When drivers use the eight day, 70-hour cycle, they must do a 34-hour reset after their hours are exhausted, unless they they prefer to recap hours of service.
Recapping hours of service allows drivers to run day-after-day without a 34-hour reset.
How recapping hours of service works
Drivers can drive no more than 70 hours per any eight day window. Hours are calculated per the window at the end of each day and the hours worked eight days ago drop out of the window. So, if a driver has been on duty for 68 hours during their eight-day window, and seven hours drop off at the end of their eighth day, they now have nine hours available per the current eight day window.