Police Radar

What is it, how it’s use, how to beat it

How is Police Radar Used & How you can Avoid Radar Speeding Tickets

Police radar remains the most common form of speed enforcement throughout the world and knowing the ins-and-outs of this popular form of traffic enforcement will go a long way in helping you avoiding a speeding ticket.

Updated: 04-01-2024 by Veil Guy

Police radar speed measurement by doppler shifted radar reflection.

What is police radar and how does it work?

Police radar is radar used by police for measuring drivers’ speeds and for issuing speeding ticket citations.

RADAR is an acronym for RAdio Detection And Ranging,

Unlike police laser, police radar directly determines a vehicle’s speed by measuring the doppler (speed induced) shift of the return of its transmitted frequency (think of the sound you sometimes hear of an approaching or receding train or emergency vehicle).


How is Police Radar Operated?

Police radar can be operated in two modes.

Hidden police radar operation.Instant-On Police Radar Operated from Hidden Position


Constant-On Radar

The first is continuously transmitted or constant-on (CO) operation.

When police radar is continuously transmitting, speeds are automatically displayed on the radar guns display console when vehicles come into detection range.

This range can be configured by the police officer so that the radar only displays speeds within a set range of distances, typically fewer than 1000 feet.

A threshold speed can also be set by the officer which if not exceeded would cause no speed readings to be displayed.

By using this, police can focus only on speeders who are driving above a predetermined speed.

For example if the posted speed limit in an area is 65 mph, the officer can set his or her radar to only report speeds of 75 mph or more, essentially allowing drivers a 10 mph leeway.

Generally constant-on police radar can be detected at more than a sufficient distance with good radar detectors.

There are, however, certain speed traps used by police that utilize constantly transmitting police radar that can be harder to detect by those who use radar detectors.

Police can operate constant-on police radar from a “covered” position—hiding among heavy foliage of a median, for example, and pointing their police radar guns across the roadway at an angle—not directly at approaching vehicles.

Such trap configurations can be very hard to detect even with the best radar detectors.

It is not uncommon to encounter state troopers in New Jersey operating police radar in this manner.

Another more difficult to detect scenario is when police are targeting vehicles from behind, such as from an on-ramp to the highway that’s after an overpass.

These sorts of targeting scenarios can even be more challenging to detect when police use a radar gun called the Kustom Signals Raptor RP-1 configured to use very lower powered K-band patch antennas.

Police Radar: What is Constant-On Radar and How is it Used from a Stationery Position.

Constant-on police radar video demonstration

Instant-On Radar

Instant-on police radar video demonstration

The second mode of police radar operation is formally called RF-hold, but is commonly referred to as instant-on police radar.

This is where the police officers operates the police radar on stand-by, where it is not transmitting.  When a suspect speeder is spotted, the officer can push a button on the radar gun’s remote and quickly begin transmitting radar and then can turn off the radar when a speed is determined.

This method of police radar operation began to appear in the early 1980’s, as radar detector usage grew in popularity, and it was originally designed to specifically defeat drivers who operate radar detectors.

A radar detector can’t alert to a signal that is not there.

This form can be especially lethal when operated during the cover of night, from an on-ramp or overpass, or from a hidden position from the median or shoulder of a roadway.

Police radar is designed to be hand held or permanently mounted to a police car.  One particularly difficult to detect radar is a hand held radar gun the Kustom Signals Falcon HR.

An officer who utilizes instant-on is more actively engaged in monitoring roadway speeds than one that uses constant-on radar.

If an officer is going by the book, so to speak, instant-on radar should only be used as a confirmation to a visual tracking history made by the officer and generally at fewer than 1000 feet away.

In other words, instant-on radar should not be indiscriminately used although in practice, this is not the case.

Is not uncommon to find officers firing their instant-on radar at any vehicle that comes into view, even at those that are quite far away, where it is impossible to visually determine whether or not a vehicle is speeding.

Speeding tickets shouldn’t be issued if the proper procedures are not followed, but again in practice, they are.

Could a speeding ticket be successfully fought in court on these grounds?  Quite possibly.

But it would require to have good documentation (ie; video evidence) and knowledge of your state’s or city’s radar operating guidelines.


Quick-Trigger Radar

Quick trigger or QT is basically instant-on radar that is performed in an especially quick (on and off again) manner.

To detect QT radar, your radar detector must no only be sensitive, but quick.

A sensitive, but slow radar detector, can miss alerting to instant-on or quick-trigger radar, so it’s essential to own a radar detector that is superior at detection I/O and QT police radar.

Police Radar: What’s Instant-On (I/O) and Quick Trigger (QT) Radar and Why you Need a Fast Detector.

Video demonstration of instant-on radar

How quickly can radar determine your speed?

Today’s digital police radar guns can determine you speed in a blistering fast 100ms, which leaves very little time to react to a radar detector’s alert, when instant-on or quick-trigger radar is used against you.

That is why it is essential that you own a radar detector that is not only sensitive to detect weak police radar from a greater distance than the distance a radar gun can get your speed, but that is sufficiently quick at detecting brief appearances of radar when it’s used.

We recently conducted two radar detector reactivity tests of several top-performing radar detectors in their ability to detect both K-band and Ka-band radar and found some surprising results.

Visible hand-held police radar operation.

What types of police radar are used?

Police radar guns operate on three frequency bands: X band, K band, and Ka band.

Most newer guns the police use operate on the super-wide Ka-band. K-band is still quite common, given its historical advantage to Ka-band. The oldest X-band radars, which have been widely used throughout the state of NJ, are slowly being supplemented with newer and smaller digital (DSP) Ka-band models and even more lethal police laser guns.

Radar transmissions are quite wide in their dispersion patterns and are often reflected in many directions. This gives a detector a lot of opportunities to detect them and as a consequence generally provides the driver ample reaction time to slow down while vehicles ahead are being targeted.

It’s also not particularly precise in pinpointing which vehicles are responsible for speed readings, requiring a visual confirmation by the officer. Some European radars—called Gatso and Multanova—are much narrower, ultra low-powered, polarized, and much harder to detect as a result even with the best radar detectors and come equipped with cameras.  These speed policing types of systems can be fixed or mobile.

Redflex, a photo enforcement company, uses a particularly lethal form of police radar to determine your speed.  The radar is horizontally polarized and very lower power.  Most detectors, give you essentially no advanced warning time.  Redflex is a for profit company that while not part of a police force, is contracted by municipalities to enforce speed.

Another form of radar is frequency modulated and can be found in a redlight and speed on green photo enforcement system called Gatso RT4.  Like Redflex, but for different reasons, it is also incredibly difficult for a detector to give ample warning.

Fortunately, both Redflex and Gatso RT4 systems are stationery and located at fixed positions meaning that a good GPS application like Waze can alert you to their presence without the need of a detector.

Portable hand held police radar can also be used either from within a patrol vehicle or in more uncommon instances from a officer standing outside of his or her patrol vehicle or motorcycle.

Which companies manufacture police radar guns in the USA?

There are four police radar manufacturers in North America:


What are the police radar frequencies used in North America?

There are three primary police radar frequency bands currently in use.  They are Ka-bandm K-band, and to a very limited extent,  X-band.

Police radar frequencies used in North America:

  • X-band centered at a frequency of 10.5 GHz
  • K-band centered at a frequency of 24.1 GHz
  • Ka-band centered at frequencies of 33.8 GHz, 34.7 GHz, 35.5 GHz

For those of you who currently drive with a radar detector, you may have read elsewhere that K-band can safely be disabled.   This couldn’t be further from the truth.

Those who recommend doing this only drive in limited areas where K-band is not used.  While your radar detector may false less, you’ll put yourself at risk.  You can find K-band operated in just about every state and in the provinces of Canada, and elsewhere abroad.


What are the most common police radar frequencies used in North America?

The most common police radar frequencies you’ll likely encounter on the highways are 34.7 GHz.  These police radars are manufactured by Kustom Signals and are often used by state police.

The second most popular Ka frequency is 35.5 GHz Stalker police radar and you can find this being used in a large number of states.

The MPH 33.8 GHz Ka police radar gun is the least used however you’ll likely encounter this radar in states like Nevada, West Virginia, and Ohio.

K-band is also quite popular as its an older police radar band relative to Ka-band and while it is operated by many state troopers, you’ll more likely to encounter 24.1 GHz K-band with country police or sheriffs and small towns.

X-band radar at 10.5 GHz is the oldest operated police radar produced primarily by MPH and is still in use in pockets of the country, such as Ohio, New Jersey, Mississippi.

For those interested in knowing more about what sort of traffic enforcement technology is used, RadarBusters, the oldest and largest independent countermeasure dealer online, provides a chart which includes police radar by state.


How do police use radar from a patrol car?

Police radar can be operated in a stationery position or while their vehicles are moving (ie; patrolling).

Stationary Mode

When in stationery mode, the officer is parked along a highway median, shoulder, or from an on-ramp.

Officers can also position their vehicles in parking lots in small towns where speed limits can drop sometimes significantly

They can also position themselves off of a highway, hidden in an open area behind trees, something that is common on highways, like the Atlantic City Expressway in New Jersey, for example.

Patrolling (ie; Moving) Mode

Most states allow radar to be operated by a patrol officer while he or she is driving (Pennsylvania is an exception).

This enables police officers to patrol the area roadways as opposed to being confined to a specific location.

When police radar is used while patrolling, it can also be quite challenging to detector with a radar detector, especially when operated in I/O mode as a driver can come upon an officer on the highway more quickly than if the vehicle were stationery since there is combined distance closure.

This can make for a difficult ambush situation to avoid getting a speeding ticket.

Police can also use radar in unmarked patrol vehicles making early detection even more difficult.

While patrolling, the police radar unit can be set to constantly transmit or be used in an instant-on fashion:

Instant-On Police Radar: Patrolling (Moving I/O Radar)

Video demonstration of moving instant-on radar


Constant-On Police Radar: Patrolling (Moving C/O Radar)

Video demonstration of moving constant-on radar


Can police radar measure speeds of vehicles coming from both directions?

The state of Pennsylvania is unique in that only state police are able to use radar. In other states, both state and local police are permitted to operate radar as a means of traffic enforcement.

Some models that are mounted to police vehicles have dual transmitters, one pointing forward (to clock approaching vehicles in the opposite direction) and one pointing towards to rear (to clock vehicle approaching from behind the patrol vehicle.

The rear facing transmitter can easily clock vehicles that are following a patrol vehicle so be mindful when approaching a patrol car on the highway.

Radar—even in I/O form—when transmitted is fairly easy to detect from ahead with a good detector and is one of the best tools a driver can use today. The quality of detectors have improved dramatically over the years and even budget priced models, such as the Whistler CR97 can be a very effective device in mitigated its risk. Higher-end (with price tags to match) are available from Escort, Radenso, Uniden, and Valentine Research.


Can police radar measure speeds or more than one vehicle?

Dash-mount police radars can capture the speed or more than one vehicle at a time, typically two.

However today’s radar can target multiple vehicles at a time and report the fastest traveling vehicle out of a group and the vehicle with the strongest radar signal reflection at the same time, but this requires the officer to make the visual determination of which vehicle is the fastest of the group of vehicles being targeted.


What is POP radar?

POP was marketed to change the ability of detectors to alert with ample range. If you think of detectors as specialized radio scanners, you will understand how POP radar sought to render them ineffective or at least give that appearance to municipalities who considered purchasing MPH’s radar guns so equipped.

The idea was simple in principle: if a gun transmits a single radar transmission lasting in duration for only 67ms, conventional detectors wouldn’t be able to detect a transmission of such short duration since they are spending time sweeping (scanning) the multiple bands (of X, K, and Ka) that all detectors must continually do.

While the 67ms version of POP has essentially been mitigated by all of the major radar detector manufacturers today – most radar detectors now have specialized circuitry to specifically detect it—MPH has introduced an even quicker version of POP that’s rated at a blistering 16ms (that’s 16 one-thousandths of a second!)

The frequency most often used for POP is 33.8Ghz Ka-band.  It can also be found on MPH’s K-band hand-held guns, although the most likely encounter you’ll have is against a patrol mounted 33.8 Ka unit.  Nevada is the place where you will most likely encounter police using MPH radar.  Police in Nevada are extremely well trained with these radar units.

Even the Valentine One detector – arguably the one of the best detectors for identifying POP radar, struggles with this form and alerts to it only about one out of every 10 transmission bursts. We have seen POP used more than once and have found that, indeed, it was capable of making accurate readings. That’s not to say it was not infallible.

Valentine Research has suggested MPH’s technology has been flawed and prone to error. Interestingly enough, MPH’s site has modified their website POP section indicating that speeding citations can not be issued solely on the use of POP.

We originally saw the potential of POP—allowing for traffic enforcement to be able to take spot-readings of traffic as a means of furtively taking speed readings prior to using the conventional operation for the purposes of issuing citations. In the final analysis, POP never became widely used and its theoretical advantages have been trumped by the proliferation of inexpensive police laser (LIDAR) guns which are much easier to operate and are far more lethal to us motorists.  Unless you know specifically that POP is being used in your area (not likely), I would suggest that don’t use that detection feature with a detector because it can actually lower its detection performance.


What states use POP radar?

Some states have contracted with MPH (the sole manufacturer of POP radar guns) and have been known to use those guns in the states of Florida, Georgia, Iowa, Mississippi, Nevada, New York, Oregon.  But that doesn’t necessarily mean that POP was used with any great frequency.  Police laser has essentially superseded any potential benefits of POP and is the preferred method of speed enforcement.  I was recently speeding in a remote part of Nevada and got pulled over by a police officer who indicated he clocked me with his MPH unit.  My radar detector did not alert, so I am assuming that the police officer used POP.

To detector POP radar, radar detectors have to enabled to detect it and not all detectors have the ability to do so.  Furthermore, when POP radar detection is enabled on most detectors, they tend to false more and their detection range of conventional I/O radar tends to drop.

Unless you know that POP is being used in your region, we recommend keeping POP detection turned off on your detector.

Police are not supposed to issue tickets solely on the use of POP, but honestly there is really no way to know if that role is being followed or not.  Fortunately for us drivers, the use of POP is rare.


Is police radar accurate?

The short answer is yes, it’s very accurate.  Sometimes radar’s performance can be reduced during times of inclement weather, but that doesn’t reduce accuracy, just effective targeting ranges.

Newer guns now use digital signal processing (or DSP), these police radars are much better at measuring speed from greater distances and with greater precision than older analogue guns.  They also tend to use much less transmission power which in turn makes them harder to detect with a detector.


How far can my speed by determined by radar?

Generally speed measurements are taken when you are within a 1000 feet and sometimes closer when an officer hides in a stationery position.  Fortunately, all detectors produced today can detect radar from distances that are generally much greater than that.  I should mention, however, that I recently received a speeding ticket by a North Carolina officer who picked me off with an instant-on shot on an open road at about 2500-3000 feet away with his Stalker Dual, 34.7 Ka police radar gun!

The latest digital police radars can obtain you speed at distances of 3500 feet or more.

Police Radar Range Tests of a Kustom Signals Raptor RP-1 at 24.1 GHz K & 35.5 GHz Ka.

Speed detection range of a Kustom Signals Raptor RP-1


Is police radar foolproof?

The simple answer is no.

Sometimes the officer’s radar can not obtain a speed in a timely manner.

Some of the reasons are that during I/O operation, the trigger is pushed to early when you are just behind the speed measurement range.

We consider this to be due to operator error.

Another instance is inclement weather. Sometimes rain can interfere with the ability to obtain a speed, since the water droplets absorb radar and it a sufficient amount of absorption occurs speed measurement ranges can be drastically reduced.

Yet another instance is when another vehicle passes between you and the radar beam, in which during that time, you will be obscured and a reading will not be possible during this time.


Are radar detectors worth it?

Absolutely!  Investing in a capable radar detector is one of the wisest investments you can make to avoid a speeding ticket.  Not only do the best radar detectors, alert to police radar, but also police lidar, and automated photo enforcement systems.  The cost of a radar detector will likely be paid for many times over with the avoidance of the cost of speeding tickets, points on your motoro vehicle abstract, and potentially high insurance rates.

For reference, we have compiled a ranking of the best radar detectors currently available.


Can you outbrake police radar if you are speeding?

The answer is yes, but only in certain conditions.

  • If your radar detector alerts you to an oncoming instant-on trap before you are targeted
  • If your radar detector alerts you to constant-on police radar (typically true)
  • If you are targeted in the situations mentioned in the previous section
  • If you visually spot an officer before you can be targeted or come within range
  • If you visually spot an officer before he or she spots you


That is why it is essential that you be situationally aware and to assist in your awareness, you own a good radar detector if you wish to maximize your chances of avoiding a speeding ticket.

Realworld Speedtrap: Outbraking an Instant-On 34.7 GHz Ka Stalker with the Uniden R9

Example of outbraking an instant-on police radar trap with a fast acting radar detector

How can you fight a radar speeding ticket?

Potential points of contention if you decide to challenge a speeding ticket was if it was your vehicle that responsible for a speed reading in an area where there were multiple cars.

Such challenges are basically useless, because it is virtually impossible to actually prove that this was the case and the court tends to accept the testimony from the police officer as more authoritative.

Another method is to have the officer prove that his gun was calibrated according to the schedule set-forth by the state.

While this method sometimes worked in the past, officers today are generally well-trained in operation and follow proper procedures.

Yet another method (one we recently used) is to raise an objection to the officer’s operating procedures.

If any of these aforementioned circumstances apply (and even if they don’t), you can file a motion for discovery request with the court.

We recently did this and were successful in doing so.

We requested all the officer’s notes concerning the stop (something that you are not typically privy to), any dash cam and body video footage that may exist.

You have a right to this information and by forcing the officer (and the court) to produce this information, your citation may be dropped on a court’s or district attorney’s (representing the city or state) prosecutorial discretion.

In other words, make them do some work before your court appearance and they may decide your case isn’t worth the effort to produce such evidence against you.

Don’t rule out a plea bargain.

If the case is strong against you (you’ll know this in your heart), attempt to plea guilty to a lessor offence (which may carry fewer or no points) which could also include a charge of a non-moving violation (such as not wearing a seat belt, even if you were).

It is worth your time to research what the state statutes are as well as alternatives carrying a lessor defense.


Can police radar be jammed?

Attempting to use a police radar jammer is a federal offense and although the equipment that has been available over the years, with very few exceptions, have had shoddy construction quality, dubious performance and companies offering them (even the ones proven not to work) have been prosecuted.

Today, we are not aware of any radar jammers that are currently being manufactured and older ones which may be still available are ineffective again today’s advanced digital police radars.

The only enforcement technology today that can be legally jammed is police laser, although the use of laser jammers is outlawed in a number of states, provinces, and countries.


How can you avoid a radar speeding ticket?

These are the primary ways to beat police radar:

  • Don’t speed
  • Be situationally aware
  • Drive with a radar detector
  • Use Google’s Waze on your smartphone
  • Use a “rabbit,” that is following/pacing a vehicle at sufficient distance that is speeding (although this may annoy the driver you are pacing)
  • Familiarize yourself with the preferred stationery positions police use in your area
  • Know the types of speed enforcement technology that’s used on your routes and anticipate them


How is police laser different from radar?

Today’s police laser guns provide the same advantages of stealth operation and offer very quick acquisition of speed (provided you are not using a countermeasure like Veil and/or a laser jammer).

They also have the distinct advantage that tickets may be issued to potential speeders with every trigger pull.

Radar is not particularly efficient at determining a single vehicle’s speed when there are many vehicles on a crowded highway. With laser, the officer can specifically target your vehicle in much the same way a sniper with a scope does.

Since police laser is a highly focused beam of infrared light which barely encompasses the front of your vehicle even at a far distance, it makes advanced detection by other detector owners very difficult. Police laser is often operated at greater distances and that fact makes police laser a much more a lethal form of traffic enforcement technology.

The powerful combination of instant-on usage coupled with no advanced warning is the real threat of police laser. Even detector manufacturers acknowledge that laser detectors when used alone have less value in detecting it.


Are police radar detectors effective?

While no single on countermeasure is 100% effective, driving with a high performance police radar detector when used effectively can be quite effective.  Today’s best performing radar detectors have plenty of sensitivity to detect police radar from a great distance.   When police operate their radar from a stationery position, even if hidden, and they transmit continuously, a radar detector will give you plenty of time to slow down.  However, if a patrol vehicle is traveling in the opposite direction (coming towards you) and is operating radar in an instant-on fashion, then it can become more challenging.

If you purchase a radar detector, it’s best to get very familiar with how it alerts and to what circumstances.  Once you gain a strong familiarity, you should find yourself having the edge in most radar encounters.


Can cops tell you are using a radar detector?

For decades, where radar detector usage is banned, police could use a radar detector detector, which could detect weak emissions of superheterodyne radar detectors, but the last company to make them (Stealth MicroSystems d.b.a. Stalcar/Spectre) has ceased operations.

Therefore, fewer Spectres are in use.

However, Spectre RDDs are not required to detect radar detector usage.

All a police officer has to do is target you with instant-on radar and observe your reaction.

If you suddenly brake, the officer can reasonably assume you are using a radar detector.


How can you avoid speeding tickets?

As mentioned earlier, your best bet is to invest in a good radar detector that is also a good laser detector and use a countermeasure like Laser Veil anti-laser stealth coating.

Fortunately you do have the ability to transform your detector from being ticket notifier into a ticket avoider when you use Veil to protect you.

Remember, always drive protected!

Stop getting tickets with the Veil stealth coating.

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