Source: https://www.federalregister.gov/articles/2007/11/21/07-5758/federal-motor-vehicle-safety-standards-seating-systems-occupant-crash-protection-seat-belt-assembly
Timestamp: 2016-08-29 18:02:17
Document Index: 759114298

Matched Legal Cases: ['§ 571', '§ 571', '§ 571', '§ 571', '§ 571', '§ 571', '§ 571', '§ 571', '§ 571', '§ 571', '§ 571']

Federal Register | Federal Motor Vehicle Safety Standards; Seating Systems, Occupant Crash Protection, Seat Belt Assembly Anchorages, School Bus Passenger Seating and Crash Protection
-65532 (24 pages)
Shorter URL: https://federalregister.gov/a/07-5758 Related Topics
Upgrade of School Bus Passenger Protection 3 actions from November 21st, 2007 to October 2008
This document proposes to upgrade the school bus occupant protection requirements of the Federal motor vehicle safety standards, primarily by amendments to Federal Motor Vehicle Safety Standard No. (FMVSS) No. 222, “School bus passenger seating and crash protection” (49 CFR 571.222), and by amendments to FMVSS Nos. 207, 208, and 210. It also provides guidance to state and local jurisdictions on the subject of installing seat belts on large school buses (school buses with a GVWR greater than 4,536 kilograms (kg) (10,000 pounds (lb)) and asks for comments on the agency's consideration of “best practices” concerning the belts on the large buses.
Requiring all school buses with seat bottom cushions that are designed to flip-up, typically for easy cleaning, to have a self-latching mechanism. The proposed guidance to state and local jurisdictions on best practices of installing seat belts on large school buses acknowledges that, in terms of the optimum passenger crash protection that can be afforded an individual passenger on a large school bus, a lap/shoulder belt system, together with compartmentalization, would afford that optimum protection. Thus, we encourage providers to consider lap/shoulder belts on large school buses. However, installing current lap/shoulder belts on large school buses would reduce the passenger carrying capacity of large buses. If children were diverted to other means of transport to school, such as transport by smaller, private vehicles, walking, or biking, the belts on the buses could result in an overall disbenefit to pupil transportation safety due to the children displaced from the large school buses having to find less safe modes of transportation to get to or from school or related events. Thus, we are not proposing to require lap/shoulder belts on large school buses, and we recommend providers to ascertain whether installing lap/shoulder belts would reduce the number of children that are transported to school on large school buses.
Effective since 1977, FMVSS No. 222 contains occupant protection requirements for school bus seating positions and restraining barriers. Its requirements for school buses with GVWR's of 4,536 kg (10,000 lb) or less differ from those set for school buses with GVWR's greater than 4,536 kg (10,000 lb), because the “crash pulse” or deceleration experienced by the small school buses is more severe than that of the large buses in similar collisions. For the small school buses, the standard includes requirements that all seating positions must be equipped with properly installed lap or lap/shoulder seat belt assemblies and anchorages for passengers.
NHTSA decided that seat belts were necessary on small school buses to provide adequate crash protection for the occupants. For the large school buses, FMVSS No. 222 relies on requirements for “compartmentalization” to provide passenger crash protection. Investigations of school bus crashes prior to issuance of FMVSS No. 222 found the school bus seat was a significant factor in causing injury. NHTSA found that the seat failed the passengers in three principal respects: by being too weak, too low, and too hostile (39 FR 27584; July 30, 1974). In response to this finding, NHTSA developed a set of requirements which comprise the “compartmentalization” approach.
III. The Issue of Seat Belts on Large School Buses Back to Top
IV. Studies Back to Top
Nonetheless, throughout the past 30 years that compartmentalization and the school bus safety standards have been in effect, the agency has openly and continuously considered the merits of a seat belt requirement for large school buses.
The issue has been closely analyzed by other parties as well, such as the National Transportation Safety Board, and the National Academy of Sciences. Various reports have been issued, the most significant of which are described below.
In 2002, NHTSA issued a Congressional Report that detailed occupant safety on school buses and analyzed options for improving occupant safety. NHTSA concluded that compartmentalization effectively lowered injury measures by distributing crash forces with the padded seating surface. Lap belts showed little to no benefit in reducing serious/fatal injuries. The agency determined that properly used combination lap and shoulder belts have the potential to be effective in reducing fatalities and injuries for not only frontal collisions, but also rollover crashes where belt systems are particularly effective in reducing ejection. However, the addition of lap/shoulder belts on buses would increase capital costs and reduce seating capacity on the buses. (“Report to Congress, School Bus Safety: Crashworthiness Research, April 2002,”http://www-nrd.nhtsa.dot.gov/departments/nrd-11/SchoolBus/SBReportFINAL.pdf.)
V. Federal Guidance on Belts on Large Buses Back to Top
This guidance is provided in response to the information that the agency received at its July 11, 2007 public meeting in Washington, DC on seat belts on school buses (notice of public meeting, 72 FR 30739, June 4, 2007, Docket 28103).
In this meeting, NHTSA brought together a roundtable of State and local government policymakers, school bus and seat manufacturers, pupil transportation associations, and consumer groups to address: State and local policy perspectives regarding whether to require seat belts on school buses; information on the type of seat belt system designs that are currently being offered on large school buses; the economic impact that implementation of seat belt requirements for school buses (including purchase and maintenance of belts) have on States and local school districts; and the experience of schools and States in training and educating children, parents and drivers to use seat belts on large school buses.
At the meeting, participants requested that NHTSA provide up-to-date Federal guidance on whether seat belts should be provided on school buses, and whether lap belts should or should not be installed.
Mr. Ken Hedgecock of Thomas Built Buses stated that two-point belts are on 27 percent of the school buses Thomas Built manufactures, and three-point belts are on 2 percent the school buses that it manufactures. Mr. Hedgecock said that the greatest concern relating to seat belts pertains to capacity and cost issues of the three-point belt system. The reduction in capacity and incremental costs of the three-point system may have the unintended consequence of transporting fewer children on the yellow school bus, thus negatively affecting the safety of our nation's children. Mr. Hedgecock recommended the following as it pertains to seat belts: Clarification is needed on the use of two-point belt systems versus three-point belt systems in school buses; clarification is needed on the designated seating position as it pertains to a seat with seat belts; and there is a need for clear performance standards for the integration of all systems: the school bus, the seat, and the belts.
In the crash test, we used Hybrid III 50th percentile adult male dummies (representing adult and large teenage occupants), 5th percentile adult female (representing an average 12-year-old (12YO) occupant), and a 6-year-old child dummy (representing an average 6-year-old (6YO) occupant). The dummies were seated so that they were as upright as possible and as rearmost on the seat cushion as possible. The agency evaluated the risk of head injury recorded by the dummies (Head Injury Criterion (HIC15)), as well as the risk of chest (chest G's) and neck injury (Nij),
as specified in FMVSS No. 208 “Occupant crash protection.”
NHTSA studied three different restraint strategies: (a) compartmentalization; (b) lap belt (with compartmentalization); and, (c) fore/aft loading.
Low head injury values were observed for all dummy sizes, except when override
Compartmentalization of 6YO and 5th percentile female dummies did not appear to be sensitive to rear loading conditions.
School buses are one of the safest forms of transportation in the U.S. Every year, approximately 474,000 public school buses, transporting 25.1 million children to and from school and school-related activities,
travel an estimated 4.8 billion route miles.
Over the 11 years ending in 2005, there was an annual average of 26 school transportation related fatalities (11 school bus occupants (including drivers and passengers) and 15 pedestrians).
The bus occupant fatalities were comprised of six school-age children, with the remaining being adult drivers and passengers.
On average, there were 9 crashes per year in which an occupant was killed. The school bus occupant fatality rate of 0.23 fatalities per 100 million vehicle miles traveled (VMT) is more than six times lower than the overall rate for motor vehicles of 1.5 per 100 million VMT.
The agency's school bus research results indicated that lap/shoulder belts could enhance the safety of large school buses, such that a child who has a seat on the school bus and who is belted with a lap/shoulder belt on the bus would have an even lower risk of head and neck injury than on current large school buses.
Thus, if ample funds were available for pupil transportation, and pupil transportation providers could order and purchase a sufficient number of school buses needed to provide school bus transportation to all children, we would recommend that pupil transportation providers consider installing lap/shoulder belts on large school buses because of the enhancements that lap/shoulder belts could make to school buses. Realistically, however, we recognize that funds provided for pupil transportation are limited, and that the monies spent on lap/shoulder belts on large school buses would usually draw from the monies spent on other crucial aspects of school transportation, such as purchasing new school buses to ensure that as many children as possible are provided school bus transportation, on driver and pupil training on safe transportation practices, and on upkeep and maintenance of school buses and school bus equipment. Bearing these considerations in mind, we recommend that pupil transportation providers consider lap/shoulder belts on large school buses only if there would be no reduction in the number of children that are transported to or from school or related events on large school buses. Reducing bus ridership would likely result in more student fatalities, since walking and private vehicles are less safe than riding a large school bus without seat belts.
Best practices compel us to encourage pupil transportation providers to make a comprehensive analysis of their needs and determine how lap/shoulder belts on large school buses accord with those needs. The best practices approach we have developed allows States the leeway to decide whether to require seat belts on large school buses, and whether lap only or lap/shoulder belts should be ordered. Given the tradeoff noted above, States should be permitted the flexibility of deciding whether to order large school buses with the seat belt safety enhancements after considering the excellent safety record of large school buses with compartmentalization, the benefits of allocating resources to belts as opposed to alternative safety measures, and the means available to ensure that the belts would be used. If a State were to determine that lap/shoulder belts are in its best interest, NHTSA encourages the State to install those systems. Today's document proposes performance requirements for the lap/shoulder belts, to ensure they will work well in a crash even if voluntarily installed. Certain highway safety grant funds may continue to be used to fund the purchase and installation of seat belts (lap or lap/shoulder) on school buses. Annually, all States, the District of Columbia, Puerto Rico, the Bureau of Indian Affairs, and the U.S. territories receive NHTSA Section 402 State and Community Highway Safety Formula Grant Funds. A wide range of behavioral highway safety activities that help reduce crashes, deaths, and injuries, including seat belt-related activities, qualify as eligible costs under the Section 402 program. Each State determines how to allocate its funds based on its own priorities and identified highway safety problems as described in an annual Highway Safety Plan (HSP).
In the July 11, 2007 public meeting, some participants asked for guidance on whether lap belts should be prohibited on large school buses. The question was asked in the aftermath of school bus research studies that found lap belts were associated with increased risk of injury on large school buses.
After considering the data and other information on lap belts on large school buses, NHTSA does not believe there is a need to prohibit lap belts on the buses. In its 1999 report on bus crashworthiness, the NTSB concluded that the compartmentalization requirement for school buses in FMVSS No. 222 is incomplete in addressing school bus occupant protection in rollovers and lateral impacts from large vehicles, in that in such crashes, passengers do not always remain completely within the seating compartment. Although we have not found a safety need exists with respect to those non-frontal crashes to warrant requiring seat belts on large school buses,
we have always permitted States to choose to require the belts over and above the Federally required compartmentalization in the school buses they purchase.
VI. Proposed Upgrades to Occupant Crash Protection Back to Top
The third set of upgrades involves requirements for voluntarily-installed seat belts on large school buses. For large school buses with voluntarily-installed lap/shoulder belts, the vehicle would be subject to the requirements described above for lap/shoulder belts on small school buses, except FMVSS No. 207 would not apply to the passenger seats. The quasi-static test procedures for small school buses would slightly vary from those applying to seats on large school buses with voluntary lap/shoulder belts, to account for crash characteristic differences of large school buses versus small school buses.(Due to the mass and other characteristics of the vehicles, in crashes small school buses are subject to higher severity forces than large school buses.)
These proposed requirements are discussed below.
In addition, NHTSA has prepared a Technical Analysis that, among other things, presents a detailed analysis of data, engineering studies, and other information supporting these proposals.
A copy of this Technical Analysis will be placed in the docket.
Seat cushion latches. At present, FMVSS No. 222 at S5.1.5 requires seat bottom cushions to withstand an upward force that is five times the weight of the seat bottom cushion. S5.1.5 specifies that, with all manual attachment devices between the seat and the seat cushion in the manufacturer's designated position for attachment, the seat cushion shall not separate from the seat at any attachment point when subjected to an upward force in Newtons of 5 times the mass of the seat cushion in kilograms and multiplied by 9.8 m/s
, applied in any period of not less than 1 nor more than 5 seconds, and maintained for 5 seconds.
The agency proposes that small school buses be required to have lap/shoulder belts at all passenger seating positions. Since the FMVSSs were first promulgated, small school buses passenger seats have been required to have passenger lap belts (defined as Type 1 belts in FMVSS No. 209) as specified in FMVSS No. 208, that meet the lap belt strength requirements specified in FMVSS No. 210. Lap belts were required because the ratio of the mass of a potential collision partner to that of a small school bus is larger than for a large school bus. Thus, for vehicle-to-vehicle collisions, the deceleration of a small school bus will be greater than for a large school bus. However, before today, we have never sought to require lap/shoulder belts for all passenger seats in small school buses.
Finally, while installation in large school buses could result in a 17 percent reduction in seating capacity, small school buses are already configured with seating positions that can accommodate lap/shoulder belts without a reduction in seating capacity.
In the agency's school bus research program, we saw examples of improper seat anchorage location. The first set of lap/shoulder belt seats supplied for testing in the school bus research program did not have the anchorages of the lap/shoulder belts located so that the seat belts would fit appropriately on any of the test dummies. The torso belt came across the dummies' heads and necks and the lap belt was high on the abdomen instead of on the hips. After consultation with the seat manufacturer, a second set of lap/shoulder belt equipped seats had seat belt anchorages such that the seat belts fit all of the test dummies (6-year-old to 50th percentile male) properly. The torso belt anchorage was higher on the seat back to allow for proper placement of the torso belt on taller people.
Also, as in the previously supplied seats, the shoulder belt had an adjustable anchorage that slides up and down a second shoulder belt so it could properly adjust for the sitting height of the typical 6-year-old through the adult size passenger.
We are aware that lap belts supplied to some states have a long buckle end that causes the lap belt to not fit low across the hips of the passengers. The long buckle end also causes problems with securing child restraints.
However, our understanding is that long buckle ends have been provided out of a privacy concern about school bus personnel fastening lap belts near the crotch area of young passengers. Comments are requested on whether long buckle stalks should be retained on lap belts because of the privacy issues, even if the long buckle stalks may result in misplacement of the lap belt across the child's abdomen and difficulty in child restraint attachment.
Maximum number of lap/shoulder seat belts and minimum seat width. In S4.1 of FMVSS No. 222, NHTSA currently considers the number of seating positions on a bench seat to be the width of the bench seat in millimeters (W), divided by 381 and rounded to the nearest whole number. This W value is used to calculate the compartmentalization requirements for seat backs on all school buses and the number of lap belt only seating positions that must meet the provisions of FMVSS No. 208 and 210 for small school buses. The agency will continue to consider W to be the number of seating positions per bench seat with optional provided lap belts on large school buses as well as the compartmentalization requirements for all school buses, except that the divisor will be 380 rather than 381. (Using 380 instead of 381 would just be for simplicity.) However, for the seating positions on small school buses with required lap/shoulder belts and on large school buses with optional lap/shoulder belts, we are defining the number of seating positions (Y) in a slightly different way. Y is the total seat width in millimeters divided by 380, rounded down to the nearest whole number. Under the definitions of W and the proposed definition of Y, a 1,118 mm (44 inch) wide seat would have W = 3 seating positions for the purposes of calculating the magnitude of the compartmentalization requirements to apply to the seat back, but only Y = 2 seating positions for determining the lap/shoulder belts installed on the seat.
The result of this “Y” calculation would be that each passenger seating position in a school bus seat with a lap/shoulder belt would have a minimum seating width of 380 mm (15 inches). A proposed minimum seating position width of 15 inches for seats with lap/shoulder belts is needed because school buses are typically purchased based on maximum seating capacity, and we seek to ensure that manufacturers will not install lap/shoulder belt anchorages that are so narrowly spaced that they would only fit the smallest occupants.
The agency is proposing to apply FMVSS No. 207 to small school buses with lap/shoulder belts because the load imposed by FMVSS No. 207 appears to be greater than the load that would be imposed by FMVSS No. 222's seat performance requirements (S5.1.3). If we assume a seat mass of 35 kg (77 pounds),
the FMVSS No. 207 load would be 6,867 N (1,544 pounds). For a school bus seat with two seating positions, the FMVSS No. 210 load would be a total of 53,376 N (12,000 pounds). So if FMVSS No. 207 were applied it would add 12 percent [((53,376 N + 6,867 N)/53,376 N) − 1)] to the total load. This would result in a more stringent test procedure. Comments are requested on whether FMVSS No. 207 should be applied to small school bus passenger seats.
Large school buses with voluntarily-installed lap/shoulder seat belts would be subject to the requirements described above for lap/shoulder belts on small school buses, except FMVSS No. 207 would not apply to the passenger seats,
and as explained in the next section, the quasi-static test procedures for small school buses would slightly vary from those applying to seats on large school buses with voluntary lap/shoulder belts, to account for the relative severity of the anticipated frontal crash conditions for each school bus type.
This testing suggested that the total peak dynamic loading sustained by the seat belts was about2/3of that applied in FMVSS No. 210. Notwithstanding the above data, the agency believes that the anchorage strength provided by FMVSS No. 210 provides the foundation for seat belt performance and there is value in maintaining consistency in this foundation. We understand that this higher factor of safety may result in seats and anchorages being constructed with heavier materials and may in turn increase the weight and cost of providing seat belts on large school buses. However, it is also possible that those putting seat belt anchorages on large school buses may use existing designs for small school buses that have always needed to meet the same strength level that is now being proposed for large school buses.
VII. Quasi-Static Test for Lap/Shoulder Belts on Small and Large School Buses Back to Top
The agency has developed a quasi-static test procedure for lap/shoulder belt-equipped seats in school buses and proposes to apply this test to small and large school buses equipped with lap/shoulder belts. The test is intended to address possible safety problems caused by having both belted and unbelted passengers on the same school bus. School bus seats designed to provide compartmentalized protection must contain the child between well-padded seat backs that provide controlled ride-down in a crash. A school bus seat with a lap/shoulder belt would have the torso (shoulder) belt attached to the seat back. In a crash involving a belted child and an unbelted child aft of the belted occupant, the seat back would be subject to consecutive force applications from the belted occupant's torso loading the seat back and the force generated by impact of the unbelted passenger. The quasi-static test replicates this double-loading scenario and specifies limits on how far forward the seat back may displace. The test helps ensure that the top of a seat back does not pull too far forward and jeopardize the protection of compartmentalized passengers to the rear of the belted occupants, or diminish the torso restraint effectiveness for lap/shoulder belted occupants.
This crash scenario is replicated in the quasi-static test. The load requirement for the quasi-static test is dependant upon the number of seating positions and also the likely seat capacity. A seat that has the minimal allowed overall seat width for either a two or three occupant seat will have a reduced loading requirement from other seats.
The agency is proposing that a 5,000 N (1,124 pounds) load per occupant be applied in the quasi-static test; however, seats with a minimal allowed overall seat width would have a 3,300 N (750 pounds) load per occupant applied.
The reason for the reduced load requirement for the minimal width seats is that students at the 50th percentile male or larger size would not be able to simultaneously occupy each of the seating positions. For example, a 45 inch seat would have a seating capacity of three, or the minimum allowed overall seat width for a three occupant seat. However, a common practice used for the seating configuration in large school buses to be equipped with lap/shoulder belts has been to install a 1,143 mm (45 inches) three position seat on one side of the aisle and a 762 mm (30 inches) two position seat on the other side of the aisle in each row of the bus. To accommodate students larger than the 5th percentile female, schools typically seat two persons in the 1,143 mm (45 inches) seat and one person in the 762 mm (30 inches) seat. Because the seat width is not sufficient to accommodate the 50th percentile occupants at the full seating capacity (i.e., three in the 1,143 mm and two in the 762 mm seats), we are proposing that the quasi-static torso belt test have a reduced load.
We believe that if the seat has the minimal allowed overall seat width it is reasonable to reduce the total torso belt loading applied to the seat in the quasi-static test to a per occupant value below the loading applied for larger seating width, since larger occupants would not occupy those seats to the full seating capacity. To estimate the appropriate load value, we assume the worst case loading condition is approached when every seating position is occupied by a child as large as a 5th percentile adult female.
We also believe the proposed loading requirements are practicable. Testing at NHTSA's Vehicle Research Test Center revealed that existing lap/shoulder belt equipped seats could meet a torso body block pull of 3,300 N (750 pounds) per occupant.
NHTSA in-vehicle testing at MGA Research Corporation of three-position, 1,143 mm (45 inches) seats with lap/shoulder belts in a large school bus, also revealed that these seats would pass the quasi-static test.
This part of the quasi-static test replicates steps 1 and 2 of the crash scenario above. The proposed procedure uses the knee and top loading bars that are currently specified in S5.1.3 of FMVSS No. 222 (seat back strength), which replicate a passenger's knee and torso loading the forward seat back
and the FMVSS No. 210 upper torso body block.
The test procedure uses the bottom loading bar to replicate the knee loading by the unbelted rear passengers (based on W), then specifies a pull test on the shoulder belts at each seating position in the seat to replicate loading of the shoulder belt by the belted passengers (based on Y). Under the proposed test procedure, the large school bus shoulder belts would be pulled using the upper torso body block specified in Figure 3 of FMVSS No. 210 with a force of 5,000 N (1,124 pounds) at each seating position for large school buses, and a force of 7,500 N (1,686 pounds) for small school buses.
The proposed rule (S5.1.6.5.4) includes a very specific procedure for positioning the torso body block. The torso body block force would be applied in not less than 5 and not more than 30 seconds. We found that an applied load of 5,000 N (1,124 pounds) for large school buses was necessary to replicate the torso belt loading from the sled test and to get the similar seat response observed from high speed video. This is slightly higher than twice the highest reading of the shoulder belt load cell (2,161 N). For small school buses, a higher force is proposed because the small school bus crash pulse has twice the peak acceleration of the large school bus, i.e., approximately 25 g.
Basically, for large school buses, the allowable displacement is equivalent to the amount of displacement that would result from the seat back deflecting forward 10 degrees past a vertical plane.
For large school buses, we propose that θ (theta) in the equation below be limited to 10 degrees as shown in Figure 9 of the proposed regulatory text. Thus, the total allowable forward horizontal displacement for large school buses would be:
The quasi-static test continues with procedures to replicate steps 3, 4 and 5 of the crash scenario above. After the torso anchorage displacement is measured, the torso body block load is released. Immediately after this load is released, forward load is applied to the seat back through the top loading bar. The seat back must be able to absorb the same amount of energy per seating position (452 joules (4,000 in-pounds)) as is required of a seat back under the compartmentalization requirement. However, for this quasi-static test, the seat back need not perform such that the top loading bar force must stay in the force/deflection corridor specified for the compartmentalization requirement.
This is because the torso body block load may have generated stresses in the seat frame that exceed the elastic limit of the material and result in residual strain. The seat back would still need to have the capability to absorb 452 joules of energy from the unbelted rear occupant, but the manner of absorbing the energy would not be as controlled as when impacting a seat back that had not been subjected to the previous loading from the seat belts.
VIII. Lead Time Back to Top
IX. Rulemaking Analyses and Notices Back to Top
This rulemaking document was not reviewed by the Office of Management and Budget under E.O. 12866 and is not considered to be significant under E.O. 12866 or the Department's Regulatory Policies and Procedures (44 FR 11034; February 26, 1979). NHTSA has prepared a preliminary regulatory evaluation (PRE) for this NPRM.
This NPRM proposes: (a) For all school buses, to increase seat back height from 20 inches to 24 inches, and to require a self-latching mechanism for seat bottom cushions that are designed to flip-up
; and (b) for small school buses (GVWR of 4,536 kg (10,000 lb) or less, require lap/shoulder belts instead of just lap belts. The belt systems would be required to meet specifications for retractors, strength, location and adjustability. Seat backs with lap/shoulder belts would be subject to a quasi-static test so that the seat backs are strong enough to withstand the forces from a belted passenger and force imposed on the seat from unbelted passenger seated behind rear the belted occupant. This NPRM also proposes: (c) Performance requirements for voluntarily-installed seat belts on large (over 4,536 kg (10,000 lb)) school buses. For large school buses with voluntarily-installed lap/shoulder belts, the vehicle would be subject to the requirements described above for lap/shoulder belts on small school buses, except that applied test forces and performance limits would be adjusted so as to be representative of those imposed on large school buses. Large school buses with voluntarily-installed lap belts would be required to meet anchorage strength requirements. This NPRM does not require seat belts to be installed on large school buses. The proposed performance requirements for seat belts on large school buses affect large school buses only if purchasers choose to order seat belts on their vehicles.
Costs of Higher Seat Backs on Large School Buses—If this NPRM were made final, all large school buses would be required to have the higher seat backs of 24 inches. NHTSA estimates the cost per large school bus of the higher seat back to be $125. If this NPRM were made final, NHTSA estimates that the total costs of the higher seat backs on large school buses to be $3,680,000 (29,362 large school buses times $125.40). Benefits of Higher Seat Backs on Large School Buses—If this NPRM were made final, the benefits from higher seat backs on large should buses is estimated to be 29.6 fewer injuries per year, and 0.2 fewer fatalities per year.
Table 1.—Total Costs (per bus and for the Fleet) Back to Top
20 Passenger.
Per Bus Costs
$2,481.
Annual Fleet Costs
Combined Annual Fleet Costs
$6.6 to $9.9 Million
Table 2.—Total Benefits Back to Top
1We did not have test data to allow us to separate out the high back seats from lap/shoulder belts for small school buses; thus, these data have been combined.
Combined below1
NHTSA has considered the effects of this rulemaking action under the Regulatory Flexibility Act. According to 13 CFR Section 121.201, the Small Business Administration's size standards regulations used to define small business concerns, school bus manufacturers would fall under North American Industry Classification System (NAICS) No. 336111, Automobile Manufacturing, which has a size standard of 1,000 employees or fewer. Using the size standard of 1,000 employees or fewer, NHTSA estimates that there are two small school bus manufacturers in the United States (U.S. Bus Corp. and Van-Con). NHTSA believes that both U.S. Bus Corp and Van-Con manufacture small school buses and large school buses. I hereby certify that if made final, this proposed rule would not have a significant economic impact on a substantial number of small entities. If this NPRM were made final, the small businesses manufacturing small buses would incur incremental costs ranging from a low of $1,166 to $2,481 per small school bus, out of a total cost of $40,000 to $50,000 per small school bus. The small businesses manufacturing large school buses would incur incremental costs of $125 per school bus (out of a total of more than $70,000) for the costs of the higher seat backs. The costs of lap/shoulder belts on large school buses is not a factor, as nothing in this NPRM would require lap/shoulder belts or lap belts at passenger seating positions in large school buses.
X. Public Participation Back to Top
Please note that pursuant to the Data Quality Act, in order for substantive data to be relied upon and used by the agency, it must meet the information quality standards set forth in the OMB and DOT Data Quality Act guidelines. Accordingly, we encourage you to consult the guidelines in preparing your comments. OMB's guidelines may be accessed at http://www.whitehouse.gov/omb/fedreg/reproducible.html. DOT's guidelines may be accessed at MACROBUTTON HtmlResAnchor http://dmses.dot.gov/submit/DataQualityGuidelines.pdf.
Appendix A to the Preamble—Proposed Amendments to Federal Motor Vehicle Safety Standards Back to Top
3. Specify lockability requirements for seat belts on school buses. c. Amend FMVSS No. 210, Seat Belt Assembly Anchorages, to:
S4.4.3.3 School buses with a gross vehicle weight rating of 4,536 kg (10,000 pounds) or less.
(c) The lap belt portion of a Type 2 seat belt assembly installed at the driver's designated seating position and at the right front passenger's designated seating position (if any) shall include either an emergency locking retractor or an automatic locking retractor, which retractor shall not retract webbing to the next locking position until at least3/4inch of webbing has moved into the retractor. In determining whether an automatic locking retractor complies with this requirement, the webbing is extended to 75 percent of its length and the retractor is locked after the initial adjustment. If a Type 2 seat belt assembly installed in compliance with this requirement incorporates any webbing tension-relieving device, the vehicle owner's manual shall include the information specified in S7.4.2(b) of this standard for the tension-relieving device, and the vehicle shall comply with S7.4.2(c) of this standard.
S4.4.5 Buses with a GVWR of 10,000 lb (4,536 kg) or less, except school buses, manufactured on or after September 1, 2007.
S4.4.5.1Except as provided in S4.4.5.2, S4.4.5.3, S4.4.5.4, S4.4.5.5 and S4.4.5.6, each bus as with a gross vehicle weight rating of 10,000 lb (4,536 kg) or less, except school buses, shall be equipped with a Type 2 seat belt assembly at every designated seating position other than a side-facing position. Type 2 seat belt assemblies installed in compliance with this requirement shall conform to Standard No. 209 (49 CFR 571.209) and with S7.1 and S7.2 of this standard. If a Type 2 seat belt assembly installed in compliance with this requirement incorporates a webbing tension relieving device, the vehicle owner's manual shall include the information specified in S7.3.1(b) of this standard for the tension relieving device, and the vehicle shall conform to S7.4.2(c) of this standard. Side-facing designated seating positions shall be equipped, at the manufacturer's option, with a Type 1 or Type 2 seat belt assembly.
S7.1.5The seat belt assembly will operate by means of any emergency-locking or automatic-locking retractor that conforms to 49 CFR 571.209 to restrain persons whose dimensions range from those of an average 6-year-old child to those of a 50th percentile adult male. The seat back may be in any position.
4. Section 571.210 is amended by revising S2, amending S3 by adding definitions for “school bus torso belt adjusted height” and “school bus torso belt anchor point,” in alphabetical order, adding S4.1.3, and S4.1.3.1 through S4.1.3.5, and adding Figure 4 to the end of the section to read as follows:
§ 571.210 Standard No. 210; Seat belt assembly anchorages.
S3.Definitions.
S4.1.3.1Seat belt anchorages on school buses manufactured on or after [insert compliance date of the final rule] must be attached to the school bus seat structure and the seat belt shall be Type 1 or Type 2 as defined in S3 of FMVSS No. 209 (49 CFR 571.209).
S4.1.3.2Type 2 seat belt anchorages on school buses manufactured on or after [insert compliance date of the final rule] must meet the location requirements specified in Figure 4. The vertical height of the school bus torso belt anchor point must be at least 520 mm above the seating reference point. The school bus torso belt adjusted height must be adjustable from the torso belt anchor point to within at least 280 mm of the seating reference point.
S4.1.3.3School buses with a GVWR less than or equal to 4,536 kg (10,000 pounds) must meet the requirements of S4.1.1 of this standard.
S4.1.3.4School buses with a GVWR greater than 4,536 kg (10,000 pounds) manufactured on or after [insert compliance date of the final rule], with Type 1 seat belt anchorages, must meet the strength requirements specified in S4.2.1 of this standard.
S4.1.3.5School buses with a GVWR greater than 4,536 kg (10,000 pounds) manufactured on or after [insert compliance date of the final rule], with Type 2 seat belt anchorages, must meet the strength requirements specified in S4.2.2 of this standard.
(b) The number of seating positions and the number of Type 1 seat belt positions considered to be in a bench seat for vehicles manufactured on or after [insert compliance date here] is expressed by the symbol W, and calculated as the seat bench width in millimeters divided by 380 and rounded to the nearest whole number.
(2) Each school bus manufactured on or after [insert compliance date] with a gross vehicle weight rating of more than 4,536 kg (10,000 pounds) shall be capable of meeting any of the requirements set forth under this heading when tested under the conditions of S6 of this standard or § 571.210. However, a particular school bus passenger seat (i.e., a test specimen) in that weight class need not meet further requirements after having met S5.1.2 and S5.1.5, or having been subjected to either S5.1.3, S5.1.4, S5.1.6 (if applicable), or S5.3. Each vehicle with voluntarily installed Type 1 seat belts and seat belt anchorages at W seating positions in a bench seat or Type 2 seat belts and seat belt anchorages at Y seat belt positions in a bench seat shall also meet the requirements of:
(iii) Standard No. 210 (49 CFR § 571.210) as it applies to school buses with a gross vehicle weight rating greater than 10,000 pounds.
(ii) In the case of vehicles manufactured on or after September 1, 1991, the requirements of S4.4.3.3 of § 571.208 and the requirements of §§ 571.209 and 571.210 as they apply to school buses with a gross vehicle weight rating of 4,536 kg or less;
(iii) In the case of vehicles manufactured on or after [insert compliance date of the final rule] the requirements of S4.4.3.3(b) of § 571.208 and the requirements of §§ 571.209 and 571.210 as they apply to school buses with a gross vehicle weight rating of 4,536 kg or less; and
(2) The requirements of S5.1.2, S5.1.3, S5.1.4, S5.1.5, S5.1.6, S5.3, and S5.4 of this standard. However, the requirements of §§ 571.208 and 571.210 shall be met at Y seat belt positions in a bench seat, and a particular school bus passenger seat (i.e. a test specimen) in that weight class need not meet further requirements after having met S5.1.2 and S5.1.5, or after having been subjected to either S5.1.3, S5.1.4, S5.1.6, or S5.3 of this standard or § 571.210 or § 571.225.
S5.1.5 Seat cushion retention.
S5.1.6Quasi-static test of compartmentalization and Type 2 seat belt performance.
S5.1.6.1This section applies to rear passenger seats on school buses manufactured on or after [compliance date to be inserted] with a gross vehicle weight rating of more than 4,536 kg (10,000 pounds), and that are equipped with Type 2 seat belt assemblies. When tested under the conditions of S5.1.6.5.1 through S5.1.6.5.6, the school bus torso belt anchor point must not displace horizontally forward more than the value in millimeters calculated from the following expression:
S5.1.6.2This section applies to rear passenger seats on school buses manufactured on or after [compliance date to be inserted] with a gross vehicle weight rating less than or equal to 4,536 kg (10,000 pounds), equipped with Type 2 seat belt assemblies. When tested under the conditions of S5.1.6.5.1 through 5.1.6.5.6, the school bus torso belt anchor point must not displace horizontally forward more than the value in millimeters calculated from the following expression:
S5.1.6.3 Angle of the posterior surface of a seat back. Position the loading bar specified in S6.5 of this standard so that it is laterally centered behind the seat back with the bar's longitudinal axis in a transverse plane of the vehicle in a horizontal plane within ± 6 mm (0.25 inches) of the horizontal plane passing through the seating reference point and move the bar forward against the seat back until a force of 44 N (10 pounds) has been applied. Position a second loading bar as described in S6.5 of this standard so that it is laterally centered behind the seat back with the bar's longitudinal axis in a transverse plane of the vehicle and in the horizontal plane 406 ± 6 mm (16 ± 0.25 inches) above the seating reference point, and move the bar forward against the seat back until a force of 44 N (10 pounds) has been applied. Determine the angle from vertical of a line in the longitudinal vehicle plane that passes through the geometric center of the cross-section of each cylinder, as shown in Figure 8. That angle is the angle of the posterior surface of the seat back.
S5.1.6.4The seat back must absorb 452W joules of energy when subjected to the force specified in S5.1.6.5.7.
S5.1.6.5.1If the seat back inclination is adjustable, the seat back is placed in the manufacturer's normal design riding position. If such a position is not specified, the seat back is positioned so it is in the most upright position.
S5.1.6.5.2Position the lower loading bar specified in S6.5 of this standard so that it is laterally centered behind the seat back with the bar's longitudinal axis in a transverse plane of the vehicle and in any horizontal plane between 102 mm (4 inches) above and 102 mm (4 inches) below the seating reference point of the school bus passenger seat behind the test specimen. Position the upper loading bar described in S6.5 so that it is laterally centered behind the seat back with the bar's longitudinal axis in a transverse plane of the vehicle and in the horizontal plane 406 mm (16 inches) above the seating reference point of the school bus passenger seat behind the test specimen.
S5.1.6.5.3Apply a force of 3,114W N (700W pounds) horizontally in the forward direction through the lower loading bar specified at S6.5 at the pivot attachment point. Reach the specified load in not less than 5 and not more than 30 seconds. No sooner than 1.0 second after attaining the required force, reduce that force to 1,557W N (350W pounds) and maintain the pivot point position of the loading bar at the position where the 1,557W N (350W pounds) is attained until the completion of S5.1.6.5.5 and S5.1.6.5.6 of this standard.
S5.1.6.5.4Position the body block specified in Figure 3 of FMVSS No. 210 (49 CFR 571.210) under each torso belt (between the torso belt and the seat back) in the passenger seat and apply a preload force of 300 N (67 pounds) on each body block in a forward direction parallel to the longitudinal centerline of the vehicle pursuant to the specifications of FMVSS No. 210 (49 CFR 571.210). After preload application is complete, the origin of the 203 mm body block radius at any point across the 102 mm body block thickness shall lie within the zone defined by S5.1.6.5.3(a) through S5.1.6.5.3(c):
S5.1.6.5.5(a) For school buses with a gross vehicle weight rating of 4,536 kg (10,000 pounds) or less, simultaneously apply the following force to each body block:
(1) If ((seat bench width in mm) − (380Y)) is 25 mm (1 inch) or less, apply 5,000 N (1,124 pounds); or
(2) If ((seat bench width in mm) − (380Y)) is greater than 25 mm (1 inch), apply 7,500 N (1,686 pounds).
(1) If ((seat bench width in mm) − (380Y)) is 25 mm (1 inch) or less, apply 3,300 N (742 pounds); or
(2) If ((seat bench width in mm) − (380Y)) is greater than 25 mm (1 inch), apply 5,000 N (1,124 pounds).
S5.1.6.5.6Reach the specified load in not less than 5 and not more than 30 seconds. Measure the torso belt anchor point horizontal displacement and then remove the body block.
S5.1.6.5.7Apply an additional force horizontally in the forward direction through the upper bar until 452W joules of energy have been absorbed in deflecting the seat back. The maximum travel of the pivot attachment point for the upper loading bar shall not exceed 356 mm as measured from the position at which the initial application of 44 N of force is attained. Apply the additional load in not less than 5 seconds and not more than 30 seconds. Maintain the pivot attachment point at the maximum forward travel position for not less than 5 seconds, and not more than 10 seconds and release the load in not less than 5 seconds and not more than 30 seconds. (For the determination of S5.1.6.5.7, the energy calculation describes only the force applied through the upper loading bar, and the forward and rearward travel distance of the upper loading bar pivot attachment point measured from the position at which the initial application of 44 N of force is attained.) If energy absorption of 452W joules cannot be obtained by the seat back, the test procedure is terminated and the seat back is determined to have failed to meet S5.1.6.4.
S5.1.7 Minimum seat width. For school buses manufactured on or after [compliance date to be inserted], each passenger seating position with a Type 2 restraint system shall have a minimum seating width and seat belt anchor width of 380 mm (15 inches).
1. “School bus” is defined in 49 CFR § 571.3 as a bus that is sold, or introduced in interstate commerce, for purposes that include carrying students to and from school or related events, but does not include a bus designed and sold for operation as a common carrier in urban transportation. A “bus” is a motor vehicle, except a trailer, designed for carrying more than 10 persons. In this NPRM, when we refer to “large” school buses, we refer to those school buses with GVWRs of more than 4,536 kg (10,000 lb). These large school buses may transport as many as 90 students. “Small” school buses are school buses with a GVWR of 4,536 kg (10,000 lb) or less. Generally, these small school buses seat 15 persons or fewer, or have one or two wheelchair seating positions.
6. HIC15, Chest G, and Nij values are used to predict injury risk in frontal crashes. HIC15 is a measure of the risk of head injury, Chest G is a measure of chest injury risk, and Nij is a measure of neck injury risk. The reference values for these measurements are the thresholds for compliance used to assess new motor vehicles with regard to frontal occupant protection during crash tests, FMVSS No. 208. For HIC15, a score of 700 is equivalent to a 30 percent risk of a serious head injury (skull fracture and concussion onset). In a similar fashion, Chest G of 60 equates to a 20 percent risk of a serious chest injury and Nij of 1 equates to a 22 percent risk of a serious neck injury. For all these measurements, higher scores indicate a higher likelihood of risk. For example, a Nij of 2 equates to a 67 percent risk of serious neck injury while a Nij of 4 equates to a 99 percent risk. More information regarding these injury measures can be found at NHTSA's Web site (http://www-nrd.nhtsa.dot.gov/pdf/nrd-11/airbags/rev_criteria.pdf).
19. FMVSS No. 208 (S4.4.5) requires buses, other than school buses, with a GVWR of 10,000 lb or less manufactured on or after September 1, 2007 to have lap/shoulder belts (Type 2 belts) at all passenger seating positions other than side-facing positions. Today's NPRM would be consistent with that requirement for the non-school buses. (We note that the heading of S4.4.5 of FMVSS No. 208 should specify that the section does not apply to small school buses. See http://dmses.dot.gov/docimages/pdf89/293807_web.pdf, NHTSA letter February 19, 2004, explaining the typographical error. Today's NPRM would correct the typographical error in S4.4.5.)
22. The short buckle length is recommended in NHTSA's pamphlet on the Proper Use of Child Safety Restraint Systems in School Buses. http://www.nhtsa.dot.gov/people/injury/buses/busseatbelt/index.html.
24. A 991 mm (39 inch) wide C.E. White seat weights 34.5 kg (76 pounds). See www.cewhite.com/cr-series-prod_info.html.