A review is made of the criteria and economic methods applicable to justification of grade separations on rural freeways. The argument is that only existing traffic should be considered and that reorganization of travel occurs after freeway construction. This reduces the travel benefits of proposed grade separations. Results for example situations are presented and an empirical population density warrant is given for justification of grade separations on minor local roads in terms of the interest rate, construction costs, road network configurations and the period for reorganization of travel. The results indicate that few grade separations on minor local rural roads are justified. It is suggested that transfer payments in lieu of construction of unwarranted grade separations would improve the efficiency of highway expenditures. /author/.
Samenvatting