Road Expansion, Urban Growth, and Induced Travel:A Path Analysis

Robert Cervero
2003 Journal of the American Planning Association  
Claims that roadway investments spur new travel, known as induced demand, and thus fail to relieve traffic congestion have thwarted road development in the United States. Past studies point to a significant induced demand effect. This research employs a path model to causally sort out the links between freeway investments and traffic increases, using data for 24 California freeway projects across 15 years. Traffic increases are explained in terms of both faster travel speeds and land use shifts
more » ... and land use shifts that occur in response to adding freeway lanes. While the path model confirms the presence of induced travel in both the short and longer run, estimated elasticities are lower than those of earlier studies. This research also reveals significant "induced growth" and "induced investment" effects-real estate development gravitates to improved freeways, .and traffic increases spawn road investments over time. Travel-forecasting models are needed that account for these dynamics. Cervero is a professor of city and regional planning at the University of California at Berkeley. His recent research has focused on informal transportation in the developing world, induced travel demand, valueadded impacts of rail transit, car-sharing evaluation, reverse commuting, and transitjoint development.
doi:10.1080/01944360308976303 fatcat:ehqjtsvp6zdclbitecozu37m4y