SCHOOL BUS ACCIDENTS: AN EXTRICATION CHALLENGE
BY LEIGH T. HOLLINS
School bus incidents present unique challenges for emergency responders throughout the country. Every firefighter, paramedic, EMT, and law enforcement officer who responds to a vehicle collision call has the potential for dealing with a major school bus incident and should prepare for it.
Statistics vary, but the following information is a general indication of the potential for responding to an incident involving a school bus.
Twenty-five million students are transported by school buses daily.
School buses cover two million miles daily.
Four hundred thousand school buses are in service.
Sixteen thousand collisions occur annually.
Eleven thousand injuries occur annually.
Twenty occupants are killed annually.
These figures are only those public and private school bus transportation providers are required to report. Not included are the thousands of school buses that have been converted by church groups, civic groups, recreational providers, canoe and rafting outfitters, private individuals, and other individuals and groups that may use school buses. The fact is that “a school bus is a school bus is a school bus.” Whether painted the familiar school bus yellow or white, black, red, or psychedelic colors, it still has the same general construction features as when it came off the assembly line, and it will act the same when it rolls down an embankment or is broad-sided by a semi.
The various agencies that track transportation accidents and injuries rate school buses as one of the safest forms of transportation, much safer than cars. When incidents occur, they tend to draw much attention. Major school bus incidents become national news. Do not be fooled. School buses are on the road every day of the week, every hour of the day and night, and under every weather condition.
The extra-heavy-duty construction of school buses create many problems for responders. In this age of cars and trucks built of lighter alternate materials such as fiberglass and aluminum, the school bus is still built like a tank. This is a double-edged sword. It is a great benefit for those riding the bus, mainly our children. When a major collision occurs, however, it is sometimes extremely difficult to displace the strong metal from which the bus is constructed. We will discuss this later.
Driver training and bus maintenance can present problems also. All public and private student transportation providers must meet licensing, training, and maintenance requirements set by the federal government. These requirements may be enhanced by local or state law. I`m sure these requirements help to prevent many accidents and collisions. The problem arises when transportation providers sell or donate a bus to the local church or preschool and the laws no long apply. Yet, people still ride these buses. Compare a school bus that drops kids off at the local public school with one used by the local canoe outfitter. Chances are you will see a major difference in the overall condition. I doubt that the college kid driving the canoe bus has any special training. Yet, both are transporting a bus full of people day in and day out. My guess is that, mile for mile, the potential for a major incident lies with the canoe bus. Is that a padlock I see on the rear door of the canoe bus? Are those tires bald? Is that brake fluid dripping on the ground? I think you get the point.
If we measure the problem by looking at past case histories, we can learn much. Look at this partial list of major school bus incidents that occurred during the past 15 years:
A pattern has developed. With few exceptions, we can draw the following conclusions:
In all major incidents, something big collided with the bus.
When buses roll over (no collision), many injuries occur.
When school buses hit school buses, there are many victims.
When something big hits a bus or it rolls, you have a mass casualty incident (MCI).
These incidents occurred in Anytown USA, not in the major cities.
If your fire truck hits a bus, you have some explaining to do.
Note that in many of the incidents listed above in which the bus collided with a truck, the bus rolled onto its side or roof. Also, the incident in Carrolton, Kentucky, was the result of a drunk driver`s hitting the bus head-on. The high death rate in this incident was due to the rupture and ignition of the school bus fuel tank, which contained gasoline. Everyone on the bus initially survived the impact, according to reports.
An emergency call for a vehicle accident involving a school bus is not that rare. About 50 of these calls are made every day in the United States. They usually involve a minor collision with a car–or sometimes a major collision with a car; the car and its occupants are always the losers. Even this type of call can involve multiple occupant injuries, usually minor, and you may have to perform a difficult extrication to remove the car occupants from their vehicle, from under the bus, or from both places. Most emergency responders receive training to prepare for these types of incidents. The problem emerges when responders are faced with an overwhelming number of victims, a situation for which MCI training is required, or when a school bus is heavily damaged and the bus occupants require extrication or disentanglement.
TYPES OF SCHOOL BUSES
School buses are grouped into four types: A, B, C, and D. Approximately 90 percent of the present school bus fleet in the United States are Type C or D. Being familiar with the type of bus is very important to responders. The type determines the following:
the size of the bus,
the weight of the bus,
the occupant capacity,
the location of the front exit in relation to the front wheel,
the number and location of additional exits, and
the engine location.
The following definitions are from the Florida Department of Education`s Florida School Bus Specifications and can be generally applied in most states.
Type A. A conversion or body constructed on a van-type compact truck or a front-section vehicle. Gross weight rating is 10,000 pounds or less; designed to carry more than 10 persons.
Type B. A conversion or body constructed and installed on a van or front-section vehicle chassis or stripped chassis. Vehicle rating is more than 10,000 pounds; designed to carry more than 10 persons. Part of the engine is beneath and/or behind the windshield and beside the driver`s seat. The entrance door is behind the front wheels.
Type C. A body installed on a flat back cowl chassis. Gross vehicle weight rating is more than 10,000 pounds. Designed to carry more than 10 persons. All of the engine is in front of the windshield; the entrance door is behind the front wheels.
Type D. A body installed on a chassis. The engine is mounted in the front, midship, or rear. Gross vehicle weight rating is more than 10,000 pounds. Designed to carry more than 10 persons. The engine may be behind the windshield and beside the driver`s seat. It may be at the rear of the bus, behind the rear wheels, or midship between the front and rear axles. The entrance door is ahead of the front wheels.
SCHOOL BUS CONSTRUCTION
Knowing the construction methods and materials used to build school buses is very important. If you are involved in an extrication or disentanglement operation, it is imperative that you choose the correct tools to safely and efficiently reach your goal. This can be accomplished only if you study the construction methods. (Notice that I distinguish between extrication and disentanglement. Far too often, the two are considered to be the same. In fact, they are not the same.)
In some instances, normal extrication techniques may be applied to Type A school buses, because they may be a van or large sport utility vehicle with very minor modifications. The overall construction methods and materials used for a Type A bus may be the same as those used for a “stock” vehicle. If a Type A bus has a standard school bus body mounted on a van chassis, though a short one, the extrication techniques for a B, C, or D bus will apply. These techniques are presented later.
Whether the standard school bus body is mounted on a commercial or custom chassis or holds 10 to 90 passengers is irrelevant in relation to bus design and construction. Therefore, the main emphasis concerning the design, construction methods, and materials will be on the passenger compartment (the body).
There are two main construction features to be concerned with: the skeleton and the skin. The skeleton will predict the action during a rollover or a collision with another object. The skeleton and the skin provide a protective “envelope” for the passengers inside.
The strength of the school bus is governed by the Federal Motor Vehicle Safety Standards–specifically, Standard #208, Occupant Crash Protection; #220, Rollover Protection; and #221, Body Joint Strength. Standard #220 requires that when a force equal to one and one-half times the unloaded bus weight is applied to the roof of the vehicle, the roof should not crush more than five inches and all emergency exits shall be capable of operating.
The basic skeleton of a school bus passenger compartment consists of the following components:
Rear body frame. 14-gauge steel framework that forms and protects the rear of the bus. Corner anchor posts are connected to a header, a threshold, and a frame for the rear door and windows.
Front body frame. 12-gauge steel framework that forms and protects the front of the bus. Corner “A” posts are connected to a header, a floor/stairwell support, and the front windshield frame. The “A” post and front door header are among the strongest, thickest parts of the bus.
Floor joists. Eight-gauge angle steel joists, spaced approximately every 18 inches; they form a platform for the floor construction.
Crash rail. 14-gauge, one-piece, full-length steel shield located just above floor level to protect occupants from side impact collisions (not on older-model buses).
Bow frames. 12-gauge “stud/trusses” that go from below floor level on one side of the bus, up and over the roof, and down the other side to below floor level. These bow frames provide fastening points for the inner and outer skins on the sides (studs) and on the roof (trusses). They also provide the structural frame for the side windows.
Roof crash rails. 16-gauge “stringers” that run the length of the roof to provide support to the bow frames.
Longitudinal girders. 14-gauge “header” runs the length of each side just above the windows. These girders form a support for the bow frames; they bend from the roof to the sides; they also serve as the top structural frame for the side windows.
Guard rails. 16-gauge “rub rails” that run the length of the bus and wrap around the back. They are the only skeletal members that are not enclosed under the skin. They provide additional support to protect the sides and rear from penetration due to collisions.
After reviewing the components of the school bus skeletal system, I think you can appreciate why I refer to school buses as “yellow tanks.” School bus extrication cannot be approached in the same manner as that involving an ordinary vehicle. It won`t work.
The basic skin of a school bus passenger compartment consists of the following components:
Exterior. Panels of sheet metal that are attached to the various skeletal members. Their main function is to keep the weather out. The sides are typically 20-gauge; the roof is 24-gauge.
Various skeletal members. Their main function, in conjunction with the exterior skin, is to keep the occupants in and to provide a “finished” surface.
Flooring. 14-gauge sheet metal is laid and attached to the floor joists to provide the floor strength. A “deck” made of one-half-inch plywood covers the sheet metal; rubber flooring is laid on the wood deck. The rubber provides the final finished floor.
The area between the interior and exterior skin is about three inches thick. Contained within the void space you will find fiberglass insulation and wiring. Locating the seams and/or rivets on the roof and ceiling will indicate the location of the bow frames. Some manufacturers are now offering seamless interior ceilings and are using as a marketing feature the fact that in a collision there are no seams to come apart, a situation that could create “cookie cutter”-type injuries.
Halfway down the interior skin, from the bottom of the window to the floor, a lip protrudes about one inch from the sidewall. The bench portion of the seat is attached to this lip. This information is important when removing seats or cutting through the sidewall, both of which will be discussed in Part 2. Other than this lip, all other interior and exterior portions of the skin are smooth.
Identifying the potential and the problem are important aspects of gaining an overall picture of school bus rescue and extrication. Reviewing case histories makes us aware of what can happen in our own communities. Becoming familiar with the types of school buses and their construction features and components are the first steps in preparing for an incident. In Part 2, the features of school buses, extrication and rescue tactics, and preparing for an incident will be addressed. This article provides the basic information you need. Turn this information into knowledge by getting your hands on a school bus and practicing. If you have any doubts about your need to do this, take another look at the photo of the Levy County, Florida, incident.
(Top, inset) This incident, which occurred in Manatee County, Florida, in March 1997, shows the scene of a minor to moderate collision. Fortunately for the children on this bus, they were all sitting toward the front. A two-county response handled this rural incident in which seven students were injured. (Top photo by Mark A. Skukowski.) (Below) The power of a major school bus collision is evident in these photos. This incident, which occurred in Levy County, Florida, claimed the lives of six bus occupants and required a three-county response. (Photos by author unless otherwise noted.)
(Top left, right) Type A school buses. Each would act very differently in an identical type of collision and would require different tactics. (Middle left) A Type B school bus. Notice the short front end and the location of the entrance door. (Bottom left) A Type C school bus. This is the type that was involved in the Levy County incident. Notice the full front end and the location of the entrance door. The emergency exit window is clearly marked and has an additional strip of reflector tape under it. (Bottom right) A Type D school bus. Notice the flat front end, rear engine design, and location of the entrance door in front of the wheels. This bus has 26 bench seats, enough for 52 high school or 78 elementary students. The white roof and tinted windows lower the inside temperature by 15 degrees in the summer.
The floor joists are among the strongest components of a school bus. Notice the clips that hold the body of the bus to the chassis rails. These clips allow the body to slide during a collision (Levy County incident photo). In a recent school bus vs. train collision in Fox River Grove, Illinois, the body completely separated from the chassis, in accordance with its design. This action may have saved lives.
LEIGH T. HOLLINS, a 21-year veteran of the fire service, is a battalion chief with the Cedar Hammock and Southern Manatee Fire Districts in Manatee County, Florida, and director of Starfire Training Systems, Inc. He is a Florida-certified firefighter, EMT, fire officer, fire inspector, and fire science instructor. He has an associate`s degree in fire science and is a member of the editorial advisory board of Fire Engineering and the FDIC educational committee.