Minivan for Nanny / Babysitter

We are deciding between TurboTax and a CPA.  We hired a nanny / babysitter, have made our tax payments. (100% legit with her) 

My question: We bought a minivan for her to drive 100% of the time with our kids. What are our tax implications? She is the SOLE driver, we have our own cars. Can I write if off as an expense?