Can I keep my vehicles if I file for bankruptcy?

Most of the time, yes.  If the vehicle is owned outright, the debtor may keep it as long as he is able to exempt it from the bankruptcy estate (learn more about exemptions here).  If the value of the vehicle is too high, there may be a problem with exempting it.  If the vehicle is being financed, the debtor can seek to reaffirm the debt in a chapter 7 and keep the vehicle, i.e., agree to continue making the monthly payments.

But what if the debtor is behind on the car payments?  Creditors will generally not allow a debtor to reaffirm a debt unless it is made current, requiring a lump-sum payment of the arrears.  In this case, the debtor may elect to file a chapter 13, and pay the arrears back over time.