Federal Motor Vehicle Safety Standards; Anti-Ejection Glazing for Bus Portals; Bus Emergency Exits and Window Retention and Release

SUPPLEMENTARY INFORMATION:

Table of Contents

I. Executive Summary

II. Background

a. NHTSA's Approach to Motorcoach Safety

b. U.S. DOT Motorcoach Safety Action Plan

c. Congressional Action: MAP-21 and the Motorcoach Enhanced Safety Act

d. NHTSA's 2013 Motorcoach Seat Belt Final Rule

e. NHTSA's 2021 Motorcoach Structural Integrity Final Rule

f. Data and Safety Need for Strengthening Motorcoach Window Glazing

g. The 2016 NPRM

III. NHTSA's Statutory Authority

a. National Traffic and Motor Vehicle Safety Act (Safety Act)

b. MAP-21 (Incorporating the Motorcoach Enhanced Safety Act of 2012)

IV. The Final Rule and Response to Comments

a. Establishing FMVSS No. 217a and New Requirements

b. Differences Between the NPRM and the Final Rule

V. Summary of Comments and Agency Responses

a. Overview of Comments

b. Applicability

c. Occupant Injury Protection

d. Test Procedures and Equipment

e. Performance Requirements

f. Organization of the Standard and Language Used in the Standard

g. Compliance Date

h. Retrofitting

i. Definitions and Descriptions

j. Costs and Benefits

VI. Overview of Costs and Benefits

VII. Regulatory Notices and Analyses

I. Executive Summary

In 2007, NHTSA published a comprehensive plan on possible improvements in motorcoach safety. NHTSA's motorcoach safety plan identified four specific areas to most expeditiously achieve our goals: requiring seat belts (minimizing passenger and driver ejection from the motorcoach), improved roof strength, emergency evacuation, and fire safety. This final rule is another step in the agency's efforts to improve over-the-road bus (OTRB ) and large bus safety. This final rule establishes a new FMVSS, FMVSS No. 217a, “Anti-Ejection Glazing for Bus Portals; Mandatory applicability beginning October 30, 2027,” to mitigate partial and complete ejection of passengers from windows on the side and roof of motorcoaches and large buses and to ensure that emergency exits remain operable after a rollover crash.

This final rule fulfills a statutory mandate in the Motorcoach Enhanced Safety Act of 2012 (Motorcoach Enhanced Safety Act), which was incorporated and passed as part of MAP-21. The Motorcoach Enhanced Safety Act required the DOT to prescribe regulations that address passenger ejection in motorcoaches. Additionally, MAP-21 required DOT to consider requiring advanced glazing standards for motorcoach portals.

The Motorcoach Enhanced Safety Act emphasizes anti-ejection safety countermeasures, particularly advanced glazing. Section 32703(b)(2) of MAP-21 directs the Secretary to consider requiring advanced glazing standards for each motorcoach portal and to consider other portal improvements to prevent partial and complete ejection of motorcoach passengers, including children. Section 32703(b)(2) also states that in prescribing such standards, the Secretary shall consider the impact of such standards on the use of motorcoach portals as a means of emergency egress. MAP-21 requires NHTSA to adopt a final rule if NHTSA determines that such standards meet the requirements and considerations in subsections (a) and (b) of section 30111 of the National Traffic and Motor Vehicle Safety Act. As discussed in this final rule, NHTSA has made such a determination regarding an FMVSS for motorcoaches and certain large buses.

The May 6, 2016, Notice of Proposed Rulemaking (NPRM) was among the rulemakings issued pursuant to NHTSA's 2007 Approach to Motorcoach Safety and DOT's Departmental Motorcoach Safety Action Plan. Both of these agency documents recognized that there was work to be done in protecting the public from death and serious injury in OTRB and large bus crashes. Although there are relatively few OTRB and large bus crashes when compared to other vehicle types, OTRB and large bus crashes tend to be serious when they do occur because they generally carry large numbers of passengers. Since producing these safety plans, NHTSA has promulgated several final rules targeted at protecting OTRB and large bus passengers. These final rules include a requirement that all seats on OTRBs and large buses be equipped with seat belts, a requirement that all OTRBs and large buses be equipped with electronic stability control, and requirements for improved structural integrity of OTRBs and large buses. This final rule is designed to work in tandem with these other requirements to further improve OTRB and large bus occupant safety.

While the agency's previous rulemakings in this area are expected to improve OTRB and large bus safety, passenger ejection in OTRB and large bus crashes remains a concern. Although seat belts are now required on OTRBs and large buses, not all states require that passengers wear seat belts on OTRBs and the agency believes seat belt use is generally low among large bus passengers. Additionally, while the structural integrity requirements enhance occupant safety by providing a “survival space” in a rollover, they do not mitigate glazing breakage during the crash, which would create ejection portals. This final rule is designed to ensure window glazing remains intact during a crash and windows do not open, even if a passenger is thrown against the glazing during the crash.

To accomplish this safety objective, the new FMVSS No. 217a specifies certain benchmarks that OTRB and large bus window glazing must meet when it is contacted by an impactor projected at the window at a specified speed. In the adopted test, a 26 kilogram (kg) (57 pound (lb)) impactor is propelled from inside a test vehicle toward the window glazing at 21.6 kilometers per hour (km/h) (13.4 miles per hour (mph)). Each side window and glass panel/window on the roof would be subject to any one of three impacts, as selected by NHTSA in a compliance test: (a) an impact near a latching mechanism, discrete attachment point, or (for windows without latches) the center of the lower window edge of an intact window; (b) an impact at the center of the daylight opening of an intact window; and (c) an impact at the center of the daylight opening of a pre-broken glazing. The windows would have to prevent passage of a 102-millimeter (mm) (4 inch) diameter sphere both during and after the impact. Additionally, emergency exits are required to remain operable after each impactor test. The impactor and impact speed simulate the loading from an average size unrestrained adult male thrown from one side of a large bus and impacting a window on the opposite side of the bus in a rollover.

These requirements would ensure that glazing is securely bonded to window frames, no potential ejection portals are created due to breaking of the glass, the windows remain closed when impacted, and emergency exits remain operable after the crash. The test with the pre-broken glazing would encourage the installation of advanced glazing. The requirement would also help ensure the advanced glazing reasonably retains occupants within the structural sidewall of the bus in a crash.

The requirements in FMVSS No. 217a apply to OTRBs and all new large buses, with limited exceptions. The standard does not apply to school buses, prison buses, buses with perimeter seating, or transit buses that are not OTRBs. The FMVSS No. 217a requirements generally apply to those buses that are also required to meet the rollover structural integrity requirements of FMVSS No. 227, “Bus rollover structural integrity.” School bus derivative buses that meet the school bus roof crush requirements of FMVSS No. 220, “School bus rollover protection,” instead of FMVSS No. 227, would also need to meet FMVSS No. 217a.

This final rule adds a new requirement to FMVSS No. 217, “Bus emergency exits and window retention and release,” that emergency exit window latches may not protrude more than 1 inch into the window opening when the window is open to minimize the potential for the latch protrusions to hinder the emergency egress of passengers. This requirement applies to all new buses that are currently subject to FMVSS No. 217, including new school buses.

NHTSA has decided not to require existing large buses to meet the requirements adopted today for new buses. Most of the commenters did not support a retrofitting requirement. Upgraded window glazing on older buses without the requisite improved structural integrity in accordance with FMVSS No. 227 may not mitigate occupant ejections because the advanced glazing could simply pop out of the portal due to excessive structural deformation in a crash. The agency has also decided not to require retrofitting of buses with improved latch designs and window glazing materials. NHTSA believes it is not practical to retrofit improved latch systems on windows of existing buses because of the unique condition (including pre-existing damage or deformation) of each existing window structure and latching mechanism.

NHTSA estimates that this rulemaking will be cost beneficial. The agency estimates the annual cost of this rule to be $0.96 million and annual undiscounted equivalent lives saved to be between 0.37 and 1.91. The main contributor to the cost of this rule is estimated as the material costs for manufacturers to upgrade their window units from a tempered/tempered double-glazed window unit to, at minimum, a laminated/tempered double-glazed window unit. This improvement in window unit construction would not result in a considerable weight change. As outlined in the Final Regulatory Evaluation (FRE), NHTSA projects that the rule would cost between $0.50 million to $4.30 million per equivalent life saved (Table 1). The net benefit/cost impact ranges from a net benefit of $1.92 million to $18.44 million (Table 2).