Three alternatives to replace an existing two-lane highway with a four-lane highway that will meet current design standards are proposed. The selected alternative will provide a more direct route between two towns that are 12.0 miles apart along the existing highway. With each alternative operating speeds are expected to be at or near the design speed of 60 miles per hour. Develop the scores for each alternative and recommend a preferred alternative for development. The following scoring method, developed by the transportation oversight board, is to be used below:

Question

The following information has been estimated for each alternative by the planning staff:





What will be an ideal response?

Answer 1

Use the approach given in Equation 13.9, in which the score for an alternative is the sum of the products of the weight for each evaluation criterion and the relative score or value for each criterion. First, the input values are to be used to calculate the relative scores, Vij. For example, to evaluate the performance measure for the criterion mobility, the travel time of each alternative must be calculated. For example, for alternative 1, the travel time is:





The relative scores, Vij, can then be calculated. For example, for the evaluation criterion mobility, the travel time of the shortest travel time alternative divided by travel time of alternative i must be determined for each alternative. The shortest travel time is for alternative 2, at 0.1633 hours. For alternative 1, the travel time is 0.1867 hr, and the relative score is 0.1633/0.1867 = 0.8750.



The scores for each alternative i can then be found by finding the products of the

weights (Kj) and relative scores (Vij) and then summing these products.



The recommended alternative is Alternative 1, with a score of 85.03, the highest score among the alternatives.