TRB 2016 Blue Ribbon Committee
16th National Transportation Planning Applications Conference

A Path to DTA for a Resource-Limited MPO: Dynamic User Equilibrium (DUE) Module Implementation within a Four-Step Model

Corresponding Author: Mary Lupa, WSP

Presented By: Mary Lupa, WSP


The Pikes Peak Area Council of Governments (PPACG), an MPO located in Colorado Springs CO, has identified limitations in their current modeling suite in addressing current and emerging planning issues, particularly at the project and corridor levels. These limitations can be addressed by an improved understanding of vehicular traffic flows on network links by finely grained time of day intervals. The deployment of a Dynamic Traffic Assignment (DTA) is desired as a method to address these needs with PPACG launching a sensitivity test using a module called Dynamic User Equilibrium (DUE). Limited MPO resources, including funding, data, staff availability and skills, and software and technical expertise, led the MPO to consider enhancement of current modeling tools versus development and deployment of a new tool. This proposed session addresses:

• The role of DTA/DUE in the MPO planning process which will include: measuring the impact of capacity changes to roadways and intersections by time of day; evaluating and ranking construction sequencing scenarios; conducting evacuation planning; special events planning; incident recovery; and screening projects for inclusion in the MPO’s fiscally constrained Regional Transportation Plan (RTP) and Transportation Improvement Program (TIP).

• The methodology and tactics used to launch DTA within the existing four-step model which will include a quick overview of DTA/DUE theory, an overview of network and time of day preparation, and a summary of outputs such as speed and queues in 10-minute intervals for the a.m. peak period.

• Four preliminary test applications which will include a regional summary of roadway speeds and queues (baseline), and tests of link outflow, traffic signal enhancement and land use. A comparison of congestion outputs from four-step vs. DUE will also be provided.

The authors will wrap up by looking at the role of mesoscopic models at MPOs, the resources required to deploy them, complementarity of four-step models with DUE, some limitations of the proposed DTA strategy, a software discussion, and a list of first-cut applications desired by the PPACG.


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