CMV drivers cannot drive after working more than 14 hours (since their last 10 consecutive hours off-duty) or 11 hours (if they did not rest for at least 10 consecutive hours). These cumulative hours are calculated from the time drivers begin working or driving (on-duty time), including off-duty time spent in the sleeper berth.
Drivers must keep a record of their on-duty and off-duty time and have it available for inspection by law enforcement officers. Failing to comply with the FMCSA's hours of service regulations can lead to fines, penalties, and even disqualification from operating a CMV.