Mr. Brian Latouf
Global Safety & Field Investigations, Regulations & Certification
General Motors LLC, Mail Code: 480 210 2V
30001 Van Dyke
Warren, MI 48093-2350
Dear Mr. Latouf:
This letter responds to a letter from M. Carmen Benavides, dated March 7, 2013, requesting an interpretation of Federal Motor Vehicle Safety Standard (FMVSS) No. 209, “Seat belt assemblies.” We unfortunately did not receive the letter until it was subsequently emailed to us by your staff on May 24, 2016.
GM asks about section S4.5(b) of FMVSS No. 209 as applied to twelve- and fifteen-passenger buses with a gross vehicle weight rating (GVWR) greater than 8,500 pounds (lb) and less than or equal to 10,000 lb (“subject buses”). GM indicates that it is considering installing seat belts with load limiters (“load-limiting belts”) in the front outboard seating positions in the subject buses; the seat belts do not comply with the elongation requirements of FMVSS No. 209. GM requests an interpretation that would permit it to take advantage of a provision in S4.5 that permits the installation of load-limiting belts that do not comply with the elongation requirements in vehicles other than the subject buses. As we explain below, we decline to issue such an interpretation.
By way of background, FMVSS No. 209 specifies performance requirements for seat belts. Some of these requirements specify the maximum amount the webbing of a seat belt assembly is permitted to extend or elongate when subjected to certain specified forces. The purpose of the elongation requirements is to help ensure that the webbing will not stretch so much that the belt provides a lesser level of protection. A load limiter is a seat belt assembly component that controls tension on the seat belt and modulates or limits the forces that are imparted to a restrained vehicle occupant during a crash. Load limiters are intended to reduce head and upper torso injuries through increased energy management. They usually work in concert with an air bag system to optimize occupant protection in a crash.
Under S4.5(a) of FMVSS No. 209, load-limiting belts are not required to meet the elongation requirements. However, S4.5(b) in turn specifies where such load-limiting belts (i.e., those that do not meet the elongation requirements) may be installed:
A seat belt assembly that includes a load limiter and that does not comply with the elongation requirements of this standard may be installed in motor vehicles at any designated seating position that is subject to the requirements of S5.1 of Standard No. 208 (§ 571.208).
S5.1 of FMVSS No. 208, “Occupant crash protection,” establishes the minimum performance standards for occupant protection as measured in a frontal crash test. Section S4.5 of Standard No. 209 thus permits load-limiting seat belts that do not meet the elongation requirements of Standard No. 209 to be installed at any seating position that is subject to the frontal crash test requirements. The reason for allowing such load-limiting belts at those seating positions is that crash testing helps to ensure the load-limiting devices work in combination with an automatic restraint system (air bag) to provide occupants with protection from overly injurious contact with vehicle interior hard points. Stated differently, an air bag would mitigate the negative effect of the belt stretching beyond that allowed by the elongation limits of FMVSS No. 209.
GM asks if the front outboard designated seating positions in the subject buses can be fitted with load-limiting belts that do not comply with the elongation requirements. Our answer is no. Section S4.5(b) of FMVSS No. 209 allows such seat belts to be installed only at a “designated seating position that is subject to the requirements of S5.1 of Standard
No. 208[.]” The issue is thus whether the front outboard seating positions in the subject buses are “subject to the requirements of S5.1 of Standard No. 208.” As we explain below, they are not. There are two bases for this conclusion.
First, as GM observes in its letter, FMVSS No. 208 S5.1 is not a compliance requirement or option for the front outboard seats in the subject buses. The relevant occupant protection compliance options in FMVSS No. 208 for front outboard seats in current production buses in the 8,500 – 10,000 lb GVWR range are specified in S4.4.5 of FMVSS No. 208. This section requires that front outboard seating positions be equipped with Type 2 seat belts, but does not specify that these seating positions may or must comply with FMVSS No. 208 S5.1. (I note that NHTSA has amended the occupant protection requirements that apply to buses. These amendments became effective November 28, 2016. The amended requirements for the subject vehicles likewise do not specify S5.1 of FMVSS No. 208 as a compliance requirement or option.) Accordingly, the subject vehicles are not “subject to” S5.1; i.e., they are not required to comply with it.
Second, we decline to interpret “subject to” in FMVSS No. 209 S4.5(b) to include vehicles that a manufacturer voluntarily produces in accordance with S5.1 of FMVSS No. 208. The plain meaning of the phrase “subject to,” as well as the agency’s prior interpretations (discussed below), indicate that the phrase may not be read to refer to voluntary compliance with the requirements of FMVSS No. 208 S5.1.
The ordinary definition of the adjectival form of “subject” includes “liable to receive; exposed (to) [subject to censure].” This suggests that in order for a vehicle to be “subject to the requirements of” an FMVSS provision, the vehicle manufacturer must be exposed to some legal liability if it manufactures a vehicle that does not comply with that provision. A manufacturer, however, can be exposed to legal liability for violating an FMVSS provision only if that provision is a requirement or compliance option for the vehicle. The agency could find it unreasonably complicated to pursue a noncompliance enforcement action for a compliance requirement or option that is not applicable to that vehicle. To illustrate, if NHTSA were to conduct a frontal crash test of a subject bus and the test dummy readings were greater than the allowed injury assessment reference values of FMVSS No. 208, would that be a failure to comply with the standard? Might a manufacturer argue that the test is invalid since FMVSS No. 208 S5.1 did not strictly apply to the vehicle? We note that this usage of the phrase “subject to” is consistent with other NHTSA regulations, which similarly use the phrase “subject to” to refer to regulatory provisions that are compliance requirements or options.
In sum, since S5.1 is neither a requirement nor a compliance option with respect to the front outboard seating positions in the subject buses, the buses cannot be said to be “subject to” S5.1. Accordingly, they fail to qualify for the S4.5 load-limiting belt exemption.
This interpretation of FMVSS No. 209 S4.5(b) is consistent with prior agency interpretations of the provision.
We reached a similar result in an interpretation to Magna Steyr.  There, the agency was asked to interpret S4.5(b) of FMVSS No. 209 to permit load-limiting belts that did not comply with the elongation requirements in the rear outboard seating positions of passenger vehicles. We found that this was not permissible. We examined FMVSS No. 208 and determined that S5.1 applies only to front outboard seating positions. Accordingly, we concluded that “belts with load limiters installed at rear outboard seating positions must meet the elongation requirements of Standard No. 209.” We further explained that the manufacturer could not take advantage of the FMVSS No. 209 S4.5(b) exemption for the rear seating positions by “voluntarily” complying with S5.1 with respect to the rear seating positions. NHTSA stated:
Your message also asks if a manufacturer wishing to install belts with load limiters in a rear outboard seating position may comply with S4.5 of Standard No. 209 by verifying the performance of the belts through testing the belts by performing testing as set forth in S5.1 on the rear outboard seats. The answer is that belts installed at rear seating positions are subject to the elongation requirements and must meet them.
The issue we addressed in the Magna Steyr letter is similar to the issue raised by GM’s letter. Just as we there interpreted FMVSS No. 209 S4.5(b) to not apply to rear seating positions in passenger cars because those were not required to comply with FMVSS No. 208 S5.1, here we similarly find that FMVSS No. 209 S4.5(b) does not apply to the front outboard seating position in the subject vehicles because they are not required to comply with FMVSS No. 208 S5.1.
We reached a similar result in an interpretation to Ford. Ford submitted an interpretation request asserting that load limiters on dynamically-tested manual belts should be exempt from the elongation requirements. At the time of Ford’s request, FMVSS No. 209 S4.5(b) specified that a seat belt assembly that includes a load-limiter and that does not comply with the elongation requirements of this standard may be installed only in conjunction with an automatic restraint system. That is, the express terms of S4.5(b) at the time did not permit load-limiting manual belts that did not meet the elongation requirements. Ford sought an interpretation that S4.5(b) permitted load-limiting manual belts that did not meet the elongation requirements to be installed in seating positions that were subjected to dynamic tests. Ford argued that the reasoning that led the agency to exclude manual belts from the exemption was outmoded because dynamic testing requirements had, in the interim, been established for certain manual belts. The agency did not concur with Ford’s proposed interpretation because it would add a requirement that was not contained in the standard. NHTSA stated:
[S]ection S4.5 expressly provides that a belt assembly that “includes a load limiter and that does not comply with the elongation requirements of this standard may be installed in a motor vehicle only in conjunction with an automatic restraint system as part of a total occupant restraint system” . . . it is not possible to interpret the term “automatic restraint system,” as used in S4.5, to mean “automatic restraint system or dynamically tested manual restraint system.” An interpretation cannot add or delete requirements that are not contained in the language of the standard itself.
In short, prior interpretations are consistent with our interpretation today of FMVSS No. 209 S4.5(b) that the phrase “designated seating position that is subject to the requirements of S5.1” includes only seating positions for which S5.1 is a requirement or compliance option.
As GM points out in its letter, passenger cars, trucks and multipurpose passenger vehicles under 10,000 lb can take advantage of the FMVSS No. 209 S4.5 load-limiting belt exemption because a manufacturer may certify compliance of the front outboard seating positions in these vehicles with FMVSS No. 208 using S5.1. Further – as GM also points out – there well may be safety benefits to extending the FMVSS No. 209 S4.5 provision to the front outboard seating positions in the subject buses. Nevertheless, we cannot interpret the existing text of S4.5(b) in a way that would permit this. If you would like NHTSA to consider rulemaking to amend the language of the standard, you may submit a petition for rulemaking.
If you have any further questions, please contact John Piazza of my staff at (202) 366-2992.
Stephen P. Wood
Acting Chief Counsel
Ref: FMVSS 209
 See S4.2(c), S4.4(a)(2), S4.4(b)(4), and S4.4(b)(5).
 See 45 FR 51626 (Aug. 4, 1980).
 See also FMVSS 208, S4.6 (dynamic testing for manual belts on buses not required); 52 FR 44898, 44899 (Nov. 23, 1987) (explaining decision “not to apply a dynamic test requirement to buses at this time”).
 78 FR 70416 (Nov. 25, 2013).
 See id. at 70472.
 Webster’s New World Dictionary, Fourth College Edition 1425 (2008) (italics in original).
 See 49 U.S.C. § 30112(a)(1) (“[ A] person may not manufacture for sale, sell, offer for sale, introduce or deliver for introduction in interstate commerce, or import into the United States, any motor vehicle or motor vehicle equipment manufactured on or after the date an applicable motor vehicle safety standard prescribed under this chapter takes effect unless the vehicle or equipment complies with the standard[.]”) (emphasis added). A manufacturer that sells vehicles or equipment that do not comply with an applicable standard, must notify owners of the noncompliance and recall the vehicles. If a manufacturer does not comply with these requirements, the agency may issue a recall order. The agency may enforce that order in court, as well as seek civil penalties.
 See, e.g., 49 C.F.R. § 565.26(b) (“Manufacturers of vehicles subject to this part shall . . . .”).
 Letter to Doris Schaller-Schnedl, Magna Steyr Engineering (Sept. 19, 2001).
 Letter to Robert H. Munson, Ford Motor Co. (Mar. 28, 1989).
 49 C.F.R. § 571.209, S4.5(b) (1989) (“A Type 1 or Type 2 seat belt assembly that includes a load-limiter and that does not comply with the elongation requirements of this standard may be installed in motor vehicles only in conjunction with an automatic restraint system as part of a total occupant restraint system.”). Section S4.5 was subsequently amended to include load-limited manual belts. See 56 FR 15295 (Apr. 16, 1991).
 See FMVSS No. 208 S184.108.40.206 (passenger cars); S4.2.6 (trucks, MPVs, and buses with a GVWR of 8,500 lb or less and an unloaded vehicle weight of 5,500 lb or less); S4.2.3 (trucks and MPVs with GVWR greater than 8,500 lb and not more than 10,000 lb, or an unloaded weight greater than 5,500 lb and a GVWR not more than 10,000 lb).