If I take 8 hours off in Canada (the required rest period in that country), can I drive in the United States?

Once you enter the United States, you must meet the U.S. DOT's federal regulations. Although you may be legal to drive in Canada, once you get to the border you must spend at least 2 hours in the sleeper berth (if using the split sleeper option) or take 10 hours off if you do not meet the U.S. regulations.