Traffic Signal Coordination

[TEEI]

I am currently working on traffic signal coordination project with 7 signalized intersections along a two-way roadway. Also, there are heavy left-turns along this corridor with exclusive pedestrian phases at 3 intersections.

Can anybody explain me on how to achieve optimum green-band in both directions (using synchro)?

 

[teeman]

Synchro will develop a coordination plan that minimizes delay in the corridor. How good it is depends on the work you put into the network or corridor you build. Synchro allows you to group adjacent signals together or break them into separate groups of signals.

You need to be aware not all corridors will benefit from coordination. The presence of exclusive peds and left turn phases means some locations will require longer cycles than others. If longer cycles are not appropriate for the adjacent signals the delay incurred in providing coordinated operation may not be worth it. Keep the cycle length as low as you can to minimize overall delay. Unless you are weighting a direction for inbound or outbound, don't worry about "greenbands". There is usually so much un-accounted for friction in a corridor model that "greenbands" are usually misleading.

The last time I evaluated an 8 intersection corridor I built the corridor model one intersection at a time using the natural cycle length to organize them into groups. Most intersections were 2 or 3 phases, one was an 8 phase quad left, one had an exclusive ped. It was an iterative process of evaluating, reorganizing and evaluating again. I eventually ended with a two intersection group, a four intersection group (including the xped) and a free intersection (8 ph quad left). The coordination plan developed worked reasonably well when implemented.