Chapter 13 - School Buses

CORE PURPOSE OF THE CHAPTER

School bus incidents are rare but high-risk, high-complexity events requiring:

• strong scene management
• heavy stabilization
• controlled access
• coordinated victim removal
• awareness of heavy structural members

TYPES OF BUSES (FUNCTIONAL CATEGORIES)

• School bus — transports K–12 students
• Transit bus — fixed urban routes
• Intercity bus — long-distance scheduled routes
• Charter/tour bus — for-hire trips
• Other — private/nonprofit/government transport

SCHOOL BUS CLASSIFICATIONS (BY CONSTRUCTION)

Type A

• Cutaway front section vehicle
• GVWR ≤ 14,500 lb (A-1) or ≤ 21,500 lb (A-2)

Type B

• Stripped chassis
• Entrance behind front wheels
• B-1 ≤ 10,000 lb | B-2 > 10,000 lb

Type C (most common)

• Conventional hood + front fenders
• Entrance behind front wheels
• GVWR > 21,500 lb

Type D

• Transit-style flat front
• Engine rear or front
• Entrance ahead of front wheels

SCHOOL BUS STRUCTURAL DESIGN (BODY-OVER-FRAME)

Built as a reinforced cage system:

• steel trusses
• vertical ribs
• crossmembers
• inner & outer metal skin
• fiberglass insulation layer

Designed to resist intrusion and protect occupants.

KEY STRUCTURAL COMPONENTS

Chassis Frame

• heavy steel channel beams
• crossmembers every ~12 inches
• extremely difficult to cut
• entry through floor not recommended unless no alternatives

Floor Deck

• 14-gauge steel + plywood + rubber/vinyl
• very thick → avoid floor entry

Bow Frame Trusses

• run floor → roof → down opposite side
• primary strength members
• rivets mark their location

Stringers

• run lengthwise roof-level
• reinforce roof structure

Rub Rails

• exterior horizontal rails
• bottom rail = floor line
• middle rail = seat cushion height
• act as visual strength indicators

Crash Rail

• heavy steel rail just above floor
• protects against side impact intrusion

DOORS & EXITS

Front Entrance Door

• outward folding
• often air-actuated
• has emergency release

Rear Emergency Door (not on Type D)

• outward swing
• main extrication access in many scenarios

Side Windows

• tempered or laminated
• pop-out style

Roof Hatches

• hinged escape openings
• large enough for rescuer — not backboard

STABILIZATION PRINCIPLES

Common resting positions:

• upright
• on side
• on roof
• on another vehicle (override)

Suspension systems:

• metal leaf springs
• or air-ride systems (air bags)

Air-ride hazards:
• rupture or release can cause sudden vehicle shift

Stabilization tools commonly required:
• heavy tow units (50/60 ton)
• cribbing
• tension buttress struts
• FRJs
• air-lift bags

SCENE MANAGEMENT PRIORITIES

Size-Up Must Address:

• bus type (C or D especially)
• damage level
• running engine
• resting position
• number of occupants
• hazards
• resource needs
• MCI activation

INCIDENT ACTION PLAN (IAP)

Includes:

• Plan A — initial access
• Plan B — removal/extrication
• emergency escape plan
• hazard zones
• resource management

ACCESS TECHNIQUES

Front Window Removal

• laminated glass
• gasket push-out or bead-cut methods

Seat Removal

• hydraulic spreader + cutter preferred

Sidewall Removal

• remove windows
• cut trusses
• peel wall section

Roof Access

• cut around heavy members
• avoid rivet lines

Rear Door Access

• remove safety panels
• cut latch mechanism
• crib for working height

LIFTING OPERATIONS

Used for:

• under-rides
• trapped occupants
• partial ejections

Tools:

• tow units with boom
• FRJs
• air-lift bags
• struts
• cribbing

Key hazard:
Massive weight shift + structural failure if poorly coordinated.

HYBRID & ALTERNATIVE FUEL BUSES

Propane Buses

• tanks under frame
• pressure relief valves
• heavier-than-air gas

Hybrid Buses

• high-voltage systems
• battery packs under chassis
• parallel hybrid systems most common

Emergency procedures vary by system design.

NFPA-STYLE TEST LOGIC (IF → THEN)

• IF rivets are visible in straight lines → THEN structural members exist beneath sheet metal

• IF bus has air-ride suspension → THEN stabilization must account for sudden air loss

• IF vehicle is Type D → THEN no rear emergency door is present

• IF cutting roof or sidewalls → THEN avoid rivet lines (structural members underneath)

• IF bus is resting on side or roof → THEN heavy stabilization resources are required

• IF mass casualties possible → THEN MCI protocols should be activated early

• IF under-ride exists → THEN lifting operations may be required before extrication

SAFETY AWARENESS ADD-ONS (FROM TEXT)

• Avoid floor entry unless no alternative — extremely heavy steel
• Avoid cutting along rivet lines
• Expect sudden movement from air-ride systems
• Heavy lifts require strict coordination
• Bus structure is far stronger than passenger vehicles

KEY TERMS & DEFINITIONS

Body-over-frame construction — reinforced skeletal structure with steel trusses and panels

Bow trusses — curved steel members running floor to roof to opposite side

Stringers — lengthwise roof reinforcement beams

Rub rails — exterior rails marking structural zones

Crash rail — heavy steel side-impact protection rail

Type A bus — cutaway front bus

Type B bus — stripped chassis bus

Type C bus — conventional hooded bus

Type D bus — transit-style flat-front bus

Air-ride suspension — air-bag supported suspension system

IAP — Incident Action Plan

MCI — Mass Casualty Incident

FRJ — Fast-response jack