Originally posted by Coookyman: There are 2 ways to make one route the fastest:
a) make it shorter or faster.
b) or you could make the alternative through route (probably that's useing trucks on your streets) more unattractive. e.g. by lowering speed limits.
^ This. The easiest to do is definitely a) where you just make more direct or faster routes, but changing speed limits on roads can also help (when there aren't a lot of other faster routes than the one you want them to use).