If you're looking for something else, perhaps you can clarify what kind of safety situation you're concerned about? For example, are you thinking about:
* Emergency situations: In a true emergency (like a fire), your best bet is to turn the key to "off" and get away from the vehicle.
* A specific problem with the car: Describe the issue, and I may be able to offer more specific advice.
* A particular accessory: Perhaps you're thinking of a switch for an accessory, like a power window or sunroof. These would have individual switches.
Provide more context and I'll do my best to help.