Since the 1973 oil crisis (as well as the mid-20th-century decline in transit service), jitneys have reappeared in some areas of the US, particularly in inner city areas once served by streetcars and private buses. An increase in bus fares usually leads to a significant rise in jitney usage. Liberalization of jitneys is often encouraged by libertarian urban economists, such as University of Chicago's Richard Epstein, Rutgers' James Dunn, and USC's Peter Gordon, as a more "market-friendly" alternative to public transportation.