If I am not mistaken, any for the Garmin "Street Pilot" models have the auto/truck/bus feature. I know my old 2610 Street Pilot does as does my new 7200 Street Pilot.
Chuck
02 Travel Supreme, 2 street side slides
02 Jeep Liberty Toad
Only GPS system I've found that has bridge height is ALK's CoPilot. Garmin & Magellan both have unofficially put out when called that there is no plan to put in bridge heights. There's a lot of liability for a fairly small market (compared to car/truck). Add to that the problem when communities pave the road and raise the crown by 1-2 inches. So don't plan too close. I max at 12'6" but watch whenever I see anything less than 13". Concrete under the bridge shouldn't be as bad, but asphalt can be a crapshoot.
I have used truck for the last year with no problems until this week when it tried to send me on a 35 miles longer route. I guess it was a better way for a truck but not for a MH. It like any GPS unit I guess some common sence is required.
RV Jim