Vehicle is on Property You Do Not Own
Call the police. Call your state department of motor vehicles. Call your county highway department. If they won't tow the vehicle, get as much advice from these sources as possible.
Contact a nationwide vehicle removal service (see "References" for two examples). See if they will remove the vehicle.
Search online for "abandoned vehicles" or "vehicle removal service" along with your zip code. Contact state or local agencies that will remove the vehicle.
If the Vehicle is on Your Property and You Want to Take Possession
Research abandoned vehicle laws on your state's Department of Motor Vehicles website. If allowed by your state, obtain the vehicle identification number (under the driver's side of the front windshield) and license plate number (if any). Take that information to your Department of Motor Vehicles and inquire about your rights. Obtain the owner's contact information, if allowed.
Mail a certified letter with your DMV form to the owner (states like Virginia and Alaska allow this). Wait to see if the owner will claim the vehicle. If they do not claim the vehicle within the stipulated period of time, states like Virginia require you to post your intention to auction the vehicle on the DMV website for a stipulated period of time before taking possession of it (see References). Other states like Alaska make it simpler. Their DMV form #825 allows you to simply take possession of the vehicle if you haven't heard back from the owner in 30 days (see http://doa.alaska.gov/dmv/forms/pdfs/825.pdf).
After you have the vehicle's title, contact a locksmith and have keys made for the vehicle. Move the vehicle, fix it, sell it, scrap it, or give it away.
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