How to compensate employees for mileage and drive time between jobs?

To be a 100$ honest, I feel like compensation on mileage just adds way to much extra work and time into math. I'd consider raising any employees pay rate, (depending on performance of course) and save yourself the trouble of doing all the extra. Better yet, allocate gas cards. If they're working for you, trust me when I say, they dont want to pay for gas while working for someone other than their own lifes commuting needs, not yours.