This from the IRS website. I think this is dispositive:
To use the standard mileage rate, you must own or lease the car and:
- You must not operate five or more cars at the same time, as in a fleet operation,
- You must not have claimed a depreciation deduction for the car using any method other than straight-line,
- You must not have claimed a Section 179 deduction on the car,
- You must not have claimed the special depreciation allowance on the car, and
- You must not have claimed actual expenses after 1997 for a car you lease.
