R. Scott King, BSME, Automotive / Mechanical Engineer ::::
School bus crashes, no matter how minor, seem to have a way of occupying the lead story of the local evening news: and for good reason. Just ask any parent that has watched their child board a bus if they have ever worried for their child’s safety. Of course they have. So when incidents do occur, it is no wonder why public interest is so high.
School bus safety, as with any mode of transportation, begins with careful design. The typical school bus begins life as an incomplete chassis, constructed in multiple stages, at multiple facilities, by multiple companies. The base chassis typically includes the frame, power and drive trains, and steering, suspension, and braking systems. Ford, Freightliner, and International are among the more common “primary” chassis manufacturers. Then, smaller, independent companies – the so-called “body builders” – purchase the incomplete chassis and add their unique systems and components. Primary manufacturers typically provide body companies with guidelines and recommendations for performing subsequent alterations. Federal and industry standards also exist to help ensure vehicle safety and compliance. Accordingly, overall school bus safety is typically a composite of various systems from a variety of sources.
As expected, school bus safety has evolved over time. Simple safety enhancements such as padded seatbacks, improved exterior lighting and reflective materials, and multiple emergency exists, are now common. The most modern school bus designs include a variety of high-tech systems and features that elevate school bus safety to new levels. One such feature is an alarm system requiring drivers walk to the back of the bus to activate a switch before exiting. Its purpose is to reduce the risk of leaving a sleeping child on board. Another system is the swing out front crossing control gate. Designed to help prevent run-over incidents, this bar extends from the front bumper when the bus door is opened, and helps create a “clear zone” immediately in front of the bus by ensuring children remain within the driver’s field of view. In some installations, when retracted parallel to the bumper this bar can automatically apply the bus brakes upon contact Other safety systems include onboard cameras, standing occupant detection and warning, GPS tracking, Event Data Recording technology, electronic Daily Vehicle Inspection Reporting, and even automatic tire chains for traction enhancement. Indeed, many of today’s modern busses possess an impressive array of safety systems and components that make busses of only a few years ago appear antiquated.
All of these significant enhancements not withstanding, there remains one persistent oddity in the effort to improve school bus safety: seat belts. Recent federal legislation was enacted requiring 3-point seat belts on certain smaller school busses; however, there remains no such requirement for larger busses. At the state and district level, seatbelt requirements are more varied. California, for example, has legislation requiring 3-point belts on all busses. Other states have 2-point belt requirements, while many states have no requirements. The school bus seatbelt debate has persisted for many years but current trends suggest seatbelt proponents are succeeding.
Effective school bus safety requires more than innovative design and equipment requirements. As with any motor vehicle, proper vehicle maintenance is vital to ensuring public safety. Generally, school bus inspection and maintenance criteria depend on bus size and configuration. However, for purposes of inspection and maintenance, a typical full-size school bus is treated in much the same way as a commercial motor vehicle, such as a typical tractor-trailer. Accordingly, the bus owner is responsible to maintain, or cause to be maintained, its equipment consistent with Federal DOT regulations as well as the North American Standard Out-of-Service Criteria. Likewise, drivers of these larger busses are required to possess a commercial driver’s license and are thus subject to trip and vehicle inspection reporting requirements.
Moreover, state-mandated school bus inspection standards are common. For example, Pennsylvania, which has long had an annual safety inspection program for all vehicles registered within the commonwealth, requires additional inspection requirements for school busses. Specifically, school busses are required to be inspected twice a year: once by an independent, state-certified inspection mechanic and once by a certified member of the PA State Police. The latter is typically performed during the summer months and is scheduled in advance with the bus owner. Further, PA school busses are also subject to spot checks by both state and local law enforcement agencies. New York, New Jersey, and Delaware are also among the states requiring biannual safety inspections.
Despite the best safety regimen, incidents and crashes do occur. According to one report by the National Highway Traffic Safety Administration, each year, on average, 19 school-age children die in incidents related to school transportation. When incidents do occur, it is important that investigators are familiar with the myriad of on-board safety systems and technologies, as well as applicable maintenance and inspection standards. Most investigations, particularly those related to the more serious incidents, are conducted initially by law enforcement agencies. Many times, such agencies are reluctant to allow bus company representatives, or other parties, to participate in these initial investigations; however, experience has shown that when permitted, involving an independent engineer or investigator in the law enforcement investigation can be invaluable. For example, certain investigating agencies might not possess the knowledge or technology required to fully utilize certain crash or other event-related data that can be vital to understanding the incident circumstances. Likewise, during a recent cooperative inspection, engineers retained by the bus company averted an out-of-service determination by the investigating officer by noting the improper identification of certain brake system components. And perhaps most importantly, issues relating to evidence alteration and preservation can be avoided through joint cooperation. Of course, each investigation is different and any level of cooperation depends largely on the will of the controlling agency; however, it might be worthwhile for interested parties to foster a dialogue and relationship as early in the investigation as possible and request involvement.
Government studies and crash statistics show that school bus incidents are rare; however, these same statistics offer a near mathematical certainty that future incidents are sure to continue. So the next time you see an incident reported on your local evening news station, remember that the job of evaluating the many factors that contribute to school bus safety will continue long after the newscast ends.DJS Announcements