Subarea focusing is a means of reducing computational requirements of large transportation networks when only a small portion of theregion is affected by a project. Relatively unimportant links are eliminated from the network and distant zones are aggregated, whereasfull detail is retained in the area of greatest impact. Errors in forecasts that can occur through reductions in numbers of zones--the principal means of saving computer time and memory--are examined. Onthe basis of results from the highway network for wausau, wisconsin, general procedures and relationships are developed for determiningthe amount of error that can occur from subarea focusing. This paper appears in transportation research record no. 1285, Transportation forecasting 1990.
Abstract