Development of the Next Generation Metro-Wide Simulation Models for the Twin Cities' Metropolitan Area: Mesoscopic Modeling

Project summary:

The collapse of the Interstate 35W Bridge over the Mississippi River in Minneapolis resulted in unexpected loss of life and had serious consequences on mobility and accessibility in the Twin Cities metropolitan area. In response to the network disruption caused by the bridge collapse, a number of traffic restoration projects were proposed and rapidly implemented by the Minnesota Department of Transportation (Mn/DOT). Selection and prioritization of these projects, however, was based mainly on engineering judgment and experience. Unfortunately, the only decision-support tool available to traffic engineers at the time was the static regional transportation planning model, better suited for expected or longer-term disruptions (on the order of five years or more).

In this project, the Twin Cities metropolitan area is simulated using a mesoscopic traffic simulator in the AIMSUN software. After establishing and calibrating the mesoscopic simulation model, researchers attempt to use it to evaluate drivers' perceived cost evolution to explain the traffic dynamics after the unexpected collapse of the 35W Bridge. Given the observation of largely underutilized sections of network, it is proposed that the tragedy generated a perceived travel cost to discourage commuters from using these sections. Applying the mesoscopic simulation model, the perceived costs on cordon lines after the 35W Bridge collapse were suggested to be best described as an exponential decay cost curve. This model is applicable to both practitioners and researchers in traffic-related fields by providing an understanding of how traffic dynamics will evolve after a long-term, unexpected network disruption.