Studies of rural transportation impacts have been carried out over the last 20 years, with emphasis on the methodology and underlying models of causal relationships. The historical sequence of rural impact methodologies and the research on rural mobility and migrationcarried out in several countries during the last 10 years are examined. Particular emphasis is placed on the kenya rural access road program research, southeast asian research for seatac, and the mexico mobility study. Present impact methodologies focus too narrowly on agricultural effects, despite early observations of wide-ranging impacts. They also fail to predict the significant increases in nonfarm traffic and related economic benefits that are signaled by the relatively high value placed on travel time demonstrated in the behavior of many rural travelers. This value reflects the importance of nonfarm employment and the benefits of increased mobility and service accessibility, which are crucial to adequate impact evaluation. A causal model of impacts is described, which defines the relationships between access change and rural socioeconomic development, including the role of intervening variables. Conclusions are drawn concerning the types of models that appear most promising for future impact analysis. This paper appears in transportation research record no. 1274, Transportation and economic development 1990: proceedings of a conference, williamsburg, virginia, november 5-8, 1989.
Abstract