If the car in question is on private property (i.e. apartment complex, church parking lot, Wal-Mart parking lot), the matter is one for Code Enforcement. (343-4141)
If the car in question is on municipal property (city park, baseball field, street, blocking a mailbox or handicapped access area) or causing a public safety problem, APD is the department to take care of it.
APD has a Junk Vehicle Hotline (786-8830) which is answered during the day. It rolls to voice-mail when no personnel are in the Impound office.
Depending on whether the car is determined to be a Safe Keep Vehicle (salvageable) or a Junk Vehicle (junky car!), it is tagged for impound or junked. CSO's (APD's Community Service Officers) tag the vehicles. Some cars are allowed 72 hours before they are towed. Others are towed immediately (if they are impeding snow plowing or if it's obvious the vehicle has been in that location for a long time.)