MOBILITY SCOOTERS AND USER CHARACTERISTICS AT CROSSINGS AND
MOBILITY SCOOTERS AND USER CHARACTERISTICS AT CROSSINGS AND INTERSECTIONS John G. Schoon University of Southampton, Transportation Research Group TRANED 2010 TRBPPTjgs 050110 1
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 TRANED 2010 TRBPPTjgs 050110 2
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 TRANED 2010 TRBPPTjgs 050110 3
USER’S SCANNING ANGLES A B Required corner scanning angle Range of actual scanning angles TRANED 2010 TRBPPTjgs 050110 4
EFFECT OF MIRRORS ON SIGHT LINES TRANED 2010 TRBPPTjgs 050110 5
EFFECTS OF CROSSING LOCATION ON USER SIGHT LINES TRANED 2010 TRBPPTjgs 050110 6
CROSSING TIME COMPONENTS Observationreaction time Vulnerability time during crossing Safety margin time TRANED 2010 TRBPPTjgs 050110 7
TIME-DISTANCE DIAGRAM OF CROSSING MOVEMENT Total time required by mobility scooter for safe crossing Observationreaction time Length of scooter time Safety margin time Distance Front of scooter Time Rear of scooter Length of scooter TRANED 2010 TRBPPTjgs 050110 8
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 TRANED 2010 TRBPPTjgs 050110 9
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