I think laws regarding interstating are outdated
When we have drivers cross into UK from Europe they can pickup 2 loads of domestic UK freight before having to take a load outbound from the UK destined for Europe
The laws surrounding cabotage (interstating as you called it) are not outdated. They are a political football, and they are extremely one-sided.
It is completely illegal for a Canadian carrier to take a load from Toronto to Philadelphia, unload, then move to Wilmington to pick up a load to go back to Toronto. The illegal part is moving the empty from Philly to Wilmington.
However, there has been a U.S. Customs directive not to enforce this part of the rules.
On the other hand, it is completely legal for a U.S. carrier to pick up a load in Miami and deliver it to Halifax, then deadhead to Montreal to pick up a load and deliver it to Vancouver, then pick up a load in Vancouver and deliver it to Los Angeles. U.S. carriers are allowed to reposition empty in Canada, then they are allowed one loaded repositioning move within Canada, provided the carrier reloads at destination back to the U.S. (or Mexico).
To illustrate further, a U.S. carrier can pick up a load in Bangor, ME and deliver it to St. Johns, NB, deadhead to Moncton, NB, pick up a load and deliver it to Vancouver, BC. In Vancouver BC the carrier can pick up a load and deliver it to Seattle, WA where he unloads, then reloads to go back to Vancouver, BC, reload again and go back to Moncton, NB, and on, and on, and on.
If you want my personal opinion on the cabotage rules, that is a story for another day, and will take a lot more time than I have today
