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Traffic Signal Systems Operations and Design: Isolated Intersections
5. What are the two conditions that separately cause the termination of the green indication?
6. Reflect on what you have observed on how a phase terminates. Write a summary of your observations.
You will observe the southbound approach (phase 4) of the intersection of State Highway 8 and Line
Street. This approach (Line Street) has two lanes, a left turn lane and a through/right turn lane. State
Highway 8 is the major street and serves as a primary east-west route through the city. It also serves
as the major access to a university. See Figure 84. You will monitor traffic on the through/right turn
lane of this approach.
Figure 84.
Aerial photograph of State Highway 8 and Line Street
In this activity, you will consider two cases, each illustrating a different method for the termination of
phase 4 (which serves the SB through/right turn movements). You will observe how the phase times
(the timing processes for the minimum green, vehicle extension, and maximum green timers), and
how it terminates for each case. The two cases have been placed side-by-side in a movie format so that
you can observe the traffic flow and timing processes at the same time. The simulation has been set to
run at less than real time, slow enough so that you can observe all timing and traffic flow processes.
A
ctivity
20: H
ow
a
T
raffic
P
hase
T
imes
and
T
erminates