Comparison of Quality of Service in Two Central Business Districts

Abstract

In 2003-2004, the City of Fort Worth, Texas, undertook an exercise to retime traffic signals, to convert several one-way streets to two-way streets, and to make significant changes to the land use in the downtown area. Those changes were expected to have a significant impact on the quality of service of the downtown street network. After an urban street network undergoes modifications of its control system or geometric configuration as in Fort Worth, there is a need to have quantifiable tools to perform before-and-after studies on network quality of service. The purpose of this study was to use the two-fluid model to compare network performance over time and after a recent major modification. In 1983 and 1994, the two-fluid model was calibrated for the Dallas and Arlington, Texas, networks. The model was then recalibrated for the two networks with data collected in 2003; this allowed comparisons of the quality of traffic service in these networks over a long time. To assess the changes in Fort Worth, a new model was calibrated with data collected in 2004 and was then compared with the previous model calibrated in 1999. This comparison helped determine the success of signal retiming strategies as well as modifications in street geometry and land use. As expected, changes occurred in the system over time, but those changes, both positive and negative, differed, depending on the city.