Case Study 1 Styner/Lauder Intersection Moscow, Idaho

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Case Study 1Styner/Lauder IntersectionMoscow,
Idaho
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Problem Should the intersection of U.S. 95 and
Styner/Lauder be converted from two way stop
control to signal control?
Overview

• Learning skills
• Apply HCM analysis procedures for interrupted
  flow facilities.
• Know common input requirements and default
  values.
• Select an appropriate analysis procedure
• Understand HCM analysis limitations
• Know how to reasonably interpret the results

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Introduction

• Moscows population is about 21,000
• U.S. 95 is the primary north-south state highway
  in Idaho
• ADT on U.S. 95 is between 15,000 and 23,000 vpd
• Average annual traffic growth is about two
  percent per year

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Introduction
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Introduction
SH 8
US 95
Sweet
Lauder
Styner
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Introduction

• What issues do you think should be considered by
  the state's traffic engineer in resolving this
  problem?

• City residents have asserted that increasing
  traffic volumes at the intersections of Styner
  Avenue, Lauder Avenue, and U.S. 95 are increasing
  delays for and reducing the safety of motorists
  traveling through the intersection.
• The city has requested that the Idaho
  Transportation Department signalize the
  intersection.

• What issues do you think should be considered by
  the state's traffic engineer in resolving this
  problem?

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Issues to consider
Getting Started

• Scope of the analysis?
• Stakeholders?
• Goals?
• Performance measures?
• Tools?
• Data?
• Technical Issues?

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Questions to be Answered
Problem 1 U.S. 95/Styner-Lauder Avenue

• What is the level of service at the existing TWSC
  intersection at U.S. 95/Styner-Lauder?
• What would the level of service be if the
  intersection were signal controlled?
• What would the level of service be at the
  intersection under future projected traffic
  conditions?

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Analyses to be Undertaken
Problem 1 U.S. 95/Styner-Lauder Avenue

• Sub-problem 1a. Analysis of the existing TWSC
  intersection
• Sub-problem 1b. Analysis of the proposed
  signalized intersection
• Sub-problem 1c. Analysis of future conditions

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Step 1. Setup analysis of existing TWSC
Sub-Problem 1a Analysis of existing TWSC
intersection

• Which tool or tools from the HCM should be used
  for the analysis of a TWSC intersection?
• What data are required for the analysis?
• What default values should be used?
• What time periods should be analyzed?
• What measure should be used to determine the
  performance of the intersection?
• What other factors should be considered?

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Sub-Problem 1a Analysis of existing TWSC
intersection
US 95
Lauder
Styner
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Step 2. Results
Sub-Problem 1a Analysis of existing TWSC
intersection
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Step 2. Results (cont.)
Sub-Problem 1a Analysis of existing TWSC
intersection
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Step 2. Results (cont.)
Sub-Problem 1a Analysis of existing TWSC
intersection
Intersection delay and LOS?
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Step 1. Setup analysis of signal control
Sub-Problem 1b Analysis of proposed signalized
intersection

• Which tool or tools should be used for this
  analysis?
• What data are required for the analysis?
• What default values should be used?
• What time periods should be analyzed?
• How do we construct a signal timing for a
  proposed traffic signal using the HCM?

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Step 2. Results
Sub-Problem 1b Analysis of proposed signalized
intersection
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Step 1. Setup analysis of future conditions
Sub-Problem 1c Analysis of future conditions

• What is the appropriate future year for this
  analysis?
• Which default values should be used for this
  future analysis?
• What other factors should be considered?

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Step 2. Results for TWSC control
Sub-Problem 1c Analysis of future conditions
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Step 2. Results for signal control
Sub-Problem 1c Analysis of future conditions
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What if our volume assumptions are uncertain?
Sub-Problem 1c Analysis of future conditions
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Graphical presentation of results
Sub-Problem 1c Analysis of future conditions
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Graphical presentation of results
Sub-Problem 1c Analysis of future conditions
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Problem 1 Analysis
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Problem 1 Discussion
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End of Problem 1