Passive Vs. Active Car Alarmby Neal Litherland; Updated September 29, 2017
It only makes sense that people would want to protect their cars from break-ins and theft by installing car alarms. Whether that alarm is a passive alarm or an active alarm is usually up to the owner, and it's a decision that should be carefully researched.
A passive car alarm is one that turns on automatically. Once the ignition is shut off and all of the doors are closed, a passive car alarm sets itself. The alarm is called a passive alarm because the driver doesn't have to do anything to arm it.
An active car alarm is one that the driver has to activate. That is usually done by clicking a remote to set the alarm once all of the doors and closed and the car is parked. Most active alarms also lock the doors at the same time that they're set. They're called an active alarm because the driver has an active role in setting the alarm.
A car alarm system can often switch between being passive and active. The owner can toggle the system back and forth, or he can call a professional to change it from one to the other. It's entirely up to the owner which option he prefers to protect his vehicle.
Protection VS Convenience
A passive car alarm is the most convenient because it's completely automatic. That means that a passive car alarm provides the best protection, even if it is inconvenient to have to disarm it just because the driver forgot something in the trunk and opened the car without disarming the alarm.
An active car alarm has the advantage of letting the driver set it when she's ready to. That means that she could unload the car and go back around it, opening all the doors as she went. Unfortunately, active car alarms can be easily forgotton, and if it isn't set then it won't protect the car.
Because most car alarm systems can be toggled between active and passive alarms, one doesn't cost more than the other. However, using a passive alarm may result in lower car-insurance premiums. A car with no alarm will have still higher insurance premiums because it has no theft deterrence to it. In that way, a car alarm may recoup its cost several times over with insurance-premium savings, even if no one ever tries to steal the car.