traned2010trbpptjgs0501101 mobility scooters and user characteristics at crossings and intersections...
TRANSCRIPT
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MOBILITY SCOOTERS AND USER CHARACTERISTICS AT CROSSINGS
AND INTERSECTIONS
John G. Schoon
University of Southampton, Transportation Research Group
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Objective: Improved geometric design of road crossings for mobility scooter users.
Current problems: Users’ risk of collision with motor vehicles not stopping due to inadequacies in:
• Driver performance• Approaching vehicle(s’) deficiencies • Infrastructure • Operational procedures
Problem consequences – reduced mobility of disabled people
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Aproach to Improved Geometric Design – Configure crossings to accommodate users
Scooter users’sight lines – to enables scooter user who is aware of his or her abilities, to cross the carriageway to a point where no risk of collision with an approaching vehicle occurs. Considerations: distance to approaching vehicles,
• clearance from obstructions;• user’s vision angle; and, • user’s scanning time.
Crossing movement timing – • User based: observation-reaction time; and, • Scooter based: acceleration, crossing velocity,
deceleration, safety margin
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USER’S SCANNING ANGLES
Required corner scanning angle
B
A
Range of actual scanning angles
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EFFECT OF MIRRORS ON SIGHT LINES
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EFFECTS OF CROSSING LOCATION ON USER SIGHT LINES
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CROSSING TIME COMPONENTS
Safety margin time
Safety margin time
Vulnerability time during crossing
Vulnerability time during crossing
Observation-reaction time
Observation-reaction time
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TIME-DISTANCE DIAGRAM OF CROSSING MOVEMENT
Time
Observation-reaction time
Front of scooter
Rear of scooter
Safety margin time
Total time required by mobility scooter for safe crossing
Length of scooter
Length of scooter time
Distance
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GEOMETRIC DESIGN REQIREMENTS FOR MOBILITY SCOOTERS AT CROSSINGS
• Analysis of sight lines
• User scanning angles
• Location of crossing relative to sight lines to approaching vehicles
• Assumption that scooter users cannot take evasive action
• Consideration of scooter and user characteristics:
• Observation-reaction time
• length of scooter
• Safety margin
• Turning radius of scooters adjacent to crossing
• Scooter crossing speed relative to approaching vehicle speed
• Footway width and slope characteristics