Effects of Highway Bypasses on Rural Communities and Small Urban Areas

This staff digest summarizes a study conducted as part of NCHRP Project 20-5, Synthesis of Information Related to Highway Problems, on the impacts of highway bypasses on rural communities and urban areas of less than 50,000 population, and current practices in using this knowledge in the planning of bypass development. The study involved a survey questionnaire to all U.S. state and Canadian provincial departments of transportation and a review of published literature and agency supplied studies. The literature review determined that there is no clear consensus on study procedures and analysis methods that should be used in bypass impact studies. The studies reviewed suggested that, for the most part, bypasses seem to have favorable impact on rural communities and small urban areas but evidence in these studies is often weak. Interviews and surveys of residents and businesses indicate that bypasses increase development potential along the fringe areas served by the new route, and at the same time relieve congestion, safety hazards, and other undesirable conditions in the central areas from which traffic is diverted. In most cases, adverse effects on otherwise viable bypassed businesses appeared to be largely recouped by improved ambiance for patrons and residents in the community, although individual businesses may suffer when a new bypass is opened. Agencies report a variety of measures to avoid or mitigate the adverse impacts of a bypass. The research literature provides no particular guidance on whether such measures have significant effect on bypass impact.