Sketch Planning Techniques to Assess Regional Air Quality Impacts of Congestion Mitigation Strategies

(PI: Kara Kockelman; Co-PIs: Chandra Bhat, Elena McDonald-Buller)

Mobile sources present air quality issues in a variety of congested regions around the state, where travel delays are rising and transportation systems are in need of improvement. Within this context, it is important to anticipate, quantify, and communicate the benefits and costs of new, congestion-abating transportation projects and policies.

While additions to existing systems may facilitate new and longer trips, thereby increasing regional vehicle-miles traveled (VMT), such VMT tends to occur at preferred times of day, to more attractive destinations and/or at lower costs. The travel time and cost savings, as well as added choice benefits for personal and commercial travelers, can be sizable, along with crash reductions and other benefits. Procedures are needed to permit early and comprehensive evaluation of project proposals, facilitate project prioritization, and enhance communication with all stakeholders, as transportation planners pursue and promote new and beneficial transportation improvement plans.

The project developed such a procedure by synthesizing, expanding, upgrading, and refining existing and emerging tools within a user-friendly, highly accessible Microsoft Access software platform. The resulting toolkit accommodates both basic and more detailed inputs, pivoting off of existing datasets while facilitating, where present, the travel demand modeling capabilities that already exist in Texas’ most congested nonattainment regions. Toolkit outputs display all impacts of interest to the Project Monitoring Committee in both tabular and graphical formats (across the region of study), while highlighting any emission reductions from existing travelers and distinguishing these from emissions increases that emerge from latent demand.