A model was developed and tested for analysing the problem of determining the optimum spacing of interchanges and grade separations in an integrated system of urban freeway and arterial streets, and the interchanges between the two parts of the system. In determining the optimum spacing, of interchanges and grade separations, consideration was given to systemwide effects of these spacings on /1/ the use of each part of the street and freeway system, /2/ the number of lanes required on the freeway and streets to accommodate traffic, /3/ the cost of construction and right-of-way for the required facilities, and /4/ the costs to the users of system. One objective of the study was to determine the sensitivity of the optimum spacing of interchanges and grade separations to various values of the input parameters /time cost per hour, interest rate, amortization period, right-of-way cost per acre, level of service and volume levels/ used in the economic analysis.
Abstract