If you use your car for business, or your business owns its own vehicle, you can deduct some of the costs of keeping it on the road. Mastering the rules of car expense deductions can be tricky, but well worth your while.

There are two methods of claiming expenses:

Actual expense method

You keep track of and deduct all of your actual business-related expenses.

Standard mileage rate method

You deduct a certain amount (the standard mileage rate) for each mile driven, plus all business-related tolls and parking fees. In 2014, the standard mileage rate is 56.0 cents per business mile driven.

As a rule, if you use a newer car primarily for business, the actual expense method provides a larger deduction at tax time. If you use the actual expense method, you can also deduct depreciation on the vehicle. To qualify for the standard mileage rate, you must use it the first year you use a car for your business activity. Moreover, you can't use the standard mileage rate if you have claimed accelerated depreciation deductions in prior years, or have taken a Section 179 deduction for the vehicle.

If your auto is used for both business and pleasure, only the business portion produces a tax deduction. That means you must keep track of how often you use the vehicle for business and add it all up at the end of the year. Certainly, if you own just one car or truck, no IRS auditor will let you get away with claiming that 100% of its use is related to your business.