Radar Detector FAQ

A radar detector is merely a tool, its effectiveness governed by the driver's skill in using it. While it's true that these gadgets are plug 'n play, a driver armed with basic knowledge of the technology stands a significantly better chance of steering clear of speedtraps. Here's the minimum you'll need to know.

Why does my detector alert for no reason sometimes?

A. It's receiving a signal, but not police radar. A conventional radar detector frequently barks warnings in town although there's no police officer around. What's up with this?

Simple: The detector alerted to a signal generated by non-police radar. Most often these are the radar-controlled automatic door openers commonly used by commercial establishments.

These transmit on police-radar frequencies—X or K band—which, to the radar detector, are indistinguishable from the real thing.

On the open road, most false alarms—especially those on Ka band—are caused by radar detectors in passing cars. (If your high-end Escort or BEL is set up correctly, Spec Display will indicate whether the signal is a police radar or merely noise. We provide a detailed guide to our customers that explains how to use this invaluable feature.)

Get acquainted with how a detector reacts to these nuisance signals and you'll be better able to decide if—and when—to nail the brakes.

Will my detector protect me from moving radar?

A. Yes, but moving radar is far more versatile and lethal than a stationary radar trap, making it tougher to counter. Most of these radars are dual-antenna models, one in front the other in back, giving them 180-degree coverage. This feature also allows the radar to track same-direction vehicles in front of or behind the moving cruiser.

By far the most common encounter with moving radar is to meet an oncoming cruiser, pass it, and watch as the officer U-turns and whistles up behind you, light bar ablaze. No time to react; the show's already long over.

Watch the video on the right and see why the latest moving radar's exceptional versatility makes it tough to beat. You'll learn why, in the freeze frame shown at right, the radar can clock four of the five vehicles ahead of the cruiser:

• White oncoming car (fastest opposite-lane target)
• Dark mid-sized pickup (strongest opposite-lane target)
• Ford Bronco ahead of the cruiser (Same Lane Mode/front antenna)
• Distant car in Lane 2, ahead of the Bronco (Same Lane/Fastest Speed Mode)

Can I be clocked even if there are cars between me and the radar?

A. The short answer: yes. This is thanks to a feature called Fastest Speed. By using this the officer instructs the radar to display the speed of the fastest vehicle within range. But the radar's incapable of denoting which vehicle is producing that Fastest speed; it merely displays a number. It's up to the officer to identify the Fastest target.

For an experienced officer this is not difficult, at least when only a few vehicles present, but it still demands extra caution. Many can't be bothered, with predictable consequences.

For example, I watched a Wyoming Highway Patrol officer, on a nearly empty I-80, stop an innocent driver and hand him a ticket for going 96 mph in a 75 mph zone.

Unfortunately, he got it wrong. Using his rear antenna and apparently clueless to the extraordinary range of his Stalker DSR radar, he blithely assumed that the Fastest speed was the closest car behind him, oblivious to the fact that his radar had been tracking a different target half a mile behind that hapless soul.

On the highway, what causes my detector to alert briefly, at a low signal strength, when there's no cop around?

A. If it's an X- or K-band alert and if there's a commercial building that's within one quarter-mile from the freeway, it may be a door opener. With no buildings present, a weak K- or Ka-band alert could be generated by a radar detector in a passing car.

But another possibility is instant-on radar working traffic up ahead. If so, you're likely to get several of these alerts before encountering the cruiser. The best radar detector (among windshield-mount models), the Escort Redline, will alert to this type of radar trap from up to 7 miles away, about twice the range of most radar detectors.

This is why it's important to learn to interpret what your detector is saying. Conventional radar detectors dutifully report every radar signal, leaving it up to you to determine what it's hearing. (This is one reason why the ability of GPS-enabled radar detectors to ignore non-police radar signals has led them to become so popular.)

GPS models are pricey but can occasionally be found at a discount, if you know where to look.

How come my detector doesn't alert to red light cameras?

A. Nearly all red light and speed cameras are triggered by pavement sensors, not radar. With no radio signal present, there's nothing to detect.

There is a defense, however, the GPS-enabled radar detector. The best one, the Escort Passport 9500ix, even tells you if the camera monitors only red light violations or if it clocks speeds as well, making it a 24/7 speed cop. It counts down the distance in hundred-foot increments, concluding the alert when it reaches the camera.

Keep in mind that this concept is only as accurate as the data in the manufacturer's camera location database. In our 18-month test of these databases, accuracy rates ranged from dismal to superb.

Sometimes I drive by cop cars and my detector doesn't go off. How come?

A. Other than state highway patrol cars, most police vehicles are not radar-equipped.

Traffic enforcement in larger cities is handled by the Traffic Division, whose officers focus on accident investigation and speed enforcement. They'll often be on motorcycles, and using lasers. Others drive vehicles, some of which are equipped with radar.