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MOBILITY SCOOTERS AND USER CHARACTERISTICS AT CROSSINGS AND

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MOBILITY SCOOTERS AND USER CHARACTERISTICS AT CROSSINGS AND Powered By Docstoc
					 MOBILITY SCOOTERS AND USER
CHARACTERISTICS AT CROSSINGS
     AND INTERSECTIONS

            John G. Schoon


University of Southampton, Transportation
              Research Group


             TRANED2010TRBPPTjgs050110      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



                  TRANED2010TRBPPTjgs050110             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
                  TRANED2010TRBPPTjgs050110            3
      USER’S SCANNING ANGLES




                  A

                            B
Required
corner
scanning angle

                      Range of actual scanning angles

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EFFECT OF MIRRORS ON
     SIGHT LINES




     TRANED2010TRBPPTjgs050110   5
EFFECTS OF CROSSING LOCATION ON
        USER SIGHT LINES




          TRANED2010TRBPPTjgs050110   6
   CROSSING TIME COMPONENTS




Observation-                           Safety margin
reaction time                         time



                TRANED2010TRBPPTjgs050110              7
 TIME-DISTANCE DIAGRAM OF
    CROSSING MOVEMENT
     Total time required by mobility scooter for safe crossing


            Observation-         Length of        Safety margin time
            reaction time        scooter time
Distance




           Front of scooter




                                                             Time

     Rear of scooter          Length of scooter


                   TRANED2010TRBPPTjgs050110                           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




                         TRANED2010TRBPPTjgs050110                         9

				
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