Education in Motion / Clinical Corner / December 2014 / Wheelchair Tiedowns and Occupant Restraint Systems and Standards

Wheelchair Tiedowns and Occupant Restraint Systems and Standards

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Hello all!

Last month, we looked at WC19 - the voluntary standard for wheelchairs used as seats in motor vehicles. This month, let's look at Wheelchair Tiedowns and Occupant Restraint Systems (WTORS) and how these work in conjunction with WC19 compliant wheelchairs. (If you missed last month's article, please click here.)

The wheelchair tiedown part of WTORS refers to securing the wheelchair to the floor of the motor vehicle, while the occupant restraint system refers to providing restraint to the person in the wheelchair. Both are required to enhance safety when seated in a wheelchair while travelling in a motor vehicle.

Wheelchair tie-downs typically refer to a four-point strap tiedown system. A four-point strap tiedown system is "a method for securing a wheelchair where four straps are attached to the wheelchair at four separate securement points and attached to the vehicle at four separate anchor points."2 A four-point strap tiedown system is most commonly used on public transit, paratransit and school buses as it can adapt to a range of wheelchair sizes and models.1

As we saw in last month's article, a WC19 compliant wheelchair has two clearly labeled securement points at the front of the wheelchair and two clearly labeled securement points at the rear of the wheelchair. When attaching the tiedown straps to the front of the wheelchair, the straps should be angled slightly outward, such that the attachment points on the floor are wider than the width of the wheelchair to add lateral stability.3,4 Recall from last month's article that people who must remain seated in a wheelchair while travelling in a vehicle are at risk of injury if the wheelchair tips, for example, during a sharp turn or sudden swerve.1 Therefore, the position of the front tiedowns is important to enhance lateral stability to minimize the risk of tipping during a sudden driving maneuver. The front tiedowns should attach to the floor at an angle between 40 and 60 degrees (relative to horizontal).3,5

The tiedowns that attach to the labeled securement points on the rear of the wheelchair should be attached "straight back to the floor."3 (p. 10). These tiedowns should attach to the floor at an angle of 30 to 45 degrees (relative to horizontal).3,5 It is noteworthy that the rear tiedowns usually take twice the amount of force compared to the front tiedowns and therefore their correct placement is important.3

Wheelchair tiedowns also may refer to docking systems, which are commercially available mechanical systems that secure particular wheelchairs to particular vehicles. A docking tiedown, therefore, is "a method for securing wheelchairs where portions of the wheelchair frame, or add-on components fastened to the wheelchair frame, engage with a securement device anchored to the vehicle."2 This would be most commonly used in a privately-owned vehicle for a specific wheelchair. This replaces the need for using a four strap tiedown system and can promote independence with securing one's wheelchair to one's vehicle.

Whether a strap tiedown system or a docking system is used, an occupant restraint system is necessary in either case. An occupant restraint is "a system or device designed to restrain a motor vehicle occupant in a crash by keeping the occupant in the vehicle seat and minimizing contact with the vehicle interior, other occupants, or objects outside the vehicle."2 An occupant restraint system is a three-point lap and shoulder belt system that has been crash-tested. As I mentioned in last month's article, a lap belt, or pelvic safety belt, is not the same as a positioning belt used for postural support. A pelvic safety belt has been specifically designed and tested for crash-worthiness and is used in conjunction with a shoulder belt anchored to the vehicle to provide restraint to the hips and torso in the event of a crash. "The shoulder belt needs to be snug and positioned over the middle of the clavicle and across the sternum, and then connect to the pelvic belt near the hip"3 (p. 11). The pelvic belt must fit low on the hips to minimize risk of injury in the event of a crash.6

Just as a wheelchair must meet certain standards to be deemed WC19 compliant, so too must tiedown and occupant restraint products. The standards for tiedown and occupant restraint products require that:

  • "pelvic and shoulder restraints be used in the tests and recommend use of both belts during transport, especially in vehicles that have occupant restraint belts normally installed,
  • a dynamic 30 mph (48kph) frontal-impact test be used to confirm the performance of the WTORS,
  • the end fittings on tiedown straps meet a specific design so that the end fitting will readily latch to the mating receptacle on the transport-compliant wheelchair,
  • the product be permanently labeled as to the test passed, instruction and warnings be provided for both installers and users."7

In addition, an effective WTORS "must provide for the release of the wheelchair and occupant in under 60 seconds by a single attendant."5 Recall from last month's article on WC19 – wheelchairs used as seats in motor vehicles – that WC19 compliant wheelchairs must have securement points that allow for one-handed attachment of the hook of the tiedown strap when the attendant reaches for the securement points from one side of the wheelchair.

Now we can see how a WC19 compliant wheelchair works in conjunction with WTORS for securement of the wheelchair and restraint of the individual in the vehicle. Next month, we will look at the standard for seating and address the use of secondary postural supports for people who remain seated in wheelchairs while travelling in motor vehicles.

References

  1. RESNA. (n.d.) RENSA's Position on Wheelchairs Used as Seats in Motor Vehicles. Retrieved from http://www.resna.org/
  2. University of Michigan. (2012). Ride Safe. A Glossary of Terms. Retrieved from http://www.travelsafer.org/
  3. Shutrump, S.E., Manary, M., & Buning, M.E. (2008). Transportation for Students Who Use Wheelchairs on the School Bus. Retrieved from http://www.rercwts.org/
  4. Fuhrman, S.I., Buning, M.E., & Karg, P.E. (2008). Wheelchair Transportation. Ensuring Safe Community Mobility. Retrieved from http://www.rercwts.org/
  5. Ordre des ergotherapeutes du Quebec. (2010). Delivery of Services Relating to the Use of Motor Vehicles: Guide for Occupational Therapists. Retrieved from http://www.cotbc.org/
  6. Rehabilitation Engineering Research Center on Wheelchair Transportation Safety. (2008). Best Practices for Using a Wheelchair as a Seat in a Motor Vehicle. Retrieved from http://www.rercwts.org/
  7. Rehabilitation Engineering Research Center on Wheelchair Transportation Safety. (2008). Wheelchair Transportation Safety Frequently Asked Questions. Retrieved from http://www.rercwts.org/

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