Even if your vehicle isn’t on the list for the most stolen make or model, you will still want to ensure that no one can get in it. Thus avoiding having personal information, loose change or anything of value stolen. Moreover, you can avoid the invasion of your personal space. Keep in mind that it isn’t just car thieves using this technique but others making a living of rummaging through many vehicles. 

First and foremost, installing a sensor light to illuminate the vehicle is the best deterrent and cost effective. As well, you would like to place the sensor light in the optimal position. Most thieves that would use the relay device will try to access through the drivers side. With that in mind, it is best to shine the light there or at the front of the vehicle. This will avoid it constantly lighting up for a simply passerby. Moreover, a noticeable camera combine with a sensor light would hopefully scare them off, completely!

Otherwise, a faraday bag will work, well! This is a bag that you would put your keys into when you are at home. Although, they range in price with the more pricey ones being more effective. More to the point, using a faraday bag and keeping the keys in the bag away from the perimeter of the home, works best!

Although, in a pinch a metal box with an overlapping metal lid will also help muffle your car key signals.