The Commute Route control allows you to specific whether an individual commuted to either All locations, or to their Work start only.
You would select Work start only for example, when the individual drives to a lockup and then commutes in a production vehicle from that point.
For individuals driving their own vehicles or commuting to all shoot locations, you would select All locations.
This is important, as it determines whether all the locations specified for a day or period are to be factored into calculating that individual's commute.