LIGHT RAIL TRANSIT GRADE SEPARATION GUIDELINES

This report discusses work that has been done, and draws conclusions that can be used as guidelines for light rail planning and design. Four general situations are identified and discussed: light rail can usually be operated at-grade with full preemption; full preemption might or might not operate satisfactorily and where site-specific conditions must be taken into account; light rail might be operable only with conditional preemption, signal progression, LRT-only actuated phases, or other solutions involving LRT delays; and LRT at-grade operation is likely to be infeasible under any conditions. It is shown that the decision on whether to grade separate is one that must be made on a site-specific, crossing-by-crossing basis, and general threshold ADT (average daily cross-street traffic) values should be used only as initial guidelines for determining surface operational feasibility