FRISCO, Texas — A TSD Conference session used videos of crash tests to underscore the need for proper securement of students in wheelchairs on board school buses.
"Wheelchair Securement and Occupant Protection Lessons from the Crash Lab" was presented Sunday afternoon by Miriam Manary, senior engineering research assistant at the University of Michigan’s Transportation Research Institute and a member of the TSD Conference national board of advisors. She used videos of crash tests conducted by her department to illustrate the consequences of improper securement.
Manary said that the best outcome of a crash when students in wheelchairs are correctly secured is that the wheelchair comes forward and is stopped by the floor tiedowns, while the occupant comes forward and is stopped by the lap-shoulder belt. While proper securements are easiest with WC19-compliant models, any type of wheelchair can be safe if all four straps are used to secure it to the floor of the school bus.
Wheelchairs should always be secured facing forward, Manary said, since frontal school bus crashes are the most frequent and most deadly. Furthermore, the structural strength of the chair is best from the front as they are often made to collapse sideways. A frontal crash test with a wheelchair secured so the side of the chair faced the front of the bus caused the chair to tip and the occupant to be flung even further, hitting an obstruction.
In a rear-facing scenario, the back of the seat came off and the occupant was thrown out the back of the chair. Using just two tiedowns caused the chair to rotate and the rider to be thrown. Additionally, if the wheelchair isn’t secured but the occupant is, in a crash they will be sandwiched between the force of the decelerating wheelchair and the restraining force of the seat belt.
If securing the wheelchair is too difficult for the driver and aide, the transportation team needs to revisit the setup and possibly involve administration so they can adjust the buses ordered or the specifications written into a student’s IEP.
A very common problem is securing the wheelchair but not the occupant, Manary revealed. She reminded that postural supports are not restraints and do not provide any protection in a crash. Independent seat belts can be anchored to the floor while integrated seat belts attach to the wheelchair or tiedown.
Lap-shoulder belts should be used, she said, and must rest on hard parts of the skeleton, not soft body parts like the stomach. A crash test demonstrated that not using a shoulder belt poses the risk of a wheelchair occupant hitting their head on nearby objects, their own legs or the wheelchair. Another common mistake Manary warned against is putting the shoulder belt over the chair’s arm and outside of the seat, which causes the student to submarine out from under it in a crash.
Other equipment like ventilators or oxygen tanks should be secured with straps and as low as possible. These items should be in rigid frames instead of soft bags so they don’t slam into the rider in a crash. Backpacks should be secured low to the floor with the seat belt or bungee cords. Hard lap-trays can splinter and fly off in a crash, so they should be removed if possible; there are better ways to achieve upper body support such as foam trays.
An update to restraint best practices in WC18 recommended five-point harnesses for children under 50 pounds. If there is no such available restraint and the child can safely be removed from the wheelchair, Manary said they should be in child safety restraint systems recommended by NHTSA.
Crash videos, information on standards and a list of compliant products can be found at wc-transportation-safety.umtri.umich.edu.
Editor's note: Manary will further discuss wheelchair securements and postural supports in the OT/PT/Transporter Forum, held from 2 to 3:30 p.m. local time on Monday.