If you do leave packages, clothing, or other articles in the car, make sure they're out of sight or covered. Park in well-lighted and busy areas. Avoid leaving your vehicle in unattended parking lots for long periods of time. If you park in a lot where you must leave the key, leave the ignition key only. When buying a car, ask about anti-theft options such as steering column locks, alarms, switches that interrupt the fuel or electronic systems, and locks for tape decks, batteries, and gas tanks.
Many insurance companies offer reduced rates to owners who install security devices.
Since 1969, the federal government has required manufacturers to engrave a unique number, the VIN, on all passenger cars in one visible and several hidden locations. One VIN is engraved on a metal plate on the dashboard near the windshield. Park it out of sight in a garage or basement or use a cover. Mark it with an operation identification number recommended by local law enforcement. Lock your bicycle with a case-hardened chain or cable and lock, winding cable through the frame and both wheels and then around a fixed object.