As I tow a caravan, I use a Navigon which has car/lorry settings. I can set the height /width although I only need width so I do not get poked down a narrow country lane. If I need to stop a few times I set the final postcode, then via all the other places we need to go in between. It seems to work alright, but you would have to read up on the Navigon site to see if it was suitable for your type of work. What I do like about it is the lane positionings on multilane roads as it gives me plenty of time to change instead of trying to cross at the last minute, with a long caravan on, not easy at times.