Case Study 1 Problem 4 Styner/Lauder Intersection Moscow, Idaho

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Case Study 1Problem 4Styner/Lauder
IntersectionMoscow, Idaho
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Problem 4. Actuated control
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Problem 4. Actuated control

• Three primary control parameters for actuated
  traffic controllers
• Minimum phase times
• Maximum phase times
• Unit extension times
• Topics in sub-problems
• Estimating phase times
• Effects of unit extension
• Actuated-coordinated control
• Left turn protection

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Sub-problem 4a Pretimed Control vs. Actuated
Control

• 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?
• What is the effect of skipped phases on lost time
  and performance at the intersection?

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Sub-problem 4a Pretimed Control vs. Actuated
Control

• Why are phase times for actuated control shorter
  than the fixed time phase lengths?

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Sub-problem 4a Pretimed Control vs. Actuated
Control

• Why is the delay for actuated control lower than
  for pretimed control?

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Sub-problem 4b Effect of Unit Extension

• What effect does a longer unit extension have on
  the performance measures for an approach?
• Would a longer unit extension increase or
  decrease overall delay on the minor street
  movement? The major street movement?
• Would a longer unit extension increase or
  decrease the overall intersection delay?
• How would the arrival type affect your decision
  to implement a relatively long unit extension?

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Sub-problem 4b Effect of Unit Extension

• Is it better to use the originally-estimated
  unit extension of 2-3 seconds or the 5-second
  unit extension value assumed here?

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Sub-problem 4c Coordinated Operation With
Actuated Control

• How will pedestrian crossing times impact the
  minor street movement phase?
• How would an actuated signal be coordinated as
  part of a network? 

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Sub-problem 4c Coordinated Operation With
Actuated Control

• C90 seconds
• Side street green time?
• Pedestrian crossing requirement 20 seconds
• WB TH/RT capacity requirements are met
• Main street split?
• 70 seconds 

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Sub-problem 4d  Coordinated Operation With
Left-Turn Protection

• Do existing or projected volumes warrant
  protected left-turn phasing at this intersection?
  
• How is the green time allocated between the
  through and left-turning phases on the major
  street?
• What are the delay implications of providing
  protected left-turn phasing on the major street?

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Sub-problem 4d  Coordinated Operation With
Left-Turn Protection

• Do existing or projected volumes warrant
  protected left-turn phasing at this intersection?
  
• How is the green time allocated between the
  through and left-turning phases on the major
  street?
• What are the delay implications of providing
  protected left-turn phasing on the major street?

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Sub-problem 4d  Coordinated Operation With
Left-Turn Protection

• Average phase time (12 sec)(1 - .46) 6.5 sec

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Problem 4 Analysis

• What are the effects of actuated control on the
  performance of the US 95/Styner-Lauder
  intersections?
• What are the primary actuated control parameters?