What about seat belts? Why don’t school buses have them?

The short answer is that small school buses do in fact require seat belts; large school buses, with a few exceptions do not. Seat belts are not required on the larger school buses because both the U.S. Department of Transportation and Transport Canada, have determined that compartmentalization is the preferred occupant protection system.

To explain these differences in a greater detail we begin as follows; a small bus is categorized as a bus under 10,000lbs in weight, which are required by federal law to have seat belt systems on them due to the fact that they are closer in nature to the size of the average automobile and/or light trucks. The federal government requires a level of occupant protection similar to those that are the standards of cars and trucks for a bus that falls into this category. Larger buses typically will weigh 23,000 lbs or more. The National Highway Traffic Safety Administration’s same regulatory update stated that local school districts were best equipped to decide whether the large “Type C” ( which are the conventional school buses) and Type D ( transit style vehicle with its body installed upon a chassis, with the engine mounted in the front, mid-ship, or rear) school buses have the seat belts. If the answer is yes, the manufacturing guidelines for how to best install these restraints comes into play.

Many parents are worried about the contradiction between the need to use seat belts and child passenger seats in automobiles and the lack of these safety devices in school buses, which do not require seat belts. One reason seat belts are not required on school buses is that the greater the weight and mass of a school bus that an automobile, and the fact that they sit above the usual point of impact. Another is the school bus passengers are not seated near doors or large window openings, so they are not likely to be thrown out from the vehicle. Protection from ejection is a primary function of automobile seats.

This primary function is the same rationale that school buses incorporate a passive restraint system known as compartmentalization, which is designed to protect the children without the aid of a seat belt.

Compartmentalization

A term that was coined in the late 1960’s by researchers from UCLA. It basically was termed compartmentalization, denoting a safety envelope or “compartment” around the passengers in school buses. The fundamental idea was that if a crash were to occur, that the child may be thrown around within this compartment but the design of the seat compartment would essentially absorb the crash force and protect the child.

After extensive research during the 1970’s the Department of Transportation and its agency, the NHTSA determined that the safest and most practical arrangement for school bus seating would be this “compartmentalization” concept. Accordingly, the new safety regulations that were effective for school buses manufactured on or after April 1, 1977, included this requirement among other improvements made that year.

Student riders are surrounded by a compartment of energy absorbing material – 4inch thick foam seats, seat frames that bend to absorb crash forces, and a vehicle designed to absorb energy. The idea is the crash force will be dissipated or absorbed before they get to the student passengers. However, compartmentalization doesn’t work well in rollover crashes, hence one of the reasons on the NHTSA’s regulatory update on seat belts

With these changes at that time seat backs were now higher in school buses, wider and thicker that before. All metal surfaces are covered with foam padding. This structure must then meet rigid test requirements for bending and absorbing energy, such as would be required if a student’s body were thrown against the padded back. In addition, the equivalent of a seat back, called a “ barrier”, is placed in the front row of seats at the front of the bus.

In addition to padding, today’s seats also must have a steel inner structure that springs and bends forward to help absorb energy when a child is thrown against it. The steel frame must “give” just enough to absorb the child in the seat ahead. Also, of course, the seat is required to be anchored to the floor so strongly that it will not pull loose during this bending action. And the floor itself must be strong that it will not be torn by the pulling action of the seat anchors during a crash.

Seats are spaced close together as another safety precaution to ensure containment of children after a potential crash. If seats are spaced too far apart, the student could be thrown too far before being cushioned and/or could be thrown outside the compartment altogether.

The federal government concluded that compartmentalization is a better safety measure than seat belts and arguments to favor this are as follows:

Compartmentalization is much more manageable. The protection exists and is in force without depending on any action of children or any extra special supervision by drivers or monitors. Seat belts require discipline and supervision to keep them clean, unraveled, in use, and properly adjusted.

Compartmentalization works equally well for one, two or three students per seat. Today’s 39” wide seats may contain three small children or two large ones or any combination in between. Arranging seat belts to properly handle any combination is difficult, if not completely impossible, the best known solution with seat belts is to restrict each seat to two students and two belts, which has the disadvantage of sharply reducing the carrying capacity of bus fleets. The 39” seat was devised many years ago by the committee then making recommendations to the National Minimum Standards for School Buses. It determining the seating capacity of a school bus, an allowable average rump width standard was established. Accordingly, 13-inch rump width was suggested where a 3-3 seating plan was used. This works reasonably well for children through the sixth grade.

Compartmentalization works whether students have fully developed areas or not. Conventional seat belts, which are lap restraints only, are not suitable for small children (under the age of 8) whose abdominal area and bone structure are not adequately developed to take the force of the lap belt alone. They would also need the aid of a chest harness, which adds to the complexity of a proper safety belt solution.

Compartmentalization, once it has done its energy absorbing job, leaves the student free to escape the bus. Seat belts could leave students strapped in, upside down, perhaps unconscious, in burning or flooding buses.

Compartmentalization is also the most affordable solution. This may not be a popular point to make it is in fact the most realistic. In evaluation the cost of seat belts, the cost of retractors and chest restraints would also need to be taken into consideration since they would most certainly appear to be necessary. Even more important than the cost projections is the probability that a seat belt solution would also lead to two student seating and greater spacing between seats which would ultimately reduce the student load for any individual bus.

Current regulations have the seats are spaced no more than 24 inches apart.

Seat Belts on School Buses

The NHTSA mandated in the spring of 2009 that all small buses manufactured as of September 2011 must be equipped with a 3 point lap/shoulder restraints. Previous NHTSA studies have consistently found that lap belts in school buses do not provide additional occupant safety beyond compartmentalization provided by the federally mandated high and padded seat backs. NHTSA also prefers the use of 3 point lap/shoulder restraint systems similar to those mandated in passenger vehicles because they better protect passengers in collisions and rollovers. It found that lap belts may increase abdominal and head injuries.

Now, assuming there was a lap belt requirement and this applied only to new buses, and that retrofitting would not be required on existing fleets then there would be about 25,000 to 30,000 large buses equipped annually. That is how many large school buses are manufactured in an average year. At an estimated cost of $1500 to $2000 per bus to install lap belts, which is about 3% of the cost of a typical $60,000 school bus, the additional cost to install lap belts on all new large school buses would range from $37,500,000 to $60,000,000 annually. Historically it takes about 12 to 15 years to convert the entire fleet, though a small percentage of pre-1977 buses remain in service. During the transition, the total cost to install lap belts would range between $450,000,000 and $900,000,000, and this leaves aside annual maintenance and replacement costs.

Retrofitting the existing fleet would make assumptions that the under floor of the bus is sound, and that is not necessarily the case. Road damage, rust and other weathering factors are to known to weaken the under floor after a few years of routine service. Since the seat which holds the seat belt is anchored to the floor, you cannot be sure that the strength of the anchorage. Bus manufacturers have also stated that they will not assume any liability should their buses be retrofitted and with that being stated it is a safe assumption that insurance companies would follow that same line of reasoning.

Although there has been talk that there has been a greater number of school bus injuries in recent years the problem that is faced with this statement is that no one really knows for certain. Since there is no standardized method to collect this type of data it is very difficult to collect. The criteria would differ between states and provinces and with that being said it is very difficult to compare data with previous year’s information.

According to the National Safety Council school buses are in fact the safest form of transportation. Nearly 40 times safer that the family car.

Fatalities – although you will be told that seat belts on school buses should be mandatory the truth of the matter is that fatalities do unfortunately occur with school buses. In an average year 25 school children are killed in school bus accidents. One third of these are struck by their own bus in the loading/unloading zone, one third are struck by motorists who fail to stop for the school bus, and one third are killed as pedestrians approaching or departing a school bus stop. Very few are killed inside the bus itself. The most common fatality involving a school bus is to a motorist who hits the bus. There are about 120 Americans killed annually in this type of fatality.

School bus fatalities are reported by three major sources: the National Highway Traffic Safety Administration, the National Safety Council, and the Kansas Department of Education.