Preferential Flow. In Fig. 2.46, one roadway in each design is labeled “preferential
flow.” This indicates the more important of the two approaching traffic flows. In
selecting the preferential flow, a designer must consider the effect of traffic volumes,
number of lanes, the continuity and importance of signed routes, vehicle speeds, and
roadway alignment. Lanes carrying the preferential flow are given the higher design
treatment. When it is necessary to reduce a number of converging lanes or where an
angular change in direction must occur, the design should favor the preferential flow.