The brain trust at Panther believes passports are required to travel between the U.S. and Canada by land. Several years ago they decreed that all drivers doing Canadian loads must have a passport. I was told to fax a copy of my passport to Panther. I declined. I wasn't about to fax my passport to Moronville, especially since it wasn't necessary. Instead I e-mailed my passport ID number and a brief explanation of why I wasn't sending a copy of my passport. I haven't been to Canada since. Haven't been to Moronville either, ever!
If you are leasing on with Panther you will need passports. Other carriers, I don't know. Definitely get a FAST card. Even when not on a FAST load I believe they can speed up the crossing process.
As for the TWIT card, I don't have one. I was held up for a short time at a gate into the Port of Panama City because I had no TWIT card. Eventually they let me in. That was the only time I was asked for one.
A FAST card, TWIT card and Hazmat endorsement all require a separate background check and separate fees. It would certainly be nice if all could be rolled into one RBGFA (Red Blooded God Fearing American) card issued by our good friends at the U.S. Department of Homeland Security.
End of rant.