"Rigorously explore" defined.

The National Environmental Policy Act requires that agencies “rigorously explore” transportation alternatives if projects are to be granted federal funding. Definitions of “explore” include to “investigate systematically,” to “explore every possibility” and to “search for the purpose of discovery.” In short, to “explore” is a far more active word than the more passive words and phrases of "examine," "check out," "verify," or "analyze."

When the NEPA language then adds the adverb “rigorously,” defined as, "extremely strict," or "austere," to “explore” it further strengthens the degree of effort that must be made in exploring alternatives.

Thus, the NEPA requirement that agencies “rigorously explore alternatives” mandates that the City and Federal Defendants in our lawsuit should have searched and probed into every possibility of alternatives to rail. Moreover, Section 4(f) mandates that the City and the FTA were required to approve any alternative to the rail project that could have avoided rail's impacts on historic resources (including Native Hawaiian burials).