Modeling Impacts of ITS Deployment on a Congested Corridor: Seattle Case Study

In an ITS alternatives analysis based on forecasts of travel demand in the 2020 time frame for the I-5 corridor north of downtown Seattle, researchers at Mitretek Systems modeled and quantified the impact of ITS technologies over a range of weather, incident and demand conditions. The primary ITS components modeled included incident management (IMS), adaptive and coordinated signal control (ATMS), and advanced traveler information systems (ATIS). These advanced, adaptive systems allow for quick reaction to events like incidents or surges in demand that an average-condition based analysis could not capture.

Therefore, the goal of the simulation effort in this study was to examine the effectiveness of these ITS systems deployed in combination over a realistic range of variation expected in both roadway supply (incidents or weather effects) and travel demand. The hypothesis of this effort was that when compared with a non-ITS alternative, the ITS alternative would be most effective under conditions which were far from the expected normal or average case (Figure 1). The results obtained through the first phase of analysis support our hypothesis for a range of measures of effectiveness (travel time, percent delay reduction, absolute delay reduction, and total system throughput).