I live close to the border Alberta Canada side and see 15 vehicles (3 transport trucks) going towards the border on my commute, no matter what time of day....every day. In that small 8 hour window I would estimate at the very least over 100 vehicles per day during the work week. Conservatively, over 500 vehicles per week, 2000 per month.
I know transport companies that this their sole purpose for business and it shows no sign of slowing down. A couple of years ago it used to be one transport truck per hour so the movement has gone up 3 fold in the past 2 years. Previously it was just pickup trucks, now I am seeing small SUV's and some cars thrown into the mix randomly. This is only the main border port from Alberta/Montana, I can't speak for all the other ports across the 49th parallel, but I imagine there will be similar reports in BC, Ontario but perhaps those might even be busier.
Very few transports coming from USA to Canada in the same fashion, if any in my region.