It seems they have a priority for routing on interstates, then U.S. Highways etc.
regardless of other factors. And, they'll do this even if there is a shorter route that
may be 4 lane controlled access - even if its not controlled access (U.S. 287
Ft. Worth to Amarillo comes to mind) if I can have a reasonable assurance I
can go at speed (4 lanes or at least passing lanes) and avoid major metros I'll do it
over the default routing
Having said that, I find the trip tic very useful for seeing whats in the
vicinity and down the road
(especially rest areas when traveling with the kids), exit numbers etc. Just tell
them the route you prefer and they'll route you that way......Greg