Red Light Camera Countermeasures Test
Can license plate covers, photo spray or radar detectors foil red light cameras?
by Radartest staff
There's no denying the allure of a gadget that can outwit the unblinking eye of the photo-enforcement camera. Whether a red light or speed camera, or the photo radar (speed) van, this technology continues to spread inexorably across the country.
Red light cameras monitor more than red lights: many also watch for a right turn on red where the vehicle fails to completely stop; also left turns on red and, most popular with municipalities, speed-on-green. The latter turns the camera into an always-on speedtrap, a function that our research shows is vastly more profitable for the government-private industry consortiums that operate these systems.
For instance, one camera in Scottsdale, Arizona (hometown of the two firms that dominate the market, ATS and Redflex) saw only 32 red light violations in a one-year stretch. But it recorded 1,348 speeding violations during the same period.
Products claiming to defeat cameras fall into three categories. Passive devices include license plate covers that mount over the plate. Constructed of clear polycarbonate, these have a thin plastic layer of prismatic material positioned over the identifying numbers and letters. Viewed at a zero-degree angle—from directly behind—the plate can be read. But as one moves to the side and the angle becomes greater, one or more of the numbers become obscured. (Think of peering through a honeycomb block of soda straws.) When the photo is processed, the missing data will prevent identification. At least that's the theory.
There's also a clear spray, Photo Blocker, that promises to make the plate so reflective that it overpowers a camera, overexposing the photo. The manufacturer boasts of the spray's effectiveness against every type of photo enforcement. (A competing spray, Photo Stopper, is sold by On Track Manufacturing.)
Active devices include a solenoid-activated plate-flipper that flattens the plate on command, making it unreadable. A few adapt electrochoic Smart Glass technology that makes clear glass cloudy by applying an electrical charge. Another blasts cameras with a strobe flash, claiming to blind them.
Electronic countermeasures include the GPS-enabled radar detector. These store camera locations on a database and, using GPS, alert when a camera location is approached. The best of these is the Escort Passport Max.
Most of the passive products capitalize on the fact that the roadside-mounted camera operates at an angle from the target vehicle's path, called the cosine. Photo radar commonly is aimed at an angle of 20 to 22 degrees across the road. But since few depend on radar, there's no universal angle to be found in all red light and speed cameras. To make the State's legal case, they only need a clear view of the plate and, in some states, of the driver's face.
Obscuring the plate is illegal in every state, but the manufacturers claim that the plate remains legible to cops directly behind, just not to cameras at roadside.
There are some potential gaps in this logic. The latest red light and speed cameras not only employ 14—megapixel-resolution digital cameras, they also have a color video camera that records the episode. If the still image fails to reveal the plate, operators can review the video—and based on our experience, they seem to get results.
That's because as the vehicle moves away from the camera, the effective angle between car and camera decreases. Even if the plate is obscured at the beginning of the sequence, according to our calculations, the constantly-decreasing angle should eventually defeat the prismatic material, allowing the plate to be read. We'd have to find out.
These countermeasures are well known to the burgeoning photo enforcement industry, a tightknit cabal of manufacturers, legislators, and the criminal justice system. Many states that roll out photo enforcement quickly enact legislation to ban plate covers. This presents a quandary: how to fool the camera without hindering an officer's ability to read the plate. Learn more...
How We Tested Them
We conducted two tests of the passive devices over a period of 18 months. In the first, we employed two vehicles, a 2008 Jeep Grand Cherokee and a 2008 Subaru WRX. For Round 2 we used a 2012 Nissan 370Z roadster. The choice of vehicles had no influence on the results, but since we'd be spending hours behind the wheel, we opted to include two fun cars. Learn more...
How We Rated Them
Passive devices were awarded no points if they failed to protect against either photo radar or red light/speed cameras. Some products that showed potential for countering one or both types of threat in a different setting earned 10 points for each. This reflects the differences found in camera sites such as varying target range, and the angle and height of the camera. Replicating every possible combination was impractical and while our test regimen was realistic, it couldn't anticipate every eventuality.
Radar detector effectiveness was a calculated number. It was derived from the detector's accuracy in alerting to cameras and its K-band photo radar range.
Test Results Summary
We found GPS-enabled radar detectors to be the most effective red light camera defense, hardly a shock given the price disparity compared to, say, a $69 plate cover. The best radar detectors had a 95% accuracy rate, failing to spot only five cameras out of every 100. One useful advantage is a detector's ability to also protect against police radar and lasers. See which radar detectors protect best against red light cameras...
Multi-role capability doesn't come cheap, though: prices range from $399 to $1999 for the few models worth having. And unlike passive countermeasures, a radar detector may sound an alert but after that, it's up to the driver to react.
We also found big differences in the level of protection offered by a radar detector. The Cobra XRS-9970G, for instance, warned of 67 cameras out of every 100 and sometimes missed several in a row.
Getting it wrong 33 percent of the time meant the Cobra lagged far behind the Escorts with their 95 percent accuracy rate. The Cobra suffered from inaccurate data in its Aura camera database and tardy updates to add new camera locations, traits we noted in an earlier test.
The Cobra XRS-9970G also proved helpless at warning of photo radar or lasers, diminishing its utility as an all-purpose countermeasure.
Without GPS, even the world's best radar detector, the Escort RedlineXR, is unable to establish its location and warn of cameras. The solution is to add Escort Live, the crowd-sourced ticket-prevention system. Escort Live links a smartphone (iPhone or Android) to the detector via Bluetooth. By using a smartphone's GPS, the Escort RedlineXR and other non-GPS Escort models can offer camera protection. Escort Live also allows nuisance signals to be blocked, cutting false alarms dramatically.
Low price aside, we found little to recommend any of the passive devices. A few of the license plate covers seemed promising, but none affected our cameras. And some are easy to spot, especially when viewed from adjacent lanes, increasing the risk of being stopped for an obscured license plate.
The Photo Blocker spray is easily applied and comparatively inexpensive. It made some of our license plates extra-shiny but had no effect on the cameras. However, we did find that it's easy to fake a photo of Photo Blocker apparently working. Learn more...
The Anti Photo Radar Club came close to hiding one plate number, but not at the shallow angle commonly used by photo radar units. And those installing the Club are practically begging to get stopped by a curious cop eager for a closer look.
We were disappointed by the lackluster performance of the passive countermeasures, finding that the only reliable camera defense is a good radar detector.
The Escort and BEL (Beltronics) GPS-enabled models we tested offer plug-n-play protection. The non-GPS Escort models tested can be transformed into camera-beaters when combined with the Escort Live system.
Although attractively priced, the Cobra and Whistler delivered far less protection from cameras, not to mention conventional radar and lasers.
Both are hobbled by the unavailability of Escort's patent-protected GPS technology, offering little more than a faint echo of the features added by GPS to the pricier Escort and BEL models.
To be fair, it's worth noting that performance in radar detectors is dictated by price. For that reason the $190 Whistler CR90 can't be compared to a $599 model: at more than triple the price, we'd expect the high-dollar unit to outperform the CR90 by a big margin.
These electronic countermeasures are hardly inexpensive, but it takes more than a sheet of Lexan or a can of spray paint to neutralize a $50,000 camera system.
Although the investment might be recouped after the first missed encounter with a photo enforcement camera, some may need additional motivation. For those, we'll confide an industry secret: many red light and speed cameras also function as automatic license plate readers. They scan the plate of every vehicle rolling by, comparing it to multiple databases. Unbelted or texting motorists, those driving without insurance, divorced parents behind on child support, you name it—the camera records everything, then passes it along to authorities.
License Plate Covers and Sprays
This cover is offered as a defense only against photo radar and, from a steep angle, it obscures the entire plate. This makes it a cinch to spot from a distance.
Like the other plate covers, the Original Protector can be combined with a license plate frame. Together, the pair looks like it belongs. Without the frame, some may feel that the naked plate cover calls attention to itself.
Unfortunately, the Original Protector was ineffective at angles below about 35 degrees and our photo radar, operating at a much shallower 22 degrees, was unaffected.
The surface of this clear cover is sprinkled with glitter-like speckles described as "light-reflecting crystals". This reflective material is claimed to amplify the intensity of the camera flash and overexpose the image.
Aside from a slightly cloudy appearance, nothing suggests this plate cover can protect from more than road spray.
Whatever the composition of this plate cover's magical pixie-dust coating, it demonstrated no ability to confuse the cameras.
The Photo Blur promises protection against red light and speed cameras, and photo radar as well. Instead of a flat sheet of polycarbonate like this same manufacturer's Original Protector model, the center section of the Photo Blur is puffed-out roughly half an inch, positioning the ends of the prismatic lens at shallow angles over the plate.
The unique design is intended to obscure only the first or last alphanumeric character—which side depends upon camera location—leaving unaffected the remaining characters. The obvious intent was to draw less attention from the fuzz while injecting just enough doubt into the ID process to score a win.
The Photo Blur had some effect on our photo radar, sometimes making the first or last number difficult to read—but not impossible. In viewing the photo we could make an educated guess to the partly obscured number, and the camera vendor likewise got it right—both times. Violation photos from the Arizona Highway Patrol accompanying the citations clearly displayed our plate number.
This plate cover had no effect on red light cameras positioned at a 10-degree angle. But at 35 degrees the last number was reliably obscured. Trouble is, comparatively few cameras are positioned at the steeper angle.
Billed as an "all-in-one solution against Photo-Radar", this plate cover employs two sections of prismatic material. Each covers half of the plate and the two are opposite-phased, intended to obscure half of the plate no matter whether the camera is low, high or to the side. Like the Original Protector, it's a cinch to spot.
The Super Protector had no effect on our photo radar: it obscures the plate only from very steep angles, far above the industry standard of 20 to 22 degrees. Although we didn't test this way, it's probably effective if the camera is mounted on an overpass or high on a pole, making for a more-extreme angle.
These are comparatively rare but if they constitute the primary local threat, it's possible a Super Protector may offer some protection.
The typical U.S. photo radar, however, is mounted in the back of a van or SUV. Its camera is at eye height and works at a shallower angle, easily outwitting this plate cover.
This cover claims to offer protection against high-mounted photo-radar and red light cameras. Its large strip of prismatic material measures 3.25 in. x 10.5 in. and covers all of the alpha-numeric characters. This XXL-size chunk of reflective material makes the Overhead Protector easy to detect; even someone who's never seen the stuff will know instantly that something's going on.
Although ineffective against conventional photo radar, we found that at angles exceeding about 45 degrees, it reliably blanks the entire plate. But at the camera angles typically encountered, it can easily be brushed aside by today's high-definition cameras.
The Tollfree Protector claims to defeat red light cameras and also toll booth cameras, which typically operate at a much greater angle than red light cameras.
It works well against toll booth cameras: we were delayed each time we exited Sky Harbor Airport as the ALPR (automatic license plate reader) struggled in vain to decipher the plate.
It failed to deter our red light camera, however, and it's easy to spot, tempering our enthusiasm for this plate cover as an antidote to photo-enforcement cameras.
Anti Photo Radar Club
The Club is a rectangular piece of black ABS material measuring 5.0 by 4.25 inches. This is affixed at a right angle to another piece of ABS that bolts to the end of the license plate using a stock retaining bolt. The flap creates a vertical shield that's claimed to partially cover the plate when viewed from the side.
We found that at a 22-degree angle it covered much of the last number, but not enough to prevent identification. Only at a 35-degree angle or greater would it completely block the number.
It's unfortunate that black ABS was ch sen for the Anti Photo Radar Club's construction; a translucent material would be far less obvious. In its current form, driving around with the Club is tantamount to dangling a sign in back: "Attention, officers: Ask me about my photo radar countermeasure."
PhotoBlocker is a clear spray that claims to make the plate so reflective that it blinds the camera with the amplified light reflected from the strobe flash. That sounded simple enough and, following the directions, we applied four coats, allowing each to dry for an hour.
We couldn't help but notice that the plate depicted in PhantomPlate advertising is the highly reflective California variety, an off-white color. This combination lends the best possible odds to a countermeasure capitalizing on reflected light.
But since many plates are far less reflective, we also applied PhotoBlocker to a retired dark-blue Michigan plate and a moderately reflective Colorado plate.
The camera was unimpressed. Although the PhotoBlocker-coated California plate was slightly brighter than its untreated sibling, its numbers were clearly legible. Plates from the other two states were unaffected.
Curious about the magic contents in this skinny spray can that weighs a featherweight six ounces, we studied the label. Some of the key ingredients looked remarkably similar to those of an Ace Hardware can of clear gloss spray ($3.49) we retrieved from the storage room. So on a hunch, we used the Ace Hardware can to coat another plate from each state and re-ran the test.
The results were identical; the camera wasn't fooled by either spray. At typical plate-capture range—60 feet for photo radar and 80 feet for red light cameras—the tiny increase in reflectivity afforded by PhotoBlocker proved powerless to interfere with the cameras.
We'd opine that three factors conspired to defeat PhotoBlocker. First, any increase in reflected light was largely nullified by the angle involved; most of it bounced off harmlessly into space. Second, the substantial distance separating plate from camera meant that any additional reflected light was dispersed into the atmosphere long before reaching the camera lens. And third, the camera's polarizing filter helped it to brush aside any extra glare. Even were none of this true, don't forget about that color video camera always running in the background.
By experimenting, we did learn that by positioning the camera 10 feet directly behind the car—and at plate height, to maximize the reflected flash—and by setting its flash exposure EV value to +5, we were able to overexpose the photo. But the dark numbers of the California plate could still be discerned, even with no assistance from Photoshop, The other plates were unaffected.
Some of these covers can be spotted from several lanes away and during the year-long evaluation, our testers were pulled over three times by curious officers. One, an unamused Arizona Highway Patrol trooper, wasted no words, "Your choice: either take it off or I'll cite you for an obscured plate," he growled.
The ticket would have been an equipment violation, a.k.a. fix-it ticket, an inexpensive, no-points citation that is typically dismissed when proof of the corrective action is presented to the court. Naturally, the dismissal isn't free—California courts in many cases ask only 10 bucks—but compared to a red light ticket—a minimum $380 fine, with points—that's a cost-effective tradeoff for many and worth the risk.
There's one other consideration: insurance surcharges. Red light violations in most states—and speeding violations everywhere—allow insurance companies to levy surcharges. Durations vary from a couple of years to as many as seven, at least if your record remains unblemished during the meantime. Do the math and an already-expensive $380 ticket can easily cost three to five times that amount.
But we'd advise caution: driving with some of these covers provides the excuse for an officer to make a traffic stop. But if you thrive on adversity or enjoy chatting with a uniformed gent wearing a gun and badge, don't let us stop you.
How The Passive Devices Were Tested
Our extended evaluation necessitated the acquisition of a $40,000, Swiss-made Multanova photo radar unit and the construction of a red light camera assembly that replicates the two prevalent U.S. systems, from >Redflex Systems and American Traffic Solutions (ATS).
Before constructing our red light camera we analyzed several camera sites around metro Phoenix, home to over 300 of the devices. Using an LTI TruSpeed S laser range finder we recorded the height of the camera and strobe units. We also measured the distance from camera lens to the rear plate of our target vehicle, at the moment the first photo is snapped. (Two still images are taken from the rear: the A photo as it passes the stop line, the B photo in mid-intersection.)
We similarly analyzed photo radar traps as they operated, measuring angles, distances and target-capture range. We also carefully noted the angle between the cameras and the target's path, by far the most crucial factor in determining a plate cover's potential for protection.
Our Multanova photo radar was mounted in a Ford Freestyle minivan parked on a city street. The van was parked exactly parallel to the curb and the camera-radar was aimed at the manufacturer's recommended 22-degree angle. The distance from the camera to the rear plate was 60 feet, the average of the several setups we'd examined.
Our red light camera system was likewise positioned next to a city street. We used a Nikon D70 DSLR with a 70-300mm Nikkor f/4.5-5.6 lens. The camera was located eight feet above ground some 80 feet from the back bumper. We used a Photogenic 600 WS strobe flash with a 7.5-inch-diameter reflector, mounted 10 feet above ground level.
We ran three sets of tests with each plate: one with the camera at 10 degrees, another at a 22-degree angle and the third at a 35-degree angle. A 10-degree angle between target path and camera is commonplace; a 35-degree angle is rare. The 22-degree angle replicates the average angle employed by photo radar (radar speed vans).
From experience we expected the plate covers to become effective only at a steep angle, much greater even than the 22-degree photo radar angle. So although a 35-degree angle is uncommon, we included it to give the covers the best chance of success.
We also employed a rather less scientific test to verify some of the test results—purposely driving past some local cameras at mildly extra-legal speeds to trigger them. The proof arrived in the mail a few weeks later.
One item we couldn't examine is the image-optimization software used by camera vendors to enhance images. But mindful of the possibilities afforded by Photoshop, it's certain that the advanced image-enhancement programs available to camera vendors are even more effective.
How The Radar Detectors Were Tested
The radar detectors were tested against Redflex photo radar, a low-powered K-band design that's especially difficult to detect. The test was conducted on a closed Interstate and multiple runs were made, using each of the two travel lanes. This altered our lateral distance from the parked radar van, varying the ease of detection. Learn more...
We tested the accuracy of their red light camera databases by visiting over 100 camera locations in three states. Learn more...
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