If you look at the reviews of ANY of the detectors on this list, or any other of the best-rated detectors you find, you’ll find there are always some complaints about false positives and failures to accurately detect.

You don’t need to doubt all of these, but it’s important to take them with a grain of salt for two reasons:

First, none of these will be perfect all the time. After all, detecting radar means detecting other things that emit similar signals as radar guns.

That means even the best radar detectors for cars will still give some false positives from time to time.

However, the better the detector, the more accurate this is, so if a product has too many complaints about false positives, that may indeed be a bad sign.

Second: alleged failures to detect radar. Why do I say “alleged”?

Because if you read these negative reviews carefully, you’ll find that often the people reviewing are simply misunderstood what a radar detector does. Put simply:

Radar detectors are not police detectors.

Many reviews say things like this:

The thing is, this guy’s review has nothing to do with the specific radar detector he’s reviewing. It has to do with the concept of radar detectors in general and what he considers a worthwhile price to be for the overall technology.

The simple fact of the matter is not all police on the road have radar guns or laser systems with them, and even those that do won’t necessarily have them on at a given time.

This person may have passed about 50 cops and detected 5 or 6—it might just be that only 5 or 6 were using radar guns at the time he drove by.

So if you see a bad review that says the radar detector didn’t give an alert when police were nearby, don’t worry right away. The best radar detectors for cars aren’t going to tell you when any police are around, just ones using radar.

That doesn’t mean you should ignore all complaints about accuracy. Enough complaints and it might be worth taking seriously. But the ones to really pay attention to are the ones that are SPECIFIC.

For example, this:

This complaint tells you unambiguously that the problem is a failure to detect a radar gun that’s in use. In contrast to the first person I showed you, whose complaint tells you nothing about whether the radar detector worked or not.

Again, the lesson here is not to simply dismiss or trust all reviews that meet certain specifications.

Rather, it’s just important to keep in mind what a radar detector actually does, as it’ll help you figure out which complaints are due to misunderstandings and which are more likely to be valid.

There are many types of detectors, of course.

First, the way it’s mounted:

There are three general types here: remote-mount, corded, and cordless. If it’s corded, there are usually some suction cups that mount the device on the windshield. They provide a good range of detection.

If it’s cordless, you can easily move it from vehicle to vehicle, though it won’t have the permanence of the other two types. Remote-mounts, in contrast, are permanently mounted to the vehicle, but are easy to install and also harder to detect.

Second, the type of detection:

Basically, radar detection and laser detection. Radar detection is guaranteed in radar detectors…duh.

But many radar detectors also include laser detection. Laser detection is a useful feature, as many police nowadays use laser beams to detect speeding in addition to or in replacement of traditional radar.

However, it’s important to note that simply having a laser sensor does not mean perfect laser detection:

A one-laser sensor basically can detect laser beams in one view, generally the front of your car. A 360-laser detector will use two sensors to detect laser beams on your sides and behind you.

As you can imagine, laser detection can add extra cost to a radar detector, and 360 laser detection definitely adds cost. However, as laser sensors are increasingly common, it’s becoming less of an extra cost.

One last note on detection:

In practice, many police radar guns have gotten better at hiding their radio signals, in part because of the popularity of radar detectors.

For that reason, having radar detectors equipped with GPS and WiFi can make a huge difference in effectiveness:

If police in your area are using more modern radar guns, a radar detector that ONLY uses radar may fail to adequately warn you. If it has GPS, however, it would be able to give you real-time information about where police are.

Keep in mind that you won’t necessarily have all these features in all your devices, and not every feature will be equally useful to every person.

However, it’s worth knowing the basic features that may be offered by radar detectors so you can prioritize the best radar detectors for you. The best radar detectors for cars will usually include at least one or more of these.

Okay, first: GPS integration/enabling. This is what it sounds like, and the reason it’s a good feature to look for is that GPS enabling can factor in your car’s speed and distance from radar. Thus, it makes the radar detector more accurate in telling your proximity to radar use.

Second: App integration. That’s when your radar detector manufacturer provides their own app or allows the device to connect to a popular app on mobile devices.

This is not something every radar detector can do, because integration with apps work best when there are many people using those apps. Essentially, these crowd-source information to make useful alerts for your area—like speed limits or red light cameras in a certain area.

It’s not essential, or the end of the world if your radar detector manufacturer doesn’t also have an app to integrate with the detector. Some of the best radar detectors for cars don’t have this feature. But some people may find it useful to have extra information.

Third: red light camera databases. These may still come preinstalled on your detector even if there’s no app connectivity.

Fourth: memory systems. This isn’t one single feature, but a class of features. For example, some built-in GPS systems in radar detectors have memory functions. Or your detector app may have memory features too.

These are very handy in avoiding false positives from your regular routes.

If, for example, the automatic doors of a grocery store on your route to work emit a signal that causes your radio detector to go off, a built-in GPS with memory would be able to remember that as a false positive and let you mute it going forward.

Many would argue that the best radar detectors for cars reduce false positives as much as possible, as they can become extremely annoying and even stressful.

At risk of being a buzzkill, this is an important issue that all potential buyers need to look into before making their purchase.

Simply put, radar detectors are of mixed legality. In the United States, it pretty much depends on local rules. Some cities and counties—and even states—might prohibit using a radar detector, period.

But usually it’s just something that’s regulated, rather than outright banned. For example, in most of the U.S., you can have a radar detector in a private vehicle, but not a vehicle used for commercial purposes.

Note that, now that radar detectors are fairly popular, police have detectors for radar detectors. These “radar detector detectors” can pick up signals emitted by the receivers in radar detectors.

Nowadays a lot of radar detectors are built to avoid those signal emissions, or to shut down when a radar detector detector is being used nearby. It may be something to look into.

Of course, however, it’d be best to circumvent those problems by simply avoiding a device if it’s not legal where you live. There’s no point in getting the best radar detectors for cars if you’ll be arrested or fined for even having one.