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Do you know how fast you drove the last time you took the highway home? A radar detector’s primary purpose is to give drivers a greater awareness of their speed.
Even the most savvied wheelman can lose a sense of his or her surroundings and drive with a heavy foot. And for those who do a lot of nighttime driving, a radar detector keeps a driver on his or her toes with alarms that are tuned to spot trouble.
Radar detectors have come a long way since their inception. Today, thanks to the internet, some more sophisticated radar detectors include crowdsourced information that adds to the overall value of the device.
But push aside your cinematic image of movie villains blasting through speed traps and outrunning the fastest lawmen courtesy of great driving skill and a souped-up radar detector. In truth, radar detectors are not geared to allow drivers to break the law.
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If you’re ready to buy a radar detector, please consult the matrix at the top of this review for a look at our five favorite products.
If you’d like to learn more about the ins and outs of radar detectors, we invite you to read on.
Some radar detectors can only identify certain types of police radars. Keep this in mind when traveling from one region to another.
A radar detector is an in-car device that identifies many of the radar guns used by law enforcement to measure the speed of a passing car. Using the Doppler shift, a radar gun measures the distance and speed between the electromagnetic beam sent out by the handheld gun to a passing car and then back to the device.
Depending on the sophistication of the device, a radar detector can alert a driver via a panel that signals the presence of police radar as well as the posted speed limit and the car’s current speed. Newer, high-end radar detectors can also send out a jamming signals that block the radar from tracking a car equipped with such a device.
The radio waves present in any one area – TV and radio signals, garage door opener signals, and so on – can create many false alarms, but some newer radar detectors can differentiate between various kinds of electromagnetic waves to limit the number of errors.
To combat drivers using radar detectors, police now use VG2 guns which can determine the presence of a radar detector in an oncoming car.
Radar guns have been used by police for more than 50 years, and as radar detectors have improved, law enforcement agencies have added lidar guns to their arsenal. Lidar, a technology used to create 3D topographic maps, sends out a laser beam which can be directed at a single object to detect its speed within 1.9 miles per hour. In addition, a lidar beam can capture a vehicle's license plate and even an image of the driver.
Lidar creates problems for most radar detectors. While some are tuned to be able to detect laser-based speed guns, many do not provide adequate warning for a driver to slow down. To combat the power and effectiveness of lidar, a number of manufacturers have come up with technologies that can absorb the lidar laser beam and nullify its ability to detect speeders.
These anti-lidar solutions are independent of the radar detector device; they are polymers that can be applied to a car’s headlights or other parts of the front grill. In many states, such laser jammers are illegal because of safety issues with laser beams.
Product in Depth
Product in Depth
The Cobra ESD7570 has a wide array of features commonly found on more expensive radar detectors. Chief among its properties is the ability to offer modes for city and highway driving; this ability helps eliminate false alarms. With the increased use of lidar, the Cobra is known for being able to accurately detect its use by law enforcement. Another key feature is its ability to detect emergency vehicles in advance to allow for a safe lane change.
Finding the right radar detector for your purposes isn’t as simple as search, click, and buy. There are a number of considerations to take into account.
The advantage of a dash-installed radar detector is that it is far more difficult for a thief to steal and equally difficult for law enforcement to detect. And when it comes to radar detectors, a less-conspicuous device is optimal.
Those who change cars frequently or rent vehicles often would be better off with a portable radar detector. If the dangling power cord is an issue or annoyance, there are radar detectors that run on battery power, although battery life could then become an issue.
If you operate more than one radar detector in your car, they will likely block one another.
In the U.S., traffic radar is done over three bands of the radio spectrum: X-band, K-band, and Ka-band.
Not all radar detectors can easily detect signals from all three bands.
It is wise to check which bands a specific device covers and whether it uses a high-end, adjustable antenna to provide the ability for greater coverage.
Many radar detectors have a feature known as “instant on,” which means the unit is in standby mode. When it comes within 200 to 300 yards of a law enforcement traffic control signal, it springs into action.
Aside from sensitivity, one of the most important factors to consider when selecting a radar detector is the number of false alarms it sets off.
With so many radio waves in the atmosphere, lower-end radar detectors can be set off by any number of devices, including automatic door openers (the kind you would find at the entrance of a supermarket) and other radar detectors.
To avoid false alarms, higher-end radar detectors have built-in filters used to tune out frequencies common to the radio waves that generate false alarms.
Police lidar units often can get a jam code from someone using a jammer to defeat a laser signal.
WiFi and Bluetooth technology have been a big plus for the radar detector industry.
Because no radar detector can be 100% accurate, a number of higher-end units come with both WiFi and Bluetooth (your car must have WiFi in order for some of these features to work) that can communicate with other drivers for crowdsourced info on speed traps and other hazards.
This information can also come in to your smartphone and then be shared with your radar detector via Bluetooth.
Police can measure your speed using radar when you are driving behind them. Some newer detectors scan in a 360-degree pattern and track radar in the front, back, and to the sides.
At the time of this writing, radar detectors were legal for passenger vehicles in 49 of the 50 states, with Virginia and the District of Columbia being the exception, and all 50 states forbid the use of radar detectors in commercial vehicles.
Also at the time of this writing, radar detectors are legal only in the Canadian provinces of Alberta, British Columbia, and Saskatchewan.
The restrictions are the same for lidar detectors.
It should be noted that in the state of Virginia, simply having a radar detector in your car – even unplugged – is against the law and could result in a fine.
Because laws can change quickly, it’s always wise to check the law detector regulations imposed by any region in which you’ll be driving.
Radar detectors are illegal in parts of Canada and some states. Using your device in these areas could lead to a major fine.
There are a number of radar detectors in this price band that might be considered bargains, but customers uniformly complain about displays that are difficult to read, weak battery life, and a large number of false positives.
Another issue some cheaper radar detectors may have is a constant beeping that makes it difficult to determine whether or not the unit has detected a speed trap.
Radar detectors with GPS use the technology to track the vehicle's speed versus the posted speed limits. GPS also can access a database of red-light cameras.
Moving up in price, you’ll find radar detectors with added features such as laser detection and the ability to filter out false alarms.
Many of these radar detectors will offer various modes for driving in the city, where false alarms are more common.
Product in Depth
Product in Depth
The higher-end Cobra ESD7570 is worth the money given its advanced features, including the ability to keep track of false alarms to avoid repeated bad alerts. Coupled with your smartphone and the Cobra app, this premium unit gathers crowdsourced alerts which can be useful information to avoid speed traps. With some restrictions, Escort is so sure of its detector technology, it will agree to pay your speeding ticket.
What you find as you climb up the price ladder are such features as the ability to detect Ka-band, which is prevalent in Europe and possibly coming to the U.S. Higher-end radar detectors may also have a shut-off feature that makes them undetectable by police in areas where the devices are illegal.
In this lofty price range, one special feature you’re likely to find is the superior ability to detect lidar from a distance. For less-expensive radar detectors, this is challenging if not impossible.
Q. Does it matter where I place my radar detector in my car?
A. The best placement for your radar is pointed slightly down and in line with the center of the vehicle.
Q. Can radar detectors pick up red-light cameras?
A. In general, only the most expensive radar detectors can pick up the radar used for such cameras. Older red-light cameras operate on a pressure pad in the highway and cannot be detected by any device.
Q. Are laser jammers legal?
A. Devices that block lidar detectors are illegal in some states. Check the specifics for any state you’ll be traveling in.
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