The IRS vehicle mileage rate for 2018 is 54.5 cents per mile. If a driver averages 20 miles per hour, then their effective hourly rate is cut in half from depreciation/fuel/maintenance/etc.
That is true, and the company doesn't have to reimburse you for that. They can leave that to you to factor in your yearly taxes, effectively putting the burden on you to track and submit all of that.
