A screenline is an imaginary line on a map, composed of one or more straight line segments. Screenline analysis provides a means of comparing the results of a traffic assignment with traffic count data. This is facilitated by comparing the directional (or bi-directional) sum of traffic count volumes across a screenline with the directional (or bi-directional) sum of the assigned traffic volumes across the same screenline and then computing the ratio of the sums, generally the assigned flow sum to the count sum.
TransCAD Transportation Planning Software provides the widest array of traffic assignment procedures that can be used for modeling urban traffic. These procedures include numerous variants that can be used for modeling intercity passenger and freight traffic.