Keep packages in your trunk and out of sight. Park your car in a well lit, heavily traveled area, and never leave the keys in your vehicle. If you choose to valet park be sure that the contents of your vehicle are secure and not assessible. For extra security, consider investing in a theft deterrent system for your car. Steering wheel immobilization devices can be purchased for a small price and often may be just enough to discourage a would-be thief.
More sophisticated systems can sound an alarm and even disable the vehicle if it is stolen.
Even if you don't feel your car is a likely target, don't tempt someone to steal it for its contents. Party Smart Holiday parties and get togethers will be starting soon as well. Having a designated driver is a good way to ensure that everyone enjoys holiday events. Be especially attentive to other drivers, and don't assume that they've been as conscientious as you have. And always remember to buckle up for safety.