Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86255 

Management, at 202–501–3822 or by 

email at travelpolicy@gsa.gov. Please 

cite Notice of GSA Bulletin FTR 25–02. 

SUPPLEMENTARY INFORMATION: 

Background 

Federal agencies authorize relocation 

entitlements to those individuals listed 

at FTR § 302–1.1 and those assigned 

under the Government Employees 

Training Act (GETA) (5 U.S.C. chapter 

41) which must be used within one 

year. Some agencies will authorize a 

househunting trip (HHT) to assist 

employees to seek permanent housing, 

while some employees are occupying 

temporary housing and have household 

goods in storage beyond the authorized 

timeframe of 150 to 180 days depending 

on the type of relocation. The FTR 

limits the timeframe to complete the 

relocation, household goods temporary 

storage, and the type of per diem for 

HHT. Hurricane/Tropical Storm/Posttropical Cyclone Helene and Hurricane 

Milton have affected locations in 

Alabama, Florida, Georgia, North 

Carolina, South Carolina, Tennessee, 

and Virginia, which has resulted in 

various travel-related disruptions to 

relocating employees. Accordingly, FTR 

Bulletin 25–02, Waiver of certain 

provisions of FTR Chapter 302 for 

official relocation travel to locations in 

Alabama, Florida, Georgia, North 

Carolina, South Carolina, Tennessee, 

and Virginia, impacted by Hurricane/ 

Tropical Storm/Post-tropical Cyclone 

Helene, Hurricane Milton, or both, 

allows agencies to determine whether to 

implement waivers of time limits 

established by the FTR for completion 

of all aspects of relocation and 

temporary storage of HHGs, as well as 

the limitation for HHTs to be 

reimbursed at the standard CONUS rate. 

GSA Bulletin FTR 25–02 can be 

viewed at https://www.gsa.gov/ 

ftrbulletins. 

Mehul Parekh, 

Acting Associate Administrator, Office of 

Government-wide Policy. 

[FR Doc. 2024–25361 Filed 10–29–24; 8:45 am] 

BILLING CODE 6820–14–P 

DEPARTMENT OF TRANSPORTATION 

National Highway Traffic Safety 

Administration 

49 CFR Part 571 

[Docket No. NHTSA–2024–0061] 

RIN 2127–AL36 

Federal Motor Vehicle Safety 

Standards; Anti-Ejection Glazing for 

Bus Portals; Bus Emergency Exits and 

Window Retention and Release 

AGENCY: National Highway Traffic 

Safety Administration (NHTSA), 

Department of Transportation (DOT). 

ACTION: Final rule. 

SUMMARY: This final rule establishes 

Federal Motor Vehicle Safety Standard 

(FMVSS) No. 217a, ‘‘Anti-ejection 

glazing for bus portals; Mandatory 

applicability beginning October 30, 

2027,’’ to drive the installation of 

advanced glazing in over-the-road buses 

(motorcoaches) and other large buses to 

reduce passenger and driver ejections. 

This final rule, issued pursuant to the 

Moving Ahead for Progress in the 21st 

Century Act (MAP–21), specifies 

impactor tests of the glazing material of 

side and roof windows. The impactor 

and impact speed simulate the loading 

from an average size unrestrained adult 

male impacting a window on the 

opposite side of a large bus in a rollover. 

DATES: 

Effective date: December 30, 2024. 

Compliance date: The compliance 

date for FMVSS No. 217a and the 

amendments to FMVSS No. 217 is 

October 30, 2027. Optional early 

compliance with the standards is 

permitted. 

Reconsideration date: If you wish to 

petition for reconsideration of this rule, 

your petition must be received by 

December 16, 2024. 

ADDRESSES: Petitions for reconsideration 

of this final rule must refer to the docket 

and notice number set forth above and 

be submitted to the Administrator, 

National Highway Traffic Safety 

Administration, 1200 New Jersey 

Avenue SE, Washington, DC 20590. 

Note that all petitions received will be 

posted without change to https://

www.regulations.gov, including any 

personal information provided. 

Docket: For access to the docket to 

read background documents or 

comments received, go to https://

www.regulations.gov at any time or to 

1200 New Jersey Avenue SE, West 

Building, Room W12–140, Washington, 

DC 20590, between 9 a.m. and 5 p.m., 

Monday through Friday, except Federal 

holidays. Telephone: (202) 366–9826. 

Privacy Act: The petition will be 

placed in the docket. Anyone is able to 

search the electronic form of all 

documents received into any of our 

dockets by the name of the individual 

submitting the comment (or signing the 

comment, if submitted on behalf of an 

association, business, labor union, etc.). 

You may review DOT’s complete 

Privacy Act Statement in the Federal 

Register published on April 11, 2000 

(Volume 65, Number 70; Pages 19477– 

78) or you may visit https://

www.transportation.gov/individuals/ 

privacy/privacy-act-system-recordsnotices. 

Confidential Business Information: If 

you wish to submit any information 

under a claim of confidentiality, you 

should submit three copies of your 

complete submission, including the 

information you claim to be confidential 

business information, to the Chief 

Counsel, NHTSA, at the address given 

under FOR FURTHER INFORMATION

CONTACT. In addition, you should 

submit two copies, from which you 

have deleted the claimed confidential 

business information, to Docket 

Management at the address given above. 

When you send a submission containing 

information claimed to be confidential 

business information, you should 

include a cover letter setting forth the 

information specified in our 

confidential business information 

regulation (49 CFR part 512). 

FOR FURTHER INFORMATION CONTACT: For 

technical issues, you may contact Mr. 

Dow Shelnutt, Office of 

Crashworthiness Standards, Telephone: 

(202) 366–8779, Facsimile: (202) 493– 

2739. For legal issues, you may contact 

Mr. Matthew Filpi, Office of the Chief 

Counsel, Telephone: (202) 366–2992, 

Facsimile: (202) 366–3820. The mailing 

address of these officials is: The 

National Highway Traffic Safety 

Administration, 1200 New Jersey 

Avenue SE, Washington, DC 20590. 

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 


ddrumheller on DSK120RN23PROD with RULES1
86256 Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 

1 Docket No. NHTSA–2007–28793, NHTSA’s 

Approach to Motorcoach Safety. 

2An over-the-road bus is characterized by an 

elevated passenger deck located over a baggage 

compartment. 

3 Generally, certain buses with a gross vehicle 

weight rating (GVWR) greater than 26,000 pounds 

(lb) (11,793.4 kilograms (kg)). 

4 In section 32702(6) of MAP–21, a motorcoach is 

defined as an over-the-road bus, not including 

transit buses or school buses. 

5MAP–21, section 32703(b) and (b)(1). 

6 81 FR 27904. 

7 In 2009, DOT also issued a Motorcoach Safety 

Action Plan that addressed additional factors, such 

as driver fatigue and operator maintenance 

schedules. An update to the Departmental plan was 

issued in December 2012 https://www.fmcsa.

dot.gov/sites/fmcsa.dot.gov/files/docs/MotorcoachSafety-Action-Plan-2012.pdf. 

8Center of daylight opening is the center of the 

total unobstructed window opening that would 

result from the removal of the glazing. 

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.1

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-theroad bus (OTRB2) and large bus 3 safety. 

This final rule establishes a new 

FMVSS, FMVSS No. 217a, ‘‘AntiEjection 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.4

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.5 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) 6 was among the 

rulemakings issued pursuant to 

NHTSA’s 2007 Approach to Motorcoach 

Safety and DOT’s Departmental 

Motorcoach Safety Action Plan.7 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 8 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 prebroken 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. 


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Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86257 

9For details concerning equivalent lives saved, 

reference the FRE docketed with this final rule. 

10 78 FR 70415 (Nov. 25, 2013); 80 FR 36049 (Jun 

23, 2015); 86 FR 74270 (Dec 29, 2021). 

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 9 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 doubleglazed 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). 

TABLE 1—NET COST TO SOCIETY PER EQUIVALENT LIFE SAVED

[In millions of 2022 dollars] 

15% belt use rate 90% belt use rate 

Undiscounted 3% 7% Undiscounted 3% 7% 

Material Costs .......................................... $0.96 $0.96 $0.96 $0.96 $0.96 $0.96 

Equivalent Lives Saved A B ...................... 1.9191 1.5064 1.1491 0.374 0.2936 0.2240 

Cost per Equivalent Life Saved ............... $0.50 $0.64 $0.84 $2.58 $3.28 $4.30 

Notes: 

A—These values from the FRE account for serious injuries (MAIS 3–5) by utilizing a relative injury factor. 

B—MAIS = Maximum AIS, AIS = Abbreviated Injury Scale, MAIS 0 = No Injury, MAIS 1 = Minor, MAIS 2 = Moderate, MAIS 3 = Serious, MAIS 

4 = Severe, MAIS 5 = Critical, MAIS 6 = Maximum (untreatable) 

TABLE 2—ANNUALIZED NET BENEFITS

[In millions of 2022 dollars] 

15% belt use rate 90% belt use rate 

Undiscounted 3% 7% Undiscounted 3% 7% 

Benefits from comprehensive costs 

avoided ................................................. $24.72 $19.40 $14.80 $4.82 $3.78 $2.88 

Material costs ........................................... 0.96 0.96 0.96 0.96 0.96 0.96 

Net benefits .............................................. 23.75 18.44 13.84 3.85 2.82 1.92 

II. Background 

Since the early 2000s, NHTSA has 

made a concerted effort to improve 

OTRB safety. These types of buses often 

carry children and the elderly, which 

are two of the most vulnerable groups in 

motor vehicle crashes. Although 

transportation via OTRBs is generally a 

safe form of travel, the agency decided 

to better protect the public against 

unreasonable risk of death or injury in 

high-occupancy vehicles through a 

series of rulemakings. In many cases, 

crashes involving OTRBs result in 

rollovers, which can significantly 

damage the vehicle and create ejection 

portals that allow part or all of an 

occupant’s body to be ejected from the 

vehicle during a crash. 

The agency has promulgated 

regulations that significantly reduce the 

risk that passengers will be ejected from 

OTRBs in the event of a rollover crash.10

This final rule represents yet another 

effort to significantly mitigate the risk of 

serious injury or death resulting from 

occupant ejection in OTRB crashes. It is 

the third rule targeted at minimizing the 

risk of ejection from OTRBs during a 

crash that the agency has promulgated 

over the past fifteen years. With this 

final rule, the agency will have taken yet 

another large stride in improving the 

safety of OTRBs, which means safer 

transportation for a significant number 

of children, the elderly, and lower 


ddrumheller on DSK120RN23PROD with RULES1
86258 Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 

11Laws requiring the use of seat belts in 

passenger vehicles are set by states. 

12 86 FR 74270 (Dec. 29, 2021); Partial grant of 

petitions for reconsideration, 88 FR 77523 (Nov. 13, 

2023). 

13Motor Coach Glazing Retention Test 

Development for Occupant Impact During a 

income individuals. What follows in 

this background section is a brief 

summary of NHTSA’s efforts in the 

recent past to improve OTRB safety, as 

well as a discussion about how the 

proposal and this final rule were 

developed. 

a. NHTSA’s Approach to Motorcoach 

Safety 

In 2007, NHTSA undertook a 

comprehensive review of motorcoach 

safety issues and the course of action 

that the agency could pursue to address 

them. The agency considered various 

prevention, mitigation, and evacuation 

approaches in developing the plan. The 

agency considered issues such as: cost 

and duration of testing, development, 

and data analysis; likelihood that the 

effort would lead to the desired and 

successful conclusion; target population 

and possible benefits that might be 

realized; and anticipated cost of 

implementing the ensuing requirements 

into the bus fleet. The results were 

published as ‘‘NHTSA’s Approach to 

Motorcoach Safety.’’ This document 

outlined four critical areas that the 

agency believed significantly 

contributed to fatalities and serious 

injuries associated with motorcoaches: 

(1) passenger ejection, (2) rollover 

structural integrity, (3) emergency 

egress, and (4) fire safety. This was the 

first of two documents that the 

Department produced on motorcoach 

safety. 

b. U.S. DOT Motorcoach Safety Action 

Plan 

In 2009, DOT issued a Departmental 

Motorcoach Safety Action Plan, which 

outlined a department-wide strategy to 

enhance motorcoach safety. In addition 

to the four priority action items 

specified in NHTSA’s 2007 ‘‘NHTSA’s 

Approach to Motorcoach Safety,’’ the 

DOT plan identified other strategies the 

Department would pursue to enhance 

motorcoach safety, such as issuing rules 

regarding electronic stability control 

systems, event data recorders, and 

programs addressing driver fatigue and 

operator maintenance. 

c. Congressional Action: MAP–21 and 

the Motorcoach Enhanced Safety Act 

On July 6, 2012, President Obama 

signed MAP–21, which incorporated the 

Motorcoach Enhanced Safety Act in 

Subtitle G. The Motorcoach Enhanced 

Safety Act included a number of 

mandates, including requirements that 

DOT issue the following regulations, 

among others: a requirement that seat 

belts be installed in motorcoaches, a 

requirement mandating improved roof 

strength and crush resistance standards, 

and requirements that mitigate the 

likelihood of occupant ejection from 

motorcoaches in the event of a crash. 

As described in more detail below, 

NHTSA has issued several regulations 

over the past fifteen years that have 

improved motorcoach safety and 

satisfied Congress’s statutory mandates 

in the Motorcoach Enhanced Safety Act. 

This final rule contributes to the 

agency’s effort to further satisfy 

Congress’s mandate to create antiejection safety countermeasures and fits 

with NHTSA’s other motorcoach related 

rulemakings described below. 

d. NHTSA’s 2013 Motorcoach Seat Belt 

Final Rule 

On November 25, 2013, NHTSA 

published a final rule (‘‘seat belt final 

rule’’) that amended FMVSS No. 208, 

‘‘Occupant crash protection,’’ to require 

that all new OTRBs as well as new 

buses with a gross vehicle weight rating 

(GVWR) greater than 11,793 kg (26,000 

lb) have lap/shoulder seat belts for each 

passenger seating position. This rule 

fulfilled the mandated rulemaking in 

the Motorcoach Enhanced Safety Act, 

which directed DOT to ‘‘prescribe 

regulations requiring safety belts to be 

installed in motorcoaches at each 

designated seating position.’’ In 

addition to satisfying the seat belt 

mandate in the Motorcoach Enhanced 

Safety Act, this rule was also the 

agency’s first step toward satisfying 

another mandate in the Motorcoach 

Enhanced Safety Act, which directed 

the Secretary to issue regulations that 

mitigate the risk of ejection from 

motorcoaches. At the time, NHTSA 

estimated that seat belts, when used, 

would be 77 percent effective in 

preventing fatal injuries in motorcoach 

rollover crashes, primarily by 

preventing ejection. 

The agency remains confident that the 

seat belt requirement is effective in 

mitigating ejection risk in crashes 

involving OTRBs and other large buses. 

However, seat belt usage rates by 

motorcoach occupants are uncertain. As 

an agency, NHTSA has the authority to 

mandate that OTRBs and other large 

buses have seat belts installed at each 

passenger designated seating position, 

but the agency does not have the 

authority to mandate usage of seat belts 

by passengers.11 The agency recognized 

at the time that the seat belt rule would 

not completely mitigate the risk of 

ejection, and the agency also recognized 

that there would be additional risks to 

belted passengers in OTRB and other 

large bus rollover crashes due to the 

lack of structural integrity requirements 

for those vehicles. 

e. NHTSA’s 2021 Motorcoach Structural 

Integrity Final Rule 

On December 29, 2021, NHTSA 

promulgated a final rule (‘‘structural 

integrity final rule’’) that established 

FMVSS No. 227, ‘‘Bus rollover 

structural integrity.’’ 12 This new 

standard requires that buses provide a 

‘‘survival space’’ in a rollover test to 

protect occupants from significant 

collapse of the bus structure around 

them. Additionally, the new standard 

requires that emergency exits remain 

closed during the rollover test. FMVSS 

No. 227 provides two significant safety 

benefits: (1) it protects occupants— 

belted and unbelted—from being 

harmed due to significant deformation 

of the bus structure or large falling 

objects such as luggage racks; and (2) it 

protects belted and unbelted occupants 

by minimizing the risk that emergency 

exits become ejection portals that 

passengers could be partially or 

completely ejected through. 

The structural integrity final rule 

satisfies the mandate in the Motorcoach 

Enhanced Safety Act that required the 

Secretary of Transportation to issue a 

regulation improving roof strength and 

crush resistance standards. 

Additionally, like the seat belt rule, the 

structural integrity final rule also 

contributes to satisfying the ejection 

mitigation mandate in the Motorcoach 

Enhanced Safety Act. 

Although the promulgation of FMVSS 

No. 227 is expected to improve safety 

outcomes in large bus rollover crashes 

when it goes into effect, the agency 

understands that occupants will still be 

at risk of ejection due to potential 

breakage of window glazing on large 

buses. Without a requirement that 

window glazing and latches on buses 

meet certain performance criteria, 

occupants could still be thrown against 

the window, break the window in the 

process, and be ejected through the 

broken window. This type of ejection is 

what spurred the agency to initiate this 

advanced glazing rulemaking. 

NHTSA’s strategy has been first to 

seek improvements to the rollover 

structural integrity of motorcoaches 

(roof strength and crush resistance) and 

then to pursue measures that would 

drive use of advanced glazing. This 

ordered approach is based on findings 

from a NHTSA funded study 13 that 


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Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86259 

Rollover (Martec Study), Final Report published on 

August 2006, Docket No. NHTSA–2002–11876–15. 

14OTRB manufacturers generally use this type of 

window for thermal and sound insulation purposes. 

Having an ‘‘air gap’’ between the window panes 

acts as a thermal barrier, making it easier to keep 

the bus a comfortable temperature. The air gap also 

prevents vibrations from passing through as easily, 

resulting in a quieter ride for occupants. 

found the integrity of the bus structure 

has a profound impact on the 

effectiveness of glazing as an antiejection safety countermeasure. Without 

a threshold standard for bus structural 

integrity, a twisting motion of a bus in 

a rollover could simply pop out any 

advanced glazing used in the windows 

and negate the potential benefits of the 

glazing in mitigating occupant ejection. 

f. Data and Safety Need for 

Strengthening Motorcoach Window 

Glazing 

Overview of Window Glazing 

In the context of motor vehicles, 

‘‘glazing’’ is a general term used to 

describe the material used in vehicle 

windows. The glazing in motor vehicles 

typically consists of either glass, which 

can be tempered or laminated, or 

transparent plastics, such as acrylic or 

polycarbonate. 

The agency expects that 

manufacturers will often use laminated 

glass to meet the new requirements 

adopted in this final rule. A single pane 

of laminated glass contains two glass 

layers held together by an interlayer, 

typically made of polyvinyl butyral 

(PVB). The PVB interlayer retains a 

strong bond with the outer layers of 

glass so that in the event the glass 

breaks or cracks, large shards of sharp 

glass do not become free and risk 

cutting or seriously injuring people. 

Laminated glass may crack or splinter 

upon impact with the ground, but it can 

still provide a barrier to retain 

passengers within the bus if the glazing 

is retained within the window frame, 

the PVB interlayer is not excessively 

torn or punctured, and the window 

latch remains closed. 

Tempered glass is also often used for 

windows on vehicles and buses. Several 

OTRB manufacturers currently use 

tempered glass as their glazing of choice 

for windows. Tempered glass is 

processed with controlled thermal or 

chemical treatments. These treatments 

strengthen the glass and create balanced 

internal stresses so that when the glass 

does break, it breaks or crumbles into 

smaller granular chunks instead of large, 

jagged shards. Tempered glass is 

stronger than laminated glass, but an 

occupant impacting the window during 

a rollover event and the bus impact with 

the ground can potentially shatter 

tempered glass, causing the glazing to 

vacate the window frame and creating 

an ejection portal. 

In most passenger cars, a single layer 

of glazing is used for the windows or 

windshield. However, multiple layers of 

glazing are often used in the side 

windows of buses.14 For example, a bus 

may have a double-glazed tempered/ 

tempered side window, which means 

within one window frame, there is an 

interior-side pane of tempered glass and 

an exterior-side pane of tempered glass 

with an air gap in between the two. This 

setup is a type of ‘‘double-glazed’’ 

window because there are two layers of 

glazing in the window frame. Based on 

NHTSA’s research and industry 

feedback from the NPRM, the most 

common type of glazing used in 

motorcoach side windows is a doubleglazed tempered/tempered window 

unit. 

Under section 32702 of MAP–21, 

‘‘advanced glazing’’ means glazing 

installed in a portal on the side or the 

roof of a motorcoach that is designed to 

be highly resistant to partial or complete 

occupant ejection in all types of motor 

vehicle crashes. This rulemaking puts in 

place a series of performance tests to 

prevent partial and complete ejection of 

bus occupants. These tests, described 

below in this preamble, include striking 

the unbroken and broken glazing with 

an impactor and measuring both the 

excursion distance of the impactor 

during impact and any resulting 

openings in the glazing after the impact. 

Data and Safety Need 

There were 73 OTRB and 38 large bus 

fatal crashes in the 14-year period from 

2006 through 2019. Among these 111 

OTRB and large bus crashes, 52 were 

rollovers, 53 were frontal crashes, and 6 

were side crashes. The anti-ejection 

glazing requirements in this final rule 

are expected to reduce ejections in all of 

these crash types. Of the 73 OTRBs 

involved in fatal crashes, 88 percent had 

a GVWR greater than 11,793 kg (26,000 

lb). 

NHTSA analyzed data from the 

agency’s Fatality Analysis Reporting 

System (FARS) from 2006 through 2019 

to analyze fatal bus crashes within the 

United States. During this period there 

were 111 fatal crashes involving all 

OTRBs regardless of GVWR and other 

applicable non-OTRBs with a GVWR 

greater than 11,793 kg (26,000 lb), 

resulting in a total of 284 occupant 

fatalities (an average of 20.3 total 

occupant fatalities per year). Tables 3 

and 4 show the breakdown of the 

number of crashes and fatalities by bus 

body type, GVWR, and crash type, 

respectively. Fatalities resulting from 

other events such as fires or occupants 

jumping from a bus were not included. 

The OTRB and large bus fatalities 

were further categorized into two groups 

representing drivers and passengers. 

Passenger fatalities were significantly 

higher than driver fatalities, accounting 

for 84 percent of the total fatalities, and 

were particularly prevalent in the OTRB 

category. Rollover events accounted for 

66 percent of all passenger fatalities 

(compared to 20 percent of driver 

fatalities). Rollover events are also the 

deadliest crash type, with 166 total 

fatalities in 52 crashes, resulting in 3.2 

fatalities per crash. 

TABLE 3—OTRB & LARGE BUS FATAL CRASHES

[FARS 2006–2019] 

Rollover Front Side Total 

Over-the-road Bus ........................................................................................... 40 30 3 73 

Large Bus GVWR >11,793 kg ......................................................................... 12 23 3 38 

Total .......................................................................................................... 52 53 6 111 


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15Ejection data include both complete and partial 

ejections. 

16See https://www.nhtsa.gov/research-data/ 

research-testing-databases#/vehicle/6934. 

17See NTSB report HAB–16/01 for September 21, 

2014, OTRB rollover crash near Red Lion Delaware; 

see also NTSB report HAR–18/03 for May 14, 2016, 

OTRB rollover crash near Laredo Texas. 

TABLE 4—OTRB & LARGE BUS OCCUPANT FATALITIES IN CRASHES

[FARS 2006–2019] 

Crash type 

OTRB Large Bus 

GVWR >11,793 kg 

Total 

Driver Passenger Driver Passenger Driver Passenger All 

Rollover .................................................... 7 134 2 23 9 157 166 

Front ......................................................... 23 39 13 26 36 65 101 

Side .......................................................... 1 9 0 7 1 16 17 

Total .................................................. 31 182 15 56 46 238 284 

Occupant fatalities were further 

broken down based on ejection (Table 5) 

and ejection path. Occupant ejection is 

highly correlated with fatality. For all 

OTRB and large bus occupant fatalities, 

39 percent were associated with 

ejection.15 Additionally, 71 percent of 

ejected occupant fatalities occurred in 

rollover crashes, highlighting the 

importance of ejection mitigation in 

rollover crashes. Rollovers remain the 

largest cause of occupant fatalities, for 

both ejected and non-ejected passengers, 

in OTRB and large bus crashes. 

However, anti-ejection glazing will help 

prevent occupant ejection in all crash 

types. During frontal impacts and side 

impacts, occupants are still at risk of 

ejection, as shown in Table 5. Any 

impact where the side windows break 

presents a risk of at least partial ejection 

for passengers. Partial ejection from a 

vehicle carries the additional risk of 

entrapment, as the partially ejected 

body part can be pinned under the bus, 

which can cause serious injury and 

prevent the immediate extraction of the 

passenger from the crash scene. Bus side 

windows can shatter upon impact even 

from frontal crashes, as evidenced 

during NHTSA’s 35 mph frontal crash 

test of a 2000 Motor Coach Industries 

motorcoach in 2009.16

TABLE 5—OTRB & LARGE BUS OCCUPANT FATALITIES BY EJECTION STATUS

[FARS 2006–2019] 

Crash type 

OTRB Large Bus 

GVWR > 11,793 kg 

Total 

Eject No Eject Eject No Eject Eject No Eject 

Rollover .................................................... 70 71 9 16 79 87 

Front ......................................................... 21 41 6 33 27 74 

Side .......................................................... 5 5 1 6 6 11 

Total .................................................. 96 117 16 55 112 172 

The aforementioned data show that 

crashes involving ejections present a 

high risk of death to the occupants of 

these buses. The majority of fatalities 

occur in rollovers, and approximately 

48 percent of rollover occupant fatalities 

are associated with ejection. 

In nearly all the OTRB and large bus 

fatal rollover events discussed above, 

there was a significant amount of 

structural damage to the roof and side 

structure of the vehicles, as well as open 

window portals.17 This is a prime 

example of why this final rule works in 

tandem with the structural integrity 

final rule. The structural integrity final 

rule will ensure that the structure of the 

bus does not cause harm to occupants 

or create ejection portals via emergency 

exits, and this final rule will take the 

final step of increasing use of advanced 

glazing that prevents partial or complete 

ejection of motorcoach passengers and 

further ensures the integrity of glazing 

mounting. 

g. The 2016 NPRM 

NPRM Proposals 

On May 6, 2016, NHTSA published 

an NPRM that proposed the 

establishment of FMVSS No. 217a, with 

the goal of reducing the potential for 

occupant ejection in a crash. The NPRM 

proposed a new dynamic impact test 

that would be used to drive the 

installation of advanced glazing in highoccupancy buses. In this test, a 26 kg (57 

lb) impactor would be propelled from 

inside a test vehicle toward a window 

glazing at 21.6 km/h (13.4 mph). The 

impactor and impact speed were chosen 

because they represent what the impact 

force would be from an average-sized 

unrestrained adult male striking the 

window on the opposite side of a large 

bus in a rollover. Each side window, 

rear window, and glazing panel/window 

on the roof would be subject to one of 

three impacts, as selected by NHTSA in 

a compliance test: (a) an impact near a 

latching mechanism 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 

window. The window would need to 

prevent passage of a 102 mm (4 inch) 

diameter sphere both during and after 

the impact to pass the test. In the 

proposed tests, the agency would assess 

the window during the impact by 

determining whether any part of the 

window passes a reference plane 

defined during a pre-test set up 

procedure. Furthermore, in the 

proposed test for the pre-broken glazing, 

the maximum displacement of the 

impactor at the center of the daylight 

opening of subject windows would be 

limited to 175 mm (6.9 inches). 


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18NTSB/HAR–11/03 PB2011–916203; 

Multivehicle Collision Interstate 44 Eastbound Gray 

Summit, Missouri, August 5, 2010; December 2011. 

19FMVSS No. 217 S3 says the standard ‘‘applies 

to buses, except buses manufactured for the 

purpose of transporting persons under physical 

restraint.’’ Accordingly, the NPRM proposed that 

the latch requirement apply to all buses except 

buses used for transporting persons under physical 

restraint. 

20Motor Coach Glazing Retention Test 

Development for Occupant Impact During a 

Rollover (Martec Study), Final Report published on 

August 2006, Docket No. NHTSA–2002–11876–15. 

21The Motorcoach Enhanced Safety Act of 2012 

is incorporated into the Moving Ahead for Progress 

in the 21st Century Act, Public Law 112–141 (Jul. 

6, 2012). 

22 Id. § 32703(b). 

23While this final rule is mainly aimed at 

addressing the rollover structural integrity of 

specific large bus types, the reduced deformation of 

the bus structure would ensure that any advanced 

glazing installed on portals would be retained on 

their mounting and reduce the risk of occupant 

ejection in rollover crashes. Further, the 

requirement that emergency exits should not open 

during the rollover test would also ensure that the 

exits do not become ejection portals. Thus, both 

subsection (b)(1) and subsection (b)(2) are relevant 

to this rule. 

24Moving Ahead for Progress in the 21st Century 

Act, Public Law 112–141, 32702(6). 

25 Id. § 32702(6)(A)–(B). 

In the NPRM, NHTSA also proposed 

to limit the protrusions of emergency 

exit latches into the openings of 

windows to ensure they do not unduly 

hinder emergency egress. This proposal 

was supported by a recommendation 

from the National Transportation Safety 

Board (NTSB), which had submitted a 

letter to NHTSA describing a crash 

(‘‘Gray Summit crash’’) 18 where 

occupants’ clothing was caught on a 

window latch as they were trying to 

egress the vehicle. A detailed 

description of the Gray Summit crash 

can be found in the NPRM for this final 

rule. The NPRM proposed a limit that 

would set the maximum protrusion of a 

window latch into emergency exit 

openings of windows at 1 inch when the 

emergency exit window is open. 

The NPRM proposed to apply the 

advanced glazing requirements to: (a) all 

new OTRBs (regardless of GVWR); and 

(b) all new buses other than OTRBs with 

a GVWR greater than 11,793 kg (26,000 

lb), with the exception of school buses, 

prison buses, transit buses, and 

perimeter seating buses. For the 

applicable bus types, the proposed 

applicable windows included bus side 

and rear windows, and windows/ 

glazing panels on the roof of the vehicle 

with a minimum dimension measured 

through the center of its area of 279 mm 

(11 inches) or greater. The NPRM 

proposed a different applicability for the 

emergency exit window latch protrusion 

requirement—the NPRM proposed that 

this requirement would apply to buses 

covered by the new FMVSS No. 217a as 

well as all buses subject to FMVSS No. 

217, ‘‘Bus emergency exits and window 

retention and release.’’ 19

Martec Study 

As discussed in the NPRM, in 2003, 

NHTSA and Transport Canada entered 

into a joint program that focused on 

improving glazing and window 

retention on OTRBs to prevent occupant 

ejection.20 This program is referenced in 

the NPRM and the sections below as the 

‘‘Martec study,’’ and the data gathered 

from the study is the basis for many of 

the proposals being adopted as part of 

this final rule. For the purposes of the 

NPRM, the agency used this study to 

develop a test procedure that 

realistically represented the impact 

loads from an unrestrained occupant 

onto motorcoach glazing during a 

rollover event. 

III. NHTSA’s Statutory Authority 

NHTSA is issuing this final rule 

pursuant to and in accordance with its 

authority under the National Traffic and 

Motor Vehicle Safety Act and the 

relevant provisions of MAP–21. 

a. National Traffic and Motor Vehicle 

Safety Act (Safety Act) 

Under 49 United States Code (U.S.C.) 

Chapter 301, Motor Vehicle Safety (49 

U.S.C. 30101 et seq.), the Secretary of 

Transportation is responsible for 

prescribing motor vehicle safety 

standards that are practicable, meet the 

need for motor vehicle safety, and are 

stated in objective terms (section 

30111(a)). ‘‘Motor vehicle safety’’ is 

defined in the Safety Act (section 

30102(a)(8)) as ‘‘the performance of a 

motor vehicle or motor vehicle 

equipment in a way that protects the 

public against unreasonable risk of 

accidents occurring because of the 

design, construction, or performance of 

a motor vehicle, and against 

unreasonable risk of death or injury in 

an accident, and includes 

nonoperational safety of a motor 

vehicle.’’ ‘‘Motor vehicle safety 

standard’’ means a minimum standard 

for motor vehicle or motor vehicle 

equipment performance (section 

30102(a)(9)). When prescribing such 

standards, the Secretary must consider 

all relevant available motor vehicle 

safety information (section 30111(b)(1)). 

The Secretary must also consider 

whether a proposed standard is 

reasonable, practicable, and appropriate 

for the particular type of motor vehicle 

or motor vehicle equipment for which it 

is prescribed (section 30111(b)(3)) and 

the extent to which the standard will 

further the statutory purpose of 

reducing traffic accidents and associated 

deaths and injuries (section 

30111(b)(4)). The responsibility for 

promulgation of FMVSSs is delegated to 

NHTSA (49 CFR 1.95). 

b. MAP–21 (Incorporating the 

Motorcoach Enhanced Safety Act of 

2012) 

NHTSA is issuing this final rule in 

accordance with MAP–21, which 

incorporates the Motorcoach Enhanced 

Safety Act of 2012 into Subtitle G.21

Section 32703(b) of MAP–21 requires 

the Secretary (NHTSA by delegation) to 

prescribe regulations that would address 

certain aspects of motorcoach crash 

performance within 2 years if the 

agency determines that the standards 

would meet the requirements and 

considerations of section 30111(a) and 

(b) of the National Traffic and Motor 

Vehicle Safety Act.22

Two subsections of section 32703(b) 

are particularly relevant to this final 

rule. Subsection (b)(1) specifies that the 

Secretary is to establish improved roof 

and roof support standards that 

‘‘substantially improve the resistance of 

motorcoach roofs to deformation and 

intrusion to prevent serious occupant 

injury in rollover crashes involving 

motorcoaches.’’ Subsection (b)(2) directs 

the Secretary to ‘‘consider advanced 

glazing standards for each motorcoach 

portal and [to] consider other portal 

improvements to prevent partial and 

complete ejection of motorcoach 

passengers, including children.’’ 23

MAP–21 contains other provisions 

pertaining to this rulemaking. Section 

32702 states that ‘‘motorcoach’’ has the 

meaning given to the term ‘‘over-theroad bus’’ in section 3038(a)(3) of the 

Transportation Equity Act for the 21st 

Century (TEA–21).24 Section 3038(a)(3) 

of TEA–21 (see 49 U.S.C. 5310 note) 

defines ‘‘over-the-road bus’’ as ‘‘a bus 

characterized by an elevated passenger 

deck located over a baggage 

compartment.’’ However, section 32702 

of MAP–21 excludes transit buses and 

school buses from the ‘‘motorcoach’’ 

definition.25

Under § 32702, ‘‘portal’’ means any 

opening on the front, side, rear, or roof 

of a motorcoach that could, in the event 

of a crash involving the motorcoach, 

permit the partial or complete ejection 

of any occupant from the motorcoach, 

including a young child. 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. 


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26 Id. § 32703(e)(1). 

27 Id. § 32703(e)(2), ‘‘Retrofit Assessment for 

Existing Motorcoaches.’’ 

28 Id. § 32706. 

29 79 FR 46090 (Aug. 6, 2014). 

30Per the August 2014 NPRM: Transit bus means 

a bus that is equipped with a stop-request system 

sold for public transportation provided by, or on 

behalf of, a State or local government and that is 

not an over-the-road bus; Perimeter-seating bus 

means a bus with 7 or fewer designated seating 

positions rearward of the driver’s seating position 

that are forward-facing or can convert to forwardfacing without the use of tools and is not an overthe-road bus. 

MAP–21 further directs the Secretary 

to apply any regulation prescribed in 

accordance with section 32703(b) to all 

motorcoaches manufactured more than 

3 years after the date on which the 

regulation is published.26 In addition, 

the Secretary may assess the feasibility, 

benefits, and costs of applying any 

requirement established under section 

32703(b)(2) to ‘‘motorcoaches 

manufactured before the date on which 

the requirement applies to new 

motorcoaches’’ (retrofit).27 Finally, 

MAP–21 also authorizes the Secretary to 

combine the required rulemaking 

actions as the Secretary deems 

appropriate.28

IV. The Final Rule and Response to 

Comments 

a. Establishing FMVSS No. 217a and 

New Requirements 

This final rule adopts most of the 

proposals from the 2016 NPRM (the 

differences between the NPRM and this 

final rule are highlighted in the section 

below). As discussed in the NPRM, this 

final rule establishes a new standard 

within 49 CFR part 571 that will now 

be referred to as FMVSS No. 217a. This 

new standard will set out requirements 

that windows in certain types of buses 

must meet when evaluated by the 

dynamic test procedure described in the 

2016 NPRM. Additionally, the new 

requirements will allow for only a 1- 

inch maximum protrusion for 

emergency exit window latches when 

the emergency exit window is open. 

Although there are some differences 

between the final rule and the NPRM, 

after reviewing the public comments to 

the NPRM, the agency has decided to 

adopt many of the proposals from the 

2016 NPRM. 

b. Differences Between the NPRM and 

the Final Rule 

This final rule makes amendments to 

several of the proposals in the 2016 

NPRM based on the comments the 

agency received. The most notable 

change between the 2016 NPRM and 

this final rule is in the applicability of 

FMVSS No. 217a. This final rule 

excludes all perimeter seating buses, 

even if those buses are also OTRBs, from 

the requirements in FMVSS No. 217a 

since these buses are also excluded from 

the structural integrity requirements in 

FMVSS No. 227 and therefore could 

lack the requisite integrity to retain 

advanced glazing within the window 

frame. Additionally, the final rule 

excludes all rear windows from FMVSS 

No. 217a requirements because the field 

data does not indicate an ejection risk 

from rear windows. Other differences 

between the 2016 NPRM and the final 

rule are minor updates to the regulatory 

text which include: (1) an adjustment to 

the location within FMVSS No. 217 for 

the new regulatory text that adds the 

emergency exit latch protrusion 

requirement; (2) new figures to the 

FMVSS No. 217a regulatory text to 

clarify the window pre-breakage 

procedure and the emergency exit 

opening space; and (3) adjustments to 

the FMVSS No. 217a regulatory text 

regarding the window pre-breakage 

procedure to specify steps to take if the 

electric staple gun used to pierce the 

glazing does not produce holes or 

perceivable damage to the glazing. 

V. Summary of Comments and Agency 

Responses 

a. Overview of Comments 

NHTSA received 11 unique comments 

on the NPRM. Comments were 

submitted by large bus manufacturers, 

including IC Bus (ICB), Van Hool N.V. 

(Van Hool), Prevost and Nova Bus 

divisions (Prevost), and Blue Bird Body 

Company (BBBC); a motorcoach 

operator, Greyhound Lines, Inc. 

(Greyhound); industry groups, including 

Enhanced Protective Glass Automotive 

Association (EPGAA), and School Bus 

Manufacturers Technical Council 

(SBMTC); a U.S. government agency, the 

NTSB; glazing manufacturers, including 

SABIC Innovative Plastics US LLP 

(SABIC) and Exatec, LLC (Exatec); and 

a consumer advocacy group, The 

Advocates for Highway and Auto Safety 

(Advocates). 

Most commenters expressed support 

for an FMVSS on advanced anti-ejection 

glazing and emergency exit latches that 

do not hinder passenger egress, but 

views differed on how these concepts 

should be implemented. For example, 

Greyhound, Prevost, and Van Hool 

expressed concern that advanced 

glazing, specifically laminated glass, 

may increase the potential for head and 

neck injuries of belted passengers. 

Additionally, several commenters stated 

that the NPRM did not account for all 

costs associated with the proposed rule. 

Most commenting bus manufacturers 

and SBMTC requested that certain bus 

types or window types be excluded 

from applicability under this 

rulemaking, including entertainer buses, 

school buses, school bus-derivative 

buses, driver’s windows, windows in 

doors, rear windows, and windows that 

are partially blocked by equipment or 

seating. Conversely, NTSB requested 

more bus types be included in the 

rulemaking, such as medium-sized 

buses with a GVWR of 11,793 kg (26,000 

lb) or less, not including school buses. 

Exatec, ICB, and SABIC all expressed 

concerns that the proposed glass prebreakage procedure did not properly 

account for advanced glazing that may 

not break upon application of a line 

load by the electric staple gun. 

No commenters supported mandating 

a retrofit for the glazing requirements, 

but NTSB did support a retrofit 

requirement for the minimum latch 

protrusion. A detailed discussion of 

comments and the agency’s responses 

can be found below. 

b. Applicability 

Bus Types 

NHTSA proposed to apply the 

FMVSS No. 217a window glazing 

dynamic impact test requirements to 

generally the same group of vehicles 

covered by the bus rollover structural 

integrity NPRM published in August 

2014.29 NHTSA noted that both 

requirements should apply to high 

occupancy vehicles associated with an 

unreasonable risk of fatal rollover 

involvement. According to the data, 

these vehicles are generally OTRBs 

regardless of GVWR, and other buses 

with a GVWR greater than 11,793 kg 

(26,000 lb). Accordingly, the NPRM 

proposed that buses subject to FMVSS 

No. 217a would be (a) new OTRBs 

(regardless of GVWR), pursuant to the 

Motorcoach Enhanced Safety Act of 

2012, and (b) all new buses other than 

OTRBs with a GVWR greater than 

11,793 kg (26,000 lb). Similar to the bus 

rollover structural integrity proposal, 

school buses, transit buses, and 

perimeter seat buses (as defined in the 

August 2014 NPRM) 30 were excluded 

from the FMVSS No. 217a proposed 

requirements. Prison buses were also 

excluded from FMVSS No. 217a 

proposed requirements because prison 

buses have bars over the windows that 

would impede the impactor for the 

glazing dynamic impact tests. 

The December 29, 2022 final rule 

establishing FMVSS No. 227, ‘‘Bus 

rollover structural integrity,’’ excluded 

perimeter seating buses that are nonOTRBs as well as those that are OTRBs 


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31 88 FR 77523. 

32Bus Loss of Control and Rollover, Dolan 

Springs, Arizona, January 30, 2009. Highway 

Accident Report NTSB/HAR–10/01 (Washington, 

DC: NTSB 2010). 

33Truck-Tractor Semitrailer Median Crossover 

Collision with Medium-Size Bus on Interstate 35, 

Davis, Oklahoma, September 26, 2014. Highway 

Accident Report NTSB/HAR–15/03 (Washington, 

DC: NTSB 2015). 34Medium-sized buses have a GVWR greater than 

4,536 kg (10,000 lb) and less than or equal to 11,793 

kg (26,000 lb). 

35Medium-Size Bus Production and Sales 

Supplemental Information Report. Docket Item #30 

from NTSB HWY17MH011 Highway Investigation. 

https://data.ntsb.gov/Docket?ProjectID=94934. 

36Medium-Size Bus Roadway Departure, Return, 

and Rollover Bryce Canyon City, Utah September 

20, 2019. Accident Report NTSB/HAR–21/01 

PB2021–100917. 

37FMVSS No. 227 has several express 

exemptions; the standard does not apply to school 

buses, school bus derivative buses, transit buses, 

prison buses, and perimeter-seating buses. 

from the requirements in FMVSS No. 

227. The November 2023 final rule 31

responding to petitions for 

reconsideration of the December 2022 

final rule expanded the definition of 

transit buses to include buses with a 

stop-request system sold for public 

transportation provided by, or on behalf 

of, the federal government. As detailed 

later in this section, this final rule 

adopts the 2015 NPRM proposals for 

applicability of FMVSS No. 217a but 

extends the exclusions to include 

perimeter seating buses that are OTRBs 

and the expanded definition of transit 

buses. These buses excluded from 

FMVSS No. 217a requirements are also 

excluded from FMVSS No. 227 and so 

may lack the requisite structural 

integrity to ensure any advanced glazing 

in windows does not pop out of its 

frame in a crash and thereby negate the 

potential benefits of the advanced 

glazing. 

Additionally, in the NPRM the agency 

proposed applying the emergency exit 

window latch protrusion requirement to 

the same buses covered by FMVSS No. 

227 and all buses governed under 

FMVSS No. 217, which includes all 

school buses. The agency is adopting 

the window latch applicability proposal 

as part of this final rule. 

Medium-Sized Buses 

NTSB commented that the final rule 

should include medium-sized nonschool buses with GVWRs in the range 

of 4,536–1,793 kg (10,001–26,000 lb). It 

noted that these buses are typically built 

as body-on-chassis vehicles without an 

elevated passenger deck over a baggage 

compartment, so they do not fall within 

the ‘‘over-the-road bus’’ definition. 

NTSB cited the 2009 bus crash near 

Dolan Springs, Arizona,32 and a 2014 

bus crash in Davis, Oklahoma 33 where 

passengers were ejected from mediumsized buses and died as a result. The 

NTSB’s Davis, Oklahoma accident 

report stated that a lack of appropriate 

crashworthiness standards contributed 

to the severity of passenger injuries. 

Agency Response 

As proposed in the NPRM, the agency 

has decided that the requirements for 

FMVSS No. 217a will not be applicable 

to medium-sized non-OTRBs.34 NHTSA 

bases this decision on a review of data 

for medium-sized buses from 2006–2019 

as shown below in Table 6. During this 

period there were 37 fatalities with 

some degree of ejection from crashes 

involving medium-sized buses. During 

the same period there were 112 fatal 

ejections in OTRBs and large buses, 

even though the population of OTRBs 

and large buses is much smaller than 

the population of medium-sized buses. 

Specifically, approximately 2,200 large 

buses (including OTRBs) are produced 

annually, compared to approximately 

16,000 medium-sized buses.35 Although 

there may be certain risks of occupant 

ejection from medium-sized bus 

crashes, the agency has concluded that 

medium-sized buses do not pose a 

sufficient safety need to warrant 

application of FMVSS No. 217a to those 

buses. 

TABLE 6—FATAL CRASHES AND EJECTED FATALITIES FOR LARGE BUSES AND MEDIUM-SIZED BUSES

[FARS 2006–2019] 

Bus size Avg. annual 

fatal crashes 

Avg. annual 

ejection 

fatalities 

Avg. annual 

fleet sales 36

Large Bus (greater than 26,000 lb GVWR) and all OTRBs ........................................................ 7.9 8.0 2,200 

Medium-Size Bus (GVWR of 10,000–26,000 lb) ........................................................................ 5.9 2.6 16,000 

Data show a considerable disparity 

between the rate of fatal ejections for 

large buses (OTRBs and other buses 

covered by this final rule) versus 

medium-sized buses. Not only are large 

buses involved in 34 percent more fatal 

crashes on average annually, but they 

also have 3 times as many ejected 

occupant fatalities annually compared 

to medium-sized buses. 

School buses and transit buses in the 

medium-sized bus range have a very 

low rate of fatal ejections in rollover 

events. The bus rollover structural 

integrity requirements for FMVSS No. 

227 only apply to OTRBs and buses 

other than OTRBs with a GVWR greater 

than 26,000 lb, meaning that if the 

agency were to apply this final rule to 

medium-sized buses, occupants in those 

buses would not receive the protections 

afforded by FMVSS No. 227.37 One of 

the reasons the agency promulgated 

FMVSS No. 227 was because windows 

were popping out of place during 

rollover events, creating ejection portals. 

Since medium-sized buses do not have 

to comply with FMVSS No. 227, 

requiring medium-sized buses to utilize 

enhanced glazing may not be effective 

in mitigating ejection because the 

advanced glazing may pop out of the 

window due to excessive structural 

deformation during a crash and thereby 

create an ejection portal. Accordingly, it 

would be illogical from a safety 

standpoint to make medium-sized buses 

subject to FMVSS No. 217a, but not to 

FMVSS No. 227. Thus, the agency has 

decided not to make medium-sized 

buses applicable under this final rule. 

Entertainer Buses 

The NPRM proposed to exclude 

perimeter seating buses from the final 

rule with the exception of, however, if 

perimeter seating buses that met the 

definition of an OTRB. Prevost 

commented that entertainer buses 

should be completely exempt under the 

final rule, regardless of whether they fit 

the definition of an OTRB. Buses 

referred to as entertainer buses are 

generally built from an OTRB shell and 

can contain interior features such as 

kitchens, bathrooms, bedrooms, lounge 

areas, dining areas, generators, and slide 

out portions of the structure. The 

window configuration may or may not 

be the same as those of other OTRBs 

built as typical passenger vehicles. 


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38According to the NPRM, perimeter-seating bus 

means a bus with 7 or fewer designated seating 

positions rearward of the driver’s seating position 

that are forward-facing or that can convert to 

forward-facing without the use of tools and is not 

an over-the-road bus. 

39 86 FR 74284–74285. 

Prevost commented that reducing the 

number of ejection-related fatalities is 

an important aspect of motorcoach 

safety and must be inherent to the 

design. Prevost further agreed with the 

intent of the proposed regulation to 

mitigate the creation of ejection portals, 

and to create uniformity throughout the 

industry products. However, Prevost 

requested special consideration for an 

exemption from the proposed 

requirements for entertainer buses. 

Prevost stated that an ‘‘entertainer coach 

is very different from the passenger 

motorcoach both in design and 

application. From a design perspective, 

they have fewer and smaller passenger 

windows, offering relatively less chance 

of a potential, partial, or full ejection.’’ 

Agency Response 

The agency believes that the term 

‘‘entertainer bus’’ is not a term of art to 

be used in the standard. The buses that 

Prevost described in its comment are 

likely considered perimeter-seating 

buses, a bus type that NHTSA defined 

in the NPRM 38 and excluded from 

compliance in the proposal, unless the 

perimeter seating bus in question fits 

the definition of an OTRB. After 

reviewing Prevost’s comment, NHTSA 

has decided to maintain that under this 

final rule the new standard will not be 

applicable to perimeter-seating buses. 

Further, to align the application of 

FMVSS No. 217a with FMVSS No. 227, 

perimeter-seating buses that also meet 

the definition of an OTRB will also be 

excluded from FMVSS No. 217a. 

As stated in the FMVSS No. 227 

motorcoach structural integrity final 

rule, the agency does not find a reason 

to distinguish between OTRBs with 

perimeter seating and non-OTRBs with 

perimeter seating.39 The safety data 

indicate no relevant differences between 

these vehicles based on safety need. In 

other words, OTRBs with perimeter 

seating do not present a greater risk of 

injury compared to non-OTRBs with 

perimeter seating. 

Furthermore, as discussed above, the 

advanced glazing requirements are most 

effective when paired with the 

improved structural integrity required 

by FMVSS No. 227. Therefore, the 

agency is excluding OTRBs with 

perimeter seating to mirror the decision 

made in the final rule for FMVSS No. 

227. Many of the safety benefits gained 

from advanced glazing are dependent on 

sufficiently strong vehicle structural 

elements, meaning it would not make 

sense to apply advanced glazing 

requirements to a set of vehicles that do 

not have to comply with the more 

stringent structural integrity 

requirements of FMVSS No. 227. 

Lastly, to synthesize the definition 

with this decision in this final rule, the 

agency has decided to amend the 

definition of a perimeter seating bus in 

the regulatory text by deleting the 

phrase ‘‘and is not an over the road bus’’ 

from the end of the proposed definition. 

School Bus Derivative Buses 

ICB recommended that commercial 

buses built from school bus designs 

should not have to meet the ejection 

mitigation requirements of the proposed 

rule. ICB noted that its commercial 

buses are ‘‘much different’’ from a 

traditional motorcoach, meaning the 

data and studies NHTSA used for the 

NPRM potentially would not apply to 

their buses. ICB stated that the operating 

environment of its commercial buses 

derived from school buses is more 

closely related to that of school buses 

than the operating environment and 

conditions of OTRBs, meaning that the 

routes ICB commercial buses are used 

on are generally routes involving lower 

speeds and frequent stops. ICB wrote 

‘‘[t]he commercial variants of school 

buses are typically used in applications 

such as church buses, college campus 

buses, local shuttles and tours, 

emergency responders, and parks and 

recreation departments.’’ 

Agency Response 

The agency disagrees with ICB’s 

generalization of school bus derivative 

bus designs and their operating 

environments. NHTSA is therefore not 

excluding school bus derivative buses 

from FMVSS No. 217a as part of this 

final rule. The agency is basing this 

decision on the fact that school bus 

derivative buses are available for use in 

intercity travel and are offered for sale 

with motorcoach-style features, such as 

larger windows than school buses. 

While these buses are not required to 

comply with FMVSS No. 227, ‘‘Bus 

rollover structural integrity,’’ these 

buses are required to comply with 

FMVSS No. 220, ‘‘School bus rollover 

protection,’’ and FMVSS No. 221, 

‘‘School bus body joint strength.’’ When 

the agency defined the term ‘‘school bus 

derivative bus’’ in FMVSS No. 227, the 

agency defined these buses as ‘‘a bus 

that meets Federal motor vehicle safety 

standards for school buses regarding 

emergency exits (§ 571.217), rollover 

protection (§ 571.220), bus body joint 

strength (§ 571.221), and fuel system 

integrity (§ 571.301).’’ To meet the 

regulatory definition of a school bus 

derivative bus, the bus must comply 

with specific school bus requirements— 

including the structural integrity 

requirements of FMVSS Nos. 220 and 

221—even if the bus is not used for 

school-related purposes. 

One of the agency’s concerns when it 

promulgated the structural integrity 

final rule was the possibility of window 

glazing popping out of place and 

creating ejection portals. The school bus 

structural integrity standards, FMVSS 

No. 220 and FMVSS No. 221, ensure the 

windows in school bus derivative buses 

are less likely to ‘‘pop out,’’ similar to 

FMVSS No. 227 for OTRBs and other 

large buses. Thus, the agency believes it 

is reasonable for school bus derivative 

buses to be subject to the new FMVSS 

No. 217a but not to FMVSS No. 227. 

ICB requested that commercial buses 

built from school bus designs should 

not have to meet the ejection mitigation 

requirements of the proposed rule. 

Although some of the commercial buses 

derived from school bus designs are 

similar to school bus vehicles not 

subject to the proposed rule, it is the use 

patterns of the buses that makes them 

distinct from school buses. School buses 

are typically used for local 

transportation of students from home to 

school and from school back home. Like 

transit buses, school buses are typically 

operated at lower rates of speed with 

frequent starts and stops. The 

commercial buses derived from school 

bus designs are sold to groups that use 

the buses for both intracity and intercity 

travel. Some of these buses utilize larger 

windows and coach-style seating, 

making them even more like OTRBs. 

A 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.’’ In other 

words, the definition of a ‘‘school bus’’ 

is use-based—if it looks like a school 

bus and operates for school bus 

purposes, it is a school bus and must 

comply with school bus requirements. If 

it looks like a school bus, but is not used 

for school bus purposes, it is not a 

school bus and does not have to comply 

with all school bus requirements. This 

distinction in the FMVSS is a critical 

reason why the agency believes school 

bus derivative buses should be covered 

under FMVSS No. 217a. Forcing 

manufacturers to comply with two 

separate structural integrity 

requirements would be illogical. 

However, unlike structural integrity, 


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40 88 FR 77523. 41 81 FR at 27921–27922. 

there is not an existing vehicle-level 

school bus-specific advanced glazing 

standard. Therefore, NHTSA has 

decided not to exclude school bus 

derivative buses from the dynamic 

impact test requirements of FMVSS No. 

217a. If a school bus derivative bus 

weighs greater than 11,793 kg (26,000 

lb), it will have to comply with FMVSS 

No. 217a. 

Transit Buses 

As part of this final rule, NHTSA is 

adopting a slightly altered definition of 

the term ‘‘transit bus.’’ The definition 

proposed in the NPRM read: ‘‘a bus that 

is equipped with a stop-request system 

sold for public transportation provided 

by, or on behalf of, a State or local 

government and that is not an over-theroad bus.’’ 

In considering how to define the term 

for this final rule, the agency considered 

its response to petitions for 

reconsideration of the final rule for 

FMVSS No. 227, ‘‘Bus rollover 

structural integrity,’’ concerning the 

definition of a transit bus. To ensure 

consistency among standards, NHTSA 

has decided to adopt the definition 

adopted in the agency’s response to 

petitions for reconsideration of FMVSS 

No. 227. This definition of ‘‘transit bus’’ 

differs from the definition proposed in 

the NPRM. 

In the petitions for reconsideration for 

the structural integrity final rule, 

petitioners argued that buses that are 

manufactured as transit buses but sold 

to entities that are not state or local 

governments (or operated on behalf of 

state or local governments) are not 

considered transit buses. The entities 

that the petitioners described are either 

private operators or the federal 

government. The petitioners stated that 

these transit-type buses are operated in 

a similar manner as transit buses 

operated by state or local governments 

and should therefore be included in the 

definition of ‘‘transit bus.’’ 

In NHTSA’s responses to petitions for 

reconsideration of FMVSS No. 227,40

the agency partially granted the 

petitioners’ request for adjusting the 

transit bus definition. NHTSA amended 

the transit bus definition by including 

transit-type buses operated by the 

federal government, but not including 

transit-type buses operated by private 

entities. NHTSA determined the federal 

government utilizes transit-type buses 

in a similar manner as other public 

transit agencies, but private operators 

may utilize these buses in higher-risk 

driving patterns. This amended 

definition is also being adopted as part 

of this final rule establishing FMVSS 

No. 217a. The amended definition of 

transit bus is now: 

‘‘Transit bus means a bus that is 

equipped with a stop-request system 

sold for public transportation provided 

by, or on behalf of, a Federal, State, or 

local government and that is not an 

over-the-road bus.’’ 

Emergency Exit Latch Protrusion Limit 

Requirements Applicability 

Two commenters requested 

clarification on the applicability of the 

emergency exit latch protrusion limit 

requirement proposed in the NPRM. ICB 

commented that it understands the 

protrusion limits are applicable to all 

buses, including school buses. SBMTC 

stated that the protrusion limit 

requirements should apply to all school 

buses, regardless of GVWR. To support 

its request, SBMTC also noted that the 

NTSB-requested latch protrusion limits 

are from a crash involving a school bus. 

Agency Response 

To clarify, in the NPRM, NHTSA 

proposed that the emergency exit latch 

protrusion requirement be applicable to 

the buses to which the dynamic 

impactor test would apply (OTRBs 

regardless of GVWR and other large 

buses, except transit buses, prison 

buses, school buses, and perimeterseating buses, and school buses). 

NHTSA also requested comment on the 

merits of requiring all buses subject to 

FMVSS No. 217 to meet the 

requirement. After reviewing the 

comments, the agency has decided to 

adopt this proposal as part of this final 

rule. To avoid confusion over the 

applicability of this emergency exit 

window latch protrusion requirement, 

NHTSA is creating a new paragraph in 

FMVSS No. 217 as part of this final rule. 

The NPRM proposed adding the 

protrusion limits into FMVSS No. 217 

S5.4.1 and S5.4.2.2. The first section, 

S5.4.1, applies to emergency exits on all 

buses except certain emergency exits on 

certain school buses outlined in S5.2.3. 

The other amended section, S5.4.2.2, 

applies only to school buses with a 

GVWR of 10,000 lb or less. The 

preamble of the NPRM states ‘‘the 

maximum latch plate protrusion 

requirement would be applicable to the 

buses to which the impactor tests would 

apply. . . . However, NHTSA is also 

proposing to extend the maximum latch 

plate protrusion requirement to other 

buses as well . . . . NHTSA is 

proposing to extend the proposed 

requirement to school buses also.’’ 41

The proposed amendment did not 

clearly indicate which bus types would 

need to comply with the protrusion 

limits. As stated in the NPRM, NHTSA’s 

intent was for the protrusion limits to 

apply to all school buses, regardless of 

GVWR. Therefore, the changes proposed 

in the NPRM for FMVSS No. 217 S5.4.1 

and S5.4.2.2 will not be implemented. 

Instead, the requirement will be adopted 

in a different location in FMVSS No. 

217, which is reflected in the amended 

regulatory text at the end of this final 

rule. 

The content of the changes is the 

same as what was proposed in the 

NPRM, but the location has changed to 

be in its own section that applies to all 

bus types within FMVSS No. 217. This 

change should alleviate any confusion 

concerning the applicability of the 

emergency latch protrusion 

requirement. 

Applicable Window Types 

In the NPRM, NHTSA proposed 

applying the dynamic impact test 

requirements to all side windows, rear 

windows, and glazing panels/windows 

on the roof of applicable buses that met 

the minimum size requirements. The 

Motorcoach Enhanced Safety Act directs 

the agency to consider requiring 

advanced glazing standards for ‘‘each 

motorcoach portal’’ (section 

32703(b)(2)). The Act defines ‘‘portal’’ 

as ‘‘any opening on the front, side, rear, 

or roof of a motorcoach that could, in 

the event of a crash involving the 

motorcoach, permit the partial or 

complete ejection of any occupant from 

the motorcoach, including a young 

child’’ (section 32702(9)). NHTSA 

applied the proposed advanced glazing 

requirements to the portals the agency 

believed pose a valid risk of ejection. 

The agency estimates that side bus 

windows account for about 80 percent 

of portals (potential ejection routes) on 

buses. 

The NPRM proposed not applying the 

dynamic impact test requirements to the 

front windshield, roof hatches, or any 

doors that do not contain glazing of at 

least the minimum size. Accident data 

from real-world rollover crashes 

indicate that passenger ejections 

generally do not occur from the front 

windshield, emergency doors, or service 

doors. As proposed in the NPRM, the 

dynamic impact test procedure applies 

to windows that have a minimum 

dimension measured through the center 

of their area of 279 mm (11 in) or 

greater. 

The NPRM proposed to amend 

FMVSS No. 217 to specify in S5.4.1 of 

the standard that emergency exit latches 

and other related release mechanisms 

not protrude more than 25 mm (1 inch) 


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into the opening of an emergency exit 

when the window is opened to the 

minimum emergency egress opening 

(allowing passage of an ellipsoid 500 

mm (19.7 inches) wide by 330 mm (11.8 

inches) high). The purpose of this 

proposed requirement was to limit the 

potential for objects such as latch plates 

to protrude into the emergency exit 

window opening space even when the 

protrusion still allows the exit window 

to meet the opening size requirements. 

These requirements were proposed in 

the NPRM to only apply to emergency 

exit windows. 

Minimum Window Size 

Regarding minimum dimensions, ICB 

and Advocates provided comments and 

recommendations for changes to the 

requirements. Advocates expressed 

concern with the lack of evidence 

supporting the exemption from testing 

of windows with a maximum dimension 

of 11 inches or less. ICB stated that the 

minimum surface dimension should be 

381 mm (15 in) based on a typical side 

passenger window size for school buses. 

Agency Response 

The testing standard, as discussed in 

the Martec report, provides that the 

window glazing impact loading event is 

modelled after a motorcoach side 

rollover with an occupant from one side 

of the bus being thrown from their seat 

and impacting glazing on the opposite 

side of the bus. 

As stated in the NPRM: ‘‘The window 

would be tested if it is large enough to 

fit the impactor face plus a 25 mm (1 

inch) border around the impactor face 

plate edge without contact with the 

window frame. The dimensions of the 

dynamic impactor the agency proposed 

to use were 177 mm by 212 mm (7 

inches by 8.3 inches).’’ The headform 

impactor used in FMVSS No. 217 has a 

6-inch diameter, and the minimum 

required dimension measured through 

the center of the window is 8 inches for 

the window to be tested. Using a 

proportional relationship for the wider 

(8.3 inch) dimension of the impactor in 

FMVSS No. 217a results in a minimum 

required dimension measured through 

the center of the window’s area of 11 

inches (279 mm). 

As discussed in the Martec report, the 

loading case was chosen as a 

representative loading situation so that 

a minimum level of protection would be 

provided for all bus occupants, drivers, 

and passengers, for all crash scenarios. 

The Martec study determined that the 

occupant impacting the opposite side 

window would primarily be through 

shoulder contact. The impactor was 

fabricated to represent the mass, 

stiffness, and contacting area of the 

United States side impact dummy (US– 

SID) shoulder. The minimum window 

dimension is based upon this impactor 

size. Testing a window smaller than the 

impactor would cause the vehicle 

structure around the window to be 

loaded during testing, thus lowering the 

force applied to the glazing material. 

Using an impacting face smaller than 

the proposed guided impactor face in 

order to evaluate smaller windows 

would not be representative of the 

loading analysis conducted. The agency 

does not agree with the request to 

evaluate other crash scenarios for 

occupant-to-window contact. 

ICB requested NHTSA increase the 

minimum window size to match the 

size of a typical school bus window, 

which ICB stated is 381 mm (15 inches). 

As discussed later in the preamble, 

since school bus-sized windows are 

large enough to satisfy emergency exit 

requirements, they are large enough to 

become an ejection portal that could 

permit the partial or complete ejection 

of a passenger if the glazing is vacated 

from the opening. Therefore, NHTSA 

will not increase the minimum window 

surface dimension as ICB has requested. 

Rear Windows 

ICB stated that the rear windows 

should be exempt from the anti-ejection 

requirements of FMVSS No. 217a. ICB 

pointed out that in traditional 

motorcoaches there is typically not a 

rear window, and that most bus crash 

injuries and fatalities involve traditional 

motorcoaches. Additionally, ICB stated 

that it is not aware of any crash reports 

for ‘‘a survivable rollover incident that 

would propel an occupant with such 

force to the rear of the vehicle that it 

would eject them through the rear 

glazing.’’ ICB further stated that rear 

windows are usually partially blocked 

by forward facing seats, which makes it 

less likely for passengers to be ejected 

out the rear of a bus. ICB pointed to a 

sentence from the Martec report which 

ICB interpreted to imply that the 

impactor anvil test does not apply to 

rear-window glazing. 

BBBC stated that the rear windows 

should be exempt on ‘‘large commercial 

buses that are constructed substantially 

the same as school buses’’ because they 

are usually partially blocked by seats. 

Additionally, BBBC stated that since 

NHTSA’s testing was only performed on 

side windows, additional research 

would be required before establishing 

performance requirements for the rear 

glazing. 

Agency Response 

After reviewing the comments from 

ICB and BBBC, the agency further 

analyzed typical bus designs, ejection 

data, and fatal crash data. The agency 

has concluded that rear bus windows 

will be excluded from testing as part of 

this final rule. 

In the NPRM, NHTSA proposed 

applying the dynamic impact test 

requirements to all side windows, rear 

windows, and glazing panels/windows 

on the roof of applicable buses that met 

the minimum window size 

requirements. The agency recognized 

that OTRBs typically have the bus 

engine in the rear, and therefore usually 

have no windows on the rear of the bus. 

However, the agency stated that nothing 

precludes bus designs from having 

windows in the rear of the bus that 

could be potential ejection portals. 

The crash type most likely to result in 

an ejection through the rear glazing 

would be a rear impact. As stated by ICB 

and BBBC and confirmed by NHTSA, 

there were no recorded fatalities in 

applicable buses from rear impact 

crashes in the 2006–2019 FARS data. 

While it is conceivable occupants could 

be ejected through the rear glazing in 

other crash types, it is less likely. 

Further, as BBBC indicated, rear 

windows in large buses that are not 

OTRBs are often substantially blocked 

by the rear seats. As a result, occupants 

are less likely to be ejected through the 

rear glazing. In the event of a partial 

ejection through a rear window, the 

occupant is less likely to experience 

serious injury or death, because there is 

a low likelihood the bus will roll onto 

its rear side. 

The requirements and evaluation 

procedures of FMVSS No. 217a are 

based upon analysis of unbelted 

passenger impacting side bus windows 

during a rollover crash scenario. This 

loading case was chosen as a 

representative loading situation so that 

a minimum level of protection would be 

provided for all bus occupants, drivers, 

and passengers, for all crash scenarios. 

Therefore, as a practical matter, NHTSA 

has decided rear windows will be 

exempt from the impact test 

requirements of FMVSS No. 217a. 

Windows Mounted on Doors and 

Hatches 

ICB questioned whether the dynamic 

impact test requirements apply to all 

window glazing, including those in 

doors and emergency exit hatches. In 

their comments, ICB argued that 

‘‘NHTSA did not intend for the glazing 

anti-ejection requirements to be 

applicable to glazings in any door or 


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42Safety Belt Usage by Commercial Motor Vehicle 

Drivers (SBUCMVD) 2013, U.S. Department of 

Transportation, Federal Motor Carrier Safety 

Administration (FMCSA). 

43According to the 2006–2019 FARS data, 6 of 

these fatal driver ejections were through a side door 

opening, 1 was through a side window, 1 was 

through the windshield, and 1 was an unknown 

ejection path. 

roof hatch emergency exit and we ask 

that NHTSA make that clear in the final 

rule.’’ BBBC stated that the NPRM did 

not ‘‘adequately convey NHTSA’s 

intention to exclude windows that are 

part of a side or rear door.’’ 

Agency Response 

Both BBBC and ICB stated that 

windows which are part of doors should 

be exempt from the anti-ejection 

requirements. NHTSA has observed that 

in current buses there are typically 

windows in the emergency exit doors 

and in regular doors. The agency stated 

in the NPRM that NHTSA would not be 

applying the proposed requirements to 

the front windshield, or to emergency 

exit doors, service doors, or roof 

hatches. The agency does not intend to 

apply the glazing ejection mitigation 

requirements to the structure securing 

side and rear doors to the vehicle. 

However, all bus windows are potential 

ejection portals if the glazing material 

breaks. If a window in a side door or 

roof hatch and has the requisite 

minimum dimensions of 279 mm (11 in) 

or greater measured through the center 

of its area, that window will be subject 

to the proposed anti-ejection 

requirements. 

The agency has concluded that this 

final rule is applicable to all side and 

roof window glazing that meet the 

minimum window dimensions. 

Furthermore, NHTSA wishes to clarify 

that the anti-ejection requirements 

proposed for FMVSS No. 217a do not 

apply to the non-window portion of 

doors, service doors, or roof hatches. 

Any window in a door, service door, or 

roof hatch would have to meet the antiejection requirements if such a window 

exceeds the minimum size (279 mm or 

11 inches) specified in S5 of FMVSS No. 

217a. 

School Bus Sized Windows 

SBMTC commented that school bus 

size windows used on commercial buses 

derived from school bus designs are too 

small to be covered by the proposed 

anti-ejection requirements. BBBC, ICB, 

and SBMTC claimed that since OTRBs 

have larger windows than the 

commercial buses derived from school 

buses, commercial buses with these 

windows should not be subject to the 

same requirements as traditional 

OTRBs. ICB indicated that it does 

‘‘install larger ‘non-typical’ school bus 

windows in some of its commercial 

buses and [it is] not asking for any 

exemption for these larger bus 

windows.’’ 

Agency Response 

First, as mentioned in the preceding 

paragraphs, if a bus derived from a 

school bus design is not a school bus 

and has a GVWR greater than 11,793 kg 

(26,000 lb), it will have to comply with 

FMVSS No. 217a. The fact that certain 

school bus derivative buses may have 

smaller windows does not change this 

requirement. Furthermore, FMVSS No. 

217 requires buses other than school 

buses to have emergency exit windows 

large enough to ‘‘admit unobstructed 

passage, keeping a major axis horizontal 

at all times, of an ellipsoid generated by 

rotating about its minor axis an ellipse 

having a major axis of 50 centimeters 

and a minor axis of 33 centimeters.’’ 

Since these school bus windows are 

large enough to satisfy emergency exit 

requirements, they are large enough to 

become an ejection portal that could 

permit the partial or complete ejection 

of a passenger if the glazing is vacated 

from the opening. FARS data from 

2006–2019 include 26 fatal ejections 

from school buses with a GVWR greater 

than 26,000 lbs. This data shows that 

school bus sized windows can become 

ejection portals. 

Lastly, although school bus derivative 

buses may use the same sized windows 

as school buses, NHTSA believes that 

school bus derivative buses are more 

likely than school buses to be used in 

a manner that has a higher risk of 

crashes. Therefore, although school bus 

derivative buses may have smaller 

windows than traditional OTRBs, these 

windows are large enough for a 

passenger, especially a child or smaller 

adult, to be fully or partially ejected 

through if such a window is broken out 

from the surrounding bus structure. 

Accordingly, a bus being equipped with 

‘‘school bus sized’’ windows will not 

create an exemption to FMVSS No. 217a 

under this final rule. If the windows are 

large enough to be tested with the 

impactor, the fact that the windows are 

‘‘school bus sized’’ will not impact their 

applicability to this standard. 

Driver Side Windows 

Both BBBC and ICB commented that 

because seat belts should protect bus 

drivers from ejection, driver side 

windows should be exempt from this 

final rule. ICB indicated that the seat 

belt usage rates for bus drivers is as high 

as or higher than the 84% rate for 

commercial truck drivers listed in a 

Federal Motor Carrier Safety 

Administration (FMCSA) study.42

Agency Response 

The agency has decided not to exempt 

driver side windows from the 

requirements under this final rule. 

FARS data from 2006–2019 show 9 

drivers were fatally ejected from school 

buses with a GVWR greater than 26,000 

lb.43 The numbers of ejected drivers are 

relatively low, but the risk is present in 

bus crashes. Also, advanced glazing in 

driver side windows will protect the 

drivers against partial ejections. Bus 

manufacturers will be able to use 

similar anti-ejection design features for 

driver side windows as those antiejection features used for the remaining 

bus windows. Under the final standard, 

if a bus driver side window meets the 

minimum size requirements, it will 

have to meet the requirements of 

FMVSS No. 217a. 

Blocked Windows 

SBMTC commented that some side 

wheelchair lift doors are ‘‘effectively 

blocked by the stowed wheelchair lift’’ 

and that as a result, these windows do 

not pose a risk for ejection. ICB 

commented that NHTSA should exclude 

glazing in ‘‘[d]oors, such as wheelchair 

lift doors, that have equipment or other 

items that would prevent or restrict 

passenger ejection.’’ ICB also 

commented that doors with no adjacent 

seat should be exempted from the 217a 

requirements. 

Additionally, BBBC argued that 

NHTSA did not intend to apply the 

dynamic test requirements to glazing in 

wheelchair lift doors, ‘‘which would 

have a wheelchair lift between the 

passenger and the window.’’ BBBC also 

stated that in many of the buses it 

manufactures, the rear seats obstruct 

much of the rear window. BBBC stated 

these obstructed windows should be 

exempt from the dynamic impact test 

requirements. 

Agency Response 

SBMTC, BBBC, and ICB stated that 

since wheelchair lift ramps block the 

window in the wheelchair access door, 

such windows should not have to meet 

the proposed anti-ejection requirements. 

The agency examined different 

wheelchair access doors and the 

wheelchair lift ramps in their stowed 

positions. Some lift ramps are stowed 

outside the bus in a storage 

compartment under the bus. Other 

configurations stow the ramp inside the 

bus in a folded position. These interior 


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86268 Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 

ramps may partially block the door 

window. 

Windows that have no blockage will 

have to meet the anti-ejection 

requirements, since no part of the 

vehicle would block a passenger from 

contacting the window. Windows 

completely blocked by wheelchair lift 

ramps will not have to meet the antiejection requirements, since passengers 

would not be able to contact such 

windows. Windows that are partially 

blocked by wheelchair lift ramps would 

need to meet the anti-ejection 

requirements if the daylight opening of 

such windows is large enough such that 

the minimum dimensions measured 

through the center of the daylight 

opening area is not less than 279 mm. 

Note that the definition of daylight 

opening states that the periphery 

includes surfaces 100 mm inboard of the 

window and 25 mm outboard of the 

window, not including gaskets, weather 

stripping, grab handles, or seats. Also, 

since bus passengers can walk about the 

bus while it is in motion, the agency 

does not agree with ICB’s suggestion to 

restrict the anti-ejection requirements to 

only those windows which have a 

seating position near that window 

glazing. 

Emergency Exit Windows and Latches 

ICB agreed with the agency that the 

window latch release mechanism 

should not be a hindrance in 

evacuations through the emergency 

window exit. Both BBBC and ICB 

argued that the protrusion limits are 

intended to only apply to emergency 

exit windows, and not to other types of 

emergency exits such as doors or 

hatches. Both respondents specifically 

asked for the word ‘‘window’’ to be 

inserted into the sentence planned for 

the end of FMVSS No. 217, S5.4.1 so 

that their interpretation of the 

protrusion requirement applicability is 

specifically written into the standard. 

Agency Response 

The NPRM was silent on protrusion 

concerns for emergency exit doors and 

roof hatches. The NPRM did discuss 

latch protrusion issues in the context of 

the emergency exit windows on the 

school bus involved in the Gray Summit 

crash. Additionally, no other 

respondents commented on the lack of 

concern for protrusions impeding 

passenger emergency egress through 

side door or roof exits. The confusion 

over which emergency exits are subject 

to the protrusion limits may stem from 

the section of regulatory text into which 

the protrusion limits were placed. 

FMVSS No. 217, S5.4.1 does not 

specifically list the emergency exits to 

which that section applies. Further, the 

title for FMVSS No. 217 S5.4 is 

‘‘Emergency exit opening,’’ not 

‘‘Window emergency exit opening.’’ 

Window emergency exits are a subset of 

roof, side, and rear emergency exits. 

Placing the emergency window exit 

protrusion limits into a section covering 

multiple types of exits may have created 

confusion for the respondents that asked 

for this clarification. The protrusion 

limit for emergency exit window latches 

is also to be applied to school bus 

emergency exit windows, through 

addition of the similar text into S5.4.2.2 

of FMVSS No. 217. However, to avoid 

additional confusion by including an 

emergency exit window specific 

provision into a section devoted to 

small school bus emergency exit doors, 

the agency has decided to place the 

emergency exit latch protrusion 

requirement at the end of S5.4. 

As mentioned above in the discussion 

on the protrusion limit applicability for 

all buses, the agency is relocating this 

requirement into a new subsection, 

FMVSS No. 217 S5.4.4, so that the 

requirement will be more easily 

understood as applicable to all buses 

included in FMVSS No. 217. This 

location also clarifies the application of 

the protrusion requirements is only for 

window emergency exits. The NPRM’s 

proposed text additions to FMVSS No. 

217 S5.4.1 and S5.4.2.2 are not being 

adopted and the new S5.4.4 contains the 

planned protrusion limit requirements. 

NHTSA is including the word 

‘‘window’’ in the standard for 

clarification as ICB and BBBC suggested. 

c. Occupant Injury Protection 

In the event of a rollover crash 

involving a large bus or OTRB, there is 

concern for more than just injury or 

death resulting from ejection from the 

bus; there is also a risk that passengers 

may suffer injuries from impacting 

reinforced glazing during a crash. While 

the main objective of this final rule is to 

protect occupants by preventing ejection 

through windows and glazing panels, 

the agency has also considered the 

impact forces bus occupants would 

experience when contacting the 

advanced glazing during a crash. 

Several commenters discussed this 

potential issue, and a summary of those 

comments along with the agency’s 

responses can be found in the 

paragraphs below. 

Rigidity of Advanced Glazing 

Greyhound, Prevost, and Van Hool 

suggested that advanced glazing would 

be too rigid, causing an increase in the 

number and severity of passenger 

injuries. Greyhound commented ‘‘that 

NHTSA should consider technologies 

that reduce ejections while not 

increasing impact injuries.’’ Van Hool 

stated that ‘‘[t]he passenger on the 

rollover-side wearing the seat belt in a 

bus according to this NPRM might be 

victimized because in a single rollover 

his head will hit a surface that is strong 

enough to retain the body of a freefalling passenger of the other, nonrollover side.’’ Prevost stated, based 

upon information in a 2007 Los Angeles 

Times article, that ‘‘[laminated] glass 

could increase head and neck injuries to 

passengers who wear seat belts.’’ 

Agency Response 

The agency shares the respondents’ 

concerns for injuries caused by 

collisions with advanced glazing and 

window panels in OTRB and large bus 

crashes. However, the agency disagrees 

with the argument that advanced 

glazing may cause injuries which would 

not otherwise occur from a broken or 

unbroken tempered glazing panel. 

The Los Angeles Times article that 

Prevost referenced provided no 

supporting information for the 

conclusion that laminated glazing is 

harder than tempered glazing material. 

The agency has force deflection data 

from the bus glazing panel research 

conducted for this final rule, which can 

be seen in Table 7 below. In tests where 

the guided impactor struck the center of 

bus windows made of a single glazing 

panel, the tempered glazing panels had 

higher peak force levels and lower 

deflections than glazing panels made 

from laminated glass, polycarbonate, 

and acrylic. This test data indicates that 

tempered glass is harder and more rigid 

than the other glazing types, including 

laminate glass. The higher force levels 

and lower deflections indicate that a bus 

occupant hitting tempered glazing at 

high speeds could receive higher 

contact injuries than if they were to hit 

a different type glazing material. 


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Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86269 

44 Duffy, S., & Prasad, A., National Highway 

Traffic Safety Administration, Motorcoach Side 

Glazing Retention Research, pg 18, (Report No. DOT 

HS 811 862) (Nov. 2013). 

TABLE 7—DATA FROM BUS GLAZING GUIDED IMPACTOR TESTING 44 SINGLE PANEL WINDOW GLAZING

Glazing configuration 

(bonding method) 

Actual impact 

velocity 

(km/h) 

Peak force 

(N) 

Peak impactor 

face excursion 

(mm) 

Interior glass 

pane broken 

Laminated glass (Rubber) .................................................................................. 21.5 4,780 116 Yes. 

Laminated Glass (Rubber) ................................................................................. 21.2 5,879 106 Yes. 

Tempered Glass (Rubber) ................................................................................. 21.3 8,030 49 No. 

Acrylic (Rubber) .................................................................................................. 21.4 6,211 66 No. 

Tempered Glass (Glued) .................................................................................... 20.8 8,518 41 No. 

Laminated Glass (Glued) ................................................................................... 20.9 7,592 57 Yes. 

Polycarbonate (Glued) ....................................................................................... 21.2 6,822 69 No. 

In the case of belted occupants, a 

belted occupant seated against the bus 

side wall is at risk of partial ejection of 

their upper torso, hands, arms, neck, 

and head if the window breaks. It is 

safer for any passenger to be retained 

inside the bus by an advanced glazing 

surface than to be partially outside the 

bus when it hits and/or slides along the 

pavement or ground. According to 

FARS data from 2006–2019, thirty-nine 

percent of all large bus and OTRB 

fatalities were ejected, as detailed in 

Table 8 below. Because the vast majority 

of occupants in large bus and OTRB 

crashes are not ejected, this data and 

study prove that, in the event of a 

rollover crash, it is safer for an occupant 

to remain inside the vehicle than to be 

ejected, even though that may mean a 

potential collision with an unbroken 

advanced glazing panel. 

TABLE 8—OCCUPANT FATALITIES BY EJECTION STATUS FARS 2006–2019 

[Large buses (GVWR greater than 26,000 lb) and all OTRBs] 

Bus type Not ejected Ejected Total 

Van-based .................................................................................................................................... 1 0 1 

Large Van .................................................................................................................................... 0 0 0 

Intercity Bus ................................................................................................................................. 117 96 213 

Other Bus ..................................................................................................................................... 46 13 59 

Unknown Bus ............................................................................................................................... 8 3 11 

Other Means of Injury Prevention 

In Greyhound’s comment, it urged the 

agency to consider alternative 

technologies to prevent passenger 

ejection and reduce injuries. Greyhound 

suggested that the advanced glazing will 

not prevent fatalities due to ejection. 

Greyhound suggested that there are 

‘‘other technologies, including those in 

use in the automotive and trucking 

industries, which may have a higher 

likelihood of retaining passengers in the 

vehicle in rollover/tipover events.’’ 

Agency Response 

NHTSA is always willing to consider 

specific proposals that may enhance 

passenger safety in the agency’s final 

rules. However, in this instance, 

Greyhound did not provide a name or 

description of the ‘‘other technologies’’ 

that may be more effective than 

advanced glazing in mitigating the risk 

of passenger ejection in OTRB and large 

bus crashes. Additionally, Greyhound 

may have overlooked several general 

aspects of occupant movement during a 

crash. All occupants come to a stop at 

some point during a crash; the main 

question is how occupants stop. The 

answer to this question plays a 

significant role in determining the 

extent of passenger injuries or even risk 

of death in rollover crashes. The 

proposed requirements of this rule 

provide partial ejection protection for 

belted occupants seated against bus 

windows as well as protection against 

partial or complete ejections of unbelted 

passengers that may fall or move into 

the ejection portal created by a broken 

window. As stated above, the agency 

welcomes comments about other 

technologies or vehicle safety 

countermeasures that others believe 

would be more beneficial than the 

requirements proposed in the NPRM. 

However, in this case, there simply is 

not enough detail in Greyhound’s 

comment to compare ‘‘other 

technologies’’ to the proposals in the 

NPRM. The agency is confident that the 

new requirements adopted in this final 

rule will be highly effective in 

mitigating the risk of passenger ejection 

during rollover crashes involving large 

buses and OTRBs. 

d. Test Procedures and Equipment 

Multiple commenters discussed the 

dynamic impact test procedure and the 

equipment used to conduct the dynamic 

impact test. The agency has decided to 

adopt a few of the recommendations 

made in the comments, which means 

the adopted test procedure will be 

slightly different from the test procedure 

proposed in the NPRM. Specifically, the 

agency is amending the proposed 

regulatory text for the window prebreakage procedure as well as the edge 

impact test procedure for increased 

clarity. 

Guided Impactor Specifications 

Two of the commenters asked for 

more details to be provided for the 

guided impactor test equipment. BBBC 

requested that NHTSA change the word 

‘‘mass’’ to the phrase ‘‘mass to bring 

total mass of impactor to 26 kg’’ in the 

proposed Figure 1 of the regulatory text, 

which illustrates the guided impactor. 

Additionally, BBBC and SBMTC 

requested more details on the foam used 

on the impactor face. 

Agency Response 

The impactor design being adopted as 

part of this final rule is the same 

impactor design proposed in the NPRM. 

The agency has decided not to change 

the language for the proposed impactor 


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86270 Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 

test as BBBC requested, as the agency 

does not believe that these changes are 

necessary to provide the clarity BBBC 

requested. Instead, NHTSA has made a 

few changes to the impactor design 

figure, shown below as Figure 1, which 

will be included in the regulatory text 

as well as a separate technical 

supporting document that can be found 

in the docket for this rulemaking 

(Technical Support Document). The 

changes to the figure are designed to 

provide additional clarity, and the 

agency believes these changes will 

resolve any confusion BBBC had 

regarding the mass of the impactor 

design. 

The changes between this figure and 

the figure proposed in the NPRM 

include (1) changing the term ‘‘mass’’ to 

‘‘ballast mass,’’ (2) changing the term 

‘‘foam’’ to ‘‘SID arm foam,’’ (3) adding 

the ‘‘thrust bearing rod’’ to the figure, 

and (4) labeling the ‘‘impactor face 

bearing.’’ This figure now illustrates and 

names all components of the impactor 

that contribute to the overall mass of 26 

kg (57 lb). The Technical Support 

Document includes more details and 

figures that provide example masses for 

each component. 

As proposed in the NPRM, the agency 

is adopting the requirement that the 

total mass of the impactor be 26 kg (57 

lb), which represents the effective mass 

measurements from the Martec study. 

The impactor is designed to represent 

the torso of the SID. To clarify, when the 

regulatory text says that the impactor 

must be a total mass of 26 kg (57 lb), it 

is referring to the mass of the entire 

impactor assembly, not just one 

component of the impactor. In Figure 1 

above—which will also be adopted as 

part of the regulatory text—the agency 

has decided to show the entire impactor 

assembly, and has labeled one 

component of the impactor as the 

‘‘ballast mass.’’ The agency believes the 

clarification of the ‘‘total mass of the 

impactor’’ combined with labeling the 

ballast mass will alleviate any confusion 

BBBC had on the mass issue. 

Regarding the foam used on the 

impactor face, in an effort to provide 

greater clarity, the agency is able to 

share the following additional details. 

The foam used on the impact side of the 

impactor plate is the 50th percentile 

male side impact dummy (SID) arm 

foam. SID arm foam is composed of a 

piece of urethane foam, conforming to 

the properties listed in the Technical 

Support Document. Additional details 

of the foam can be found in the 

Technical Support Document, and a 

copy of the engineering drawing, SID– 

069, is also in the docket of this final 

rule. 

Window Pre-Breakage Test Procedure 

In the NPRM, NHTSA proposed a 

breaking specification and method that 

involves applying a line load to the 

glazing, to simulate the damage the 

glazing could experience in a rollover 

prior to impact by an occupant. The line 

loads would be applied at set distances 

on both the interior and exterior glass 

plies of the laminated glazing. The 

window breaking procedure would 

damage but not destroy laminated 

glazing, while it would obliterate 

tempered glazing. Since tempered 

glazing would be obliterated, this 

proposal would have the effect of 

prohibiting manufacturers from having 

applicable bus windows made solely 

from tempered glazing. 

The first step in the proposed test 

procedure is to mark the glazing surface 

on the occupant-side interior glass in a 

horizontal and vertical grid of points 

separated by 75 mm (3 inches), with the 

first point coincident with the geometric 

center of the daylight opening. Next, the 

grid on the opposite side of the glazing 

would be marked. For most glazing, the 

grid on the opposite side of the glazing 

would be staggered to avoid tearing the 

PVB interlayer. For laminates, ‘‘the 

opposite side of the glazing’’ means the 

opposing glass ply directly opposite of 

the PVB interlayer. ‘‘Staggered’’ means 

that the 75 mm (3 inch) offset pattern 

has a 75 mm × 75 mm (3 inch × 3 inch) 

pattern on the occupant-side interior 

glass and the same pattern, offset by 

37.5 mm (1.5 inch) horizontally and 

vertically, on the outside exterior glass 

surface. 

For windows that are a single-pane 

unit, NHTSA would use the grid pattern 

on the occupant-side interior surface 

and the staggered grid pattern on the 

outside exterior surface of the glazing. 

For double-glazed windows, the 

agency proposed using a grid pattern on 

the occupant-side interior surface of the 

interior pane and on the outside of the 

exterior pane. For double-glazed 

windows that consist of one pane of 

tempered glass, that pane would be 

broken and removed, and the remaining 

glazing (that is not of tempered glass) 

would be pre-broken on both sides 


ddrumheller on DSK120RN23PROD with RULES1ER30OC24.017</GPH>

BALLAST MASS IMPACTOR FACE 

BEARING 

THRUST BEARING ROD 

HOUSING 

BEARING ROD 

(SPRING CUT AWAY FOR CLARITY) 

llll'ACTOR FACE 

BEARING 

All dimensions shown are in millimetres. 

SID ARit FOAM 

C-1-77---.:+-.... 

@ 212 

FOAM RElllYED FOR CLARITY 

Figure 1: Components of the Guided Impactor 
Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86271 

45 Duffy, S., & Prasad, A., National Highway 

Traffic Safety Administration, Motorcoach Side 

Glazing Retention Research, pg 18, (Report No. DOT 

HS 811 862) (Nov. 2013). 

(occupant interior and outside exterior) 

with the grid and staggered grid 

patterns, respectively. For double-glazed 

windows that do not consist of any 

tempered glass pane, it would not be 

practical to apply the 75 mm (3 inch) 

pre-break pattern to the insulated 

surface (inside the air gap) of the 

individual panes. For cases in which 

neither pane is tempered glass, both the 

occupant side of the interior pane and 

the outside of the exterior pane would 

be marked in the grid pattern, but the 

patterns would not be offset (one side 

would not use the staggered pattern) 

due to a lack of need. That is, for those 

windows there would be little 

likelihood of tearing the PVB interlayer 

even when the patterns are not offset. 

The agency proposed breaking the 

defined grid points using an unloaded 

electric staple gun, since the device 

worked well for that purpose in our 

developmental testing. The staple gun 

would apply a 12.7 mm (0.5 inch) line 

load (with a thickness of 1.3 mm (0.05 

inches)) (the size of a standard staple) 

onto the glazing with a force in the 

range of 3,500 newtons (N) (787 lb) to 

5,000 N (1,124 lb) when the front nose 

opening of the staple gun is held 

parallel to the glazing surface. These 

staple gun specifications are intended to 

break the glass with a single punch 

without producing tears in the PVB 

interlayer. These line loads would be 

applied to the glazing starting with the 

inside surface of the glazing, and 

starting with the forwardmost, lowest 

hole in the pattern. NHTSA would 

continue applying the line loads 75 mm 

(3 inches) apart, moving rearward on the 

bus. When the end of a row is reached, 

the agency would move to the most 

forward hole in the next higher row, 75 

mm (3 inches) from the punched row. 

After completing the applications on the 

inside surface, the agency would repeat 

the process on the outside surface. 

When applying the line load, NHTSA 

would place a 100 mm (4 inch) by 100 

mm (4 inch) piece of plywood on the 

opposite side of the glazing as a reaction 

surface against the punch. If a particular 

window were constructed such that the 

inner laminated material is penetrated 

or damaged, the procedure would not be 

halted or invalidated. The impactor test 

would be conducted at the conclusion 

of the glazing breakage procedure. If 

punching a hole causes the glazing to 

disintegrate, as would occur when 

testing tempered glazing, the procedure 

would be halted for that item of glazing 

and the impactor test would be 

conducted on what glazing, if any, 

remains. If there is no glazing remaining 

after the hole-punching procedure, there 

would be a failure to comply since the 

window would not be able to restrain 

the impactor or prevent passage of the 

102 mm (4 inch) diameter sphere. 

BBBC requested that the specific 

electronic staple gun used during the 

agency’s research testing be specified in 

the final rule. ICB commented that it 

does not understand why the FMVSS 

No. 226 spring-loaded center punch 

breakage method is not practical for this 

proposed regulation. SABIC, Exatec, and 

ICB each noted that it may not be 

possible to break or even force holes 

into all types of glazing, specifically 

glazing made from polycarbonate 

material. ICB also requested improved 

clarity through the addition of figures or 

diagrams for the glazing pre-breaking 

procedure. 

Agency Response 

While the agency understands BBBC’s 

preference for a glazing material 

breakage procedure identical to that 

used during the agency’s testing, 

NHTSA does not believe it is necessary 

to specify a model of electronic staple 

gun to be used in the regulatory text and 

will not being doing so as part of this 

final rule. Instead, the agency has 

decided to specify the length over 

which the line load is to be applied as 

well as the force applied by the staple 

gun to the glazing. Although the agency 

did not list any force level in the 

NPRM’s proposed regulatory text, 

NHTSA believes it will be useful to 

include the average force level (4,200 N 

(994 lb)) and standard deviation (850 N 

(191 lb)) obtained from sampling the 

Duo Fast Model EWC electric staple gun 

force levels as the target force in this 

final rule. This force was adequate to 

break the laminate glazing’s glass layer 

without tearing the inner PVB material. 

For these reasons, NHTSA declines to 

accept BBBC’s suggestion to list a 

specific electric staple gun model in the 

final rule. 

ICB questioned why NHTSA 

developed a new glass breakage 

procedure that differs from the existing 

glass breakage procedure in FMVSS No. 

226. As stated in NHTSA’s ‘‘Motorcoach 

Side Glazing Retention Research,’’ 45

‘‘[i]t was quickly determined that the 

automatic center punch used in FMVSS 

No. 226 was not practical for large bus 

windows and was not tested in this 

study.’’ Due to the effort required to 

actuate the center punch and the large 

size of motorcoach windows, NHTSA 

determined the center punch used in 

the FMVSS No. 226 glazing pre-breaking 

procedure would not be a practical tool 

for the FMVSS No. 217a glazing prebreaking procedure. Accordingly, 

NHTSA developed the breakage 

procedure proposed in the NPRM and is 

adopting that procedure as part of this 

final rule. 

SABIC, Exatec, and ICB each shared 

concerns that the glazing breakage 

procedure could effectively preclude 

usage of their polycarbonate glazing 

material. These commenters stated it 

may be possible that certain glazing 

types would receive little to no marking 

when attempting to break that glazing 

using the required glazing breakage 

procedure. Their stated concern is that 

if no hole can be made, then their 

glazing cannot pass the test. A similar 

concern was addressed in the final rule 

for FMVSS No. 226. 

Like FMVSS No. 226, the hole break 

pattern for FMVSS No. 217a will be 

marked onto the bus’s window glazing, 

as shown in the regulatory text below, 

then the electric staple gun would be 

used once at each marked location. It is 

possible that certain glazing may have 

smaller, or no holes produced. Similar 

to the agency’s response to the comment 

in response to the FMVSS No. 226 

NPRM, NHTSA believes that even if 

certain glazing may have smaller, or no 

holes produced by the breakage 

procedure being adopted in this final 

rule, the window may still be weakened 

and should be tested in accordance with 

the rest of the procedures outlined for 

the impact test. 

Even though the agency has decided 

to adopt the pre-breakage test procedure 

as proposed in the NPRM as part of this 

final rule, NHTSA has decided to 

include an additional figure to the 

regulatory text to aid in the clarification 

of the glazing pre-breakage procedure as 

ICB requested. The combined proposed 

revision to FMVSS No. 217a is shown 

in the appendix of this final rule. 

Edge Impact Test Procedure 

During agency review, NHTSA 

determined the edge impact test 

procedure could be improved with three 

distinct updates, which are described 

briefly here. The first update is to 

describe the impactor positioning for an 

additional glazing orientation. For the 

scenario where a window on the bus 

roof does not have a latch or other 

discrete attachment point, the agency 

has decided to define which edge with 

which to align the impactor. In order to 

be consistent with side windows that do 

not have a latch, the agency is using the 

rearmost edge of a roof window as the 

reference edge because if a latch were 

present, it would likely be located on 

the rearmost edge due to the 


ddrumheller on DSK120RN23PROD with RULES1
86272 Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 

46 Duffy, S., & Prasad, A., National Highway 

Traffic Safety Administration, Motorcoach Side 

Glazing Retention Research, pg 18, (Report No. DOT 

HS 811 862) (Nov. 2013). 

requirement in FMVSS No. 217 

S5.2.3.2(b). Second, the agency 

determined a tolerance to properly 

define the lateral distance between the 

impactor face plate edge and the 

window frame. NHTSA is defining a 

tolerance of ± 2 mm based on the 

positioning of a similar impactor as 

described in FMVSS No. 226, ‘‘Ejection 

mitigation.’’ The third update is 

necessary to further clarify the 

alignment of the impactor face plate 

with respect to a latch. Due to varying 

latch designs, the center of the latch 

may not necessarily correspond to the 

center of the location where the latch 

attaches to the movable portion of the 

window. Because the location where the 

latch attaches to the movable portion of 

the window is where the latch is most 

likely to fail, the agency has decided to 

specify that location for the edge impact 

procedure by referencing the latch 

attachment point when aligning the 

impactor. The agency is adopting these 

three updates to the edge impact test 

procedure as part of this final rule. 

e. Performance Requirements 

Impact Testing Displacement Limits 

In the NPRM, NHTSA proposed to 

specify performance requirements for 

windows comprised of unbroken and 

broken glazing when the glazing is 

subjected to impactor testing. In 

NHTSA’s impactor test of glazing near 

a latching mechanism and in the 

impactor test of glazing at the center of 

the daylight opening, an ‘‘ejection 

reference plane’’ would be determined 

prior to the test. The plane would be 

based on the passage of a 102 mm (4 

inch) diameter sphere through a 

potential ejection portal of the window. 

The agency would require that no part 

of the window (excluding glazing 

shards) may pass this ‘‘ejection 

reference plane’’ during the dynamic 

impact test. If any part of the window 

glazing or window frame passes the 

plane, there would be a failure to 

comply. 

For unbroken glazing, the window 

would be subject to either of the 

following two impacts, as selected by 

NHTSA in a compliance test: (a) an 

impact near a latching mechanism, and 

(b) an impact at the center of the 

daylight opening. The displacement 

limit for these tests on the unbroken 

glazing was proposed to be 102 mm (4 

inch) both during and after the test. 

For pre-broken glazing, the window 

would be subject to an impact test at the 

center of the daylight opening. The 

displacement limit for this test was 

proposed to be 175 mm (6.89 inch) 

during the test and 102 mm (4 inch) 

after the test. 

Advocates expressed concerns that 

the pass/fail criteria for the rule had not 

been adequately supported. Advocates 

stated that the 6.9-inch excursion limit 

and the 4-inch dynamic displacement 

limits are inadequate requirements. 

Advocates was concerned that ‘‘[a]ny 

amount of excursion exposes the 

occupant in contact with the window to 

impacts with objects outside of the 

vehicle such as the roadway, and as 

such should be reduced the greatest 

extent possible.’’ Advocates requested 

that the agency ‘‘establish requirements 

that push the industry to adopt the 

safest reasonable practices, as opposed 

to the bare minimum or current average 

performance.’’ 

Regarding permitted deflections, ICB 

provided comments and 

recommendations for changes to the 

requirements. ICB stated that there 

should not be a deflection requirement 

based on the ejection reference plane as 

part of the requirement. 

Agency Response 

The agency has decided not to adjust 

the proposed excursion limit of 175 mm 

for the pre-broken glazing impact test. 

Advocates stated that the agency used 

the International Code Council (ICC) 

guardrail spacing requirements as 

justification for 102 mm excursion 

limits in FMVSS No. 226. Advocates are 

incorrect in this belief, as the final rule 

notice establishing FMVSS No. 226 

noted that other FMVSSs (FMVSS No. 

206 and FMVSS No. 217) as well as the 

ICC have a 100 mm maximum limit on 

a portal/opening to minimize the risk of 

an occupant being ejected or of a child 

passing through the portal/opening. The 

final rule establishing FMVSS No. 226 

reported that test data highlighted an 

increased likelihood of large portals 

forming when excursions were over 100 

mm. The agency believes that the 102 

mm excursion limit based upon the 

ejection reference plane remains an 

appropriate requirement. 

Concerning the 175 mm displacement 

limit for the pre-broken glazing test, the 

agency asked for comments and 

additional data in the NPRM. NHTSA 

noted in the NPRM that this limit was 

based on two tests of a single 

production bus window design. It was 

also noted in the NPRM that results 

from laminate glazing testing conducted 

for the Martec study resulted in an 

average displacement of 175 mm for the 

impactor in the center of daylight 

opening impacts (using the 75 mm (3 

inch) diagonally offset pattern). 

No other respondents commented 

either for or against the excursion limits. 

Advocates stated that ‘‘excursion 

exposes the occupant in contact with 

the window to impacts with objects 

outside of the vehicle such as the 

roadway, and as such should be reduced 

the greatest extent possible.’’ As 

discussed earlier, the manner in which 

occupants come to a stop during a crash 

will contribute to the extent and 

severity of their injuries. Based on data 

from NHTSA’s ‘‘Motorcoach Side 

Glazing Retention Research,’’ 46 where 

different configurations of pre-broken 

laminated glass window units were 

impacted at the Martec conditions, the 

thicker PVB layer resulted in lower 

excursion limits and higher impact force 

values for almost all of the pre-broken 

glazing configurations. 

Advocates did not offer any 

additional data, studies, or suggestions 

for what a better, lower excursion limit 

should be for the pre-broken glazing 

test. Using the data at the agency’s 

disposal, an excursion limit of 175 mm 

is reasonable and sufficient. NHTSA 

chose this excursion limit based on 

practicability, costs, and safety needs. 

Using a 100 percent thicker PVB layer 

yielded a 14 percent lower excursion 

limit in our testing. This method is 

effective for manufacturers to reduce the 

excursion limit if necessary to comply 

or for slight improvements. The NPRM 

requested comments on the 

practicability, costs, and potential 

benefits of using a lower excursion limit 

such as 146 mm, which is the average 

excursion found during the testing with 

the thicker PVB layer (using the same 75 

mm diagonally offset breaking 

procedure). Advocates did not provide 

any comment on this aspect of the 

excursion limit, nor did any other 

commenter. Therefore, the agency will 

not adjust the proposed excursion limit 

of 175 mm for the pre-broken glazing 

impact test. 

ICB also expressed doubt regarding 

the appropriateness of deflection limits 

as part of the bus glazing anti-ejection 

requirements. ICB suggested that the 

glazing and window frame should be 

allowed to flex. The agency understands 

that window glazing, and perhaps even 

the window frame, will flex when hit by 

the guided impactor face. However, 

unlimited flexing, or displacement, is 

undesirable because glazing deflection 

past the ejection reference plane would 

allow tears to develop in glazing that 

could lead to an ejection portal. 

Additionally, the displacement limit 

provides a means of ensuring the 


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Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86273 

47NTSB/HAR–11/03, https://www.ntsb.gov/ 

investigations/AccidentReports/Reports/ 

HAR1103.pdf, 

window does not open during the 

impact test, which would result in a 

portal for occupant ejection. Limiting 

the deflection to the ejection reference 

plane ensures that a minimum level of 

passenger retention will be maintained 

by the bus window glazing material. 

Therefore, the agency is not adopting 

ICB’s recommendation to remove the 

deflection limit for the unbroken 

window test. 

Emergency Exit Window Latch 

Protrusion 

The NTSB investigation into the Grey 

Summit bus crash noted that passenger 

egress through the emergency exits was 

hindered when passengers snagged their 

clothing on the emergency exit latch 

hardware protruding into the egress 

route.47 Several passengers in the lead 

school bus, and a witness who assisted 

in the evacuation, stated in post-crash 

interviews that emergency egress was 

hindered by the design of the emergency 

exit window. Particularly, the 4-inch by 

3-inch emergency release latch plate for 

the emergency exit window was 

elevated about 1 inch from the window 

base and snagged the clothing of several 

passengers as they were exiting through 

the window opening. 

The additional requirements as 

outlined in the NPRM proposed to limit 

how far emergency exit latches may 

protrude into the emergency exit 

opening. The NPRM for this rule 

proposed that emergency exit latch 

protrusions cannot extend more than 1 

inch into the opening of the window 

when the window is opened to the 

minimum emergency egress opening 

specified under FMVSS No. 217. This 

opening is described in S5.4.1 as ‘‘large 

enough to admit unobstructed passage, 

keeping a major axis horizontal at all 

times, of an ellipsoid generated by 

rotating about its minor axis an ellipse 

having a major axis of 50 centimeters 

and a minor axis of 33 centimeters.’’ 

The NPRM proposed making all buses 

governed under FMVSS No. 217 

applicable under this requirement. 

The NTSB agreed that emergency exit 

window latches need to be functional 

after a crash to ensure passengers can 

egress through all viable exits; 

consequently, the NTSB supported 

testing the latches after impact tests. 

Advocates also supported the agency’s 

proposals to minimize emergency exit 

latch protrusions and to require these 

latches to remain operable following the 

impact testing. 

Concerning the 1-inch protrusion 

limit proposed in the NPRM, both the 

NTSB and Advocates requested a lower 

limit for allowable protrusion. NTSB 

noted that the emergency latch in the 

Gray Summit crash protruded 1 inch 

into the emergency exit opening; 

therefore the proposed 1-inch maximum 

limit would not have prevented clothes 

from snagging in that crash scenario. 

NTSB noted that the manufacturer has 

since decreased the height of its buses’ 

emergency release latch plate so that it 

does not protrude into the window 

opening more than 0.5 inches. 

Advocates stated in their comments that 

there exist ‘‘flush-mount [latch] designs 

that entail no protrusion at all.’’ 

However, they added that these latches 

are implemented in non-motorcoach 

designs. NTSB stated that, if NHTSA 

allows any degree of latch protrusion, 

the latch should be designed to 

eliminate its potential to snag clothing 

or otherwise impede evacuation. 

SBMTC suggested NHTSA should 

provide a formal definition of 

‘‘opening’’ as used in the proposal that 

‘‘emergency exit latches, or other related 

release mechanisms, shall not protrude 

more than 25 mm into the opening of 

the emergency exit when the window is 

in the open position.’’ ICB commented 

that the ‘‘protrusion requirement applies 

to a latch or latch mechanism that is 

attached and remains with the bus body 

structure and not to a latch or latch 

mechanism that is attached to and 

moves with the exit window itself.’’ ICB 

wrote that the protrusion limit applies 

to anywhere in the window opening, 

even if the opening is larger than 

required for the passage of the ellipsoid 

specified in S.5.4.1. ICB also asked if ‘‘a 

latch or latch mechanism, that is spring 

loaded and protrudes more than 25 mm 

into the window opening in order to 

release the window, but then returns to 

a position that protrudes less than 25 

mm, would be compliant with this 

requirement.’’ 

Agency Response 

The agency has decided that it cannot 

justify a reduction in the emergency exit 

window latch protrusion requirements 

based on the comments and data 

provided in response to the NPRM. It is 

unknown at this time what the financial 

burden on the industry would be to 

require emergency exit latches to be 

replaced with flush-mount designs or 

reduced protrusions. It is also unproven 

at this time whether flush-mount latch 

designs would withstand the impact 

forces from the FMVSS No. 217a impact 

tests without additional modifications. 

The commenters did not provide 

information on the current status of 

latch designs used in different bus 

types, or what changes would be needed 

to comply with their suggested lower 

protrusion limits. Therefore, although 

we acknowledge that a one-inch 

protrusion may hinder egress in certain 

cases, NHTSA is denying the requests to 

reduce the emergency exit window latch 

protrusion limit. 

ICB is correct that the protrusion 

limits apply only to the latch 

components that remain with the bus 

structure. The latch protrusion in the 

Grey Summit bus crash that snagged on 

occupants’ clothing was mounted to the 

bottom of the window frame. Latches 

and related components that protrude 

into the window opening from the fixed 

bus structure are difficult for occupants 

to avoid when attempting to climb 

through the window opening during an 

emergency. This difficulty results in a 

high likelihood of the protrusion 

snagging onto occupants’ clothing. If the 

latch components are located on the 

portion of the emergency exit window 

that opens, the occupant would likely 

be able to reduce the risk of snagging 

any protrusion by opening the window 

farther. Thus, the protrusion limits 

apply only to the latch components that 

remain with the bus structure when the 

emergency exit window is in the open 

position to allow passage of the 

ellipsoid specified in S5.4.1 of FMVSS 

No. 217. 

ICB stated the protrusion limit applies 

to anywhere in the window opening 

even when the window is opened 

beyond what is required by S5.4.1 of 

FMVSS No. 217. This statement is 

incorrect. As proposed in the NPRM, the 

protrusion limit only applies to the 

window opening when the emergency 

exit is opened to the amount necessary 

to admit unobstructed passage of the 

ellipsoid specified in S5.4.1 of FMVSS 

No. 217. 

ICB asked if ‘‘a latch or latch 

mechanism, that is spring loaded and 

protrudes more than 25 mm into the 

window opening in order to release the 

window, but then returns to a position 

that protrudes less than 25 mm,’’ would 

be compliant with this requirement. An 

emergency exit opening system in 

which part of the latch mechanism 

protrudes into the opening space while 

the window latch lock is being released 

would be acceptable, as long as the latch 

components are all below the protrusion 

limit once the window is opened to the 

amount specified in S5.4.1. For 

example, a lever handle could protrude 

more than an inch into the opening 

while it is being moved from the closed 

position to the open position. However, 

once the lever is in the position to allow 

the window to be opened, all parts of 


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86274 Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 

the lever and its attachment bracket 

must protrude less than one inch from 

the structure to which it is attached. 

Force Required To Open Emergency 

Exits 

NTSB stated that from its accident 

investigations it ‘‘found that some 

passengers have difficulty in opening 

motorcoach windows and evacuating 

from them because of the weight of the 

windows and the challenge of keeping 

them open.’’ NTSB cited results from its 

crash investigations that support this 

concern. NTSB also requested that 

NHTSA take action in this, or a future, 

rulemaking to address the ease of 

opening such windows and their ability 

to remain open independently. NTSB 

stated ‘‘[s]uch action is needed to 

improve evacuation from emergency 

exit windows for motorcoaches and 

school buses.’’ 

Agency Response 

While NHTSA shares the NTSB’s 

concern for the capability of school bus 

occupants to easily open emergency 

exits, this aspect of emergency egress is 

not within the scope of this rulemaking. 

Therefore, NHTSA will not be 

mandating requirements concerning the 

force required to open emergency exits 

on school buses as part of this final rule. 

f. Organization of the Standard and 

Language Used in the Standard 

Several commenters provided 

feedback on the organization of the 

proposed standard, as well as the 

language used in the proposed standard. 

In response to these comments, the 

agency has decided to make several 

amendments to the proposed 

organization and language of the 

standard, which will be adopted as part 

of this final rule. The amendments to 

the proposed organization and language 

are highlighted in several of the agency 

response sections below. 

Merging FMVSS No. 217a Into FMVSS 

No. 217 

ICB suggested ‘‘that there should not 

be a separate and distinct regulation for 

FMVSS 217a Anti-Ejection Glazing for 

Bus Portals.’’ ICB stated that it would be 

better to have all bus window and 

glazing requirements included in 

FMVSS No. 217. However, ICB did note 

that it is ‘‘helpful to keep the latch 

protrusion requirements separate from 

the anti-ejection requirements.’’ 

Agency Response 

The agency has chosen to keep the 

bus anti-ejection requirements and 

procedures in a separate standard. 

Having FMVSS No. 217a separate from 

FMVSS No. 217 serves to highlight the 

differences in the two standards. 

Additionally, having the bus glazing 

anti-ejection requirements in a separate 

standard avoids confusion with existing 

FMVSS No. 217 requirements and 

procedures. This separation is useful for 

school bus applicability, since the 

planned FMVSS No. 217a has no 

applicability to school buses whereas 

FMVSS No. 217 does have specific 

requirements for school buses. 

102 mm Sphere Application Force and 

Passage 

Section 5.2(b) in the NPRM’s 

proposed regulatory text states that 

‘‘[e]ach piece of window glazing and 

each surrounding window frame shall 

be retained by its surrounding structure 

in a manner that prevents the formation 

of any opening large enough to admit 

the passage of a 102 mm diameter 

sphere under a force, including the 

weight of the sphere, of up to 22 

newtons.’’ This wording is different 

from the language used in S5.1(b) and 

S5.3(b). Those two sections use the 

phrase ‘‘. . . when a force of no more 

than 22 newtons is applied with the 

sphere at any vector . . .’’ The text in 

S5.1(b) and S5.3(b) correctly states a 22 

N force is applied to the glazing by the 

sphere. To be consistent, the agency has 

decided that the same wording in 

S5.1(b) and S5.3(b) will be used in 

S5.2(b). Additionally, the agency has 

decided to amend S5.1(b), S5.2(b), and 

S5.3(b) so that ‘‘passage’’ is amended to 

‘‘complete passage.’’ This change is 

based upon agency feedback 

recommending improved clarity in the 

regulatory text for compliance purposes. 

It was noted that without usage of the 

word ‘‘complete,’’ there would be no 

distinction between minimal, partial, 

and complete passage of the sphere 

through the glazing. The amended 

language is reflected in the final 

regulatory text for FMVSS No. 217a. 

Testing Requirements Organization 

ICB requested separate sections in the 

standard for each impact test (center 

impact, edge impact, and pre-broken 

glazing impact tests) with the 

requirements for each type of test in that 

section. 

Agency Response 

After reviewing the organization of 

the three types of tests (center impact, 

edge impact, and pre-broken glazing 

impact tests), the agency concluded that 

the requirements for each are already in 

separate sections. Within the proposed 

regulatory text for FMVSS No. 217a, 

S5.1 includes the requirements for the 

edge impact test, S5.2 includes 

requirements for the center impact test, 

and S5.3 includes requirements for the 

pre-broken glazing impact test. 

Accordingly, NHTSA does not see any 

need to adjust the organization of these 

requirements as part of this final rule. 

g. Compliance Date 

When the NPRM for this rule was 

published, NHTSA proposed a 

compliance date of 3 years after 

publication of a final rule. Based on 

research from NHTSA’s Vehicle 

Research and Test Center, the agency 

believes that some manufacturers would 

need to redesign their emergency exit 

latch systems or adopt a design that 

would meet the proposed requirements. 

Also, manufacturers would have to 

transition from double-glazed tempered/ 

tempered windows to a new setup that 

has at least one layer of laminated glass 

or advanced glazing that can meet the 

proposed requirements. The agency has 

determined that a 3-year lead time after 

publication of a final rule is appropriate 

as some design, testing, and 

development will be necessary to certify 

compliance to the new requirements. 

The rollover structural integrity final 

rule has a compliance date of December 

30, 2024, which is 3 years after the 

publication date of December 29, 2021. 

Similarly, the agency proposed a 

compliance date of 3 years after 

publication of the final rule for this 

advanced glazing rulemaking. Since the 

two rulemakings were initially being 

developed concurrently, and since the 

anti-ejection requirements are 

dependent upon the rollover structural 

integrity requirements, the agency 

proposed in the NPRM to make the 

compliance date of the two rulemakings 

the same. The agency also proposed 

that, to enable manufacturers to certify 

to the new requirements as early as 

possible, optional early compliance 

with the standard would be permitted. 

EPGAA commented that the glazing 

industry should have no issue 

supporting the three-year phase-in 

period since ‘‘the manufacturing 

technology and capacity already exist to 

produce advanced glazing solutions.’’ 

BBBC stated that making the 

compliance date the same for the two 

rulemakings (FMVSS No. 227 and 

FMVSS No. 217a) is preferred only if 

the date is a minimum of 3 years after 

the publication of both final rules. ICB 

also requested alignment of the 

implementation time for FMVSS No. 

227 and FMVSS No. 217a. Van Hool 

stated that it would prefer to extend the 

crash requirements for the retention of 

glazing and the opening of emergency 

exits after the crash. 


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48Since the impact tests no longer apply to rear 

windows in this final rule, there is no need for 

defining daylight opening for rear windows. 

Agency Response 

Since the rollover structural integrity 

final rule was published significantly 

earlier than this anti-ejection glazing 

final rule, the agency has decided not to 

align the compliance date of the two 

standards. The agency agrees with 

EPGAA that the MAP–21 mandated lead 

time of 3 years is sufficient for the 

necessary design, testing, and 

development to comply with this 

standard. To align the compliance dates 

of FMVSS No. 227 and a final rule for 

advanced glazing, the agency would 

either need to delay the compliance date 

of FMVSS No. 227 or accelerate the 

compliance date of advanced glazing 

final rule establishing FMVSS No. 217a. 

As stated in the NPRM, NHTSA believes 

a lead time of 3 years is an appropriate 

amount of time to account for the 

changes required to comply with this 

anti-ejection glazing standard. The 

agency will not decrease the lead time 

of this standard to align the compliance 

date with FMVSS No. 227. Additionally, 

the structural integrity improvements 

due to compliance with FMVSS No. 227 

will benefit occupants during a rollover 

crash even if the anti-ejection glazing 

improvements have not yet been 

implemented. Therefore, the agency will 

not delay the compliance date of 

FMVSS No. 227 to align with a final 

rule establishing FMVSS No. 217a as 

BBBC and ICB have requested. 

The agency is unclear about what Van 

Hool was requesting in it comment on 

the compliance date. If Van Hool was 

asking for additional lead time, it did 

not state how much additional time it 

was requesting before implementation 

of improved passenger anti-ejection 

benefits. Accordingly, NHTSA has 

decided not to grant Van Hool’s request. 

For the reasons discussed above, 

NHTSA is adopting the 3-year 

compliance date as proposed in the 

NPRM as part of this final rule. 

h. Retrofitting 

Greyhound and ICB agreed with the 

agency that it would make little sense to 

require retrofitting of bus windows 

without improving the structural 

integrity of the bus. Greyhound 

indicated that any requirements for 

enhanced window standards should 

apply only to buses manufactured after 

the implementation date of those 

standards. NTSB requested NHTSA 

consider requiring retrofit of existing 

buses for improved window latch 

design, stating that ‘‘NHTSA has 

identified simple countermeasure latch 

designs that reduce latch openings 

when the window is struck near the 

latch.’’ 

Agency Response 

The agency has decided to not require 

retrofitting of buses with improved latch 

designs and window glazing materials 

as part of this final rule. As stated in the 

NPRM, the simple countermeasure for 

latch designs was to add a washer 

screwed onto the top of the existing MCI 

E/J-series striker post. The agency has 

no data to determine if this fix would 

work for other latch systems, or if other 

redesigns to those latch systems would 

be necessary. For example, it is not 

known if the other buses have enough 

strength at the latch anchorage locations 

of each window for the improved latch 

system. Every window system would 

require analysis and most likely testing 

to verify its capability to successfully 

manage the new loads. Each window 

structure would need to be inspected for 

pre-existing damage that would cause 

the improved latch system to fail when 

subjected to the new loads. Therefore, 

NHTSA disagrees with the NTSB’s 

argument that a simple countermeasure 

exists for retrofitting all existing buses. 

It is not practical to retrofit improved 

latch systems onto existing buses 

because of the unique nature of each 

existing window structure and latching 

mechanism. 

Additionally, NHTSA retains its plan 

to not require retrofitting of advanced 

glazing into existing buses. The agency 

agrees with Greyhound and ICB that it 

makes little sense to upgrade the 

window glazing without also improving 

the bus structure in accordance with 

FMVSS No. 227. Therefore, NHTSA will 

not require retrofitting for any 

requirements of this standard. 

i. Definitions and Descriptions 

Daylight Opening 

BBBC commented that the proposed 

S4 definition of ‘‘daylight opening’’ 

through its use of the terms ‘‘horizontal’’ 

and ‘‘vertical’’ assumes the opening is 

essentially purely horizontal or vertical, 

respectively. While BBBC stated that 

openings are usually one or the other, 

BBBC recommended that NHTSA 

consider how to apply that definition to 

an opening that may be in a plane that 

is not purely vertical or horizontal, such 

as one 45 degrees to either plane. 

Replying to the questions asked in the 

NPRM concerning Executive Order 

(E.O.) 12866 and E.O. 13563, ICB and 

SBMTC requested improved clarity 

through the addition of figures and 

diagrams for various terms, including 

daylight opening and periphery. ICB 

stated that the definition for daylight 

opening given in the NPRM is 

‘‘confusing and overly complicated.’’ It 

also asked for clarification concerning 

the items to be included in the daylight 

opening measurement and further 

suggested that any window frame, 

weather stripping, or flexible gasket 

material should not be included in 

portal size measurements. 

Agency Response 

NHTSA is adopting the proposed 

definition of daylight opening; however 

the specifications for daylight opening 

for rear windows have been deleted.48

Due to the number of comments 

received concerning the definition of 

daylight opening, NHTSA has elected to 

add figures and additional details in the 

Technical Support Document to aid in 

understanding the definition as part of 

this final rule. This Technical Support 

Document is included in the docket for 

this final rule. For the purposes of 

FMVSS No. 217a, ‘‘daylight opening’’ is 

the opening generated when the visible 

glazing, including flexible material, is 

removed from the window. It is the 

opening bounded by the bus structure’s 

window frame. ‘‘Daylight opening’’ 

applies to all side and roof windows of 

the vehicle, including emergency exit 

windows. ‘‘Daylight opening’’ is used to 

help determine where the FMVSS No. 

217a guided impactor will hit. 

BBBC commented that the proposed 

definition for daylight opening does not 

account for window openings that are 

not purely vertical or horizontal. BBBC 

is correct that while most windows are 

oriented vertically or horizontally, there 

are applications where the window may 

be installed at an angle or consist of 

curved glazing. The agency believes the 

proposed definition of daylight opening 

properly accounts for these situations 

where the window is not purely 

horizontal or vertical. The proposed 

definition specifies the orientation of 

the ‘‘daylight opening’’ to be based on 

the bus’s longitudinal axis and whether 

the window is on the bus’s side wall or 

roof. If the window is installed at an 

angle or uses curved glazing, the 

daylight opening would still be 

measured based on the proposed 

definition depending on whether the 

window is located in the bus side wall 

or roof. Therefore, whether a window is 

purely vertical or horizontal, the 

daylight opening would be determined 

in the same manner. The Technical 

Support Document provides 

illustrations and examples for 

determining the daylight opening for 

curved glazing. The Technical Support 

Document also addresses the comments 

from ICB and SBMTC, which requested 


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49 81 FR 27925. 50The agency estimated that a fully framed and 

assembled double-glazed tempered/tempered 

window (approximately 25 square feet) costs $340. 

Likewise, the agency estimated that a fully framed 

and assembled single-glazed laminated window 

(approximately 25 square feet) costs $353.75. The 

incremental cost of choosing a single-glazed 

laminated window over a double-glazed tempered/ 

tempered window is $13.75 per window or $165.00 

per bus assuming 12 windows. The weight of the 

double-glazed tempered/tempered window units 

used in NHTSA’s testing were 100 lb and 110 lb 

(avg of 105 lb). The single-glazed laminated 

window unit weighed 77 lb. This difference results 

in an average weight savings of 28 lb per window 

unit. Assuming an average of 12 windows per bus 

results in 336 lb of weight savings per bus. 

51The agency estimated that there are 2,200 new 

over-the-road and applicable large buses 

manufactured annually. NHTSA estimated that MCI 

manufactures about 47.7 percent of the market 

population and already includes laminated glazing 

as part of its production window options. Assuming 

12 windows per bus, the cost to equip laminated 

glass instead of tempered glass is $13.75 per 

window, and the cost of latch improvements is 

$0.05 per window, the total annual incremental cost 

for new buses covered under this proposal is 

$191,169 (= 2,200 × 0.477 × $0.60 + 2,200 × 0.523 

× $165.60) in 2013 dollars. 

additional figures and clarification 

surrounding the definition of daylight 

opening and periphery. 

Portal 

ICB commented that a portal is related 

to the opening created in the bus 

structure when the window is opened. 

ICB stated that the term ‘‘portal’’ is 

confusing and that the term be replaced 

with ‘‘opening.’’ 

Agency Response 

NHTSA has decided not to replace the 

term ‘‘portal’’ with ‘‘opening’’ as part of 

this final rule. The definition of a portal 

according to the proposed FMVSS No. 

217a text is ‘‘an opening that could, in 

the event of a crash involving the 

vehicle, permit the partial or complete 

ejection of an occupant from the 

vehicle, including a young child.’’ This 

definition comes directly from MAP–21. 

An opening is a more general term, and 

a portal is a specific type of opening. A 

portal can be any type of opening in a 

bus wall, floor, or roof that could allow 

even a partial ejection of an occupant in 

the event of a crash. Some examples of 

a portal include an open window or 

door, a broken window with some 

glazing removed, a hole in the bus wall, 

or an open roof hatch. While there are 

no minimum dimensions associated 

with portals, it must be large enough to 

admit at least partial passage of an 

occupant, even if they are a smaller 

child. NHTSA will not replace the word 

‘‘portal’’ with ‘‘opening,’’ because an 

opening does not have to be large 

enough to admit at least partial passage 

of an occupant. 

Miscellaneous Comments on 

Clarification of Terms 

In addition to the clarifications 

discussed above, ICB requested 

improved clarity through the addition of 

figures and diagrams for measuring 

minimum surface dimension of an 

opening and glazing pre-breaking 

procedures. 

Agency Response 

NHTSA believes these topics are 

discussed in sufficient detail in the 

NPRM and in this final rule. Additional 

details for the glazing breaking 

procedures, the latch protrusion into the 

emergency exit when the window is in 

the open position, and how to measure 

minimum surface dimension of an 

opening are items that will be included 

in the agency’s compliance test 

procedures for this rule. 

j. Costs and Benefits 

In the NPRM and Preliminary 

Regulatory Evaluation (PRE), NHTSA 

anticipated that tempered glazing would 

not meet the requirements of the 

dynamic impact tests, particularly the 

pre-broken impact test, and the agency 

believed the double-glazed tempered/ 

tempered windows would need to be 

replaced, at minimum, with a singleglazed laminated window. Thus, the 

cost and benefit estimates assumed the 

manufacturers would be upgrading from 

double-glazed tempered/tempered 

glazing to single-glazed laminated 

glazing. 

The target population for total lives 

saved was based on fatalities from 

rollover crashes in applicable buses and 

was reduced by the expected lives saved 

due to Electronic Stability Control 

(ESC), seat belt usage, and rollover 

structural integrity. The NPRM noted 

that advanced glazing would also 

prevent fatalities in other crash types, 

but it did not include those crash types 

in the estimation due to lack of need to 

further justify the rule.49

For the governing scenario of 

replacing double-glazed tempered/ 

tempered glazing with single-glazed 

laminated glazing, NHTSA estimated 

the costs and benefits as summarized in 

Table 9 below. NHTSA determined 

replacing a double-glazed tempered/ 

tempered glazing with a single-glazed 

laminated glazing would result in a 

weight decrease and cost increase.50 For 

additional details and the calculations 

associated with these data, refer to the 

PRE included in the docket with the 

NPRM. 

TABLE 9—ADVANCED GLAZING ANNUAL COSTS AND BENEFITS FROM PRE 

Costs Benefits 

Item Value 

($M) Item Amount 

Material .................................................... $0.191 Lives Saved A .......................................... 0.33–1.54 lives per year. 

Fuel Savings B ......................................... 0.04 mpg. 

Notes: 

A Range is dependent on seat belt usage, from 15 percent usage to 84 percent usage. 

B Fuel savings due to weight savings estimated at 336 lb per vehicle. 

According to the PRE and NPRM, the 

main cost associated with the 

requirements in this rule would be the 

material costs for the new glazing types 

and window units. The agency also 

anticipated that modifications to the 

window latch systems would be needed 

to meet the dynamic impact test 

requirements. Applying these material 

costs to the population of new, large 

buses and motorcoaches produced 

annually resulted in approximately 

$191,000.51

Switching from a double-glazed 

tempered/tempered window unit to a 

single-glazed laminated window unit 

would reduce the overall weight of the 

window unit. This weight reduction 

would result in improved fuel economy 

for each bus. The weight of the doubleglazed tempered/tempered window 

units used in NHTSA’s testing were 100 

lb and 110 lb (avg of 105 lb). The singleglazed laminated window unit weighed 


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52A typical large bus travels 56,000 miles per 

year and has an average fuel economy of 6.1 mpg. 

With the 47.7 percent current compliance rate, an 

estimated 1,151 buses would benefit from this fuel 

economy increase. 53 Duffy, S., & Prasad, A., National Highway 

Traffic Safety Administration, Motorcoach Side 

Glazing Retention Research, pp. 10–13 (Report No. 

DOT HS 811 862) (Nov. 2013). Washington, DC:. 

77 lb. This difference resulted in an 

average weight savings of 28 lb per 

window unit. Assuming an average of 

12 window units per bus resulted in 336 

lb of weight savings per bus. Based on 

the calculations outlined in the PRE, 

this change resulted in an increase of 

0.04 mpg per bus. Projecting that fuel 

economy benefit over the life of each 

affected bus produced annually resulted 

in approximately $2.90 million worth of 

fuel economy savings at a 3% discount 

rate.52 Table 10 below summarizes the 

costs and benefits of the rule as outlined 

in the PRE. 

TABLE 10—SUMMARY OF ANNUALIZED COSTS AND BENEFITS DUE TO THE ANTI-EJECTION GLAZING NPRM 

[Costs are in millions of 2013 dollars] 

15% belt use rate 84% belt use rate 

Undiscounted 3% 7% Undiscounted 3% 7% 

Equivalent Lives Saved ........................... 1.60 1.37 1.03 0.34 0.29 0.22 

Net Cost A ................................................. ($5.57) ($4.30) ($3.20) ($3.98) ($3.05) ($2.25) 

Cost per Equivalent Lives Saved ............ ($3.48) ($3.14) ($3.11) ($11.71) ($10.52) ($10.23) 

Benefits from Comprehensive Costs 

Avoided ................................................. $15.44 $13.22 $9.95 $3.30 $2.82 $2.12 

Net Benefits ............................................. $21.02 $17.52 $13.15 $7.28 $5.87 $4.37 

Notes: A Net costs are negative because the fuel savings are expected to outweigh the material costs. 

Glazing Construction for Compliance 

BBBC, Prevost, Van Hool, SBMTC, 

and ICB expressed concerns that usage 

of laminated glazing could result in 

increased weight and cost per bus, 

leading to increased fuel usage and 

possibly resulting in reduced seating 

capacity in buses close to their weight 

limit. Prevost questioned the agency’s 

assumption that double-glazed 

tempered/tempered windows could be 

replaced with a single pane of laminated 

glazing. Van Hool and Prevost expressed 

concern for changes in thermal 

properties, which would directly 

influence costs associated with heating 

and cooling of the bus interiors. Prevost 

also obtained a price quotation for 

installing laminated glazing in its 

motorcoaches. According to Prevost, for 

equivalent sizes, shapes, and tinting, the 

estimated cost increase when compared 

to its current double-glazed tempered/ 

tempered configuration was ‘‘on the 

order of five thousand dollars ($5,000) 

per vehicle.’’ ICB stated it uses singlepaned tempered glazing for bus 

windows. According to ICB, replacing 

this material with single paned 

laminated glazing ‘‘could add up to 200 

lb of additional weight.’’ Van Hool also 

stated that ‘‘[d]ouble laminate or 

tempered/laminated glazing might do 

the trick at no expense for seating 

capacity, but with no gain either.’’ 

EPGAA agreed with the agency’s 

conclusion that there is a weight 

reduction in direct replacement of 

laminated for tempered glazing in 

situations where the overall thickness 

remains the same since the density of 

the plastic interlayer is about half that 

of glass. EPGAA expressed doubt that 

there will be a significant change in the 

desire of bus OEMs to employ doubleglazed insulating assemblies for buses 

used in colder climate zones. EPGAA 

stated that the insulating units are 

employed to increase the interior glass 

temperature and thus reduce any 

propensity for condensation or fogging 

while increasing occupant thermal 

comfort. EPGAA stated that advanced 

glazing does not in itself create a 

significant impact in thermal 

performance compared to monolithic 

glass since it has a similar thermal 

conductivity. 

EPGAA commented that advanced 

glazing would offer a benefit through 

reduced sound transmission when 

compared to monolithic tempered glass, 

creating a quieter cabin. EPGAA also 

commented that advanced glazing 

would result in a significant reduction 

in UV exposure of occupants and 

interior components. EPGAA stated that 

with the addition of optional low 

emissivity or solar control layers the 

advanced glazing may also be used to 

significantly reduce the solar load and 

hence air conditioning load. EPGAA 

also stated that certain added layers may 

function to reduce condensation or 

fogging thresholds and could in some 

cases help to eliminate the need for the 

double-glazed insulating assemblies. 

EPGAA concluded that while the fuel 

savings based on reduction in use of 

insulating glass assemblies may be 

overestimated, there are unstated 

monetary savings associated with air 

conditioning load reduction as well as 

reduced UV exposure of occupants. 

Agency Response 

Based on comments and feedback 

from the bus manufacturers and 

SBMTC, NHTSA understands most bus 

manufacturers will not be replacing 

double-glazed tempered/tempered 

windows with single-glazed laminated 

windows. Instead, it is more 

representative of the industry to assume 

the manufacturers will simply exchange 

at least one pane of tempered glazing 

with laminated glazing but keep the 

double-glazed window construction. In 

other words, the double-glazed 

tempered/tempered windows will likely 

be replaced with double-glazed 

laminated/tempered windows, where 

either the interior or exterior pane is 

laminated glazing. This replacement 

will maintain or improve the thermal 

and sound insulation properties that are 

experienced by occupants with the 

current glazing units. The cost-benefit 

analysis in this final rule uses this 

change as the governing scenario, 

instead of the scenario presented in the 

PRE. 

This change in governing scenario 

results in the removal of the weight 

reduction benefit that was estimated in 

the PRE. EPGAA stated in its comments 

that there is some weight reduction 

when directly replacing tempered 

glazing with laminated glazing due to 

the lower density of the PVB interlayer 

compared to glass. However, the 

laminated glazing is often thicker than 

the tempered glazing it replaces, and the 

PVB interlayer only makes up 

approximately 6 percent of the glazing 

thickness.53 Therefore, any weight 

difference is considered negligible for 


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86278 Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 

54 77 FR 3076 NPRM for new FMVSS No. 136 

(May 23, 2012); Effectiveness of Stability Control 

Systems for Truck Tractors, DOT HS 811 437 (Jan. 

2011). 

55Seat Belt Use in 2021—Overall Results, Traffic 

Safety Facts Research Note, Report number DOT HS 

813 241 (Dec. 2021), https://crashstats.nhtsa.

dot.gov/Api/Public/Publication/813241, last 

accessed December 18, 2023. 

56Matolcsy, M., ‘‘The Severity of Bus Rollover 

Accidents,’’ 20th International Technical 

Conference for the Enhanced Safety of Vehicles, 

Paper 989, Lyon, France (2007). Available at: wwwnrd.nhtsa.dot.gov/pdf/esv/esv20/07-0152-O.pdf. 

the purposes of the cost and benefit 

calculations. 

As Prevost commented, there are 

additional costs to consider if 

manufacturers would be replacing their 

current double-glazed window units 

with single-glazed laminated windows. 

Switching from a double-glazed 

tempered/tempered window 

construction to a double-glazed 

laminated/tempered window 

construction will be more expensive for 

bus manufacturers than switching to a 

single-glazed laminated window as 

previously calculated. The agency 

estimates that a fully framed and 

assembled double-glazed tempered/ 

tempered window (approximately 25 

square feet) costs $377.73. Likewise, 

NHTSA estimated that a fully framed 

and assembled double-glazed 

laminated/tempered window 

(approximately 25 square feet) costs 

$438.84. The incremental cost of 

choosing a double-glazed laminated/ 

tempered window over a double-glazed 

tempered/tempered window is $61.11 

per window or $733.32 per bus 

(assuming 12 windows per bus). As 

outlined in the costs and benefits 

section of this final rule, even with the 

higher costs associated with this 

governing scenario this final rule is still 

cost beneficial. 

Previous Rulemakings 

Van Hool expressed concern that the 

possible positive influences of ESC on 

bus rollovers were not properly 

accounted for. Van Hool asked how 

effective an ESC system would be 

during a bus rollover. Further, Van Hool 

proposed that the severity of an 

unbelted occupant’s contact with the 

opposite side glazing during a rollover 

would be mitigated by the effects of 

ESC. 

Prevost stated that it ‘‘believe[s] that 

the estimated usage of seat belts is 

higher than what is listed in the 

NPRM.’’ Prevost also stated that ‘‘[s]eat 

belt usage is the single most important 

safety system to mitigate passenger 

ejection and we commend NHTSA on 

the attention they continue to give to 

this. We believe that pre-trip safety 

briefings will further increase the 

percentage of seat belt usage.’’ Van Hool 

stated that any seat belt usage data is 

speculative at best and that the agency 

manipulated the seat belt estimates ‘‘in 

order to make the numbers work.’’ 

Van Hool commented that the effects 

of the requirements from FMVSS No. 

227 have not been taken into account 

and that there has not been enough 

consideration of the performance 

changes to the vehicle structure that 

will be created by bus designs changing 

to meet FMVSS No. 227. Van Hool 

stated that its bus windows do not break 

in a rollover test under Regulation No. 

66 of the Economic Commission for 

Europe of the United Nations (ECE 

R.66). Van Hool stated the agency has 

not adequately proven that the FMVSS 

No. 217a impactor test represents 

rollover forces acting on the windows of 

future buses that fulfill the requirements 

of FMVSS No. 227 and/or ECE R.66. 

Agency Response 

Details concerning the effectiveness of 

ESC for buses was discussed in both the 

agency’s 2012 NPRM proposing to 

require ESC on heavy vehicles and a 

2011 agency research note.54 The 

analysis estimated that ESC would be 

40–56 percent effective against a 

rollover event. In other words, 44–60 

percent of the rollover events would 

still occur, even with ESC installed in 

the heavy buses. Since ESC alone only 

partially mitigates the risk of rollover 

crashes, there remains a need to protect 

passengers from ejection conditions in 

applicable vehicles. NHTSA has 

accounted for the crash reducing effects 

of ESC when calculating the estimated 

lives saved from the advanced glazing 

requirements in this final rule. 

The agency agrees with Prevost on the 

importance of seat belt usage in all 

motor vehicles. The agency examined 

seat belt usage rates of 15% and 84% in 

the NPRM. For the cost-benefit analysis 

in this final rule, the upper bound was 

increased to 90 percent. Nationally the 

seat belt usage rate in passenger vehicles 

has been approximately 90 percent very 

year from 2016 to 2021.55 Therefore, the 

agency analysis based on the 90 percent 

usage rate in motorcoaches is reasonable 

as a conservative upper bound since 

usage rates in buses are not believed to 

be as high as passenger vehicles. 

NHTSA has accounted for a range of bus 

occupants using seat belts when 

calculating the estimated lives saved 

from the advanced glazing requirements 

in this final rule. 

The bus structural integrity rollover 

test used in FMVSS No. 227 and ECE 

R.66 is an effective test to determine a 

bus’s capability to maintain a survival 

space during a rollover event.56

However, in that test, ballast weight for 

each occupant is strapped to the seats 

for the FMVSS No. 227 evaluation. 

Windows are not intended to be 

evaluated under loading from moving 

objects in that test. While the increased 

structural rigidity is expected to reduce 

the number of fatal ejections, those 

requirements do not account for 

passengers being ejected through 

windows that have been broken by 

internal impacts. The rollover structural 

integrity FRE estimates a 74 percent 

effectiveness of ejection mitigation in 

preventing fatalities. It also states that 

the enhanced rollover structural 

integrity test procedure does not include 

a condition to simulate occupant 

loading, and therefore estimates a 

midpoint effectiveness of 37 percent for 

unrestrained ejected fatalities. As 

outlined above, this effectiveness is 

accounted for when calculating the 

expected number of lives saved from the 

requirements in this final rule. 

Supporting Data 

Van Hool stated that ‘‘the data driving 

this NPRM seems to be from 1980– 

2004’’ and that this data was collected 

well before seat belts were in use. Van 

Hool commented that if 2010–2015 data 

were used there would not be a strong 

case for requiring anti-ejection glazing. 

Van Hool commented that ‘‘recently 

released FMCSA crash data indicates 

the lowest fatality rates given the higher 

numbers of coaches on the road and the 

highest number in miles traveled.’’ 

Van Hool also expressed doubt for the 

particular occupant loading chosen in 

the Martec study, and the agency’s 

usage of that loading to develop the 

proposed anti-ejection requirements for 

this rule. Van Hool expressed a 

preference to use the structural integrity 

rollover test used in FMVSS No. 227 as 

the bus motion to study for window 

glazing loading during crashes. Van 

Hool stated a ‘‘passenger could not be 

projected against the window, nor could 

he be ejected out of the bus through the 

opposite side.’’ 

Agency Response 

The 1980–2004 data to which Van 

Hool refers was used for the Martec 

report, which was completed in 2006. 

The data presented in the report was the 

most recently available information at 

the time that study was conducted. 

Those crashes were investigated to 

identify the rollover events most likely 

to produce worst-case occupant to 

glazing impact loads. While the Martec 

report and its source data are over 10 


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57Motor Coach Glazing Retention Test 

Development for Occupant Impact During a 

Rollover (Martec Study), Final Report published on 

August 2006, Docket No. NHTSA–2002–11876–15. 

58For details concerning equivalent lives saved, 

reference the FRE docketed with this final rule. 

59For the analysis, both complete and partial 

ejections are included as ‘‘ejected occupants’’ since 

the anti-ejection glazing is expected to reduce the 

risk of both ejection types. 

years old, data indicate that passengers 

continue to be ejected from 

motorcoaches during rollover and other 

crashes. NHTSA did not rely on the 

Martec report data as the ‘‘driving data’’ 

for this rule. The driving data used for 

the NPRM and PRE was from 2004– 

2013. NHTSA has updated that data to 

be from 2006 to 2019 for the final rule. 

The Martec report stated that its 

objective was ‘‘to improve the level of 

safety protection of passengers in 

motorcoach crashes by reducing the 

likelihood of ejection during vehicle 

collision or rollover, as such ejections 

are associated with a high probability of 

fatality.’’ The report authors examined 

Transport Canada bus crash 

investigation reports and then chose to 

model the passenger motion in a bus 

during a crash where 

. . . the bus rolled onto its side after yawing 

while trying to negotiate a sharp turn at 

elevated speed. The bus had a significant 

lateral velocity, the underside of the bus 

contacted the ground, furrowed into the sod, 

and the bus rolled over on its side. A rear 

hinged/latched emergency window (on the 

impacted side) was either dislodged during 

the crash or had been opened prior to the 

rollover, and there were fatalities due to 

ejections through the window opening.57

The claim that a passenger could not 

move unobstructed to the opposite side 

of a bus during a vehicle rollover does 

not apply to all bus seating 

configurations. The Martec study 

appropriately used a severe bus crash 

event and conducted computer 

simulations to determine a possible 

window loading scenario caused by a 

passenger’s unrestrained movement 

during such a crash event. With this bus 

glazing anti-ejection rule the agency is 

establishing requirements such that the 

retained windows will mitigate partial 

ejections of belted occupants seated 

next to the windows as well as retain 

the estimated 10 to 85 percent of 

unbelted occupants. The anti-ejection 

requirements will mitigate the 

occurrence of window portals being 

created by movement of unrestrained 

passengers. Accordingly, the agency 

will not be adopting Van Hool’s 

recommendation to use the motion from 

a belted passenger in a rollover test as 

the load basis for window glazing antiejection requirements as part of this 

final rule. 

VI. Overview of Costs and Benefits 

After accounting for the above 

comments from the NPRM, NHTSA 

analyzed the anticipated effects of a 

final rule and determined the net result 

is cost beneficial. The agency 

anticipates that tempered glazing will 

not meet the requirements of the 

dynamic impact tests, particularly the 

pre-broken impact test. Therefore, the 

governing scenario we use for the costbenefit analysis assumes the 

manufacturers will replace at least one 

pane of their double-glazed tempered/ 

tempered window units with laminated 

glass. 

For fatality data analysis, NHTSA 

used FARS data from 2006–2019. The 

agency decided not to use 2020 data for 

data summaries and averages due to the 

effect of the COVID–19 pandemic on the 

industry. NHTSA believes the 2020 data 

could disproportionately skew the costs 

and benefits analysis. For injury data 

analysis, NHTSA used the National 

Automotive Sampling System—General 

Estimates System (NASS–GES) data 

from 2006–2015 and Crash Report 

Sampling System (CRSS) data from 

2016–2019. The NASS–GES system was 

retired in 2016 and replaced by the 

CRSS system. The same 14-year period 

2006–2019 was used to match the time 

frame of fatality data. 

The costs resulting from today’s final 

rule are the material costs attributed to 

upgrading the window glazing material 

and improving the latching mechanisms 

as necessary. As discussed in the FRE 

for today’s final rule, approximately 

47.7 percent of motorcoach 

manufacturers currently use laminated 

glass in their window units. The 

remaining 52.3 percent of motorcoach 

and large bus manufacturers are 

assumed to use double-glazed 

tempered/tempered window units, or 

some other glazing construction that 

may not comply with the performance 

requirements in this final rule. These 

windows will need to be upgraded to at 

least a double-glazed laminated/ 

tempered glazing window unit 

construction. Additionally, NHTSA 

estimates that modifications to the 

window latch systems for all 

motorcoach and large bus manufacturers 

will be needed in order to meet the 

dynamic impact test requirements. 

Table 11 summarizes the incremental 

costs associated with administering the 

upgrades necessary for compliance with 

today’s final rule. 

TABLE 11—INCREMENTAL COSTS FROM REPLACING TEMPERED/TEMPERED GLAZING WITH LAMINATED/TEMPERED

GLAZING AND UPGRADED WINDOW LATCHES

Glazing type Cost per 

window 

Cost for 

improved 

latch per 

window 

Number of 

side glass 

positions 

Cost per 

vehicle 

Number of 

applicable 

vehicles 

Total cost to 

upgrade all 

applicable 

vehicles 

Total cost 

assuming 

47.7% 

compliance 

rate 

Double-glazed tempered/tempered ......... $430.62 $0.00 12 $5,167.48 2,200 $11,368,457 NA 

Double-glazed laminated/tempered ......... 500.28 0.06 12 6,003.40 2,200 13,209,144 NA 

Incremental cost ....................................... 69.66 0.06 12 835.92 2,200 1,840,687 963,477 

The benefits of today’s final rule are 

calculated based on the number of 

expected equivalent lives saved 58 from 

ejections during crashes involving the 

applicable buses. NHTSA calculated the 

fatal target population using FARS data 

from 2006–2019 and injury data from 

NASS–GES (2006–2015) and CRSS 

(2016–2019). The target population was 

estimated using both a 15 percent seat 

belt usage scenario and a 90 percent seat 

belt usage scenario based on the 2021 

large bus rollover structural integrity 

final rule. The resulting target 

population (i.e., unrestrained ejected 59

occupants) estimated for today’s final 

rule after accounting for the benefits 

from the other initiatives applicable to 

the same group of buses (seat belts, ESC, 

and structural integrity) is 6.38 fatalities 

at the 15 percent seat belt use rate and 

1.18 fatalities at the 90 percent seat belt 

use rate. Based on the various rollover 

tests on buses performed by the agency, 


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60 44 FR 11034 (Feb. 26, 1979). 

NHTSA believes that the required 

advanced glazing would maintain its 

retention capability in single and double 

1⁄4-turn bus rollover crashes. 

Accordingly, the agency expects that the 

requirements would result in 0.37 to 

1.91 equivalent lives saved annually. 

Table 12 below summarizes the costs 

and benefits of today’s final rule. 

TABLE 12—SUMMARY OF ANNUALIZED COSTS AND BENEFITS DUE TO ADVANCED GLAZING

[Costs are in millions of 2022 dollars] 

Discount rate 

15% belt use rate 90% belt use rate 

Undiscounted 3% 7% Undiscounted 3% 7% 

Equivalent Lives Saved A B ...................................... 1.9191 1.5064 1.1491 0.3740 0.2936 0.2240 

Material Costs .......................................................... $0.96 $0.96 $0.96 $0.96 $0.96 $0.96 

Cost per Equivalent Lives Saved ............................ 0.50 0.64 0.84 2.58 3.28 4.30 

Benefits from Comprehensive Costs Avoided ......... 24.72 19.40 14.80 4.82 3.78 2.88 

Net Benefits ............................................................. 23.75 18.44 13.84 3.85 2.82 1.92 

Notes: 

A These values from the FRE account for serious injuries (MAIS 3–5) by utilizing a relative injury factor. 

B MAIS = Maximum AIS, AIS = Abbreviated Injury Scale, MAIS 0 = No Injury, MAIS 1 = Minor, MAIS 2 = Moderate, MAIS 3 = Serious, MAIS 4 

= Severe, MAIS 5 = Critical, MAIS 6 = Maximum (untreatable). 

VII. Regulatory Notices and Analyses 

E.O. 12866, E.O. 14904, E.O. 13563, and 

DOT Regulatory Policies and Procedures 

NHTSA has considered the potential 

impact of this final rule under E.O. 

12866, E.O. 14094, E.O. 13563, DOT 

Order 2100.6A and the DOT’s regulatory 

policies and procedures. This final rule 

is not considered to be significant under 

the DOT’s regulatory policies and 

procedures.60

This final rule creates a new FMVSS 

(FMVSS No. 217a) and makes several 

changes to FMVSS No. 217. 

Specifically, the final rule creates a new 

standard that will establish 

requirements for advanced glazing in 

over-the-road buses and buses weighing 

over 26,000 lb. The final rule also 

creates a requirement establishing a 

minimum protrusion limitation 

requirement for emergency exit latches. 

The agency estimates that compliance 

with the final rule would result in an 

annual cost of $0.96 million to 

manufacturers. More information on 

costs can be found in section VI above. 

Regulatory Flexibility Act 

Pursuant to the Regulatory Flexibility 

Act (5 U.S.C. 601 et seq., as amended by 

the Small Business Regulatory 

Enforcement Fairness Act (SBREFA) of 

1996), whenever an agency is required 

to publish a notice of rulemaking for 

any proposed or final rule, it must 

prepare and make available for public 

comment a regulatory flexibility 

analysis that describes the effect of the 

rule on small entities (i.e., small 

businesses, small organizations, and 

small governmental jurisdictions). The 

Small Business Administration’s 

regulations at 13 CFR part 121 define a 

small business, in part, as a business 

entity ‘‘which operates primarily within 

the United States.’’ (13 CFR 121.105(a)). 

No regulatory flexibility analysis is 

required if the head of an agency 

certifies that the rule will not have a 

significant economic impact on a 

substantial number of small entities. 

The SBREFA amended the Regulatory 

Flexibility Act to require federal 

agencies to provide a statement of the 

factual basis for certifying that a rule 

will not have a significant economic 

impact on a substantial number of small 

entities. 

NHTSA has considered the effects of 

this rulemaking action under the 

Regulatory Flexibility Act. According to 

13 CFR 121.201, the Small Business 

Administration’s size standards 

regulations used to define small 

business concerns, manufacturers of the 

vehicles covered by this final rule 

would fall under North American 

Industry Classification System (NAICS) 

No. 336111, Automobile Manufacturing, 

which has a size standard of 1,000 

employees or fewer. NHTSA estimates 

that there are 26 manufacturers of these 

types of vehicles in the United States 

(including manufacturers of 

motorcoaches, cutaway buses, secondstage motorcoaches, and other types of 

large buses covered by this final rule). 

Using the size standard of 1,000 

employees or fewer, we estimate that 

approximately 10 of these 26 

manufacturers would be considered 

small businesses. 

The agency does not believe that this 

final rule will have a significant 

economic impact on those small 

entities. First, the agency estimates that 

the incremental costs to each vehicle 

that currently does not comply with the 

requirements would be approximately 

$836 per unit to meet the final rule. This 

incremental cost will not constitute a 

significant impact given that the average 

cost of the vehicles covered by this final 

rule ranges from $200,000 to $400,000. 

Further, these incremental costs, which 

are very small compared to the overall 

cost of the vehicle, can ultimately be 

passed on to the purchaser and user. 

In addition, the agency believes that 

certifying compliance with the rule will 

not have a significant impact on the 

manufacturers. Small manufacturers 

have various options available that they 

may use in certifying compliance with 

the standard. Manufacturers are not 

required to use NHTSA’s test as the 

basis for their certification. While the 

agency’s test defined in the regulatory 

text will be an objective test capable of 

determining which vehicles meet the 

minimum requirements, manufacturers 

can use other methods in certifying the 

compliance of their own vehicles. 

For instance, a manufacturer could 

obtain advanced glazing windows from 

a glazing supplier and test the glazing 

on body sections of the vehicle. NHTSA 

used this approach in its motorcoach 

side glazing retention research program. 

The manufacturer could ‘‘section’’ the 

vehicle or otherwise obtain a body 

section representative of the vehicle, or 

test the glazing on test frames. It could 

base its certification on these tests, 

without testing a full vehicle. 

Unlike NHTSA, manufacturers 

certifying compliance of its own 

vehicles have more detailed information 

regarding their own vehicles and can 

use reasonable engineering analyses to 

determine whether its vehicles will 

comply with the requirements. We 

believe that a small manufacturer would 

be closely familiar with its own vehicle 

design and would be able to use 

modeling and relevant analyses on a 

vehicle-by-vehicle basis to reasonably 

predict whether its design will meet the 

requirements of this final rule. 


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Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86281 

We also note that the product cycle of 

the covered buses is significantly longer 

than those of other vehicle types. With 

a longer product cycle, we believe that 

the costs of certification for 

manufacturers would be further reduced 

as the costs of conducting compliance 

testing and the relevant analyses could 

be spread over a significantly longer 

period of time. 

Finally, we note that the requirements 

in this final rule may affect the 

operators of the buses that are the 

subject of today’s final rule—some of 

which may be small businesses—but 

only indirectly as purchasers of these 

vehicles. As mentioned above, we 

anticipate that the impact on these 

businesses will not be significant 

because the expected price increase of 

the vehicles (those that do not comply 

with the requirements) used by these 

businesses is small ($836 for each 

vehicle valued between $200,000 and 

$400,000). 

For the aforementioned reasons, I 

hereby certify that this final rule will 

not have a significant economic impact 

on a substantial number of small 

entities. 

Federalism 

NHTSA has examined this final rule 

pursuant to E.O. 13132 (64 FR 43255; 

Aug. 10, 1999) and concluded that no 

additional consultation with states, 

local governments, or their 

representatives is mandated beyond the 

rulemaking process. The agency has 

concluded that the final rule does not 

have sufficient federalism implications 

to warrant consultation with state and 

local officials or the preparation of a 

federalism summary impact statement. 

The final rule does not have 

‘‘substantial direct effects on the States, 

on the relationship between the national 

government and the States, or on the 

distribution of power and 

responsibilities among the various 

levels of government.’’ 

NHTSA rules can have preemptive 

effect in two ways. First, the National 

Traffic and Motor Vehicle Safety Act 

contains an express preemption 

provision: When a motor vehicle safety 

standard is in effect under this chapter, 

a state or a political subdivision of a 

state may prescribe or continue in effect 

a standard applicable to the same aspect 

of performance of a motor vehicle or 

motor vehicle equipment only if the 

standard is identical to the standard 

prescribed under this chapter. 49 U.S.C. 

30103(b)(1). It is this statutory command 

by Congress that preempts any nonidentical state legislative and 

administrative law address the same 

aspect of performance. 

The express preemption provision 

described above is subject to a savings 

clause under which ‘‘[c]ompliance with 

a motor vehicle safety standard 

prescribed under this chapter does not 

exempt a person from liability at 

common law.’’ 49 U.S.C. 30103(e). 

Pursuant to this provision, state 

common law tort causes of action 

against motor vehicle manufacturers 

that might otherwise be preempted by 

the express preemption provision are 

generally preserved. 

NHTSA rules can also preempt state 

law if complying with the FMVSS 

would render the motor vehicle 

manufacturers liable under state tort 

law. Because most NHTSA standards 

established by an FMVSS are minimum 

standards, a state common law tort 

cause of action that seeks to impose a 

higher standard on motor vehicle 

manufacturers will generally not be 

preempted. However, if and when such 

a conflict does exist—for example, when 

the standard at issue is both a minimum 

and a maximum standard—the state 

common law tort cause of action is 

impliedly preempted. See Geier v. 

American Honda Motor Co., 529 U.S. 

861 (2000). 

Pursuant to E.O. 13132, NHTSA has 

considered whether this final rule could 

or should preempt state common law 

causes of action. The agency’s ability to 

announce its conclusion regarding the 

preemptive effect of one of its rules 

reduces the likelihood that preemption 

will be an issue in any subsequent tort 

litigation. To this end, the agency has 

examined the nature (e.g., the language 

and structure of the regulatory text) and 

objectives of this final rule and finds 

that this final rule, like many NHTSA 

rules, prescribes only a minimum safety 

standard. 

Accordingly, NHTSA does not intend 

that this final rule preempt state tort law 

that would effectively impose a higher 

standard on motor vehicle 

manufacturers than that established by 

this final rule. Establishment of a higher 

standard by means of state tort law 

would not conflict with the minimum 

standard finalized in this document. 

Without any conflict, there could not be 

any implied preemption of a state 

common law tort cause of action. 

National Environmental Policy Act 

NHTSA has analyzed this final rule 

for the purposes of the National 

Environmental Policy Act. The agency 

has determined that implementation of 

this action will not have any significant 

impact on the quality of the human 

environment. 

Paperwork Reduction Act 

Under the procedures established by 

the Paperwork Reduction Act of 1995, a 

person is not required to respond to a 

collection of information by a federal 

agency unless the collection displays a 

valid Office of Management and Budget 

(OMB) control number. This rulemaking 

will not establish any new information 

collection requirements. 

Unfunded Mandates Reform Act 

(UMRA) 

The Unfunded Mandates Reform Act 

of 1995 (UMRA) requires federal 

agencies to prepare a written assessment 

of the costs, benefits and other effects of 

proposed or final rules that include a 

federal mandate likely to result in the 

expenditure by state, local or tribal 

governments, in the aggregate, or by the 

private sector, of more than $100 

million annually (adjusted annually for 

inflation, with base year of 1995). 

UMRA also requires an agency issuing 

an NPRM or final rule subject to the Act 

to select the ‘‘least costly, most costeffective or least burdensome alternative 

that achieves the objectives of the rule.’’ 

This final rule would not result in a 

federal mandate that will likely result in 

the expenditure by state, local or tribal 

governments, in the aggregate, or by the 

private sector, of more than $100 

million annually (adjusted annually for 

inflation, with base year of 1995). 

E.O. 12778 (Civil Justice Reform) 

When promulgating a regulation, 

agencies are required under E.O. 12988 

to make every reasonable effort to 

ensure that the regulation, as 

appropriate: (1) specifies in clear 

language the preemptive effect; (2) 

specifies in clear language the effect on 

existing federal law or regulation, 

including all provisions repealed, 

circumscribed, displaced, impaired, or 

modified; (3) provides a clear legal 

standard for affected conduct rather 

than a general standard, while 

promoting simplification and burden 

reduction; (4) specifies in clear language 

the retroactive effect; (5) specifies 

whether administrative proceedings are 

to be required before parties may file 

suit in court; (6) explicitly or implicitly 

defines key terms; and (7) addresses 

other important issues affecting clarity 

and general draftsmanship of 

regulations. 

Pursuant to this Order, NHTSA notes 

as follows. The preemptive effect of this 

final rule is discussed above. NHTSA 

notes further that there is no 

requirement that an individual submit a 

petition for reconsideration or pursue 


ddrumheller on DSK120RN23PROD with RULES1
86282 Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 

other administrative proceedings before 

they may file suit in court. 

National Technology Transfer and 

Advancement Act 

Under the National Technology 

Transfer and Advancement Act of 1995 

(NTTAA) (Pub. L. 104–113), all federal 

agencies and departments shall use 

technical standards that are developed 

or adopted by voluntary consensus 

standards bodies, using such technical 

standards as a means to carry out policy 

objectives or activities determined by 

the agencies and departments. 

Voluntary consensus standards are 

technical standards (e.g., materials 

specifications, test methods, sampling 

procedures, and business practices) that 

are developed or adopted by voluntary 

consensus standards bodies, such as the 

International Organization for 

Standardization and the Society of 

Automotive Engineers. The NTTAA 

directs us to provide Congress, through 

OMB, explanations when we decide not 

to use available and applicable 

voluntary consensus standards. There 

are no voluntary consensus standards 

developed by voluntary consensus 

standards bodies pertaining to this final 

rule. 

Plain Language Requirement 

E.O. 12866 requires each agency to 

write all rules in plain language. 

Application of the principles of plain 

language includes consideration of the 

following questions: 

• Have we organized the material to 

suit the public’s needs? 

• Are the requirements in the rule 

clearly stated? 

• Does the rule contain technical 

language or jargon that isn’t clear? 

• Would a different format (grouping 

and order of sections, use of headings, 

paragraphing) make the rule easier to 

understand? 

• Would more (but shorter) sections 

be better? 

• Could we improve clarity by adding 

tables, lists, or diagrams? 

• What else could we do to make the 

rule easier to understand? 

NHTSA has considered these 

questions and attempted to use plain 

language in promulgating this final rule. 

If readers have suggestions on how we 

can improve our use of plain language, 

please write us. 

Regulatory Identifier Number (RIN) 

The DOT assigns a RIN to each 

regulatory action listed in the Unified 

Agenda of Federal Regulations. The 

Regulatory Information Service Center 

publishes the Unified Agenda in April 

and October of each year. The RIN 

contained in the heading at the 

beginning of this notice may be used to 

find this action in the Unified Agenda. 

Privacy Act 

In accordance with 5 U.S.C. 553(c), 

DOT solicits comments from the public 

to better inform its decision-making 

process. DOT posts these comments, 

without edit, including any personal 

information the commenter provides, to 

www.regulations.gov, as described in 

the system of records notice (DOT/ALL– 

14 FDMS), which can be reviewed at 

www.transportation.gov/privacy. 

Anyone is able to search the electronic 

form of all comments received into any 

of our dockets by the name of the 

individual submitting the comment (or 

signing the comment, if submitted on 

behalf of an association, business, labor 

union, etc.). You may review DOT’s 

complete Privacy Act Statement in the 

Federal Register published on April 11, 

2000 (Volume 65, Number 70; Pages 

19477–78). 

List of Subjects in 49 CFR Part 571 

Imports, motor vehicles, motor 

vehicle safety. 

Amended Regulatory Text 

In consideration of the foregoing, 

NHTSA amends 49 CFR part 571 as 

follows: 

PART 571—FEDERAL MOTOR 

VEHICLE SAFETY STANDARDS 

■ 1. The authority citation for part 571 

continues to read as follows: 

Authority: 49 U.S.C. 322, 30111, 30115, 

30117, and 30166; delegation of authority at 

49 CFR 1.95. 

■ 2. Section 571.217 is amended by 

■ a. In paragraph S.4 removing the 

definition of ‘‘Daylight opening’’;, and 

■ b. Adding paragraph S5.4.4 to read as 

follows: 

§ 571.217 Standard No. 217; Bus 

emergency exits and window retention and 

release. 

* * * * * 

S5.4.4 Protrusion Limit on Emergency 

Exit Window Latches and other related 

mechanisms 

For buses applicable under S3 of this 

standard, manufactured on or after 

October 30, 2027, any emergency exit 

window latch and other related release 

mechanisms shall not protrude more 

than 25 mm (1 inch) into the opening of 

the emergency exit window when that 

window is in the open position as 

described under S5.4.1 and S5.4.2. 

* * * * * 

■ 3. Section 571.217a is added to read 

as follows: 

§ 571.217a Standard No. 217a; Antiejection glazing for bus portals; Mandatory 

applicability beginning October 30, 2027. 

S1. Scope. This standard establishes 

requirements to improve side and roof 

bus portals by way of glazing that is 

highly resistant to partial or complete 

occupant ejection in all types of crashes. 

S2. Purpose. The purpose of this 

standard is to reduce death and injuries 

resulting from complete and partial 

ejections of bus occupants through side 

and roof portals during rollovers and 

other crashes. 

S3. Application. 

(a) Subject to S3(b) of this section, this 

standard applies to: 

(1) Over-the-road buses manufactured 

on or after October 30, 2027, and 

(2) Buses, other than over-the-road 

buses, that have a gross vehicle weight 

rating (GVWR) greater than 11,793 

kilograms (kg) manufactured on or after 

October 30, 2027. 

(b) This standard does not apply to 

school buses, transit buses, prison 

buses, and perimeter-seating buses. 

S4. Definitions. 

Daylight opening means, for openings 

on the side of the vehicle (other than a 

door opening), the locus of all points 

where a horizontal line, perpendicular 

to the vehicle longitudinal centerline, is 

tangent to the periphery of the opening. 

For openings on the roof of the vehicle, 

daylight opening means the locus of all 

points where a vertical line is tangent to 

the periphery of the opening. The 

periphery includes surfaces 100 

millimeters (mm) inboard of the inside 

surface of the window glazing and 25 

mm outboard of the outside surface of 

the window glazing. The periphery 

excludes the following: Any flexible 

gasket material or weather stripping 

used to create a waterproof seal between 

the glazing and the vehicle interior; grab 

handles used to facilitate occupant 

egress and ingress; and any part of a 

seat. 

Over-the-road bus means a bus 

characterized by an elevated passenger 

deck located over a baggage 

compartment. 

Perimeter-seating bus means a bus 

with 7 or fewer designated seating 

positions rearward of the driver’s 

seating position that are forward-facing 

or can convert to forward-facing without 

the use of tools. 

Portal means an opening that could, 

in the event of a crash involving the 

vehicle, permit the partial or complete 

ejection of an occupant from the 

vehicle, including a young child. 

Prison bus means a bus manufactured 

for the purpose of transporting persons 

subject to involuntary restraint or 


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Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86283 

confinement and has design features 

consistent with that purpose. 

Stop-request system means a vehicleintegrated system for passenger use to 

signal to a vehicle operator that they are 

requesting a stop. 

Transit bus means a bus that is 

equipped with a stop-request system 

sold for public transportation provided 

by, or on behalf of, a Federal, State, or 

local government and that is not an 

over-the-road bus. 

S5. Requirements. When tested 

according to the procedures specified in 

S6 of this section and under the 

conditions specified in paragraph S7 of 

this section, each applicable bus shall 

meet the following requirements 

specified in this section. The 

requirements of this paragraph S5 n do 

not apply to portals other than side and 

roof portals, and do not apply to a side 

or roof portal whose minimum surface 

dimension measured through the center 

of its area is less than 279 mm. 

S5.1 Edge impact. 

(a) When the ejection impactor 

described in S8 of this section contacts 

the target location specified in S6.1.1 of 

this section of each side or roof daylight 

opening of a vehicle at 21.6 km/h ± 0.4 

km/h, no portion of the window 

(excluding glazing shards) may pass the 

ejection reference plane defined under 

the procedures of S6 of this section. 

(b) Each piece of window glazing and 

each surrounding window frame shall 

be retained by its surrounding structure 

in a manner that prevents the formation 

of any opening large enough to admit 

the complete passage of a 102 mm 

diameter sphere when a force of no 

more than 22 newtons (N) is applied 

with the sphere at any vector in a 

direction from the interior to the 

exterior of the vehicle. 

S5.2 Center impact. 

(a) When the ejection impactor 

described in paragraph S8 of this 

section contacts the target location 

specified in paragraph S6.1.2 of this 

section of each side or roof daylight 

opening of a vehicle at 21.6 km/h ± 0.4 

km/h, no portion of the window 

(excluding glazing shards) may pass the 

ejection reference plane defined under 

the procedures of paragraph S6.3 of this 

section. 

(b) Each piece of window glazing and 

each surrounding window frame shall 

be retained by its surrounding structure 

in a manner that prevents the formation 

of any opening large enough to admit 

the complete passage of a 102 mm 

diameter sphere when a force of no 

more than 22 N is applied with the 

sphere at any vector in a direction from 

the interior to the exterior of the vehicle. 

S5.3 Center impact to pre-broken 

glazing. 

(a) When the ejection impactor 

described in S8 of this section contacts 

the target location specified in S6.1.3 of 

this section of each side or roof daylight 

opening of a vehicle at 21.6 km/h ± 0.4 

km/h, no portion of the impactor may 

displace more than 175 mm past where 

the surface of the glazing had been in an 

unbroken condition. 

(b) Each piece of window glazing and 

each surrounding window frame shall 

be retained by its surrounding structure 

in a manner that prevents the formation 

of any opening large enough to admit 

the complete passage of a 102 mm 

diameter sphere when a force of no 

more than 22 N is applied with the 

sphere at any vector in a direction from 

the interior to the exterior of the vehicle. 

S5.4 Post-Impact Emergency Exit 

Release and Operability. 

After the impacts described in 

paragraphs S5.1, S5.2, and S5.3 of this 

section, each emergency exit provided 

in accordance with Standard No. 217 

(§ 571.217) shall be capable of releasing 

and opening according to the 

requirements specified in that standard. 

S6. Test procedures. 

S6.1 Target locations. 

S6.1.1 Edge impact. Position the 

impactor face on the glazing adjacent to 

a latch or discrete attachment point 

such that, when viewed perpendicular 

to the glazing surface, the center of the 

impactor face plate is as close as 

practicable to the center of the latch 

attachment point or discrete attachment 

point with the impactor face plate either 

horizontal or vertical, whichever 

orientation provides the shortest 

distance between the two centers, while 

maintaining at least a 25 mm ± 2 mm 

distance between the impactor face 

plate edge and the window frame. 

‘‘Window frame’’ includes latches, 

handles, attachments, and any solid 

structures other than the glazing 

material or flexible gaskets. If the 

window does not have any latches or 

discrete attachment points (e.g., it is 

fully rubber bonded or glued), position 

the impactor as follows: 

(a) For side windows, directly above 

the center of the lower window edge, 

with the impactor face plate either 

horizontal or vertical, whichever 

orientation provides the shortest 

distance between the two centers, with 

the bottom edge of the impactor face 

plate 25 mm ± 2 mm above the daylight 

opening periphery when viewed 

perpendicular to the glazing surface. 

(b) For roof glazing panels or roof 

windows, directly forward of the center 

of the rearmost window edge, with the 

impactor face plate either horizontal or 

vertical, whichever orientation provides 

the shortest distance between the two 

centers, with the rearmost edge of the 

impactor face plate 25 mm ± 2 mm 

forward of the daylight opening 

periphery when viewed perpendicular 

to the glazing surface. 

S6.1.2 Center impact. 

Position the center of the impactor 

face, with the long axis of the impactor 

face plate either vertical or horizontal, at 

the center of the daylight opening area 

of the window with the glazing intact. 

S6.1.3 Center impact to pre-broken 

glazing. 

Position the center of the impactor 

face, with the long axis of the impactor 

face plate either vertical or horizontal, at 

the center of the daylight opening area 

of the window with the glazing prebroken following the procedure in 

paragraphs S6.2.1 and S6.2.2 of this 

section. 

S6.2 Window glazing pre-breaking 

procedure. 

S6.2.1 Breakage pattern. Locate the 

geometric center of the daylight 

opening. Mark the surface of the 

window glazing in a horizontal and 

vertical grid of points separated by 75 

mm ± 2 mm with one point coincident 

within ± 2 mm of the geometric center 

of the daylight opening (Figure 2). 

(a) If the window is a single-pane 

unit, then both the occupant space 

interior and outside exterior surfaces of 

the glass pane are marked with the 75 

mm grid pre-break pattern. The patterns 

are offset diagonally from one another 

(the points on one surface of the glass 

pane are offset 37.5 mm ± 2 mm 

horizontally and 37.5 mm ± 2 mm 

vertically from the points on the 

contralateral surface of the glass pane). 

(b) If the window is an insulated unit 

or double-glazed window, then both the 

occupant space side of the interior pane 

and the outside of the exterior pane are 

marked with the 75 mm grid prebreak 

pattern. 

(1) If one of the glass panes is 

constructed of tempered or toughened 

glass, the insulated surface of the 

remaining glass pane (within the air 

gap) is marked with the 75 mm grid prebreak pattern. The patterns are offset 

diagonally from the remaining glass 

pane’s contralateral surface. 

(2) If neither pane is tempered glass, 

then both the occupant space side of the 

interior pane and the outside of the 

exterior pane are marked with the 75 

mm grid pre-break pattern. The patterns 

are not diagonally offset from one 

another. The insulated surfaces of the 

glass panes (within the air gap) are not 

marked. 

S6.2.2 Breakage method. 


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(a) Use a 100 mm ± 10 mm × 100 mm 

± 10 mm piece of rigid material as a 

reaction surface on the opposite side of 

the glazing to prevent to the extent 

possible the window surface from 

deforming by more than 10 mm when 

pressure is being applied by the staple 

gun. 

(b) Start with the inside surface of the 

window and forwardmost, lowest mark 

made as specified in S6.2.1 of this 

section. Use an electric staple gun 

without any staples to apply a load 

along a line of 12 to 14 mm onto the 

glazing. The applied force shall be 4,200 

N ± 850 N. Apply the line load only 

once at each marked location, even if 

the glazing does not break or no 

perceptible mark or hole results. 

(c) Continue applying the line load 

with the electric staple gun by moving 

rearward in the grid until the end of a 

row is reached. Then move to the 

forwardmost mark on the next higher 

row and apply the line load. Continue 

in this pattern until the line load has 

been applied to all grid points on the 

inside surface of the glazing. 

(d) Repeat the process on the outside 

surface of the window. 

(e) If applying the line load causes the 

glazing to disintegrate, halt the breakage 

procedure and proceed with the next 

step in the compliance test. 

S6.3 Determination of ejection 

reference planes. 

(a) For side windows, the ‘‘ejection 

reference plane’’ is a vertical plane 

parallel to the longitudinal vertical 

center plane of the bus passing through 

a point located at a lateral distance of 

102 mm from the lateral most point on 

the glazing and surrounding frame, with 

the window in the closed position. 

(b) For roof glazing panels/windows, 

the ‘‘ejection reference plane’’ is a 

horizontal plane passing through a point 

located at a vertical distance of 102 mm 

from the highest point on the glazing 

and surrounding frame, with the 

window/panel in the closed position. 

S7. Test conditions. 

During testing, the ambient 

temperature is between 18 degrees C. 

and 29 degrees C., at any relative 

humidity between 10 percent and 70 

percent. 

S8. Guided impactor. 

The impactor test device has the 

dimensions shown in Figure 1 of this 

section. It has a total impactor mass of 

26 kg ± 1.0 kg and a spring stiffness of 

258 N/mm ± 39 N/mm. The impactor is 

propelled in the horizontal direction in 

impacts to the side daylight openings 

and is propelled vertically in impacts to 

the roof daylight openings. 


ddrumheller on DSK120RN23PROD with RULES1ER30OC24.018</GPH>

BALLAST MASS IIIPACTOR FACE 

BEARING 

THRUST BEARING ROD 

HOOSING 

BEARING ROD 

(SPRING CUT AWAY FOR CLARITY) 

IMPACTOR FACE 

BEARING 

All dimensions shown are in millimetres. 

SID ARit FOAM 

t=-1-77 ____ _ 

@ 212 

FOAM REIIJVED FOR CLARITY 
Federal Register / Vol. 89, No. 210 / Wednesday, October 30, 2024 / Rules and Regulations 86285 

Issued in Washington, DC, under authority 

delegated in 49 CFR 1.95 and 501.5. 

Sophie Shulman, 

Deputy Administrator. 

[FR Doc. 2024–24462 Filed 10–29–24; 8:45 am] 

BILLING CODE 4910–59–P 

DEPARTMENT OF COMMERCE 

National Oceanic and Atmospheric 

Administration 

50 CFR Part 622 

[Docket Nos. 090206140–91081–03 and 

120405260–4258–02; RTID 0648–XE422] 

Revised Reporting Requirements Due 

to Catastrophic Conditions for Federal 

Seafood Dealers, Individual Fishing 

Quota Dealers, and Charter Vessels 

and Headboats in Portions of Florida 

AGENCY: National Marine Fisheries 

Service (NMFS), National Oceanic and 

Atmospheric Administration (NOAA), 

Commerce. 

ACTION: Temporary rule; determination 

of catastrophic conditions. 

SUMMARY: In accordance with the 

regulations implementing the individual 

fishing quota (IFQ) and Federal dealer 

reporting specific to the commercial reef 

fish fishery in the Gulf of Mexico (Gulf) 

and the coastal migratory pelagic (CMP) 

fisheries in the Gulf, the Regional 

Administrator (RA), Southeast Region, 

NMFS has determined that the 

catastrophic conditions caused by 

Hurricane Helene in the Gulf for certain 

Florida counties still exist. This 

temporary rule authorizes in the 

described affected area any dealer who 

does not have access to electronic 

reporting to delay reporting of dealer 

reports (trip tickets), any Southeast 

Region Headboat Survey (SRHS) 

program participant to delay reporting 

electronic logbooks, and authorizes IFQ 

dealers within the affected area to use 

paper-based forms, if necessary, for 

basic required administrative functions, 

e.g., landing transactions. This 

temporary rule is intended to facilitate 

continuation of IFQ and dealer reporting 

operations during the period of 

catastrophic conditions. 

DATES: The RA is authorizing Federal 

dealers, for-hire electronic reporting 

program participants, and IFQ dealers in 

the affected area to use revised reporting 

methods from November 2, 2024, 

through December 1, 2024. 

FOR FURTHER INFORMATION CONTACT: IFQ 

Customer Service, Britni Lavine, 

telephone: 866–425–7627, email: 

nmfs.ser.catchshare@noaa.gov. Federal 

dealer reporting, Fisheries Monitoring 

Branch, telephone: 305–361–4581. 

NMFS Southeast For-Hire Integrated 

Electronic Reporting Program: 1–833– 

707–1632. 

SUPPLEMENTARY INFORMATION: The reef 

fish fishery of the Gulf is managed 

under the Fishery Management Plan 

(FMP) for Reef Fish Resources of the 

Gulf of Mexico (Reef Fish FMP), 

prepared by the Gulf of Mexico Fishery 

Management Council (Gulf Council). 

The CMP fishery is managed under the 

FMP for CMP Resources in the Gulf of 

Mexico and Atlantic Region (CMP 

FMP), prepared by the Gulf Council and 

South Atlantic Fishery Management 

Council. Both FMPs are implemented 

through regulations at 50 CFR part 622 

under the authority of the Magnuson 

Stevens Fishery Conservation and 


ddrumheller on DSK120RN23PROD with RULES1ER30OC24.019</GPH>

75 

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37.5 

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e Exterior surface of glazing I 

I __ .J ___ ~ 

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Center of glazing surface 

75 

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