Impact of freeway-arterial interchange closures: an alternate route assessment using travel demand modeling for the state of Delaware

Kropat, Elisa
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University of Delaware
Although the National Highway System provides an efficient network to move people and goods across the country, disruptions in the system can quickly bring the flow to a halt. The freeway-arterial corridors of the highway system are crucial nodes allowing users to enter and exit yet are vulnerable to considerable disruptions in the flow of traffic due to the frequency of closely spaced grade separated roadways and high traffic volumes surrounding interchanges. By analyzing the closure of the interchanges and assessing the subsequent traffic conditions throughout the network using travel demand modeling software, it is possible to determine the effects, adverse or not, of major closures. Such an assessment is purposeful, ensuring the resiliency of the freeway by understanding the resulting congestion to relieving or preventing its occurrence. Through a detailed understanding of the effects, transportation authorizes may be better able to maintain an efficient flow of people and goods. This research analyzes the prevailing traffic conditions along the I-95 corridor in New Castle County, DE due to the closure of three separately analyzed freeway-arterial interchanges along I-95: SR 896, SR 1, and US 202. It examines the change in volume, change in speed, and change in volume to capacity ratio on the network from before to after conditions. Each interchange closure produced distinctive network traffic conditions. While SR 896 primarily induces local effects SR 1 and US 202 results in a wider expanse of effects along the I-95 corridor. Significant disruptions in the flow of the network were contained to a few major arterials particularly during morning and afternoon peak periods.