Traffic Signal Effectiveness Study

 The City of Richardson sought out WGI Engineering to complete a traffic signal system effectiveness study to respond to concerns regarding safety and travel speeds along Richardson’s major corridors. In this study, WGI Engineering conducted interviews with City Council members and City traffic engineering staff and collected significant traffic data, including traffic volumes, travel times, corridor speed data, and collision data. Using this information, we reviewed the data and findings to compare to similar corridors within the vicinity of the City. 

WGI Engineering conducted interviews with five of the seven City Council members and several traffic engineering staff members to understand the concerns and the existing traffic signal equipment limitations across its 130 signalized intersections. WGI Engineering also gained insight into the City’s priorities for the present and future, as well as the City staff’s plan to continue to improve the existing system. 

After hearing the comments and concerns from City Council members, staff, and residents, WGI Engineering evaluated travel times and speeds along the City’s major corridors. The study’s goal was to assess existing periods of congestion (and bottleneck locations) on each of the corridors and compare selected corridor characteristics to similar corridors in other cities in the Greater Dallas area to determine the effectiveness of the City’s system. WGI Engineering also reviewed collision data along these corridors and matched the collision profiles to intersection designs and volume data. We completed the analysis by building a model of the City’s signal system to test potential modifications to the City’s signal timing strategies. 

The Roadway Analytics platform from INRIX was used to analyze the corridors to get fine-grained data regarding travel speeds at specific locations during specific time periods. INRIX Roadway Analytics is an on-demand, cloud-based analytics suite that leverages global traffic data to help public agencies and consultants more effectively monitor, measure, and manage the performance of road networks and is based on the INRIX high-definition roadway network and historical data. 

The remainder of the study outlined the specific corridors included in the study, summarized the characteristics of those corridors, compared the corridors to similar facilities in other cities, and examined the existing signal timing program to determine if there were improvements that could be made or if City staff required additional technical capabilities to better serve the City of Richardson residents and workers. Lastly, we identified technology needs for the City to further improve its performance, equipment costs, and funding strategy.