Wheelchair Transport Safety
Development of Improved Options

Nordic Seating Symposium, October 6, 2001
Stockholm, Sweden
Douglas Hobson, Ph.D


Slide 26
B - What is being done about the problems today?

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Voluntary industry performance standards

  • a forum for consensus building

Education of transporters, clinicians and users

Research on the next generation of wheelchair securement and occupant restraints

Slide 27
Why Standards??

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benchmark test for product performance

repeatable testing methods world-wide

fosters compatibility between securement system and wheelchair

installation and operational information for users

comparable information in manuf's literature

provide manuf's with design guidelines

Slide 28
Standards Development

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Ideally- world-wide long range standards plan

In reality----

Solutions are evolving sequentially--

  • Wheelchair securement-belt type-(done)
  • Vehicle mounted occupant restraints-(done)
  • Wheelchairs designed for transport-(done)
  • Wheelchair seating-(started-’98)
  • Wheelchair mounted occupant restraints (2-4yrs)
  • Wheelchair self-docking securement systems (3-5yrs)

World wide harmonization occurring via ISO.

Slide 29
ISO Wheelchair Transport Safety Standards- three areas

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1) ISO10542: Wheelchair tiedown and occupant restraints (WTORS) series.

  • Part 1- General requirements and test methods-(done)
  • Part 2- Four-Point Strap Type Systems-(done)
  • Part 3- Docking Devices (in process)
  • Part 4- Clamping Devices (in process
  • Part 5- Specific Combinations (in process)

2) ISO7176/19 Wheelchairs: Wheelchairs for use as seats in motor vehicles-(final sage)

3) ISO16840-4: W/C Seating intended for use in a motor vehicle (in process)

ISO 10542, Parts 1&2 are 95% complete, and proceeding through the ISO fial approval process (as of 10/98).

ISO CD 7176-19 Wheelchairs is the standard that is concerned about the transport safety of the wheelchair itself.

Slide 30
ISO-10542: WTORS Series
Wheelchair Tiedown & Occupant Restraint Systems

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Voluntary standard

Intended to reduce potential for injury to W/c-seated occupants in a frontal crash

Specifies design/performance requirements, test procedures, installation instructions and information disclosure requirements

Slide 31
ISO-DIS 10542-WTORS: Part 1 (Cont.)
General requirements

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Adult passengers or drivers

Public or private vehicles

Forward facing orientation only

Requires pelvic & shoulder belt restraints

Applicable to all W/Cs, including scooters

Requires dynamic testing of WTORS

Requires labeling and user instructions

Requires disclosure of test information

Slide 32
ISO-DIS 10542-WTORS: Part 1(Cont.)

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  • Dynamic testing
    • Sled impact test
    • Utilizes surrogate (reusable) WC
    • 20 G, 30 mph deceleration pulse
    • 50th percentile male hybrid III ATD
  • Other testing
    • Partial engagement of components
    • Belt length and webbing slippage

Testing of the wheelchair tiedown devices involves a simulated ( impact sled) crash test using a surrogate (simulated standard) wheelchair with a mass of 185 lbs. In the suurogate wheelchair seat is placed an anthropometric test dummy ( ATD) with a mass distribution representing that of the average male, 75kg(168lbs). The secured wheelchair and restrained ATD is then subjected to a 20g, 48kph (30mph) simulated crash.

Slide 33
ISO7176/19: Wheelchairs
for use as seats in motor vehicles

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manual WCs, powered WCs, scooters,
tilt-in-space WCs,

forward-facing WC-seated adult occupant

W/Cs for use in both public and private vehicles

W/Cs secured by variety of tiedown devices

occupant restraint by pelvic and upper torso belts

Slide 34
SO7176/19: Wheelchairs for use as seats in motor vehicles
Design Requirements:

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Securement Points:

four securement points for tiedowns shall be provided and clearly marked

securement points on W/C shall comply with standard tiedown geometry

Slide 35
ISO7176/19: Wheelchairs for use as seats in motor vehicles

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Pelvic Restraint

Allow independent pelvic restraint to cross pelvis to anchor points within 30-75° range

If integrated, provide a pelvic restraint angle within the 30-75° range

Provide a clear path for anchorage of pelvic restraint to vehicle

Slide 36
ISO7176/19: Wheelchairs for use as seats in motor vehicles

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Postural Supports:

Postural supports intended for use as
occupant restraints shall comply with ISO
10542-WTORS--(restraints std.)

Postural supports not intended for use as
an occupant restraint shall be labeled accordingly

Slide 37
ISO7176/19: Wheelchairs for use as seats in motor vehicles
Performance Requirements:

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Dynamic Strength:

  • Sled impact test specified
  • 30 mph / 20 g deceleration pulse

Post test-W/c must meet criteria for:

  • component failure
  • W/c and dummy excursions
  • no W/c loading of occupant
  • detachable seat inserts remain attached
  • batteries restrained with no leakage

Slide 38
Application Guidelines

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  • Explain rationale for requirements in stds.
  • Explain what the test results mean
  • Provide additional application information
  • Provide guidelines for product designers


  • SAE-J2249 WTORS Companion Guideline-(completed)

Transport Wheelchairs-(in process)

Slide 39
C-What can you do today?

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Become knowledge about transport safety issues,

Communicate options to consumers, and


Graphic description: graphic text says, " products in compliance with standards"

Slide 40
Wheelchair Securement

graphic description follows

Industry standard:
four-point strap-type tiedown.

Know how to use the devices as intended
Discourage use of non-tested devices

Graphic description: photo showing manual wheelchair being secured in a laboratory setting with the industry standard four point strap securement devices.

Slide 41
Transit Wheelchairs/Bases

graphic description follows

Mainly pediatric available to date

Locate and mark securement points

Graphic description: Two photos showing pediatric products that have been tested to the transport standards. Both photos emphasize the marked attachment points for the attaching securement strap end fittings

Slide 42
Transit Wheelchairs/Bases

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Four ISO 7176-19 compliant securement points

Graphc description: A side view showing the Part 19 compliant securement hardware.

Slide 43
D- What might the future bring?

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tested adult-size transport wheelchairs

totally integrated occupant restraints

universal docking interface

self- docking technologies

seating and accessories stds.

application guidelines for clinicians and users

new transit vehicle options

Slide 44
Universal Docking Interface Geometry (UDIG)

graphic description follows

Graphic description: a schematic to illustrate the Universal Docking Interface Geometry ( UDIG) concept. It shows a wheelchair on one side with transport vehicles. Jioning the two are two mating boxes: on the left box are two arrows that are alligned with two identically shaped recepatacles on the rifht box. The implcation being the the UDIG calls for mating hardware on both the wheelchair and on the vehicle so that the two can be universally interefaced or latched to provide inproved securement between a wide variety of wheelchairs and variety of transport vehicles.

Slide 45
Universal Docking Interface Geometry (UDIG)

graphic description follows

Graphic description: slide showing a woman riding a her scooter up a hill. On the back of the scooter is a U-sahped bumper bar that looks much like the proposed UDIG.

Slide 46
Universal Docking Interface Geometry (UDIG)

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Graphic description: A rear view of another scooter ( Shoprider) sho\wing a simpler type of u-shaped metal bumper located on the rear of the scooter frame.

Slide 47
Universal Docking Interface Geometry (UDIG)

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Graphic description: A drawing of the u-shaped tubular geometry that if accepted would become the UDIG standard.

Slide 48
Docking Technologies

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possible system for transit vehicle or

passenger station in private vehicle

Graphic description: An illustration showing how a wheelchair containing a UDIG could be docked into a wheelchair station that had a docking securement device that used the same UDIG standard.

Slide 49
Totally Integrated Occupant Restraints

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W/c-19 integrated lap belts-2 yrs.

on-board lap and shoulder restraints options (2-3 yrs)


  • independence from vehicle-mounted restraints
  • improved body fit
  • possibly higher usage rate??

Slide 50

graphic description follows

standards for seating inserts, including accessories

guidelines for designers

education of prescribers, parents and users

availability of safer products

more knowledgeable clinicians users and caregivers

Graphic description: photo of child's seating insert that presently does not have any transport safety standards.

Slide 51

graphic description follows

Low Floor Buses

Low ‘g’ compartments

Graphic description: The newer low floor buses and use of low 'g' securement compartments in some countries offers opportrunities to enhance wheelchair securement and user independence. Left photo shows a low floor bus with door open and ramp out. Right photo shows the wheelchair station in the low floor bus made possible by two fold up seats.

Slide 52
E- Summary/Discussion

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Occupant Restraint devices...

  • use both lap and shoulder restraints
  • forward facing in largest vehicle possible
  • restraints should be snug and well fitting
  • seat belt angle range: 45-70°
  • transfer to car seat whenever possible


  • use child’s car seats as long as possible
  • check the attachment of seating inserts
  • child’s head should not be restrained
  • lap trays and other accessories removed
  • home made tie-downs a no-no

Slide 53
Summary/Discussion (cont.)

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Industry standards say......

  • compliant products must pass a 20g/48kph impact test
  • w/c wheels or brakes should not be used for securement
  • compliant W/cs shall have four marked securement pts.
  • specific test results required in presale literature
  • labeling, installation, warning and user info. required

Slide 54

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The crystal ball says........

  • tested adult w/cs will become market options in ‘02’
  • on-line application manuals (w/cs & WTORS)-01
  • totally integrated adult restraint systems -02
  • w/c seating inserts std., 2003
  • UDIG std. in US by 2002, ISO-2003
  • UDIG compatible products in NA, 2004
  • frontal/rear/side impact requirements, 2003

Slide 55
F- More information

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How to contact:
Douglas Hobson: dhobson@pitt.edu

Standards information/application guidelines:

  • http://www.wheelchairstandards.pitt.edu/
    (then click: ISO-WG-6, SAE-J2249)
  • Slide Presentation:
    http: //www.wheelchairnet.org

The End

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Updated: February 28, 2002

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