The individual Combat Commands for each armored division would drive as far and deep as they could each day until they could advance no more (and a good day was 15 miles), often to the point of being entirely cut off from support.
Bypassed German resistance (who now had very tenuous supply lines) were left for the following infantry and artillery.
Cooper's job was to drive between the Combat Command and the tank repair depot reporting the number and location of damaged tanks so they could be recovered, and occasionally lead formations of fresh armor up to the CC.