Unexpected delays due to traffic incidents represent a significant proportion of overall delay, especially in urban areas. The resulting uncertainty can represent major costs to businesses and travelers, as well as restrict employment opportunities. This study focuses on North Carolina's Interstate facilities and businesses across the State that rely on these facilities for their daily operations and are influenced by traffic congestion due to their shipping needs. The first portion of the study examines the occurrences and costs of unexpected delay for North Carolina businesses, using telephone and face-to-face interviews.

Results show that delays due to incident-induced congestion impose significant costs, which may increase over time as expected congestion and the number of incidents on the North Carolina interstates continue to grow. These costs are most severe in the Manufacturing industrial sector and in the Charlotte metropolitan area. Additionally, numerous firms commented on the need for better communication between NCDOT and the business community. The second portion of the study is devoted to developing case studies to simulate the impact of strategies to reduce incident congestion costs in North Carolina. Results show that incident management assistance patrols and advanced traveler information systems can significantly reduce unexpected delays and associated costs. The implications of the findings for economic growth are discussed.