A radar detector is a useful tool and is best treated as such. When combined with high levels of situational awareness and making intelligent decisions, a good radar detector acts as an extra "sense" in paying attention to the road. Radar detectors are primarily designed to detect the usage of radar within its operating range, hence the name. The mere presence of a police car is not enough to trigger an alert unless a radar device is active.
Not all radar detectors are created equal. The ones worth any consideration are usually pricey, so buyers must decide whether the investment is worth it compared to the cost of even a single ticket. There is no such thing as a "budget" radar detector— only good ones and bad ones. We've narrowed down the wide array of radar detectors offered for sale to recommend only the best since the difference between a 'close call' and a speeding ticket can be quite expensive.
Factors to Consider Before Buying the Best Radar Detector
Sensitivity
A sensitive radar detector will alert users to even the slightest hint of radar presence. The best radar detectors on the market will sound an alert if there is an active radar trap around the corner, over a hill, and way out of visual contact. The more sensitivity a radar detector has, the more likely it is to alert you to the presence of a radar speed trap. Unfortunately, this also often includes non-threats such as automatic door openers, microwaves, and even other poorly-shielded radar detectors. False alerts can get annoying and tedious, though many of the newer GPS-equipped radar detectors can automatically lock out false alarm signals at the source. For more information about this feature, scroll down to the "features" section of the buying guide.
LIDAR is becoming increasingly popular with some police agencies. Instead of using sound waves as a medium to measure speed, LIDAR sends out invisible laser pulses and calculates the closing speed. This laser beam is extremely narrow compared to radar, and traffic enforcement officers can use a LIDAR gun to pick out a single car from a crowd. LIDAR is also extremely quick and does not have the same spread as radar, making it very difficult to detect. The car in the next lane could be targeted by an officer using LIDAR, and your detector may not even alert you. By the time your own detector alerts you to LIDAR, you have already been clocked.
This is not all doom and gloom, however. There are inherent drawbacks to laser speed detection, and several instances of case law acknowledge this fact. LIDAR also operates on a light principle, which means variables such as humidity, precipitation, and other weather factors can affect the reading. On top of that, there are highly effective countermeasures available. While high-end radar detectors can sometimes alert drivers to LIDAR before they themselves become the target, laser jammers can prevent a LIDAR gun from registering a speed.
Range
The detection range of a radar detector is another important factor. A highly sensitive radar detector is of little practical use if it cannot detect the presence of speed traps past 500 feet. On an open road, some of the best radar detectors sold today, such as the Escort RedLine and Beltronics STI Driver, can pick out radar from more than 10 miles away. Better detection range always works in your favor to buy you time before you fall within ticket range. When looking at potential radar detectors to purchase for yourself, prioritize the ones that offer a longer detection range even if you plan on driving mostly in the city.
LIDAR is a different story. At further ranges, a radar beam can be hundreds of feet wide. A speed-measuring laser pulse is never more than a few feet wide, even past a quarter-mile. Though the accuracy of LIDAR at that range is questionable, the beam itself is still present and can be picked out by more capable radar detectors. This means that even if the car in front of you is being targeted, you have a chance to react before your speed can be measured. The Escort RedLine, Beltronics STI Driver, and Valentine One are particularly talented at picking out laser from a distance.
Additional features
These days, radar detectors are no longer just simple devices that sniff out radar frequencies. The general trend nowadays is that manufacturers are including GPS capabilities with their high-end detectors, combining ultra-high sensitivity and range with a GPS function that can pinpoint the location of false alerts. This means that the radar detector will stay quiet until a genuine threat is encountered. Models sometimes come with pre-loaded databases of photo enforcement locations, making it much easier to avoid any problems before they come up. You can also program these models manually in case the auto false alert lockout fails for whatever reason.
Some radar detectors feature signal shielding so that they are undetectable to a police radar detector detector (RDD). For passenger cars, radar detectors are illegal in Virginia, the District of Columbia, and on military bases. Federal regulations prohibit the use of radar detectors in commercial vehicles over 10,000 pounds. Radar detectors are also illegal in most of Canada, with the exceptions being British Columbia, Alberta, and Saskatchewan. If you fall into any of these categories and insist on using a radar detector, do so at your own risk. Some models are undetectable to the latest Spectre RDDs used by law enforcement and provide class-leading detection capabilities. However, we do not condone skirting the law, and you can expect stiff fines and penalties if you are caught using a radar detector illegally.
Price and value
This is a tricky segment for radar detectors. While spending $400-$500 for a box to sit on your dashboard may seem absurd, you need to keep detection performance in mind. At nearly $500, a radar detector is a much better value than something you can buy for $49.99 at a local electronics store simply because it offers superior performance. A radar detector that will not alert you to police speed traps is a waste of money at any price while one that will spare you those precious few seconds before you're clocked is worth every penny. This is something to keep in mind when considering which radar detector to purchase.