60 likes | 136 Views
ACS-Lite Offset Tuning Algorithm. Offset Tuning Process. Collect data from advance detectors on coordinated approaches Develop a Statistical Flow Profile correlated to the phase state Perform analysis to capture the most arriving flow during the green interval
E N D
Offset Tuning Process Collect data from advance detectors on coordinated approaches Develop a Statistical Flow Profile correlated to the phase state Perform analysis to capture the most arriving flow during the green interval Implement offset adjustment STEP 1 STEP 2 STEP 3 STEP 4
As vehicles approach the intersection advanced detectors usually 250 feet or more upstream of the stop bar collect volume and occupancy data. STEP 1
ACS-Lite develops a statistical flow profile using the volume and occupancy data and correlating it to each interval within the coordinated phase. STEP 2 Green Interval Phase State Volume Occupancy Vehicles arriving during yellow and red intervals
STEP 3 ACS-Lite performs an analysis to determine the optimal offset to capture the greatest number of arrivals during the green interval. Green Interval Phase State Volume Occupancy Red Arrow points out vehicles arriving before the start of green. Shifting the offset to the left will match the green interval to a greater percentage of arrivals.
ACS-Lite implements the offset adjustment for the coordinated phase. As traffic conditions change ACS-Lite will continue to provide the optimal setting for the offset. STEP 4 Green Interval Phase State Volume Occupancy The new offset accommodates more arrivals during the green interval reducing delays and improving travel time.