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Are Radar Detectors Illegal in Texas & Do They Work?

We get it. Before you spend hundreds of dollars on a new radar detector to prevent a potential speeding ticket, you want to know: 

Are radar detectors illegal in Texas? 

According to Texas State Law, radar detectors are legal in Texas in private vehicles, but are illegal on commercial vehicle weighing over 10K pounds, like an 18-wheeler truck.

But read further to understand if radar detectors actually work, which states radar detectors are illegal in, and the legality of radar jammers across the US.

Note: Just because radar detectors are legal in Texas, mounting them on your windshield, side window, or rear window, which could reduce or obstruct your field of view, could potentially result in a ticket. It’s up to the officer’s discretion if an obstruction exists.

So, if you’re going to use a radar detector, mount your radar detector on your dashboard.

Are Radar Detectors Illegal in Texas
Warning: Mounting a radar detector on your mirror could obstruct your vision.

In Which States Are Radar Detectors Illegal

Radar detectors are illegal in Virginia and Washington D.C., but some gray areas remain about the law in DC and Virginia. According to a Virginia state law, it’s okay to have a radar detector as long as you have it turned off, not visible, and you don’t have a power source.

In other words, in illegal to use a radar detector versus owning a radar detector.

Summary of Radar Detector Law in the US:

  • Radar detectors are legal in passenger and private vehicles in all states except Virginia and Washington D.C.
  • Radar detectors and laser speed detectors are illegal in commercial vehicles weighing over 10,000 pounds.
  • Radar detectors are illegal in any vehicle on military installations and bases.

Texas Legality – Types of Vehicle

The first thing to understand is that radar detectors are not illegal in Texas if they are used on a passenger vehicle. In fact, the only parts of the US in which radar detectors cannot legally be used on passenger vehicles are Virginia and the District of Columbia.

In Texan law, a “passenger vehicle” is any kind of car (not a motorcycle) that is designed to hold ten or fewer people, including the operator. This covers just about anything that anyone would be likely to call a car.

However, it is illegal to use them on any kind of commercial vehicle. Whether they carry passengers or products, commercial vehicles are used for the purpose of business. You won’t be surprised to hear that 18 wheeler trucks and other big rigs are legally considered commercial vehicles.

radar detector legality for commercial vehicles in Texas
Radar Detectors Are Illegal in Texas Inside Commercial Vehicles > 10K lbs.

It doesn’t end there, however. Here is a list of all the vehicles that could be considered commercial vehicles under Texas law:

  • A self-propelled or towed vehicle used to transport goods or passengers with
  • A gross vehicle weight rating or combination weight rating of 26,001 points or more
  • Seats to transport more than eight passengers for money
  • Seats to transport more than 15 passengers, not for money
  • A bed or trailer to transport a large quantity of hazardous material

If your vehicle meets any of these criteria, then it’s illegal to install a radar scanner on it.

Radar vs Lidar Detectors: Do They Work?

One problem you might run into involves the difference between radar and lidar. Now, this isn’t a legal problem, but it’s definitely something you’ll be interested in knowing about if you’re looking to stay a step ahead of police speed checks.

In the past, the police did use radar scanners to check for speeding drivers. Radar scanners work by beaming a radio wave that bounces back off the car to the scanner to track an object. However, police departments now almost always use lidar scanners instead.

are radar detectors legal in San Antonio, Texas

Lidar works differently. Lidar (Light Detection And Ranging) is an optical remote sensing technique that measures distance to objects in three dimensions using light pulses.

In other words instead of a radar wave, lidar scanners use a beam of infrared light to track an object. This means that radar scanners won’t be all that useful for keeping tabs on police scanners, so whether or not they’re legal isn’t really the problem.

Another problem with radar scanners is that these days, there are lots of things which can give false positive results. For instance, car safety features like cruise control and lane assist use the same type of radar as police cars do, so a radar scanner might be set off by any of these things even if there are no police cars anywhere near you.

Lidar scanners do exist and are perfectly legal to attach to passenger vehicles. However, they can be a very expensive piece of equipment to buy. Also, you might have one of the same problems as with radar sensors – functions like cruise control and lane assist sometimes use lidar instead of radar, which means that potential for you to get false positives is still there.

Frequently Asked Questions

Can Cops Tell if you Have a Radar Detector?

The answer to this one is that it depends. Technology definitely does exist that allows cops to check if you have a radar detector. They’re unimaginatively called radar detector detectors and it’s certainly possible that that cop behind you has one.

On the other hand, since it’s not illegal to use a radar detector in Texas (as long as it’s not on a large commercial vehicle, as we’ve seen), there’s less of an incentive for cops to check for radar detectors. And even if they do find that you have one, you’re not breaking any laws.

However, if you would still like to keep your radar detection activities a secret, it’s possible. Most radar detectors can be seen by radar detector detectors but some come with a stealth mode which will prevent them from being detected. Of course, even this won’t be much use to you if a cop physically sees the device attached to your car.

Why Doesn’t my Radar Detector Go Off When I Pass a Cop?

As we’ve seen earlier in this article, it might just be that the cop is using lidar instead of radar. Since lidar uses a small, focused beam of light rather than a wide radio wave, radio detectors generally don’t pick them up.

The other reason might just be that the cop doesn’t happen to be running radar as you go by! Many radar (and lidar) detectors cops use can be set on or off, sometimes by pulling a trigger. If they’re not set on, then you have nothing to worry about. Maybe the cop was on the phone or having a drink as you drove by.

Are Radar Jammers Legal?

Unfortunately, radar jammers are not legal. Radar jammers for cars are devices that can be used to block radar signals or disable radar in order to prevent detection by police radars. They are often installed on vehicles to avoid being detected by speed traps.

Radar jammers are illegal in all 50 US states because not only can they stop the police tracking speeding drivers but they can even cause serious trouble for airplanes too. They are considered “malicious interference” and even a first offense can result in jail time and heavy fines, so please don’t try it.

Final Thoughts

As we’ve established, radar detectors are not illegal to use in Texas, unless your vehicle meets the commercial vehicle criteria. So, if you do get pulled over by a cop and have a radar detector attached to your car, you will not face any legal repercussions.

However, as most police cars now use lidar scanners, radar detectors might prove to be useless in detecting passing cop cars. Also interferences like cruise control and lane assist can effect your radar scanners signal.

In other words, radars detectors might not be the best insurance policy to avoid a speeding ticket. You and I both know, the best way to avoid a speeding ticket is drive the proper speed limit. (But you don’t want to hear that ;-))

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