Lead Presenter Biography

Mr. Lam is a travel demand modeler and transportation planner at CDM Smith. He eagers to adopt innovative practices in travel demand forecasting, data analysis, and general planning. He has over 20 years of experience updating, validating, applying, and developing regional travel demand model for toll traffic and revenue studies, corridor studies and public transportation plan. He is knowledgeable in traditional 4-step model, the activity-based model, and mesoscopic assignment.

Co-Authors

Presentation Description

The Houston Urban Core Planning Study is an in-depth transportation data and modeling analysis of the central Houston region under existing year 2019 and horizon year 2045 conditions. This presentation will focus on two aspects: 1) Combining collected data and third-party passively collected data to describe existing traffic conditions and hot spots, and 2) Application of a mesoscopic dynamic traffic assignment (DTA) model as an exploratory tool to evaluate the mobility benefits of various resiliency, technology, managed lane, and added capacity scenarios for the horizon year. Twenty-five scenarios were modeled and evaluated. The presentation will describe an innovative way to present data analysis as a corridor profile, applying DTA to simultaneously forecast demand, mobility, bottleneck, and operations of various scenarios, and to present the model results in interactive dashboard and geographic format.
The data analysis collected from existing traffic counts, crash databases, and third-party passively collected speed and count data. The analysis describes congestion, speed, and crash profiles of the most congested corridors. The profiles include graphs and maps of congestion and safety hot spot locations.
The presentation will also discuss passively collected data on the Houston region’s 8-County mesoscopic model validation (the region’s Transportation Management Area (TMA)). Day-to-day 15-minute level INRIX speeds were processed to develop speed validation targets. The validation used StreetLight Data counts to supplement collected traffic counts in model validation.
The study used a regional DTA to identify bottlenecks on existing year condition and evaluate mobility benefits of various proposed solutions. The macroscopic travel demand model does not accurately model the operation details such as the peak congested speed and vehicle queuing. The DTA is applied not only for forecasting the demands but also for evaluating operational details of each scenario, especially if a proposed scenario could relieve existing bottlenecks, create unintentional new bottlenecks on downstream or nearby facilities, or capture rerouted traffic demands.
Using a three-tier geospatial evaluation criteria to evaluate the mobility effectiveness of the scenario including regional, corridor-specific, and location-specific measures, the model results were aggregated to various time periods. The regional and corridor-specific criteria measure the project effectiveness in term of familiar statistics such as vehicle miles traveled (VMT), vehicle hours traveled (VHT), and travel time reliability. The location-specific criteria used heat-map, diversion maps, and other tools to evaluate the operational impacts (speed and queuing) at the bottlenecks and level of vehicle rerouting of scenarios.
The study successfully applied the DTA model as an exploratory and operational analysis tool. This included the application of resiliency scenarios (a flooding scenario on a major freeway) and technology scenario (adding a connected vehicle only lanes) within the DTA model.
With many statistics generated, this study used an interactive dashboard and geographic format to present the statistics in a user-friendly and interactive format. The presentation will show the evaluation criteria and operation benefits in this interactive format for the resiliency and technology scenarios. 

Presentation File