Assignments must be made considering logical routings,
available roadway capacities, left turns at critical intersections
and projected (and perceived) minimum travel times. In addition, multiple
paths should often be assigned between origins and destinations to
achieve realistic estimates rather than assigning all of the trips
to the route with the shortest travel time. The assignments must be
carried through the external site access points and in large projects
(those producing 500 or more additional peak direction trips to or
from the site during the development's peak hour) through the internal
roadways. When the site has more than one access driveway, logical
routing and possibly multiple paths should be used to obtain realistic
driveway volumes. The assignment should reflect conditions at the
time of the analysis. Assignments can be accomplished either manually
or with applicable computer models.