With the Collier–Burns Highway Act of 1947, California pioneered a new system of highway finance. In response to estimates of enormous highway needs in the postwar period, the state planned substantial increases in funding. The key debate was about who would pay what share. Legislators planned a significant increase in the motor fuel tax and a shift of more of the tax burden onto heavy vehicles, which inflicted most damage to roads. However, the proposal met with intense opposition from motorist groups, oil companies, and truckers. California eventually passed legislation that established the first-ever trust fund dedicating highway user tax revenue to roads, a law that was later copied widely, including by Congress in 1956, when the Interstate system was funded. The trucking industry in California defeated proposals to require it to shoulder more of the financial burden; this outcome too would be repeated elsewhere, including at the federal level. Finally, the inclusion of urban freeways eased the California legislation’s passage, and this provision also became a key element of the federal Interstate legislation. Thus, the legacy of Collier–Burns reaches well beyond California to influence transportation and public finance across the United States to the present day.