In this FHWA study, one of the alternative methods for rating the design consistency is
alignment indices (see chapter 3). Alignment indices are quantitative measures of the general
character of a roadway segment’s alignment. Problems with geometric inconsistencies arise
when the general character of alignment changes between segments of roadway. A common
example is where the terrain transitions from level to rolling or mountainous, and the alignment
correspondingly changes from gentle to more severe. Proposed indicators of increasing
geometric inconsistency are a large increase in the magnitude of alignment indices for successive
roadway segments or a high rate of change in alignment indices over some length of roadway