Abstract
A method for determining when traffic flow should be grade separated would be an invaluable tool for the traffic engineer/planner. The results of this study facilitate choosing proposed grade separation improvements on the basis of an evaluation of the reduced delay benefits to the cost of a grade separation. This methodology can assist decision-makers in determining when grade separations are appropriate. The analysis is centered on the federal highway administration's transyt 7f model. An economic analysis that presents the benefit/cost methodology for ranking a grade separation project is included.This paper appears in transportation research record no. 1239, Geometric design and operational effects.