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Police Radar – What you Need to Know

Police Radar - What you Need to Know

What is Radar? 

Radar is simply an acronym which stands for Radio Detection and Ranging. We’ve all heard of the Doppler Effect (aka the Doppler Shift) when watching the weather. It basically means that waves change in length based on their movement as compared to the observer. A great example is a plane in the sky moving towards an observer sounds different than the same plane flying away. The noise didn’t change but the audio waves did! 

How Do Police Radar Guns Work? 

Simply put, they use the doppler effect. The radar gun emits a radio wave at an approaching car. A portion of those waves will bounce off of the car and come back to the gun. The gun then analyzes them and the doppler effect lets them know very accurately at what speed the car is travelling. The bigger the difference in frequency between the waves sent out and the waves coming back, the faster you’re going. Even small changes in speed are measurable by today’s equipment. 

Do They Use Specific Frequencies? 

Yes, law enforcement in the United States primarily uses three frequencies, known as the X, K, and KA bands. Early radar detectors used only the X band. The FCC regulates which bands are allowed and for what purposes. Over time they opened up the K band, followed by the KA band, and then later expanded the KA band. As radar gun manufacturers sought to stay ahead of radar detector manufacturers, they quickly changed their signal types as new bands became available. That means older radar detectors may not detect the newest frequencies. 

Radar versus Laser (Lidar) 

Police lasers (Lidar) use infrared light pulses instead of radio but they are still using the Doppler Effect to measure speed. Lasers offer two distinct advantages over radar. First, they are able to operate in a much narrower beam. Second, they can capture enough information to determine speed much faster. A standard radar gun will take 2-3 seconds to get an accurate reading, while a laser can register the same information in less than half a second. Police are often trying to avoid radar detectors, so a smaller beam and a shorter run time make them harder to detect. 

What is POP Radar? 

POP radar was designed to help avoid radar detectors. The longer a radar unit is on, the more radio waves it puts out and the greater the chance for detection. POP units turn off and on in short bursts, allowing them to gather accurate speed data with a minimal amount of radio waves emitted. The early versions emitted waves in a burst with each individual unit being only 67ms, or about 1/15 of a second. This was far superior to the 2-3 seconds for standard radar guns. The newest POP radar guns can operate in as little as 16ms, about 1/60 of a second. This format, however, hasn’t really hit widespread usage because of stiff competition from Lidar. 

Radar with Cameras 

Some portable units include cameras to help police determine which car was speeding when there are several in view, however this is often unnecessary. Courts have traditionally sided with the officers’ opinions on which vehicle was speeding, and it is very difficult for a driver to provide evidence of other vehicles on the road. The one exception would be a footage from a dash camera. Radar with cameras are more common in a permanent installation, light a speed trap or a red-light camera. 

What is the Maximum Distance It Can Measure Speed? 

While there is a good deal of variation between different units and weather conditions can have a significant impact, consensus seems to be around 1,000 feet, or two-tenths of a mile, though it is sometimes possible to obtain accurate results at further distances. 

How Can I Avoid Them? 

The best way to avoid speeding tickets is to avoid speeding. Monitor your own speed as well as any posted signs. If you have trouble keeping track of changing speed limits, consider using a navigation app that can also track the speed limit. 

How Can I Fight Them? 

Tickets used to be more commonly overturned because of a poor maintenance record on the radar unit, a lack of calibration records, and no record of officer training. Advances in technology have made this much easier to prove, so these defenses rarely work. Courts also rely heavily on the officer’s judgement and opinion over that of the driver. Once you have the ticket, your best bet is to seek a deal with the prosecutor or hire a lawyer. 

What Other Options Do I Have? 

If you do tend to speed from time to time, the best way to prevent a ticket is to avoid being detected. Companies like ESCORT provide a variety of devices to warn you of both radar and laser detectors like the ESCORT MAX 360C to warn you of any potential threats. It can also be connected to their cloud network help rule out false alarms. They also provide laser shifters to defend against the more difficult to detect lidar units.   

Is This Legal? 

Radar and lidar detectors are currently only illegal in Washington DC and Virginia but you should always keep abreast of local laws when using these devices. Laser shifters are legal in all states, however some have regulations about using them against police equipment. Even where they are legal, keep in mind that most police will not view them favorably. If you are to use one consider form factors that are less noticeable or even hidden.

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