UC Davis Institute of Transportation Studies

The Rural Counties Task Force (RCTF) commissioned the Rural Induced Demand Study (RCTF report) to review evidence on the extent to which induced travel – the phenomenon whereby increasing roadway capacity increases vehicle miles traveled (VMT) – occurs in rural areas and to formulate recommendations for analyzing induced travel in environmental analyses for roadway expansion projects and regional plans. The authors evaluate the primary analyses, conclusions, and recommendations (including recommendations for the California Calculator – a web tool that is based on empirical evidence of the induced travel effect - that are presented in the literature review, induced VMT sensitivity analysis, and technical guidance sections of the RCTF report. The authors conclude that the RCTF report’s central argument – that induced travel rarely occurs in rural areas because it does not occur without preexisting congestion – is not supported by the evidence. The empirical research suggests that induced travel occurs in both urban and rural areas.The RCTF report’s sensitivity analysis and case studies fail to demonstrate a contrary result – that the magnitude of the induced travel effect is substantially lower in rural areas than what an elasticity-based tool based on the empirical research would estimate. The RCTF report’s recommendations for induced VMT analysis are similarly unsupported, including its proposed screening criteria and its recommended hybrid method for estimating induced VMT.  The recommendations for the California Calculator are similarly unsupported and/or unworkable.