2. Develop and Evaluate Multiple Alternatives
If it appears that meeting design criteria may not be feasible at a particular location, multiple alternatives should be developed, evaluated, and compared, including the alternative that meets full criteria. As discussed in Chapter 1, good design involves making tradeoffs and achieving a balance between cost, safety, mobility, and impacts. Examining multiple alternatives provides a way to understand and evaluate these tradeoffs.
From the standpoint of risk management and minimizing tort liability, evaluating multiple alternatives demonstrates the complex, discretionary choices involved in highway design.
Case Study 1 (presented in Chapter 5) illustrates how one State considered multiple combinations of lane and shoulder widths on an urban freeway reconstruction project with constrained cross-sectional width. This process allowed the design team to compare the various combinations, examine and weigh the tradeoffs, and come to a consensus on the combination that would best maintain a high level of substantive safety and efficient traffic movement while preserving resources important to the community.
