11.3.8 Cost-Benefit Analysis

Another method of alternative analysis for interchanges is a cost-benefit analysis. This is typically done for all interchange analysis that demand analyzing multiple interchanges to select the preferred alternative. All costs associated with an interchange are accounted for and compared when performing a cost-benefit analysis:
  • OPCC Perform rough order of magnitude costs;
  • Review similar completed projects for an approximation;
  • Include costs for ROW acquisition, utility relocations, and environmental impacts due to construction;
  • Life Cycle Cost;
  • Compares interchange control costs, including construction, maintenance, and operational costs;
  • NCHRP’s Life-Cycle Cost Estimation Tool (see
    Appendix L, Section 4
    );
  • For cost parameters, use TxDOT’s Road User Costs and the NSC’s average economic costs per injury severity; and
  • For crash prediction estimates use FHWA’s Interchange Comparison Safety Tool, User Guide, 2023. This tool implements the crash prediction models for diamond, compressed diamond, roundabout diamond, diverging diamond, single-point diamond, tight diamond, and partial cloverleaf (parclo) interchanges (see
    Appendix L, Section 4
    ).
Weigh each cost in relation to its importance to the overall project purpose when comparing alternatives. Collect additional data if needed.