Either:

A: compensate them equally and let Bob leave 20 minutes earlier and arrive 20 minutes later

B: compensate them equally for to traveled, meaning Bob would be compensated for 35 minutes and Alice 10.

C: pass through the tax deduction that I would get if it were company vehicle (xyz a mile) to the employee directly

If they’re putting their time and their equipment to show up for my business they should be compensated. Period.