The Fundamental Guide to Police Radar and Laser | Lounge

By: Jonathan Kwan
September 10, 2010

When I whipped out my Beltronics Vector 995 radar detector and secured it on my windshield a couple weeks back in my 2008 Honda Odyssey EX-L, there were more than a few questions from my friends who were riding along in the back. "Is that a parking sensor?” one of the girls asked, as my V995 went through cycles of beeps during its startup cycle. Another guy inquired if it was one of those "police detectors". It seems to me that, despite these little gadgets being legal in most of US and three provinces in Canada (One of which I reside in), there has been much confusion and misunderstanding about the very purpose of these devices. Some people flat out don't know what it is, as they have never seen one before. Others who know what they are and what they do, but are not thoroughly educated on this subject, have a tendency to think that radar detectors are merely products notorious speeders use in their cars to get away from the police. As yours truly is an enthusiast in police radar and laser in conjunction with a background in Electrical Engineering, let's take a look at how automated speed measuring devices -- both radar and laser -- work, as well as discussing this subject in more detail of these controversial products to a surprisingly large amount of people.

It is not a police detector

Depending on where you live, a lot of times a patrol vehicle won't have their radar running actively in the city. Here is a good case of one.

Let me be straight up with you right from the start: This little thing that sticks to your windshield is called a 'radar detector', not a 'police detector'. While a good one can notably alert you significantly ahead of time in areas where speed enforcement is primarily achieved by the use of radar guns, the use of such devices are absolutely no excuse to driving at unsafe speeds at any time -- and neither would it be your pass out of every deserved or undeserved speeding ticket. Users new to radar detectors who have outwitted a couple police officers would probably begin to think that they are now invincible against speeding tickets; unfortunately to say, you are still quite a while away from that.

But what makes these devices so invaluable to the road warrior?

Before we get to the meat of the article, it is important to understand how speed enforcement works. This falls into two main categories: Automated and non-automated. There are also two main types of automated speed enforcement methods in use by police departments today, one of which is radar, with the other being laser.

Radar technology is probably the most popular means of automated speed enforcement around the world, because it is relatively cheap, can be used while stationery and on the move, and less susceptible to weather than laser. It sends out a wide beam of radio wave that deflects off any objects in its path, and by measuring the Doppler shift on the return signal frequency, the system provides information on how fast the target is moving. The downside is that a radar gun detects either the fastest or closest object only, depending on its operating mode (Generally the vehicle that reflects the best signal), and cannot single out individual cars -- making it impractical in heavy traffic. If you have a vehicle that has a large frontal area, you will have a higher chance of reflecting the best signal back to the police radar gun. This means it is purely up to the police officer operating the radar gun to visually determine which car their reading on the screen corresponds to. The problem boils down to a high possibility of human errors. Driving a car too common? You could end up being pulled over mistakenly. Driving your sports car close to a big rig? Chances are that they may have gotten a reading off the speeding 18-wheeler and think it was you. This generally requires good training, competence, and experience of the officer in order to determine which is the correct vehicle to pull over, and in turn, it is not too uncommon speeding tickets are handed over to the wrong person.

As radar is unable to single out individual cars, and instead sends out a wide beam that often travels extremely long distances, a good radar detector is able to pick up radar signal long before you reach the police car -- and because radar guns can only pick up readings from the fastest or closest car, there is quite a considerable distance for you to check your speed before a law enforcement officer can obtain the reading corresponding to your car. Think of it this way: Imagine you are in a large field at night playing hide and seek with your friend. Your friend is holding a flashlight. Chances are that you can spot the light coming from his flashlight long before he can see you. A similar principle goes with radar technology.

Instant on, or POP radar technology, was one of the things invented to counteract the effectiveness of radar detectors. By sending out a short pulse of radar of approximately 67 milliseconds along, many older radar detectors are defeated -- or so to say. This is known to be an inaccurate method, and is recommended to use for estimates only by manufacturers of such devices. Realistically, many police officers don't even bother using POP, because they need to establish a proper tracking history anyway, so it should not be a significant concern for most people. That said, most modern radar detectors has POP radar detection capabilities for those who still tries to uses it, and often uses it inappropriately without proper tracking history, but enabling it makes it more prone to false alerts (I never had a problem with POP falses on my Beltronics Vector V995 with POP on, however).

Laser, on the other hand, are becoming more and more popular with various police departments around the world. I happen to live in Calgary, where the entire city uses almost exclusively laser for stationary speed traps during the day. Unlike radar, by shooting out a relatively narrow beam of invisible light in pulses (904nm, 33 MHz), it measures the time for the light to travel from the gun to your car and back as well as the differences between each pulse to measure your speed. The laser gun operator will normally aim at the most reflective part of your car; usually that being your front license plate or headlights. The advantage to laser is that it can be used to single out individual cars -- creating easier enforcement in heavy traffic locations, as well as rendering radar detectors almost useless. While pretty much all modern radar detectors can detect laser, since laser scatter is hard to come by, most of the time if your detector goes off, all it means is the police got you already -- so get your license and registration ready.

Fortunately for us, laser is not all magic. Statistics indicate about 25% of all laser shots fail to obtain a reading, and they are expensive. While there is moving radar, laser has to be used stationery. Laser is also more prone to weather interference. The sun too bright out? It can overexpose the gun, causing it to fail to obtain a reading. This in combination also makes laser speed enforcement not very effective in poor weather -- no police officer really wants to stand outside in the rain along with an ineffective device. And unlike radar, it is actually legal to actively jam laser in most places where radar detectors are permitted. So instead of passively picking up radar from a certain distance, you can now check your speed even after you get hit directly by a laser speed gun with laser jammers. Additionally, about 25% of all laser shots fail to obtain a reading as aforementioned, you can actually easily turn off your laser jammer for the officer to get your adjusted speed, if necessary, without causing much suspicion. That's also to say that laser jammer heads are designed to be installed concealed out of the box, it is safe to say they are probably even more convenient to use than windshield mounted radar detectors. There are also legal accessories you can use to make your license plate and headlights less reflective to reduce the effective range of laser guns (Shots are normally taken at no more than 200 to 300 meters). Did I mention laser does not false, so when your laser jammer does go off to alert you, it is almost always the real deal?

Just remember that radar and laser enforcement systems only work when the device hits your car in front or behind. A speed of zero will be obtained when the gun is directly perpendicular to you. This is called the cosine error, and the good news is it always works in your favor for a lower reading. When the radar or laser beam hits you in parallel, let's say your actual speed is 50, then it should ideally return the same number (cos(0)*50 = 50). If you are around a curve, say the gun is 15 degrees from the instantaneous direction your car is traveling, then the reading will be 48 (cos(15)*50 = 48). cos(90) is zero (cos(90)*50 = 0), so the math should all add up of why radar and laser does not work when it is perpendicular to your car.

Common non-automated methods of speed enforcement include VASCAR and pacing. VASCAR, which stands for Visual Average Speed Computer And Recorder, is pretty much just a fancy name for a stopwatch. The officer will measure the time it takes for your car takes to travel between two points a known distance apart to obtain your average speed. On ground enforcement is extremely tedious to conduct, so in places where radar and/or laser are legal, this is a seldom used method. For aircraft highway enforcements -- usually signified by lines marked across the highway -- is quite expensive, so it is also not used all that often either. If you are traveling on a highway with VASCAR lines, just glance periodically at the sky to see if there are nearby aircrafts. If you suspect you are being tracked in any of these methods, move to the right and slow down significantly below the speed limit.

Then there is the good old method of pacing, where the officer will simply follow you to see how fast you are going. Check your mirrors often like you are supposed to anyway. No technology will save you from either of these non-automated means of determining speed, so keep your eyes on the road and pay attention to your surroundings. Again, these are not police detectors, and they are only as useful as the person is capable of using it wisely!

Why you should (or shouldn't) own one

While there may be many arguments on whether you should own a radar detector and/or laser jammer, from what I have seen, they all fall into three categories: moral, legal, and economic-related reasons. The latter two are easy to justify, but in the end you will see that answers to all three somehow links them all together to a certain extent.

Let's go over the easy ones first. In places where such equipment is legal, you will not get in trouble with the law directly (More on this later). In places where these things are illegal, please do obey your local laws. For those who insist on owning a radar detector regardless of what the books say, there are products out there with local oscillators that do not radiate any intermediate frequencies for police radar detector detectors to pick up. Like laser jammer implementations, there are remote radar detectors available for a concealed setup rather than a classic windshield mount, so you can get rolling with a radar detector in your car with little potential enforcement counteraction. However, here at APH Networks, I am writing this for information purposes only, and we do not condone installation or use of any illegal equipment in your vehicle. Please contact your local law enforcement agency for the most accurate up to date information.

As far as economic reasons are concerned, I would consider radar detectors and laser jammers a very easy to justify investment for most motorists. Whether you are running into a deserved or undeserved ticket, both could end up being very costly, and potentially very time consuming to fight in court. And here's an investment you don't want to skimp out on: A good radar detector and laser jammer could save you hundreds, or even thousands, of dollars down the road. So while your upfront costs may seem high at first, for the cost of just a couple tickets, you could easily buy a very decent radar detector. Many laser jammers double as parking sensors as well, not to mention the fact they are usually even cheaper than factory parking sensors, haha. And remember, it is not just the cost of the tickets -- keeping your driving record clean will keep your insurance rates lower, too. Additionally, while your radar detector and laser jammer will continue to protect you for years after you handed over your credit card, paying for a ticket and dealing with higher insurance rates is simply throwing your money away with zero return.

Moral reasons are probably the hardest to justify to your friends and family, or even yourself. There is a wide misunderstanding among the general public on radar detectors. Even I used to think radar detectors are devices used by notorious speeders in their cars to get away from the police as mentioned in the beginning of the article, but after being educated on radar and laser technology and its use in law enforcement, I am thoroughly convinced to place at least a radar detector on the dash. Here's where you may be asking, "How about that idiot that drove 20 over through the construction zone yesterday? I saw a radar detector mounted in the middle of his windshield!"

Well, as you may have said, that driver is... just an idiot, haha. Unfortunately, it does happen quite often, and these are the people who give radar detectors a bad name.

First of all, we must understand anything can be used for good or bad purposes. Let's take your computer, for example. One may argue that the internet is bad for society, because people have been scammed through it, used it to commit cyber crimes, have met sexual predators, spent countless hours playing online games when they should have been working, kids have access to pornography where they otherwise won't, and the list goes on and on and on. While all these things are undeniably true, in the end it is really up to the person who is using it. The same logic applies to the use of radar detectors and laser jammers as well. It is indeed true some people use it for speeding and getting away from the police, and while good equipment may save you more often than not, such technology does not grant you complete invincibility from the speed enforcement as discussed earlier in this article -- their overconfidence will most likely backfire on them big in the future. Even things designed for a good nature can be used for bad reasons. Please do not be one of those people!

Secondly, I would go as far as saying radar detectors and laser jammers actually improve road safety. Statistics indicate drivers who have radar detectors are involved in fewer accidents, because owning and using a radar detector made them more aware of their environment -- and get this -- speed limits. Isn't that what you are supposed to do when you are driving? I actually did not drive any faster after owning a radar detector; if all I actually slowed down after gaining more knowledge on this subject. Let's do a few case studies:

1. You are going downhill, speeding up unknowingly, and your radar detector alerts you of a speed trap ahead. You check your speed and adjust it accordingly, so you are within legal limits. The radar detector has just made you aware how fast you are supposed to be driving. Isn't traffic law enforcement not about money, but instead about making you aware you are causing public danger by driving too fast?

2. There is a road that suddenly drops from 80 km/h to 50 km/h, then goes to 80 km/h again. A law enforcement officer hides in the 50 zone to hand out tickets. Although you may be driving through that place on a daily basis, it is easy to be caught off guard. If your radar detector or laser jammer activates during this time, you immediately become aware of the fact that you are speeding, and slows down. If speed limits are truly for safety and not about the cash, and because you are aware of your environment and slowed down accordingly, you have just made safety happen. Isn't that a good thing?

3. September just rolled around. There is a confusing road having a speed limit set at 50 km/h, but suddenly drops to 30 km/h for a school zone, but the school is fairly hidden, so you don't really see it. An unmarked photo radar van parks on the side of the road, catching speeders unaware of the school zone, or the fact school just resumed a few days ago. You get a ticket in the mail a couple weeks later, with a pretty picture of your car for a hundred bucks. How did that improve safety since you proceeded though that zone at normal speed anyway? Let's face it: it didn't. If you had a radar detector, it would have picked up the radar van, and you would have slowed down accordingly to ensure the safety of the kids. Photo radar did absolutely nothing to improve safety here, but rather your radar detector did -- because it gave you a heads up to slow down.

If you think these scenarios are something I have made up to justify the ownership of radar detectors and laser jammers and could never happen to you, I have actually seen all of these happen in more than one city. Talk to a few of your friends, and you can probably find a few places in where you live carrying the exact same setup!

Thirdly, I simply don't see why your speed can be monitored by the police, and often times even ambushed by them, that you cannot justify owning equipment to make you aware of this. It can even save you some trouble from being the wrong car pulled over as aforementioned. If radar detectors and laser jammers are legal in where you will be driving, I simply don't see why not.

Okay, you convinced me. But which one should I get?

I think you should get the black one.

Just kidding, haha. Different people living in different places have different needs, so I will go over some details in order to assist you in making the right choice. I will go over radar detectors first, before discussing laser jammers.

The ideal radar detector has maximum range in detecting police radar, and does not false at all. Unfortunately, such radar detector does not exist, for various reasons. Let's go over radar bands used by traffic law enforcement agencies first.

The oldest radar band used is X band, with a frequency range set between 7.0 to 11.2 GHz. It is physically the widest commonly used radar band, and is extremely easy to pick up by radar detectors. Many supermarket automatic door openers uses X band as well, so radar detectors picking up this signal will begin to alert you. In many places, use of X band radar for speed detection is minimal, so many users who are confident enough usually disables X band to reduces false alerts.

Later on, K band radar guns came into service, with a frequency range set between 18 to 27 GHz. The physically narrower than X band, but nevertheless still quite easy to pick up by radar detectors. Like X band, many supermarket automatic door openers operate on K band, so radar detectors picking up this signal will also begin to alert you. I have seen signs with speed detection capabilities (But with no enforcement) use K band as well. However, K band is also very commonly used for photo radar applications, so you will want to leave it enabled -- not to mention rolling patrol cars may be equipped with K band radar guns, too.

Ka band is virtually used exclusively by the police, with a frequency range set between 26.5 to 40GHz. Again, it is physically narrower than K band, but modern radar detectors should have no problems with Ka band radar range. A quality radar detector that does not false on its own will accurately notify you of a speed trap ahead if it goes off on this signal, so it is generally advisable to take all Ka alerts seriously. Just last week, my V995 picked up a police car parked on the side of the road running a Ka band radar unit 1.7km away (About 1.1 miles).

Ku band ranges from 12 to 18 GHz, but only used for speed enforcement in Europe and not North America. While many radar detectors can pick up Ku band signals, it is usually disabled by default and unnecessary if you reside in the United States or Canada.

Here's a little tip though: In manned radar operations, equipment is usually not transmitting continuously -- so if your radar detector alerts you from the same source with the right band intermittently for 10-20 seconds each time with increasing strength, you should know it is near!

Driving through a construction zone. Let me tell you this: That white Ford F-150 is an unmarked police car. How did I know that? Full Ka band alert. Did anyone around me know that? Not a chance.

With that aside, let's talk about different types of radar detectors. The most common is the windshield mount unit, where it is normally used by sticking it to your windshield via suction cups. These radar detectors are convenient to use, and can easily be transferred between cars since no installation or modifications are required. All you need is to do is plug it into your 12V power outlet, and you are good to go. There are also cordless units for those who don't like to see wires running around, but it comes at the price of reduced performance. Others like to hard wire their detectors into their car by tapping into their vehicle's 12V circuitry, but you will need to mount it up high to catch less attention (More on this in the next section), and it will no longer be transferable between cars.

The second type of radar detector is the remote radar detector, or concealed radar detector. These radar detectors have heads installed into the front of your vehicle, and controlled by a wired remote mounted anywhere inside the cabin. If you don't like to advertise the fact that you are using a radar detector, or the idea of having electronics stuck to your windshield turns you off, this is by far the best choice. Of course, models with comparable features will run you more cash, requires automotive knowledge for proper installations, and it is fixed to your vehicle only.

Some new high end radar detectors are also GPS-enabled to enhance its functionality. The GPS is used for a variety of purposes; such as alerting you of approaching speed or red light cameras stored in its internal database, marking locations that usually falses so it will stop alerting you when you are there, as well as adjusting sensitivity based on your speed in automatic mode. Its camera database is typically updated online, but is usually subscription based -- so unless unmanned automated speed enforcement is very prominent in your area, you probably won't need one. Meanwhile, other high end radar detectors have multiple antennas facing the same direction to improve range; it is not necessary to have a rear facing antenna other than to tell the direction of the source. Radar bounces off any objects in its path, and you will be able to pick up a rear signal regardless of which way the antenna is facing.

Back on the topic of which radar detector you should get, look for a good performing one that suits your needs with the features you want. Remember, not all radar detectors are created equally, and performance is the number one priority. You will also want one that is easy to use, sufficient programming flexibility, and has a simple non-distractive display. Like I said earlier on, radar detectors are an investment, and you will want to spend your money on one that works well -- and that does not include $30 units at a local retailer's closeout bin. If it does not perform with the necessary detection range, you are just wasting your money. If it falses often, it is annoying, and when a real threat comes, you won't take it seriously. The general rule of thumb is practically nothing under a hundred bucks provides satisfactory performance. From what I have seen, I have found that in general Cobra and Rocky Mountain Radar products exhibit poor performance compared to the competition, and while many swear by the Valentine One, it is often regarded as being oversensitive resulting in frequent false alerts. Whistler provides decent performance for the lower end of the spectrum, and Beltronics/Escort (Same company now) delivers generally very balanced products to consumers looking for midrange to high end radar detectors. There are many credible websites with tons of test data on radar detector performance, and remember to go thorough research from many different sources before taking out your wallet.

My V995 began alerting the presence of a police car parked on the side of the road running his radar at 1.7km range -- in town, uphill, and around a slight curve, too.

On the topic of jammers, it is important to note that while laser jammers are legal in many places in North America, radar jammers are pretty much universally illegal. Active radar jammers are effective, but they are hard to come across, and you would up getting into much more trouble with the law than you want. On the other hand, no so-called 'passive radar jammers' work, end of story. If you even have basic understanding of how radar works, it does not take a person with an electrical engineering background to realize methods used in so-called 'passive radar jammers' simply do not make any sense at all.

Making a choice on which laser jammer to get is quite simple. Active laser jamming systems come with a wired remote control and several jamming heads; similar to remote radar detector setups. It works on a principle as if you shine your little 1W flashlight at me, I come back with a large 100W light source to make your 1W flashlight negligible. An optimal laser jammer should have no punchthrough range and be able to jam to gun; usually referred to as JTG, against all laser gun models. This means that the laser jammer is able to defeat any laser gun used at any range, preventing punchthroughs (The laser jammer cannot jam the gun because it is too far away) and JTG (Ability to jam the gun up to point blank range). Because laser speed traps have to be stationary, 95% of all laser shots are made towards the front of your car, rather than from behind. If you drive a car with a small front, low profile headlights, and optimally no front plate, all you need are two laser jamming heads under your grille. If you drive a large truck with a huge chrome grille, large headlights, and in a jurisdiction where front plates are required, it is recommended that you install as many as for laser jamming heads at the front. If you want all-round protection, rear jammers can be installed near your rear plate as well, but it is much more conspicuous to others. Blinder and Laser Interceptor provide excellent performing solutions at press time; but again, I highly recommend you to do thorough research from many different sources to see which model best suits your requirements.

All in all, radar detectors and laser jammers are invaluable devices for the road warrior if used in a correct manner. Which radar detector and/or laser jammer you need really depend on how speed enforcement is done in the place you are driving. Even if you live in an area where speed traps are primarily done in laser, a radar detector is still highly recommended -- because more often than not, stationary laser speed traps are much easier to spot than unmarked cop cars with moving radar, especially if they are coming down from the opposite lane on the highway. Remember that the latest radar units used in police cars can have two antennas -- one for tracking front, and the other for tracking back -- operating either in same lane mode or opposite lane mode. It's safe to say that you are always potentially "under their radar" regardless of where you are, haha.

Mounting it right for safety and performance

You have made up your mind and purchased a good radar detector. Now what? If you want to get the most out of your windshield mounted unit, the first thing you need is to mount it correctly.

Many enthusiasts agree the best way to mount your radar detector is to mount it on the dash. Because you will need to buy a separate mount, and might not work for all dash configurations, personally I like to stick with the good old windshield mount. Most people mount it in the center middle of their windshield, but I can assure you it is not advisable for several reasons. This includes aspects such as causing interference with your view on the road. You are advertising to everyone around you -- especially the guy behind -- that you have a radar detector. Some people might follow you closely to leech off your detector, making it a safety concern. And while there are many legitimate reasons for using radar detectors as aforementioned, many police officers believe these are "burglar's tools", and might keep an extra eye out on you. You don't want any of that. The best way to mount your radar detector is to mount it as low as possible on your windshield, but right above your wipers to give it a clear view of the road ahead. This improves laser detection (Not that it really matters, but it might still come in handy) since officers aim at either your headlights or your plate -- and your detector should be as close to that as possible. It prevents or reduces the amount of traffic behind you from seeing your radar detector; using a radar detector is nobody else's business but your own. This also makes the screen easier to read when an alert goes off, without interfering with your view on the road ahead. In my 8th generation Honda Civic sedan, my low mounted Beltronics Vector 995 simply cannot be seen if the car behind me is another sedan. If it is a minivan, truck, or SUV, they might be able to see it, but only if they are close enough, and are paying specific attention to my car. I programmed my detector to only display the first letter of each sensitivity mode (Ie., "H" rather than the full word "Highway") in normal operation in medium brightness so it is less likely to be seen at night as well.

Most radar detectors have several different sensitivity modes, mainly being Highway and City. Some have a third mode in automatically optimizing the scan cycle for best performance and reduced false alarms, or in the case of a GPS enabled unit, adjusting sensitivity based on your speed. City mode has the lowest sensitivity, so it is less prone to picking up automatic door openers, but since you are driving slower, this is an acceptable tradeoff. Highway mode is usually the most sensitive setting, and is a necessity since you are covering much more distance in the same amount of time. Use Highway mode on the highway, and Auto or City in the city. This should be pretty easy to understand, haha.

Many users new to radar detectors are tempted to slam their brakes immediately after an alert goes off. It is highly recommended to react as soon as possible, but there are a few things you need to consider -- whether traffic behind you is following too close, how strong the alert is, and whether it is from a legitimate source or not. Additionally, some police officers like to flick on their radar just to see who has something that gives them a heads up, and if they see your brake lights immediately they might pay extra attention to you. You don't want that. In cases like this, just ease off the brake pedal and/or downshift. Don't fall into their trap!

In the unfortunate event that you are still pulled over by the police for whatever reason, immediately remove your radar detector and related accessories and throw them under the seat. Even if these devices are legal where you are in, as I said earlier, many officers believe these are "burglar's tools" -- and they don't like seeing them. If they see you using a radar detector in your car, they are not likely to let you off the hook. You will still have a better chance to talk yourself out of a ticket if they don't know you that have one.

Before I close off today, if you have a windshield mounted radar detector, remove it and take it with you when you are out of your vehicle. At the very least, hide it somewhere so it is not visible to people walking past your car. Leaving one on is just asking people to break into your car. You paid lots of cold hard cash for one, and thieves know these things are often quite costly. Many radar detectors have quick release mechanisms for easy removal. If you live in a place where theft is rampant, remove the suction cups from your windshield, or consider installing a remote radar detector. Keeping your radar detector out of your car when not in use will also extend the life of your unit, especially during hot summer months.


I hope this article has gave you more fundamental basic understanding of how traffic law enforcement technology works. There are many great resources on the internet from radar and laser experts to further your knowledge on this subject. But regardless of which, remember radar detectors and laser jammers are merely tools to assist you in your daily commute. Please drive safely for the benefit of yourself, and for the benefit of others, at all times!

APH Networks purchased all equipment used in this article to facilitate this report.

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