This document summarizes a study of the performance and safety of Interstates 89 and 189 in Chittenden County under existing conditions and in twenty years. This study was initiated through the FY 1996 Unified Planning Work Program (UPWP) of the Chittenden County Metropolitan Planning Organization (CCMPO). It responds to a 1994 Vermont State Legislature directive to the Vermont Agency of Transportation to study congestion and the effect of proposed interchanges on I-89 in Chittenden County.