Mileage reimbursemnt doesn't take into consideration your auto make,model, or event he current price of gas. Mostplaces use the federal standard which is enough to supposedly include wear and tear.
A company i used to work for didn't want to pay for airline tickets for me to go to NYC for them so I drove and got $180 for mileage. A plane ticket back then was $59. I don't remember what gas cost then but my S15 got 36mpg roundtrip both times I had to go.