One thing you can be sure of; the GPS will send you in to the center of most towns if you travel the 2 lanes. We had a NUVI 765T and even when set to truck mode it would send us places we should not have been. The best example was when we were looking at real estate around Branson. We were in the toad thankfully with the GPS still set in truck mode and wanted to how far away we were and how long it would take to get to the hospital from a potential purchase. Our wonderful Garmin sent us past every theater in downtown Branson and it took us 45 minutes. Before leaving the hospital I went to a high spot in the parking lot and saw a couple of known landmarks. It took us 10 minutes to get back to the piece of real estate we were looking at. This is only one of many examples I could give you. Use a map. They are more accurate. We now use our GPS only to find specific addresses in towns we do not know.
And to those of you that will say I need to switch the parameters. It does not matter that much and the choices are extremely limited. The only restrictions that seemed to have any effect were; no dirt roads and no u-turns.
Randy
p.s.
I just remembered another glaring example of a GPS's programming. We were in Mitchell, SD with my MIL, she was 90 at the time, and needed to get her to the emergency room. Our GPS sent us around the outskirts of town and then brought us back in to the hospital. Travel time was just over 15 minutes. When we were finished I used street signs for navigation and we were 6 blocks from where she tripped not the 40 or so that the Garmin decided was the best route.