ensure that your product would not interfere with safety belt retraction, that any adhesive used with your product would not cause deterioration of the safety belt webbing, and that your product would not obscure the information required by FMVSS No. 209 to be labeled on the webbing. Safety belt webbing is designed to have some "give" to help absorb crash forces. If your product were to make the webbing too stiff, it could raise safety concerns. Finally, you should be aware that originally-installed safety belts must meet the requirements of FMVSS 302. Again, we would encourage you to evaluate your product against the requirements of this standard to ascertain whether your product would degrade the flammability performance of seat belts.
In either case, as a manufacturer, you would also be subject to federal requirements concerning the recall and remedy of products with defects related to motor vehicle safety (49 U.S.C. 30118-30121).
Any commercial business that would install your product would also be subject to the provisions of the Safety Act that affect modifications of new or used vehicles or motor vehicle equipment. The Safety Act provides at 49 U.S.C. 30122(b) that:
This section would prohibit any of the named type of businesses from installing your product if such installation would cause the vehicle to no longer be in compliance with FMVSS Nos. 208, 209, 210, or 302. Violations of this make inoperative prohibition are subject to a civil penalty of up to $5,000 for each violation. Even if your product were simply modifications to a vehicles existing seat belts (e.g., stickers or additional stitching), any of the above businesses installing your product would still be subject to the make inoperative provision.
Additionally, there may be state law considerations regarding potential liability in tort in these circumstances. I have enclosed a brochure for new manufacturers that discusses the basic requirements of our standards and regulations, including the provisions relating to manufacturers' responsibilities to ensure that their products are free of safety-related defects.
I hope you find this information helpful. If you have any further questions please call Mr. Chris Calamita of my staff at (202) 366-2992.
Mr. Dick Keller
Dear Mr. Keller:
This responds to your letter in which you ask about the application of the "make inoperative" provision to the removal of advanced air bag sensors during the installation of driver seats that accommodate individuals with disabilities. As explained below, the National Highway Traffic Safety Administration (NHTSA) will exercise its enforcement discretion and refrain from taking action under the circumstances described in your letter.
In your letter you discussed the installation of a product your company calls the Turning Automotive Seat (TAS) to facilitate vehicle access by individuals with disabilities. You described the TAS as being offered in two models, but you explained that both models are essentially "a swivel seat base mechanism rotating approximately 90 degrees with articulation to clear the B-pillar during entry and egress."You stated that the TAS system is used with the originally equipped (OEM) seat belts and bolts into the OEM seat mounting points. Your letter explained that with the newer air bag systems relying on seat sensors to modulate air bag deployment, replacing the OEM seat with the TAS requires removal of these sensors. You asked if such modifications were covered by the make inoperative exemption in 49 CFR 595.7(c)(14).
By way of background, NHTSA has authority to issue Federal motor vehicle safety standards (FMVSSs) applicable to new motor vehicles and items of motor vehicle equipment. Manufacturers are required to certify that their products conform to all applicable FMVSSs before the products can be offered for sale. After the first retail sale of a vehicle, manufacturers, distributors, dealers, and repair businesses are prohibited from "making inoperative" any device or element of design installed on or in a motor vehicle in compliance with an applicable standard. 49 U.S.C. 30122. However, NHTSA has recognized that it is appropriate to permit some modifications that could cause a vehicle to no longer comply in order to accommodate people with disabilities. 49 CFR Part 595 Subpart C, Vehicle Modifications to Accommodate People with Disabilities, lists modifications of certain portions of specific FMVSSs that are exempt from the "make inoperative" provision in order to accommodate people with disabilities.
On May 12, 2000, the agency published a final rule amending FMVSS No. 208 by establishing requirements to reduce the risk of serious air bag-induced injuries, especially to small women and young children, and to improve safety for all occupants by means that include advanced air bag technology. (65 FR 30680; Advanced Air Bag Rule.) Motor vehicles certified as complying with the provisions of the Advanced Air Bag Rule will be required to minimize air bag risks by automatically turning off the air bag in the presence of an occupant who is a young child or deploy the air bag in a manner less likely to cause serious or fatal injury to an "out of position occupant."Among the technologies used to comply with these requirements are a variety of seat position, occupant weight, and pattern sensors incorporated into the seat structure. The advanced air bag technology requirements are being phased in beginning September 1, 2003, with full compliance required starting September 1, 2006. 
While 49 CFR 595.7 includes some specific requirements of FMVSS No. 208 among the requirements subject to the "make inoperative" exemption, the provisions established under the Advanced Air Bag Rule are not included. As you are aware, the agency has granted a petition for rulemaking to include the provisions of the Advanced Air Bag Rule in the exemption list under Part 595. If the agency issues a final rule incorporating the advanced air bag requirements into Part 595, Subpart C, then a vehicle modifier that meets the conditions set forth in that subpart would be permitted to make such modifications as you described.
Until this rulemaking is completed, the agency will use its enforcement discretion and refrain from taking action in the limited instance of a vehicle not complying with the advanced air bag requirements because of the installation of a replacement seat to accommodate persons with disabilities. This is conditioned on the vehicle modifier complying with the modifier and modification requirements of Part 595, including the label and documentation requirements of 595.7(b). If you have any additional questions, please contact Mr. Chris Calamita of my staff at (202) 366-2992.
 A majority of vehicle manufacturers are required to certify that a percentage of their fleet complies with these requirements according to the following phase-in schedule, with credits for early compliance: September 1, 2003 to August 31, 2004--20 percent; September 1, 2004 to August 31, 2005--65 percent; September 1, 2005 to August 31, 2006--100 percent.
Tony Klasing, Manager
Dear Mr. Klasing:
This responds to your request for an interpretation of Federal Motor Vehicle Safety Standard No. 217, Bus emergency exits and window retention and release. Specifically, you wish to know whether in test procedures for school buses specified at S188.8.131.52(a)(1) of the standard, a parallelepiped is used or a template. The answer is the agency uses a parallelepiped, as specified in the standard, rather than simply measuring from the rear of the seat back to the exit door.
As specified at S184.108.40.206(a), the rear emergency exit door must be manually extendable by a single person to a position that permits "an opening large enough to permit unobstructed passage of a rectangular parallelepiped 114 centimeters high, 61 centimeters wide, and 30 centimeters deep" when "keeping the 114 centimeter dimension vertical, the 61 centimeter dimension parallel to the opening, and the lower surface in contact with the floor of the bus at all times."Contrary to what may be your understanding, the agency has not "approved" the use of a template that tapers at the top.
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.
 In some school buses, the rear of the bus may curve inward, towards the passenger compartment. In such cases, in testing, although the bottom of the parallelepiped is in contact with the floor of the bus at all times, the top part of the parallelepiped may extend outside of the bus. When it conducts its school bus compliance testing for the rear emergency exit door, NHTSA would deem the school bus to meet S220.127.116.11(a)(1) of Standard No. 217 as long as the bottom of the specified parallelepiped is in contact with the floor of the bus at all times.
Mr. Robert M. Clarke
Truck Manufacturers Association
225 New York Ave. NW
Washington, DC 20005
Dear Mr. Clarke:
This responds to your letter, co-signed by Mr. Timothy Kraus of the Heavy Duty Brake Manufacturers Council, requesting an interpretation of Federal Motor Vehicle Safety Standard (FMVSS) No. 121, Air Brake Systems. We are sending an identical letter to Mr. Kraus.
You asked that we confirm your interpretation of the requirements of FMVSS No. 121 as they relate to the check of lamp function for the in-cab indicator lamp used to signal an antilock brake system malfunction in a towed unit. For reasons discussed below, we agree that S18.104.22.168(b) of the standard does not require a check of lamp function for the in-cab trailer ABS malfunction lamp when there is no post-2001 trailer or towed unit attached to the tractor. (As with your letter, we refer for purposes of convenience to trailers subject to the relevant ABS requirements as post-2001 trailers and ones built before those requirements applied as pre-2001 trailers.)
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 approve motor vehicles or motor vehicle equipment; nor do we endorse any commercial products. Instead, each manufacturer must self-certify that its products meet all applicable safety standards prior to sale.
Paragraph S22.214.171.124(b) of FMVSS No. 121 requires truck tractors and single unit trucks that are equipped to tow another air braked vehicle to be equipped with an in-cab indicator lamp (separate from the lamp for the tractor or truck required by S126.96.36.199(a)) which is to be activated whenever the malfunction signal circuit detects an ABS malfunction on a towed vehicle. The indicator lamp must also be activated as a check of lamp function whenever the ignition is turned to the on (run) position, and deactivated at the end of the function unless a trailer ABS malfunction signal is present.
In your letter, you stated that the members of HDBMC and TMA generally agree that the best interpretation of S188.8.131.52(b) is that there is no requirement to perform a check of lamp function for the in-cab trailer ABS malfunction indicator lamp when there is no post-2001 trailer or towed unit attached to the tractor. In support of this view, you made several arguments, including the following:
. . . the requirements of S184.108.40.206(b) as a whole make sense only in the context of the presence of a post-2001 trailer that is connected to the tractor. . . . the first sentence of the section clearly states that the tractor electrical circuit must be capable of transmitting an ABS malfunction signal from the antilock brake system(s) on one or more towed vehicle(s). The second sentence of the section clearly states that the in-cab lamp shall be activated whenever the malfunction signal circuit described above receives a signal indicating ABS malfunction. The last sentence of the section requires deactivation of the indicator lamp after the check of lamp function unless a trailer ABS malfunction signal is present. These requirements clearly envision a tractor that is connected to a post-2001 trailer. (All emphasis added by HDBMC/TMA)
You stated that consistent with this understanding, SAE Recommended Practice J2497 (October 2002) states that the logical control of the in-cab trailer ABS indicator lamp shall be made by a device on the trailer. You stated further that according to SAE J2497, the trailer ABS device initiates the power up (bulb check) logic sequence when power is applied and the trailer ABS device becomes active, and [i]f no lamp control messages are received [from the ABS device on the trailer], then the tractor device will not perform a bulb check [on the in-cab trailer ABS indicator lamp].
You indicated that SAE J2497 was issued upon the recommendation of the SAE Truck and Bus Power Line Carrier Task Force. According to your letter, records from those deliberations indicate that there was concern among human factors experts working on the proposal that having the in-cab trailer ABS malfunction indicator activate as a check of lamp function when either a pre-2001 trailer was present or when no trailer was present at all would, at a minimum, confuse drivers or, worse, incorrectly lead them to believe the trailer they were towing was equipped with functioning ABS. In this regard, you noted that, as explained by NHTSA in the preamble to the final rule establishing these requirements, NHTSA has decided to require the malfunction indicator lamp to activate when a problem exists and not activate when the system is functioning properly. Thus, extinguishing the malfunction lamp at the end of the check of lamp function signals proper functioning of the trailer ABS system, which would not be the case if there was no post-2001 trailer connected to the tractor (or single unit truck that is equipped to tow another air-braked vehicle).
After considering the overall language of S220.127.116.11(b) and its purposes, and the arguments presented in your letter, we confirm that this paragraph does not require a check of lamp function for the in-cab trailer ABS malfunction lamp when there is no post-2001 trailer or towed unit attached to the tractor. S18.104.22.168(b) states, in relevant part:
Each . . . truck tractor and single unit vehicle shall also be equipped with an indicator lamp, separate from the lamp required in S22.214.171.124(a), mounted in front of and in clear view of the driver, which is activated whenever the malfunction signal circuit described above receives a signal indicating an ABS malfunction on one or more towed vehicle(s). The indicator lamp shall remain activated as long as an ABS malfunction signal from one or more towed vehicle(s) is present, whenever the ignition (start) switch is in the on (run) position, whether or not the engine is running. The indicator lamp shall also be activated as a check of lamp function whenever the ignition is turned to the on (run) position. The indicator lamp shall be deactivated at the end of the check of lamp function unless a trailer ABS malfunction signal is present.
49 CFR 571.121, S126.96.36.199(b) (2006).
In interpreting the relevant language, we note that the requirement specifying that the indicator lamp must be activated as a check of lamp function whenever the ignition is turned to the on (run) position does not expressly state whether it applies in situations where there is no post-2001 trailer attached. This is relevant in the context of S188.8.131.52(b) because the in-cab trailer ABS malfunction lamp itself only indicates malfunctions when a post-2001 trailer is attached. Moreover, the sentences immediately preceding the specific one at issue contemplate a post-2001 trailer being attached to the tractor. Given this, we believe that it is reasonable to read the requirement for check of the in-cab trailer ABS lamp function as applying only when a post-2001 trailer is attached.
In providing this interpretation, we have considered the issues you raise concerning avoiding potential confusion. Of particular concern is the possibility of drivers mistakenly believing they are towing a functioning ABS-equipped trailer when they are not as a result of observing an in-cab trailer ABS malfunction lamp activating and then extinguishing when no ABS-equipped trailer is connected to the tractor.
Please bear in mind, however, that the purpose of the check of lamp function is to alert drivers to problems with the bulb or the electrical system. We note that under this interpretation, the requirement that the in-cab trailer ABS indicator lamp must be activated as a check of lamp function whenever the ignition is turned to the on (run) position applies whenever the vehicle is towing a post-2001 trailer, i.e., the situations where the in-cab trailer ABS malfunction lamp will operate.
We note that this interpretation reflects the very specific language and policy concerns discussed in this letter. This interpretation applies only to this particular situation, and should not be read as an interpretation of how we would interpret requirements for check of lamp function in any other situation.
If you have any further questions, please contact Rebecca Schade of my staff at (202) 366-2992.
Anthony M. Cooke
Teresa Stillwell, Public Relations Director
Dear Ms. Stillwell:
This responds to your request for an interpretation of how Federal Motor Vehicle Safety Standard (FMVSS) No. 217, Bus emergency exits and window retention and release, applies to used school buses that your company wishes to carry forest fire-fighters and fire-fighting equipment.
In your letter, you write that the used school "buses in our fleet range from 1980 to 1992" as the dates of manufacture. In a telephone conversation with Dorothy Nakama of my staff, you stated the used school buses range from 45 to 63 in passenger capacity, and thus are over 4,536 kg (10,000 pounds) in gross vehicle weight rating (GVWR). You will modify the buses to carry 22 passengers (including the driver).
The Federal motor vehicle safety standards do not apply to used motor vehicles. That is, persons selling a used vehicle are not required to sell vehicles that meet the FMVSSs. Thus, there is no NHTSA requirement that the modified buses meet FMVSS No. 217.
There is a limit in Federal law on the modifications that certain commercial businesses may make to vehicles for compensation. This "make inoperative" provision is discussed below.
Making Safety Devices and Elements Inoperative
In general, this section prohibits the entities listed in 30122 from removing, disabling or otherwise "making inoperative" any of the safety systems or devices installed on the vehicle to comply with a safety standard. However, with regard to modifications that change a vehicle from one vehicle type to another (e.g., from school bus to bus  ), the National Highway Traffic Safety Administration (NHTSA) has interpreted the provision to hold that the modifications do not violate the "make inoperative" prohibition as long as the converted vehicle complies with the safety standards that would have applied if the vehicle had been originally manufactured as the new type. Applied to the situation you present, and assuming that ACF is modifying the buses for compensation, this means that ACF would have to ensure that the buses meet the "bus" emergency exit requirements to preclude a violation of 30122.
The emergency exit requirements that apply to "buses" are explained in an enclosure to this letter. As you requested, the enclosure also explains the requirements for "school buses."
The make inoperative provision does not apply to owners modifying their own vehicles. Thus, if ACF is modifying used school buses for its own use, there is no NHTSA requirement not to make inoperative the safety systems or devices installed in the vehicle. However, NHTSA urges owners not to degrade the safety of their vehicles.
Storing Fire-Fighting Equipment
You told Ms. Nakama that fire-fighting equipment (such as axes, shovels, and chain saws) would weigh between 2,300 to 3,000 pounds and would be secured in the bus by storage in cages. Separate cages can be designed for opposite sides of the bus, leaving a clear aisle to the rear emergency exit door. You stated that it was also proposed to put one large storage cage in such a way as to block the rear emergency exit door. In your letter, you ask whether, if the rear exit is blocked, installing a roof exit in front of the cage door fulfills the required number of exits. You asked Ms. Nakama whether Federal law permits blockage of the emergency exit door.
We assume for this answer that you are regulated by the "make inoperative" provision of 30122. Because your company would change the vehicle type (i.e., from school bus to bus), and there is no requirement for rear emergency exit doors for buses, NHTSA law would not prohibit the blockage of the rear emergency exit door with a permanent structure such as the cage, as long as a roof emergency exit is provided. If you are modifying your own vehicles and are thus not regulated by the make inoperative provision, you are not required by NHTSA to install an exit. If an exit is not provided, we strongly recommend that the emergency exit label be removed from the rear door.
Your final question to Ms. Nakama was whether it would be permissible to transport gasoline on the buses for fueling forest fire-fighting equipment such as chain saws. The Research and Special Projects Administration (RSPA) of the Department of Transportation has regulations that may apply to transport of gasoline. You can contact RSPAs Office of Hazardous Materials Standards toll free at 1-800-467-4922 for information about RSPA regulations. We also suggest that you contact your State motor vehicle administration for information about any State regulations in this area.
I hope this information is helpful. If you have any further questions, please feel free to contact Dorothy Nakama at this address or at (202) 366-2992.
 By NHTSAs definition, a bus is "a motor vehicle with motive power, except a trailer, designed for carrying more than 10 persons." (See 49 CFR 571.3, "Definitions.")
ID: 001688cmc_DC_acc releaseOpen
Mr. Robert E. Norton II
Dear Mr. Norton:
This responds to your letter dated March 12, 2003, in which you inquire about the requirements of Federal Motor Vehicle Safety Standard (FMVSS) No. 209, Seat belt assemblies. You ask if there are objective criteria to evaluate compliance with the requirement under the second sentence of S4.1(e) of FMVSS No. 209 that a "[b]uckle release mechanism shall be designed to minimize the possibility of accidental release." As explained below, compliance with S4.1(e) requires viewing that provision of the standard in the context of FMVSS No. 209 as a whole.
In your letter, you question how the agency would evaluate compliance with this provision of S4.1(e). You state that if the provision is read in the context of the entirety of FMVSS No. 209, then compliance with the "accidental release" requirement could be demonstrated by satisfying the performance requirements of S4.3(d)(3) of FMVSS No. 209, which refers to a test procedure set out in S5.2(d)(3). In the alternative, you contend that if compliance with S4.1(e) cannot be ascertained using this test procedure, then this provision of S4.1(e) would be invalid for lack of objective test procedures.
The S4.1(e) requirement that a seat belt buckle be designed to minimize the possibility of accidental release during an impact must be viewed as part of FMVSS No. 209 as a whole. FMVSS No. 209 requires, among other things, that seat belt buckles meet minimum performance and material requirements. S4.3(d)(3) establishes criteria to address accidental release, stating that:
Under the test procedure in S5.2(d)(3), a curved cylindrical bar is used to apply the compressive force to the buckle.
S4.3(d)(3) was added to FMVSS No. 209 to "eliminate buckle designs that are prone to accidental damage, or that release during the initial phase of the accident." 36 Federal Register 4607; March 10, 1971. S4.3(d)(3) provides an objective standard for minimizing accidental release during an impact, thus providing objective criteria for the requirement under S4.1(e). S4.3(d)(3) does not address accidental release not associated with a crash. Although we recognize that the "accidental release language of S4.1(e) could be read broadly to cover various scenarios, for compliance purpose, we interpret it to only refer to accidental releases that might occur during a crash. Non-crash accidental releases are not regulated by FMVSS No. 209, notwithstanding the arguably broader language of S4.1(e), as the only test procedure designed to address accidental release utilizes a force level much greater than would be contemplated in a non-crash environment.
In an August 31, 1976, letter to Volvo, the agency stated that for buckles unlikely to be damaged by compressive forces in a crash, the requirements of S4.3(d)(3) would not be applicable. While the Volvo letter stated that the original motivation for adopting this requirement was to guard against possible damage to a buckle caused by the steering wheel in a crash situation, the language of the requirement is broad enough to guard against other potential compressive forces as well, as evidenced by the fact that the requirement is not limited to buckles in the seating position with a steering wheel. In response to the notice that proposed extending the crush release requirements to all Type 1 and Type 2 seat belts, commentors did request that the requirement only be made applicable to buckles that could contact the steering wheel. (See comments from Britax and Irvin Industries, Inc. at Docket No. 69-23.) However, the agency did not amend the requirement to limit it to that narrower purpose. Accordingly, any current or future buckle with the likely potential to experience any compressive force during an impact would be required to comply with S4.1(e) and S4.3(d)(3), as tested under S5.2(d)(3).
I hope this addresses your concern. If you have any further questions please contact Mr. Chris Calamita of my staff at (202) 366-2992.
Stephen P. Wood
Dr. Barry D. Faguy
Dear Dr. Faguy:
This responds to your letter seeking information about the labeling requirements in Federal Motor Vehicle Safety Standard No. 218, Motorcycle Helmets (49 CFR 571.218). Your letter correctly notes that section S5.6.1 of Standard No. 218 requires that motorcycle helmets be permanently labeled with a "DOT" mark as the manufacturers certification that the helmet complies with Standard No. 218. You indicate that Quebec courts interpreting Quebec law have held that the "DOT" certification mark must be accompanied by a reference to "FMVSS 218" in order for a helmet worn by a rider to comply with Quebecs helmet law. Your letter further states that an example of such a decision is enclosed for our information. However, the decision you discuss was not in the letter we received. You then ask us to state without "any possible ambiguity" whether S5.6 (e) is intended to require that the legend "FMVSS 218" appear on the exterior of a helmet as evidence that the helmet has been certified as complying with Standard No. 218. You also ask if the legend "FMVSS218" must appear on the DOT label or any other label on the inside or outside of a helmet. Finally, you ask how a law enforcement officer can, through a visual inspection, determine if a motorcycle helmet complies with Standard No. 218.
By way of background information, the National Highway Traffic Safety Administration (NHTSA) has the authority under Chapter 301 of Title 49, U.S. Code, to establish Federal motor vehicle safety standards (FMVSSs) applicable to new motor vehicles and new items of motor vehicle equipment, including motorcycle helmets. This statute requires each person manufacturing, selling, or offering for sale any new vehicle, or item of equipment, covered by an FMVSS, to ensure that the new vehicle or equipment item is certified as meeting all applicable FMVSSs. These provisions apply to products manufactured, sold, or offered for sale in the United States. We express no view as to what may be required under the laws of Canada or any of its provinces.
The "DOT" certification mark and other required labels provide important information regarding the helmet, including the fact that the manufacturer has certified that the helmet meets Standard No. 218. Section S5.6.1 of the Standard requires that each helmet be permanently and legibly labeled with certain warnings, identifying information, size, and the DOT certification mark. Our agency requires permanent marking of these items because we believe this information is needed for the life of the helmet. However, S5.6.1 does not require that any label contain the legend "FMVSS218" or "FMVSS 218." Furthermore, Standard No. 218 does not require that a compliant helmet be marked or labeled, either on the outside or the inside, with the legend "FMVSS218" or "FMVSS-218."
You also ask how a law enforcement officer can determine if a motorcycle helmet complies with Standard No. 218 by visual inspection. Whether a law enforcement official's inspection of a helmet is sufficient to justify either the detention of an individual or the issuance of a summons is a matter of state, or in your case, provincial law. As such, this office cannot comment on whether such an action by law enforcement official is in compliance with the laws of Quebec. Similarly, this office cannot render an opinion regarding either the laws of the Province of Quebec or the application of those laws by any court. Accordingly, we are unable to provide any comments on the propriety of the court decisions discussed in your letter or the requirements of Quebecs laws.
I hope this information is helpful. If you have any further questions or need some more information on this subject, please do not hesitate to contact Mr. Otto Matheke of my staff at this address, or by telephone at (202) 366-2992.
cc: Dr. Barry D. Faguy
Mr. Don Weidman
Re; Number of Identification Lamps
Dear Mr. Weidman:
This is in reply to your letter of August 20, 2002, asking "how many lamps can be installed as identification lamps on a vehicle . . . and still be in compliance with Standard No. 108."
You related that a customer wishes to have a five-lamp array of lamps rather than the cluster of three identification lamps specified in Standard No. 108. It is your opinion that these additional lamps are not allowed because they would detract from the purpose of the three-lamp array to identify a large vehicle in the roadway.
We confirm your interpretation. Late in 1973, we were asked by Darrell Gambill of Crane Carrie Company whether a system of four identification lamps would be permissible.I enclose a copy of our response stating that only the three-lamp system specified by Standard No. 108 is permissible.
Mr. Agus The
Dear Mr. The:
This is in response to your letter asking whether the Locktec child restraint buckle release meets the "two or more finger" requirement of Federal Motor Vehicle Safety Standard (FMVSS) No. 209, Seat belt assemblies, as incorporated into FMVSS No. 213, Child restraint systems. As explained below, the two-finger standard is a width requirement, which is not satisfied simply by the use of two fingers in actuating the buckle release.
S184.108.40.206(c) of FMVSS No. 213 requires any buckle in a child restraint system to "[m]eet the requirements of S4.3(d)(2) of FMVSS No. 209, except that the minimum surface area for child restraint buckles designed for push button application shall be 0.6 square inch [387 mm2]." You state in your letter that: "The Locktec buckle has [a sliding mechanism for release] and not a push button or a lever application." Since your buckle release is not designed for push button application, the 0.6 square inch minimum surface area requirement in S220.127.116.11(c) does not apply.
S4.3(d)(2) of Standard No. 209 reads:
Because your buckle release is designed for slide application rather than push button or lever application, your buckle release falls under the "other design for release" category.
Under the last sentence of S4.3(d)(2), your buckle must have adequate access for two or more fingers to actuate the release. In the photos you provided of the release being actuated, one finger is in the slide action release button and an additional finger is on the buckle base opposite of the sliding mechanism. The placement of the finger on the base merely provides support to the buckle while the release is actuated. Only one finger is accessing the slide action release button.
FMVSS No. 209 requires that a slide action release button be large enough to be accessed by a minimum of two fingers, placed side-by-side. While there is no clear indication of what is meant by "two fingers" in terms of a minimum width, the two-finger requirement of FMVSS No. 209 was included in FMVSS No. 213 to ensure that child restraint buckles are easy to operate.(See, 50 Federal Register 33722.)The buckle release mechanism must be sufficiently large enough to reduce the force to surface ratio required to actuate release. The need to conveniently unbuckle a child restraint system (CRS) is of particular importance in emergency situations when there is a need to quickly remove a child from a CRS.
The release mechanism on your buckle does not accommodate two fingers of a majority of adults. The width of the index finger of a small, 5th percentile adult female at the knuckle nearest the hand is approximately 16 mm, and the width of the index finger of a 50th percentile male at the same position is approximately 21 mm.  Given the normal reduction in finger width at the tip as opposed to the knuckle nearest the hand and approximating the combined width of the index and middle finger, "two or more fingers" for a 5th percentile female is approximately 28 mm. The contactable surface for actuating the release on the Locktec buckle is less than 25 mm. As such, the vast majority of adults would be unable to place two fingers side-by-side to actuate the Locktec buckle.
We recognize that there is some ambiguity in the two-finger specification and that a more objective criteria, specifying a minimum linear width would be appropriate. We plan to address this requirement in future rulemaking. If you have any further questions, please feel free to contact Mr. Chris Calamita of this office at (202) 366-2992.
 Stephen Pheasant, "Bodyspace: Anthropometry, ergonomics, and the design of work" 49 (Taylor & Francis) (1996).
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.