The U.S. Interstate Highway System is the backbone of American commerce and personal travel. Funded on a pay-as-you-go basis largely through federal excise taxes on motor fuel, today it accounts for 25% of total vehicle-miles traveled despite accounting for just 2.5% of total road network lane-miles. Yet, much of the Interstate system, construction of which began in the 1950s, is nearing the end of its functional life, along with the infrastructure of other surface transportation modes. Over the next two decades, trillions of dollars of investment will be needed to rehabilitate and in some cases rebuild this infrastructure, according to...