41.4. Interval design

Try these first

1. 1.

   What is the default range for the change interval in seconds?

   Hint

   Consider typical traffic signal timings.

2. 2.

   Is the clearance interval always required?

   Hint

   Think about smaller vs larger intersections.

3. 3.

   What is the typical duration of the change interval at traffic signals?

   • 1-2 seconds
   • 3-6 seconds
   • 7-10 seconds

   Hint

   Think about the common duration for warning signals.

4. 4.

   True or False: The clearance interval is mandatory at all intersections.

   • True
   • False

   Hint

   Consider different types of intersections.

5. 5.

   A traffic signal has a green light duration of 45 seconds. Calculate the total time needed for change and clearance intervals if the change interval is 5 seconds and the clearance interval is 4 seconds.

   Hint

   Simply add the two intervals together.

6. 6.

   At an intersection with a heavy left-turning traffic volume, decide if a clearance interval should be employed or not. Justify your decision.

   Hint

   Consider the safety implications at busy intersections.