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Sub-problem 4a - Page 1 of 3

ID# C104A01

Sub-problem 4a: Pretimed Control vs. Actuated Control

Whenever signalized control is considered for an intersection, it is usually worthwhile to spend at least some time thinking about and evaluating the different types of signal control that are available for implementation. Signalized intersection analyses described earlier in this case study have assumed the signal will operate in a pre-timed mode, but most new signals today also have the ability to operate in an actuated mode. Typically, the kinds of questions that the analyst would want to answer before deciding between pre-timed and actuated control would include the following:


Will a traffic-actuated signal reduce delay at the intersection?


Will either the major or minor street movement experience greater delay with an actuated control as compared to a pretimed control?

bulletWhat is the effect of skipped phases on lost time and performance at the intersection?
bulletIs the intersection part of a coordinated signal system?
bulletDoes the intersection have any high-speed approaches that might suffer from a dilemma zone problem under pre-timed control?

Take a few minutes to consider these questions. When you are ready to continue, click continue below to proceed.

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