In 1989, business travelers can deduct 25.5 cents per mile for the first 15,000 miles and 11 cents a mile for each additional mile for a vehicle that is not fully depreciated and 11 cents a mile for a full depreciated vehicle, according to the Internal Revenue Service.
This standard mileage rate cannot be used, however, if the vehicle is leased or used for hire, or if more than one vehicle is used in the business at one time. If the standard mileage rate is used, it must be chosen in the first year the car is placed in service.As an alternative, business travelers can deduct their actual expenses for the business use of a vehicle. In using either method, the business traveler also may deduct the business portion of parking fees and tolls.
More information on these subjects can be obtained from the IRS in Form 210, Publication 917 or Publication 463.