Choose wisely to win the radar detector arms race

It’s late at night; you are heading home from a social gathering. The late hour means there is no traffic, and you are taking full advantage, cruising down the highway at speeds somewhat above the posted limit. You might even be playing a favorite song, enjoying the hum of the engine, the soft whine of tires on asphalt. It’s a good time.

Then it happens. The ultimate party-crasher. Red and blue lights in your rearview mirror. The state police have decided that you are, in fact, not allowed to have fun this evening. You slow down, put on your blinker, and pull over to the side of the road. As the trooper gets out of his car, you pray he’s in a good mood. Your insurance cost is already high enough. A citation is really not going to help those rates.

There has been something of an arms race going on for some time between police radar tech and advanced radar detectors.

Now consider an alternative scenario. You are once again speeding down the highway, reveling in the absence of late-model pickups hogging the left lane. This time, as you are enjoying the drive, the music is interrupted by a series of quick, high-pitched beeps. Calmly, you reduce speed and shift over into the middle lane. As you come around the next curve, you smile at the police car camped out by the entrance ramp. Better luck next time.

What is the difference between these two scenarios? A radar detector.

A radar detector is a device that picks up police radars in the area and alerts the driver to their presence. Radar detectors have been a staple for adventurous drivers since the 1970s. They are legal for passenger vehicles, except in Virginia and D.C., and can be a lifesaver if you’re one of those people who take speed limits as either suggestions or personal challenges. But before you go thinking all your police-related traffic woes are over, there’s a little more to it than that.

Let’s talk about what a radar detector does, which means establishing what radar does. A police radar works by sending out radio waves at a particular frequency. These waves hit a vehicle and bounce back. If the vehicle is moving, we get something called the Doppler effect, which means that the waves bouncing off the vehicle are compressed if it is moving toward the source of the waves and stretched out if it is moving away. The radar device uses the level of wave change relative to its own position and speed to determine the speed of the vehicle.

What a radar detector does is scan for waves on the frequencies used by police radars. When it detects them, it sounds the alarm. It sounds quite simple, but how does it actually work?

First, the device (which is in part basically just a radio receiver) picks up incoming radio waves. Then its internal processor filters out the waves from other sources and flags any waves from police frequencies. Early radar detectors were bad at the filtering part and constantly sounded false alarms. Today, the quality of a radar detector is largely determined by how good its processor is at making this distinction. You don’t want to be speeding down the highway and then slam on the brakes because of the automatic door at the Buc-ee’s up ahead.

So what’s the catch here? Why are these devices not mounted in every car? Well, first of all, a good one will run you at least a few hundred dollars. You can pick up a cheap version for a little over $100 in some places, any halfway decent option is over $200, and the model recommended by various automotive outlets goes for $800. (It’s the Valentine One V1 Gen 2, if you’re looking to splurge.)

Furthermore, our nation’s various law enforcement agencies weren’t just going to stand by and let you enjoy the full capacity of your 2016 V6 Honda Accord EX-L in peace, now were they? There has been something of an arms race going on for some time between police radar tech and advanced radar detectors.

RELATED: Our new robot overlords are algorithmically auditing you

Photo by Kevin Carter/Getty Images

There are two types of police radar commonly in use: radar and LIDAR (laser radar). Traditional radar can be easily picked up by radar detectors, while LIDAR uses short pulses of infrared light to determine the speed of a vehicle. Since these light pulses are narrower and more focused than traditional radar, they are much harder to detect. The downside for law enforcement is that these systems are able to focus on only one vehicle at a time and are more expensive than traditional radar systems.

There have also been significant advancements made in more traditional Doppler radar. Two of the most important advancements are Instant-On radar and MultaRadar. These systems are both Doppler radars, but Instant-On radar is dormant until used to target a specific vehicle, meaning that the quick pulse of radio waves is much harder to detect. MultaRadar is able to track multiple vehicles while the radar itself is in motion. It also uses something called frequency-modulated continuous wave, which modulates the waves emitted by the radar, changing the frequency to create a more complex signal, which makes it much harder for radar detectors to pick up on.

At this point you might be wondering why anyone bothers with radar detectors any more if the police have made these advances. Fortunately, the radar detector industry has made its own advancements. Modern radar detectors have increased range and are better at picking up the pulses from Instant-On and LIDAR systems. One example is the Escort Max 330c MK II, which features increased range and is designed to detect incoming waves across all radar bands and alert the driver instantly.

The results of this arms race are mixed. Today, a good radar detector is a significant investment. It is not a foolproof device that lets you careen down the road with reckless disregard for potential speed traps. However, it can be a useful tool for lowering the odds of your rushed commute or late-night ride ending in a nasty fine and another insurance rate hike.