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Chapter 9: Right of Way Change: Change and Clearance Intervals
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The purpose of this activity is to give you the opportunity to learn how the yellow and red clearance
intervals are set in practice.
•
Describe the factors considered when the yellow and red clearance intervals are set by practicing
traffic engineers
•
Traffic Signal Timing Manual
Prepare a document that includes
•
Answers to the Critical Thinking Question
•
Completed Concept Map
Read the section of the
Traffic Signal Timing Manual
relating to Vehicular Change and Clearance Intervals
as assigned by your instructor.
The
Traffic Signal Timing Manual
notes that:
“The intent of the vehicle phase change and clearance intervals is to provide a safe transition
between two conflicting phases. It consists of a yellow change interval and, optionally, a red
clearance interval. The intent of the yellow change interval is to warn drivers of the impending
change in right-of-way assignment. The red clearance interval is used when there is some benefit
to providing additional time before conflicting movements receive a green indication.”
The yellow display warns the drivers that the right-of-way is about to change, while the red clearance
display allows drivers to safely clear the intersection.
When you have completed the reading, prepare answers to the following questions:
1. Consider the method that you used in Activity #56 to set the yellow and red clearance intervals, as
well as your results. How do they compare and contrast with the methods and recommendations
described in the
Traffic Signal Timing Manual
?
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Yellow and Red Clearance Intervals