Per the regs:

“Rest period means a continuous period determined prospectively during which the flightcrew member is free from all restraint by the certificate holder, including freedom from present responsibility for work should the occasion arise.”

The carrier is not restraining a crewmember during a commute since it is not scheduled by the carrier.

Question and answer 74 here also provide additional clarification.
http://www3.alpa.org/portals/alpa/committees/ftdt/FTDTGuidePart117_May2015.pdf#page25