The decision making process in transportation is often about making a choice between alternative solutions to a problem. To select the best alternative, the decision should be based on results from a careful study of the implications of the alternatives. This paper presents the results of a study comparing two alternative interchange designs- Diverging Diamond and Conventional Diamond Interchange. The two alternatives are studied for a range of volume scenarios using traffic micro simulation and the better performance in each scenario for Diverging Diamond Interchange in terms of delay, travel time, maximum queue length etc are reported. The comparison also consists of cost-effectiveness analysis of the two alternatives. The results from the analysis help in providing guidelines to the decision makers for selecting the best alternative in terms of performance and cost.