All the money spent on antitheft devices doesn't help if drivers don't follow the basic precaution of locking doors, taking the key, and activating or installing any antitheft devices they have purchased.
There is no statistical evidence that alarms reduce auto theft. After so may false alarms, people just stop paying attention. Any serious antitheft device must do more than make noise. Cost: $50 and above.
A "kill" switch is a simple toggle device that shuts off the engine's ignition system. A risk is that they may be accidentally engaged by the driver, or if they are improperly installed, damage the electrical system of the car. Cost: $10 to $125.
Steering Wheel Locks
Steering wheel locks are visible from outside the car and prevent the wheel from being turned more than a few degrees.
Steering Column Collars
Collars prevent the steering column from being broken into in order to hot-wire the vehicle. Some are installed permanently and others must be installed manually each time the driver leaves the vehicle. Cost: $100 to $200, installed.
Similar to the circular steel "boots" used by police departments, these locks make the car nearly impossible to move. Cost: $80 to $200.
The vehicle identification number etched into the windows or other parts deters the sale to chop shops, etc. Cost: $20 to $100.
These are complete systems that may include all of the above mentioned items. A beeper can alert the owner when the system is tripped. These combinations are the most effective deterrents when combined with window etching. Cost: $300 and up.