The Washington Department of Transportation (WSDOT), under contract with the Social & Economic Sciences Research Center (SESRC) at Washington State University, conducted a study that designed and implemented a mixed-mode (telephone and Internet) survey of Washington State freight-dependent businesses and the trucking industry. This survey was used to determine the economic impact on the trucking industry of the I-5 and I-90 emergency closures that occurred during winter 2007-2008. This survey was also used to profile and quantify the economic impacts of road closures caused by natural interruptions. Three types of economic impacts were quantified:
Direct revenue losses incurred by the freight community.
Additional costs incurred during the closures.
Additional costs incurred after the closures.
This appendix details the methodology used to assess the economic impacts of the I-5 and I-90 winter storm closures during winter 2007-08.