Thinking about buying a radar detector for your car? Well, there are a bunch of things you need to know. Larry Kosilla of put together a comprehensive video covering any and all possible questions you may have about how speed-measuring radars and lasers work, as well as how to counter them with equipment (like detectors) you can install yourself. He also covers the legality of these devices for whichever state your in.
Shown above, a Passport-branded radar detector from 1986.
Since speed radars use wavelengths regulated by the FCC, and therefore, detectors are legal in every US state, save for Virginia and Washington D.C. Detectors are also illegal to use on military bases, federal parks, and vehicles over 18,000 pounds. So if you regularly drive in these regions (or are planning a trip through them), make sure to unplug your detector so you don't get into trouble. Kosilla also mentions Windshield laws for California and Minnesota that forbid anything from being mounted to the glass. So if you want to run a detector in those states, it'd be best to get it hardwired into your car (as Kosilla does with his Audi R8 in the video below).
Speed-detecting lasers are a little different. Instead of using a wide range of waves like a radar, lasers use a more focused wave that's pointed directly at a car, using a reflective bounce signal to read speed. Most new radar detectors will give you an alert if you're hit with a laser, but by the time you get the message, it's already too late. Devices called laser "shifters" can be installed into the grille of your car (as Kosilla does here) that overexpose the laser signal so it can't bounce back to the sender. These devices are legal on the federal level, but are prohibited on the state level in Colorado, Illinois, Minnesota, Nebraska, Oklahoma, South Carolina, Tennessee, Texas, Utah, Virginia, and Washington D.C.
If you want to know all there is to know about radar and laser detectors, as well as how hardwired detector systems are installed into cars, check out Kosilla's full video below.