Capacities of Signalized Intersections
Over the course of the case studies, you have compared signal timing plans in Case Study 1, and in Case Studies 3 and 4. In this case study, you will calculate the capacities of the intersections under the different signal timing plans.
Worksheet:
For this case study, we have an Excel worksheet which you may use or print out. If you decide to use Excel, be sure to right-click the link and "save target as" or "save link as." If you are asked for a password, just press escape.
For Case Study 1:
Using the Capacity background page, find the capacity of this intersection with the existing signal timing and with the improved signal timing.
For Case Studies 3 & 4:
Using the Capacity background page, find the capacity of this intersection with the 3 phase plan (3) and with the overlapped timing plan (4).
Questions
For Case Study 1, why are the capacities so much higher than the volumes? Why are the total volumes for both signal timing plans almost identical?
For Case Studies 3 and 4, which case was most efficient? Why are the v/c ratios different from the desired v/c ratios? What does this mean in regard to traffic flow?
Continue on to Case Study 6.