If you've been the victim of identity theft, violent crime or some other type of violation against you, gas station or convenience store surveillance tapes may provide you with some clues to help your case. If you're a member of the media investigating a crime, you may be granted access to video surveillance, but it may only happen once a case is closed and the police have released the video to the public. Since gas stations are typically private property, it's the prerogative of the owner whether or not they release the tapes to you. Whatever your reason for wanting the tapes, you won't know whether you can have them until you ask.
TL;DR (Too Long; Didn't Read)
The easiest way to get hold of the footage is to ask the gas station owner. If you're the victim of a crime, the police will request the surveillance tapes on your behalf.
Call the gas station and ask the manager whether you can have a copy of the surveillance tape. Businesses often tape over their tapes if they don't have any major incidents that require documentation, so if you've been the victim of a crime, be sure to ask them as soon as possible.
Contact Head Office
Contact the gas station's corporate office if you don't have any luck with the local manager. Gas stations are typically part of a chain, and they are often not allowed to release any information without the consent of their higher authorities. Ask the corporate office whether they have any special "request for information" forms you need to fill out to get the tapes. Sometimes corporate offices will release a copy of the tape for a small fee.
Involve the Police
Contact your local police department and get a "request for information" form. If you've been the victim of a crime, you should have already informed the police about the incident and provided them with a statement. If the police are investigating the crime, they will have requested the surveillance tapes from the gas station, and will likely be investigating them. Depending on the policy of the police force and their adherence to local privacy laws, they may provide you with a copy of the tape, or may allow you to view it in their office.