1. ACS-Lite Offset Tuning Algorithm

2. 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

3. As vehicles approach the intersection advanced detectors usually 250 feet or more upstream of the stop bar collect volume and occupancy data.

4. Phase State Volume Occupancy Green Interval Vehicles arriving during yellow and red intervals ACS-Lite develops a statistical flow profile using the volume and occupancy data and correlating it to each interval within the coordinated phase.

5. Phase State Volume Occupancy Green Interval ACS-Lite performs an analysis to determine the optimal offset to capture the greatest number of arrivals during the green interval. 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.

6. Phase State Volume Occupancy Green Interval The new offset accommodates more arrivals during the green interval reducing delays and improving travel time. 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.