The goal of this work is to calculate the full costs of transportation for autos, trucks, and buses in the Twin Cities region for the years 1998 and 2020. Our midrange estimate is that the costs were $27 billion in 1998, and the costs will grow to $42 billion in 2020 ($9,000 and $11,200 in per capita terms, respectively). These estimates include monetary and nonmonetary costs to individuals, firms, and units of government. Costs are divided into three main categories: governmental costs, internal costs, and external costs. Our midrange estimates were that 84 percent of full costs were internal, 9 percent were governmental, and 7 percent were external. Road construction and maintenance accounted for approximately 70 percent of governmental costs. Most time costs were nonmonetary and internal. The costs of travel time accounted for 40 percent of all costs and the costs of owning and operating vehicles also accounted for 40 percent. Approximately 98 percent of external costs were due to congestion, crashes, air pollution, and petroleum consumption. We project that most types of costs will increase at approximately the same rate as regional economic output between 1998 and 2020.