Can you deduct travel expense for side work?

Commuting costs are not deductible; however, if your home office is your principal place of work traveling to other sites where you do business may be deductible. When deducting automobile expenses (Schedule C, Line 9) you can either take the standard mileage deductions or you can calculate actual expenses and depreciation and multiply that by your business use percentage. Either way you need to keep accurate records of your business vehicle use. Parking fees and tolls are added to these figures before entering them on Line 9. Depending on your particular situation you may need to file a Form 4562.