Iowa Crash Test Identifies Limits of Protection in School Bus Compartmentalization

The Iowa Pupil Transportation Association (IPTA) performed a controlled bus crash demonstration this summer to address child safety concerns. IPTA concluded that compartmentalization of student passengers between high, padded seat backs doesn’t always work as it is supposed to.

Chris Darling, executive director of the IPTA, told School Transportation News that the crash that was held on July 15 during the annual state conference at Des Moines Central School District was developed in conjunction with the Midwest Association of Technical Accident Investigators (MATAI).

The event was designed to be a rollover crash, since the association sought to change perceptions about seatbelts in the state of Iowa. However, the International school bus furnished by the Hoglund Bus Company did not roll over as planned.

Darling added, however, that the Iowa crash did confirm to the organizers that compartmentalization did not keep unbelted occupants from flying out of their seats. The most effective option, he continued, is to supplement compartmentalization with lap/shoulder three-point seatbelts. Previously, compartmentalization has been widely believed to be most effective in frontal- and rear-impact collisions.

In recent years, the National Transportation Safety Board especially has championed three-point seatbelts as completing compartmentalization in rollover and side-impact crashes.

The school bus was traveling at 44 mph via remote control when it crashed nearly head-on into two parked vehicles, the first a car and the second an SUV. The school bus propelled through the cars and into the air before landing and proceeding upright into a grassy field.

The school bus contained eight anthropomorphic test devices or crash-test dummies. These were equipped with electronic head and neck sensors that provided real-time impact data analysis.

Four crash-test dummies were positioned in lap/shoulder seatbelts and four were unbelted. Darling said that despite the bus not rolling over after impacting the other vehicles, the test still showed the potential severity of injuries to children when they are not buckled up. He explained that the unbelted dummies were thrown out of their seats and ended up on the bus floor beneath their seats or in the middle aisle.

Citing information provided by Dave Hallman and his team of specialists at MATAI, which helped plan and execute the crash test, Darling posted on his personal Facebook page that the impact of force on the unrestrained dummies was six-times higher than the dummies that were restrained.

Darling said the potential for injury is also six times greater for the unrestrained passengers than it would be for a passenger that is restrained in a lap/shoulder seatbelt.

REI provided eight, 170-degree, wide-view surveillance cameras throughout the bus to capture 720-p resolution footage of the crash on impact, and to allow conference attendees to watch the results of the belted and unbelted crash test dummies.

Tyler Technologies provided its GPS solution to provide additional crash investigation information and IMMI provided its line of SafeGuard lap/shoulder seatbelts.

Darling said that the IPTA board also examined evacuation times for children wearing the seatbelts versus children who aren’t wearing them. However, he pointed out that the demonstration using two Thomas Built Buses that were furnished by the Des Moines Public Schools, was not a complete apples-to-apples comparison—since more children were evacuated via the front loading doors during the unbelted demonstration than did during the belted demonstration.

Darling added, however, that the IPTA board was able to confirm that it took 44 seconds for 36 children ranging in age from kindergarten to sixth grade who were wearing lap/shoulder belts to evacuate from a school bus, either by using the front-loading door or the rear emergency exit. He noted that one of those children was his grandchild, who had never before ridden a school bus and was unfamiliar with the type of three-point seatbelts used.


Related: School Bus Lap/Shoulder Seatbelts: Are Students Safe Enough without them?
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Related: A Changed Seatbelt Perspective at STN EXPO Indy
Related: SafeGuard School Bus Crash Demo Kicks Off STN EXPO Indy
Related: Iowa Debating Lap/Shoulder Belts as School Bus Directors Witness Test Crash


The Iowa State Board of Education recently adopted rules requiring the installation of seatbelts on new school buses. The rules will return to the state’s Administrative Rules Review Committee for final review.

Currently, Darling said he is aware of 18 Iowa school districts that have already implemented lap/shoulder seatbelts. He added that he has heard from a few private contractors that after the crash test demonstration additional transportation directors had called the companies to inquire about adding lap/shoulder seatbelts to buses that have already been purchased for the new school year.

Darling shared that while three-point seatbelts are most often talked about in terms of providing additional safety during crashes, he said behavioral improvements of students who buckle up are just as important. He said with the installation of seatbelts, drivers can focus more on driving and watching the road rather than making sure students remain in their seats.

Additionally, he said feedback from several Iowa school districts that already are using the occupant restraint systems show that they are also helping to reduce bullying, as students are unable to turn around in or jump over the seats to taunt other children.

The Iowa bus appeared to perform similarly to the one used in a similar crash test at the IMMI Center for Advanced Product Evaluation in conjunction with the inaugural STN EXPO Indianapolis in June. But unlike the Iowa test, IMMI launched its bus off a 30-degree ramp at the right front wheel. The bus went airborne and landed on the left front and rear tires before slamming into a concrete barrier.

Results from the IMMI test were aired by NBC News on Tuesday.