The second option is to claim deductions for vehicle expenses while performing qualified activities. To claim the standard mileage deduction, you must maintain a log of your qualifying miles.

Distance — enter the total distance in miles you traveled. If your report is for mileage from multiple days, attach a mileage log to your expense report as supporting documentation.

Instead, mileage can be claimed on line 9 for car and truck expenses ... If you're audited, the IRS will want to see a log that includes dates, destinations and the reasons for travel.

The IRS allows taxpayers to claim deductions for the use of a vehicle. The standard mileage deduction requires you to log odometer readings from the beginning and end of a qualifying trip ...