Case Study 1 Problem 3 Styner/Lauder Intersection Moscow, Idaho

Problem 3 Event Traffic Analysis - U.S. 95 Styner-Lauder Avenue Intersection Using the HCM, what would be the LOS at U.S. 95/Styner-Lauder Avenue during a University of Idaho football game if the intersection were signalized? How would this LOS estimate change if a microscopic simulation model were used instead? What would the critical movement analysis technique tell us about the intersection’s sufficiency under these circumstances? Questions to be answered:

Sub-problem 3a: Oversaturated Intersection Analysis What is the difference between volume and demand, and why is it important to distinguish between these two terms? Can the intersection operate at LOS F even when demand is less than capacity? What is the appropriate value of the duration-of-analysis parameter when demand exceeds capacity? When should multiple time periods be considered in a capacity and level of service analysis?

Sub-problem 3a: Oversaturated Intersection Analysis How will the intersection perform, under both signal control and stop sign control, for these demand conditions? How should we proceed with this analysis?

Sub-problem 3a: Oversaturated Intersection Analysis US 95 Lauder Styner Step 2. Results How will the intersection perform under signal control?

Sub-problem 3a: Oversaturated Intersection Analysis US 95 Lauder Styner Step 2. 1 st period results: signal control

Sub-problem 3a: Oversaturated Intersection Analysis Step 2. 2 nd period results: signal control

Sub-problem 3a: Oversaturated Intersection Analysis Step 2. 3 rd period results: signal control

Sub-problem 3a: Oversaturated Intersection Analysis Step 2. 3 rd period results: signal control

HCM chapter 34 provides information on simulation models Microscopic simulation has several distinct attributes: Individual vehicle interactions Detailed operation of traffic controllers Oversaturated conditions can be directly modeled Multiple period inputs Probabilistic nature of traffic flow and driver behavior More data are required Needs to be calibrated to local conditions Sub-Problem 3b: Using a Microscopic Simulation Model Microscopic simulation models

Sub-Problem 3b: Using a Microscopic Simulation Model Screen capture from a typical CORSIM animated display What insights can we draw from a comparison of CORSIM and HCM results?

Problem 3c: Critical movement analysis What is critical movement analysis? What data are needed? What outputs are produced? Are the results any more or less valid than the results produced by the HCM or by microscopic simulation models? Why is there virtually no difference between estimated delay on the eastbound and westbound approaches to the intersection? What is the effect of grade and heavy vehicles? How do changes in vehicle mix affect the intersections when the intersection operates near or at capacity? What effects do heavy vehicles have on the intersection beyond changes to saturation flow rate?

Problem 3c: Critical movement analysis What is critical movement analysis? What data are needed to conduct critical movement analysis? Critical movement analysis is a method to determine whether the projected volumes at a signalized intersection will be under, near, or over the intersection's capacity to accommodate them. Data necessary to conduct a critical movement analysis include: - Approach volume - Number of lanes - Lane configuration on each approach

Problem 3c: Critical movement analysis Are the results from critical movement analysis any more or less valid than the results produced by the HCM or by microscopic simulation models? Why is there virtually no difference between estimated delay on the eastbound and westbound approaches to the intersection? What is the effect of grade and heavy vehicles? How do changes in vehicle mix affect the intersections when the intersection operates near or at capacity? What effects do heavy vehicles have on the intersection beyond changes to saturation flow rate?

Problem 3c: Critical movement analysis What is the primary result of critical movement analysis? What are the limitations of critical movement analysis?

Problem 3: Analysis The ability of a traffic signal to handle fluctuations is a function of the signal timing that is in the controller in the field. In time period 3 (4:30 - 4:45 pm) of our previous analysis, we changed the green ratio slightly to serve the traffic at the post- game traffic at the intersection. Would this green ratio be possible under the existing pre-timed control?

Problem 3: Discussion Will the consideration of actuated traffic controller settings affect our analysis?

End of Problem 3