The general purpose of vehicle affidavits is to address changes in a vehicle's licensing or ownership status. The purpose of an affidavit in general is to make a statement of fact under oath before an individual whose authority is to administer oaths, such as a notary public.
The specific purpose for a vehicle affidavit varies from state to state. For example, Washington state Department of Licensing requires vehicle affidavits to replace a lost title, registration, license plate or tabs, as well as to release interest in a vehicle being sold. West Virginia Department of Licensing requires vehicle affidavits in situations in which an owner is transferring a vehicle without monetary consideration, such as gift transactions or trade-ins; or when the vehicle's owner is deceased and the vehicle is being transferred to an heir.