Are you a W2 employee or a 1099Misc independent contractor?
If you are on a W2 mileage is not deductible anymore. Deductions for job expenses have been suspended with the new tax act. See Deductions that have been suspended
https://ttlc.intuit.com/questions/4482873-which-federal-tax-deductions-have-been-suspended-by-tax-re...
