I'm building a rather large metropolis, I'v tried to use outer loop freeways at least 6 or 7 times only to find that sims will not use them unless there is no other way. I'm using the lessons from the previous cities to bulid my current metropolis. Instead if using a large city map as the central city, I'm using it only as the downtown area, and running the outer loop around the outermost maps of the region. There are no roads or avenues with exits off the freeway that go into the city. All roadways that have exits either go out farther into suburbia away from the loop or go into neighboring maps on either side (away from the city center). As long as the roads with exits do not intersect with roads that lead into the city ( I use overpasses) sims seem to take the loop.
