Hate to be embarrassed at border

Inevitably whichever lane is open will be out of alignment for a sraight shot and will appear too narrow!
It seems that the people in charge of design have never tried to maneuver a Motor Coach or Truck and Trailer through their handiwork. They build them as close together as possible with lanes only wide enough to allow the legal width through.
I think it is so the Border Inspector doesn't have to reach out the window too far to grasp Your Passport.(Ergonomics) and scan it in one motion. While making Eye contact with the Driver and Front seat passenger.
It's not as though there is a shortage of Real Estate and every inch counts !

Tubaronnie wrote:
Heading back into Canada-1st time with motorhome. Entry/exit @Port Huron/Sarnia. What lanes do motorhomes use coming/going?.............

Sarnia? - you will use the regular car lanes for sure. That's the left lane as you head over the bridge towards the booths.
The middle lane is for Nexus/Fastpass holders and the right lane is for trucks.
Watch for the red/green light over each booth to see the ones that are open.
Go slow and use the lane width guides as you will be quite wide, especially the mirrors.
BTDT :)
Good luck

Every crossing I've seen (about a dozen of them) there are signs which CLEARLY indicate which lanes are for which type of vehicle. SOME have only one lane or several which make no distinction while some have overhead clearance issues where tall vehicles must use prescribed lanes.
Good luck / Skip

You would use the same lanes as the cars.