Above the daily limits sit two weekly ones, and § 395.3(b) makes which applies a fact about your employer rather than a choice you make. A driver may not drive after having been on duty 60 hours in any period of 7 consecutive days if the employing motor carrier does not operate commercial motor vehicles every day of the week — or 70 hours in any period of 8 consecutive days if it does. A driver moving between carriers can therefore move between limits without anything about their own work changing.

Note what is being counted. These are ON-DUTY totals, not driving totals, so every hour § 7.1 swept into on-duty time — waiting to be dispatched, inspecting, loading, attending a disabled vehicle — consumes the weekly allowance exactly as driving does. A week of short trips with long waits can exhaust 60 or 70 hours while leaving the 11-hour daily budget barely touched. The phrase “any period of 7 consecutive days” also means the window is rolling: it is not a calendar week that resets on a particular day, but any seven or eight consecutive days ending now.

§ 395.3(c) provides the way out. Any period of 7 consecutive days, and any period of 8 consecutive days, may end with the beginning of an off-duty period of 34 or more consecutive hours. Read the words carefully: the off-duty period ENDS the period rather than erasing hours from it. Once it begins, the 7- or 8-day period is over and a new one starts, which is why drivers speak of restarting the clock. Thirty-four hours is the minimum and the hours must be consecutive and off duty — a rest broken by an hour of paperwork is not a restart.