AN INVESTIGATION HAS BEEN CARRIED OUT TO DETERMINE ANY POSSIBLE IMPROVEMENT TO THE OVERALL PERFORMANCE OF A TRAFFIC SIGNAL CONTROLLED INTERSECTION WHEN A BUS-ACTUATED SYSTEM IS SUPERIMPOSED ON FIXED-TIME CONTROL. A HYPOTHETICAL SITE DOWNSTREAM FROM A SET OF GENUINE SIGNALS WAS SELECTED AND DATA CONCERNING FLOWS, JOURNEY TIMES AND ARRIVAL PATTERNS OF VEHICLES WERE RECORDED. THE TRANSYT PROGRAM WAS USED TO OBTAIN THE APPROPRIATE OFFSETS AND SPLITS AT THE HYPOTHETICAL SITE FOR DIFFERENT LEVELS OF SIDE ROAD VOLUME AND THESE WERE FED INTO A SIMULATION PROGRAM TOGETHER WITH THE ARRIVAL TIMES OF VEHICLES TO CALCULATE THE RESPECTIVE PERFORMANCE INDICES. THE SIMULATION PROGRAM WAS THEN ALTERED TO REPRESENT A BUS-ACTUATED SYSTEM WHERE THE SIGNALS WOULD CHANGE AT THE DETECTION OF BUSES ACCORDING TO A PREDETERMINED POLICY BUT SUBJECT TO OVERRIDING CONSTRAINTS IMPOSED BY THE FIXED-TIME SETTINGS. IT WAS FOUND THAT THE BUS-ACTUATED SYSTEM OF CONTROL BEST SUITED A LOW FLOW OF BUSES WHILE FIXED-TIME CONTROL GAVE A BETTER PERFORMANCE INDEX WITH A HIGHER BUS FLOW.(Author/publisher).
Samenvatting