CEE 764 – Fall 2010 Topic 7 Special Issues on Signal Coordination

CEE 764 – Fall 2010 Signal Timing with Large Systems  Difficult to obtain high bandwidth efficiency with a large number of signals in a system.  Only a small portion of the traffic goes through the entire arterial.  Seeking a system progression band with low efficiency may not be a good signal timing strategy.

CEE 764 – Fall 2010 System Partition Technique  Step 1. Divide the system into sub-systems (3~5 signals) Divide at locations of capacity bottleneck and large spacing Divide at locations of capacity bottleneck and large spacing  Step 2. Obtain maximum bandwidth solution for each subsystem  Step 3. Form the peak direction progression band Adjust offsets to achieve an one-direction bandwidth (peak) Adjust offsets to achieve an one-direction bandwidth (peak) Subsystem progression is retained for the other direction Subsystem progression is retained for the other direction  Step 4. Fine tune the solution Possible signal phasing change to improve the off-peak direction progression band; Possible signal phasing change to improve the off-peak direction progression band; Cross street with split phasing should be set at a sequence favoring progression of the left turns. Cross street with split phasing should be set at a sequence favoring progression of the left turns.

CEE 764 – Fall 2010 EXAMPLE

EXAMPLE

EXAMPLE

EXAMPLE

EXAMPLE

Speed Comparison – Arterial All Vehicles

CEE 764 – Fall 2010 Speed Comparison –Through Vehicles

CEE 764 – Fall 2010 Advantages  Maintain maximum progression for the peak direction. The one directional progression band for the peak direction is the maximum that can be achieved from any optimization solutions. The one directional progression band for the peak direction is the maximum that can be achieved from any optimization solutions.  Maintain maximum progression for the subsystems. Subsystems have larger bandwidths on both directions. Subsystems have larger bandwidths on both directions.  More control and handle on queue and stops Progression on the off-peak direction is partially maintained. But the users have complete control on where to stop vehicles and store queues. Progression on the off-peak direction is partially maintained. But the users have complete control on where to stop vehicles and store queues.

CEE 764 – Fall 2010 Pedestrian Timing Treatment  Pedestrian crossing times are handled by concurrent vehicle through phases  Green time of vehicle phase must satisfy the WALK + FDW  Vehicle demands are low at minor streets, but pedestrian crossing times are high (wide street)  Split phasing presents more challenges  Two timing treatments Vehicle minimum Vehicle minimum Pedestrian minimum Pedestrian minimum

CEE 764 – Fall 2010 Pedestrian Timing Treatment Left Turn Leading Lead/Lag Time

CEE 764 – Fall 2010 Pedestrian with Split Phasing

CEE 764 – Fall 2010 Advantages/Disadvantages Vehicle Minimum Pedestrian Minimum  Optimal Cycle Length  Signal Out-of-Coordination  Timing Plan Reflects Actual Progression  Easy Timing Plan Development  Cycle Length Constraint  Remain Coordination  Progression According to Early Release  Major Manual Adjustments

CEE 764 – Fall 2010 IDENTIFY EARLY RELEASE POINT

CEE 764 – Fall 2010 EFFECTIVE USE OF PHASING SCHEME 35

CEE 764 – Fall 2010 USE OF MAXIMUM RECALL Eastbound

CEE 764 – Fall 2010 Grid Network

CEE 764 – Fall 2010 Grid Network Φ2Φ2 Φ4Φ4 Φ4Φ4 Φ2Φ2 Φ2Φ2 Φ4Φ4 Φ4Φ4 Φ2Φ Time 0θ 12

CEE 764 – Fall 2010 Grid Network Φ2Φ2 Φ4Φ4 Φ4Φ4 Φ2Φ2 Φ2Φ2 Φ4Φ4 Φ4Φ4 Φ2Φ Time 0θ 12 Φ4Φ4 Φ2Φ2 θ 12 +Φ2+θ 23 Φ2Φ2 Φ4Φ4 θ 12 +Φ2

CEE 764 – Fall 2010 Grid Network Φ2Φ2 Φ4Φ4 Φ4Φ4 Φ2Φ2 Φ2Φ2 Φ4Φ4 Φ4Φ4 Φ2Φ Time 0θ 12 Φ4Φ4 Φ2Φ2 θ 12 +Φ2+θ 23 Φ4Φ4 Φ2Φ2 θ 12 +Φ2+θ 23 +Φ4+θ 34 Φ2Φ2 Φ4Φ4 Φ2Φ2 Φ4Φ4 θ 12 +Φ2+θ 23 +Φ4 θ 12 +Φ2

CEE 764 – Fall 2010 Grid Network Φ2Φ2 Φ4Φ4 Φ4Φ4 Φ2Φ2 Φ2Φ2 Φ4Φ4 Φ4Φ4 Φ2Φ θ 12 Φ4Φ4 Φ2Φ2 θ 12 +Φ2+θ 23 Φ4Φ4 Φ2Φ2 θ 12 +Φ2+θ 23 +Φ4+θ 34 Φ2Φ2 θ 12 +Φ2+θ 23 +Φ4+θ 34 +Φ2+θ 41 +Φ4 Φ2Φ2 Φ4Φ4 Φ2Φ2 Φ4Φ4 θ 12 +Φ2+θ 23 +Φ4+θ 34 +Φ2

CEE 764 – Fall 2010 Grid Network θ 12 +Φ2+θ 23 +Φ4+θ 34 +Φ2+θ 41 +Φ4 = NC θ ij = t ij = L ij /S ij Φ2 + Φ4 = C 4θ ij +2C = NC 4θ ij = NC θ ij = NC/4 = C/4

CEE 764 – Fall 2010 Example  For a grid one-way street network, each block has 300 ft. Suppose both directions at each signal have the same phase splits. (1) What would be the cycle length if the progression speed is designed to be 20 mph? (2) If the cycle length is 60 sec, what would be the fastest progression speed?