I'd be really curious how this works, if it ever works. I was on the east coast last week with a 13'9" trailer so I was a bit nervous. But it's not just about clearance. Regular nav took me through cities on streets that more than likely took longer than truck routes would have taken. Not sure if towing nav would fix that or not though. Honestly I hate nav in the first place, it's just become a necessary evil in my opinion. I really like when it tells you to turn the wrong way on a one way street. That's impressive.