This Clever Radar Detector Is Like Siri for Dodging Cops

I’ve recently learned that mounting a radar detector in your car isn’t just about fooling the fuzz. Sure, use one and you’ll be better equipped to avoid any number of very expensive moving violation tickets. But if you use a detector that pairs with your smartphone like Cobra’s iRad 230, you get a host of fringe benefits too: crowdsourced speed trap warnings, live maps with traffic info, and a more refined experience overall. It’s like Siri for giving Smokey the slip.

To test iRad, I plotted a circuit north out of San Francisco and through Napa Valley, on roads known to be littered with radar detection equipment and red-light cameras. The $100 unit, a 5.5-ounce plastic box about the size of a pack of Marlboros, attaches to the windshield with a pair of bra-shaped suction cups. Be careful where you mount it — though most radar detectors are perfectly legal, you can be dinged for “obstructing vision.” A detachable power cord plugs into your 12V cigarette lighter port. There’s a handy pass-through USB port on the power cord so you can keep your phone juiced as well. This was vital, since most of the Cobra’s functions are controlled by the free smartphone app. There are iOS and Android versions of the iRadar app, and it works with almost any device that can pair to the unit via Bluetooth.

Ten minutes after hitting the highway, the Cobra sounded a warning, first from a rather friendly sounding female voice announcing “K band detected,” followed by some pulsating beeping sound effect. “Great,” I thought, “this thing works, but what the hell does K stand for?” I pulled off the highway to find out, since that’s the only intelligent (read: safe) way I can check the radar lingua franca and adjust the Cobra’s app settings on the phone.

Here’s what I learned. Most speed detectors work by sending out high frequency radio waves, then measuring the time it takes for the reflected waves to return to the device. These signals operate on various frequency bands, which for speed detection are X, K, and Ka. The oldest of these bands, X, is still in use by cops in Indiana, New Jersey, North Carolina, and Ohio. Elsewhere, it has been replaced by newer speed detection systems that stick to the K and Ka bands. The K band is used primarily by municipal police, and since the late 1990s, the Ka band has become a favorite of the highway patrol. If the troopers in your state use pulse laser guns to track speed, the iRad 230 can sniff those out, too.

The K band is crowded. It’s also the frequency on which many automatic door openers operate, leading to occasional false alarms if you’re driving past a 7-Eleven. To get around this, the Cobra, like most other radar detectors, has a Highway/City toggle. The City setting filters out the majority of false reads.

After getting back on the interstate, I spotted a CHP cruiser alongside bushes at the side of the road. By that point I had slowed down. I drove on, and every few miles the box squawked with another K alert. But there were no police in sight. Toggling the Cobra’s setting from Highway to City caused the K alerts to stop, but I’d still get the occasional Ka warning.

Within a block of leaving the interstate and hitting city streets, I got an alert for a “photo-enforced intersection.” In addition to an audible warning, an icon appeared on a map on the phone’s screen. The detector can’t discover these on its own, but it keeps constant tabs on my whereabouts via the phone’s GPS and matches my location with a list of known traps. The info is pulled from Cobra’s AURA Alerts database of verified, crowd-sourced location points for red light cameras, caution areas, known speed traps, and speed cameras. The company claims it has more than 10,000 pinpoints in its database. If you discover a new trap, you can share it, so the database is forever growing stronger and (presumably) more accurate.

Using the phone’s GPS, you’re also able to get route directions with live maps displayed in the Cobra app. You can toggle live traffic information to avoid upcoming congestion. The app also has a car finder function that saves the last known location of your vehicle when you disconnect from the radar detector. This proved handy when I forgot where I’d parked.

Because of all this functionality, you have to take some time to study and understand the layers of menus on the app before getting behind the wheel. Each setting has an info tool tip explaining its function, and once you choose all your settings, you’ll rarely need to return to the menus. Just don’t ever try to fiddle with the app when you’re driving.

One other bummer: The suction cups never really worked properly, so I ended up securing the unit to my dash using one of those sticky dashboard mats made for cellphones. This kept it in place and also solved any issues with breaking the law by placing the detector in the “wrong” place on the windshield.

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