How can our daughter (our dependent) claim mileage expenses for a self-employment job if we are the owners of the car?

[morettina]

We have also used the same vehicle for self-employment so we also claim it on our own Schedule C.

[AlanT · Accepted solution]

If your daughter is not the owner, she cannot claim the mileage deduction, however, she can claim her actual expenses such as gas and her portion of the maintenance.  

[morettina]

This car is used by all 3 of us not only for our self-employment activities but for all our personal activities too. How do you determine what part of your gas & other expenses goes for your self-employment activity? For my husband & I, we use the standard mileage deduction since we track those miles. According to things we've read, if your spouse is the owner but allows you to use the car for self-employment mileage, you can claim it. Why would she be any different?