Using data from the state of Hawaii input-output (I-O) table, the economic impact of the transportation sector in Hawaii was described, modeled, and forecast under a number of alternative scenarios. Transportation is compared with the key economic sectors in the state in output, exports, household consumption, visitor spending, number of employees, and compensation of employees. Next, the overall transportation sector was disaggregated into key activities and functions to present a more complete picture of the important role of transportation in Hawaii. A computable general equilibrium (CGE) model of the economy with a special focus on transportation is developed. Because tourism is the state's leading sector, the effects of both an increase and a decrease in visitor expenditures were modeled. Both measuring the economic importance of transportation in Hawaii and estimating probable consequences of potential economic changes are of interest. The visitor industry dominates Hawaii's economy, with small increases in visitor expenditures contributing significantly to the gross state product. Transportation industries, along with restaurant and accommodation services, account for a disproportionately large share of this growth. Key residential transportation sectors (transit and motor vehicles) contract in response to cost increases generated by a growth in visitor demand. The use of the I-O table and CGE modeling provides a useful analytical and planning tool for evaluating economic scenarios within a region such as Hawaii. The increased availability of both data sets and new modeling techniques offers opportunities to planners, engineers, and transportation policy makers.