Transportation Safety for Wheelchair Occupants

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Transportation Safety for Wheelchair Occupants
March 2004 ISS-Instructional Course

• Linda van Roosmalen, PhD
• Douglas Hobson, PhD
• Department of Rehabilitation Science and
  Technology
• University of Pittsburgh
• Funding National Institute on Disability and
  Rehabilitation Research

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Application to practice

• Wheelchair transit and associated risks
• Methods to prevent occupant injury
• Safety guidelines and Standards
• Resources

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Wheelchair Transportation Safety

• 1.6 million wheelchair users
• Access to motor-vehicle transportation is the key
  to functioning in society
• ADA prohibits discrimination in public
  transportation services
• 2001 New Freedom initiative calls for integration
  of disabled persons into workforce and community
  - transportation critical factor in meeting
  this priority
• 82 of wheelchair users indicate difficulty with
  using public transportation
• Wheelchair users have 10 higher unemployment rate

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Impact Direction

NHTSA, FARS Database
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Impact Severity

• Injury Risk
• Proportional to velocity change
• Loading velocity body weight
• Occupant Restraints protect by
• Prevent occupant ejection from vehicle
• Prevent excessive occupant motion
• Reduce occupant loading
• Increasing time of energy exposure

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Safety Guidelines

• Secure the wheelchair
• Restrain the occupant
• Remove loose accessories from wheelchair
• Remove parts that can injure occupant during an
  impact
• Lap trays, loose objects, postural supports,
  communication devices, neck rings

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Sled Impact Testing
Frontal 30mph 20g
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Safety System 1

• Secure the Wheelchair to the Vehicle

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Wheelchair Securement Systems

• Four point strap type tie-downs
• Docking systems
• Other wheel-clamps, hybrids
• Rearward facing compartments (in large buses)

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Strap type tie-down system

• Advantages
• Four securement points (improves crash response
  and stability)
• Adaptable to most wheelchair types
• No additional wheelchair hardware required
• Withstands crash forces

IMMI-Westfield (IN)
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Strap type tie-down system

• Disadvantages
• Invasion of personal space
• Lengthy securement times
• Requires operator/attendant for securement
• Tiedowns easily misplaced or soiled
• Lack of defined wheelchair securement points
• Requires operator training when securing a
  variety of wheelchairs

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Easy Accessible Securement Points
NO!!!
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Easy Accessible Securement Points
YES!!!
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Docking Systems

• Advantages
• Quick securement times
• Independent securement
• Eliminates need for human judgment of securement
  point location
• Minimizes error
• Withstands crash forces

EZ-Lock (Baton Rouge, LA)
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Docking Systems

• Disadvantages
• Requires add-on hardware
• Requires adaptations to all wheelchair types
• Hardware adds weight and length
• Hardware affects ground clearance
• Fewer securement points (less stability and
  control of crash response)

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Wheel Clamps
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Wheel Clamps

• Disadvantages
• Unable to safely withstand crash forces
• Not compatible with all wheel types
• Requires attendant for securement
• Advantages
• Fairly quick securement
• Less invasive

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Passive RestraintContainment

• Wheelchair is positioned rearward facing in the
  vehicle

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Passive RestraintContainment

• Easy to use
• Quick
• Non-constraining
• Independent use
• HOWEVER.
• For use in low-g vehicles only
• More research is needed to evaluate safety during
  emergency driving situations

(Van Hool, Belgium)
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Safety System 2

• Restrain the Occupant
• To vehicle and/or wheelchair

Lap belts mounted to wheelchair frames are
generally for positioning purposes and NOT for
safety during transit!!!
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Occupant Restraints Reduce Risk of Injury

• Prevent occupant ejection
• Increasing time over which the occupant comes to
  a stop
• Decreasing deceleration or G-loads
• Higher weight means higher loads!
• Decrease occupant forward travel
• Reduce risk of occupant impact with vehicle
  interior

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Sled Impact Testing without use of Occupant
Restraints
Frontal 30mph 20g
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Sled Impact Testingwith proper Occupant
Restraints
Frontal 30mph 20g
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3-Point Occupant Restraint
Upper torso belt (shoulder belt)
Pelvic belt (lap belt)
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Harness Type Restraint
EZ-On Vest
Gorilla Car Seat
Snug Seat Car Bed
Carrie Bus Seat
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Occupant Restraint Safety

• Improperly positioned pelvic belt
• Abdominal injury due to submarining
• Lumbar vertebra injury in frontal crashes
• Improperly positioned shoulder belt
• Excessive head excursions
• Secondary impact with vehicle surfaces
• Injuries to vital thoracic cavity organs

Adomeit Heger, 1975 Leung et al., 1985
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Occupant Restraint Problems

• Appropriate belt fit related to
• Shoulder belt anchor point
• Pelvic belt anchor point
• Wheelchair and occupant size
• Location of wheelchair in securement zone
• Available clearance for belt placement

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Common Problems

• Shoulder belt slip off users shoulder
• Due to shallow angle of torso belt
• Shoulder belt rubs against users neck
• Discomfort,
• Resistance to using belt
• Decreased upper torso restraint
• Anchoring upper torso restraint below shoulder
  may result in downward loading of torso and spine

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Occupant Restraint Best Practices

• Use both pelvic and shoulder belt to restrain the
  occupant
• Lead restraints over bony anatomy
• Shoulder restraint over the Sternum
• Pelvic restraint over the (pelvis) Iliac Crests
• Avoid loading soft tissues (abdomen)
• Remove belt slack
• Use a retractor to reduce upper torso belt slack
• Restraint pre-tensioner reduces belt loading

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Wheel clamps Sideward facing position
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4-Point Tiedown Systems
Twisted Belts
Belt interferes with tires
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Occupant Restraints Postural Supports

• No use of shoulder belts
• Pelvic belt over armrests

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Ongoing Research

• Automated Wheelchair Securement
• Universal docking
• Customized Occupant Restraints
• Wheelchair integrated
• Consumer friendly

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Safety System 3

• Support the Occupant
• Wheelchair seating system
• Wheelchair frame
• Wheelchair components