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Chapter 6: Timing Processes on One Approach
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The purpose of this activity is to give you the opportunity to learn how to determine the vehicle extension
time based on the detection zone length and the desired maximum allowable headway (MAH).
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Relate the MAH to unoccupancy time
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Determine the vehicle extension time based on the length of the detection zone and the desired MAH
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Movie file: A35.wmv
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Prepare a spreadsheet that includes the following information:
Tab 1:
Title page with activity number and title, authors, and date completed
Tab 2:
Answers to the Critical Thinking Questions
Tab 3:
A brief summary of your observations from the tasks which follow. Note any patterns that you
see between the headway data and the unoccupancy time data. What would be the basis of a
relationship between these two parameters?
Tab 4:
The data that you collected in Table 19
As you begin this activity, consider the following questions. You will come back to these questions once
you have completed the activity
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1. What is your recommendation for the vehicle extension time, based on your recommended desired
maximum headway? Explain your answer.
2. If the detection zone length was longer than 22 feet, would your recommended vehicle extension time
value be higher or lower? Explain your answer.
Relating Headway to Unoccupancy Time and
Vehicle Extension Time