Yes, as an agent under a power of attorney, you probably have the authority to sign titles to the grantor's vehicles.  You have the authority if the power of attorney gives you authority over vehicles or personal property or the like.A durable power of attorney is one that continues with authority if the principal (the grantor) becomes incapacitated.  Of course, it does not continue if the principal dies.  A non-durable power of attorney ceases to provide authority if the principal becomes incapacitated.