Speed cameras like this Redflex unit along U.S. 60 in Mesa, Arizona are enormously profitable. Our studies show that they also increase rear-end collisions while failing completely to lower speeds or affect driver behavior.
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 cabals that operate these systems.
For instance, one camera in Scottsdale, Arizona (hometown of the two firms that dominate the market, ATS and Redflex) recorded a scant 32 red light violations in a one-year stretch. But it recorded 1,348 speeding violations during the same period.
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Go directly to the test results:
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Not long after the first of these cameras appeared, products claiming to defeat it also arrived. These fall into three categories—passive devices, like the license plate cover; active devices that mechanically make part or all of the plate unreadable, and the GPS-enabled radar detector, like the Escort Passport 9500ix. Active devices include a solenoid-activated plate-flipper that flattens the plate on command. (But it's driver-activated, raising the question, If he knows there's a camera, why not just refrain from committing the violation for ten seconds instead?) All of these devices claim to make it impossible to identify the plate, leaving no way to enforce the alleged violation.
The simplest passive device is a license plate cover that mounts over the plate. Constructed of clear polycarbonate, it has a thin plastic layer of prismatic material positioned over the identifying numbers and letters. Viewed at a zero 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.
Active devices range from clear coverings that become opaque when charged with electricity to those motorized plate-flippers. There's even 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.)
Subaru WRX wearing an On Track Original Protector license plate cover. Somewhat effective at angles over 35 degrees, it had no effect on our red light camera or Multanova photo radar unit.
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Most of these products capitalize on the fact that the roadside-mounted camera operates at an angle from the target vehicle's path, called the cosine, in technical terms. Photo radar commonly is aimed at an angle of 20 to 22 degrees across the road. But since they don't depend on radar, there's no common angle found in red light and speed cameras; they only need a clear view of the plate and, in some states, of the driver's face, to make the State's case.
Obscuring the plate is patently illegal in every state, but their 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 entire 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.
Legal Issues
These countermeasures are well known to the camera vendors and lawmen. 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.
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 interested officers. One, an Arizona Highway Patrol trooper, wasted no words, "You got a choice; either take it off or I'll write you a ticket for it," 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.
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 We Tested Them
Red light camera "A" photo, taken as vehicle's rear wheels clear the stop line. Data box at top right of photo shows that the light had been red for 0.65 second.
Red light camera "B" photo, taken in mid-intersection. The light had been red for 1.75 seconds at this point.
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We conducted two tests 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 a WRX and 370Z. (Having driven both, we'd take a pass on the 2008 Subie—this bigger, softer iteration of the iconic rally car was more Impreza GT than hardcore backroad racer. But the Nissan 370Z remains one of the better sports cars at its price point.)
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 first 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 and measured the distance from camera lens to the rear plate of our target vehicle at the moment the first photo is snapped. (Automated enforcement cameras take two still images from the rear: the A photo as it passes the stop line, the B photo in mid-intersection.)
We installed our $40,000 Multanova speed camera system in a Ford Freestyle van. The strobe flash was mounted near the front bumper. |
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.
From the camera manufacturers' own equipment specifications we duplicated their powerful strobe flash, polarizing lens filter, shutter speed, lens focal length and other parameters.
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 35-degree angle is uncommon, we included it to give the covers the best possible chance to perform.
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, say, Photoshop, it's certain that the megabuck programs available to the vendors are even more effective.
The Contenders
Original Protector
On Track Manufacturing
$29.95
Red light camera photo of Original Protector license plate cover
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Photo radar camera photo of Original Protector plate cover
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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; anyone with average vision will know something is covering the plate.
Like all of these plate covers, the Original Protector can be combined with an ornamental license plate frame, the way many choose to employ it. As an assembly, 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 found to be ineffective at angles below about 35 degrees and our photo radar, operating at a much shallower 22 degrees, was unaffected.
- Stealth factor: Low
- Effectiveness vs. photo radar: None
- Effectiveness vs. red light/speed cameras: None
Reflector Cover
PhantomPlate, Inc.
$19.95
Red light camera photo of Reflector license plate cover.
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Photo radar's camera photo of Reflector license plate cover.
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The surface of this clear cover is sprinkled with glitter-like speckles the manufacturer describes as "light-reflecting crystals", reflective material said to amplify the camera flash and overexpose the image.
Aside from a slightly cloudy appearance, there's nothing to suggest that this plate cover is intended to do anything more than protect the plate from, uh, whatever menace buyers are trying to protect their plates from.
Whatever this plate cover's mysterious pixie-dust coating might be, it demonstrated no ability to confuse our cameras.
- Stealth factor: High
- Effectiveness vs. photo radar: None
- Effectiveness vs. red light/speed cameras: None
On Track Manufacturing
$29.95
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 characters—which side depends upon camera location—leaving unaffected those in between. 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 bubbled housing makes for a thicker assembly and the stock license plate bolts proved to be too short. Longer 8mm-diameter bolts from Ace Hardware solved the problem.
Red light camera photo of Blur license plate cover
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Photo radar camera photo of Blur license plate cover
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A Radartest staffer's violation photo from a Redflex speed camera in Phoenix. A Photo Blur cover is affixed to the Arizona plate, to no apparent effect.
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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.
- Stealth factor: Poor
- Effectiveness vs. photo radar: Poor
- Effectiveness vs. red light/speed cameras: Poor
Super Protector
On Track Manufacturing
$39.95
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.
Red light camera photo of Super Protector plate cover
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Photo radar camera photo of Super Protector license plate cover
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The Super Protector had no effect on our photo radar: it blanks a plate only from very steep angles, far in excess of the industry standard of 20 to 22 degrees. Although we didn't test it 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.
But the typical U.S. photo radar is mounted in the back of a van or SUV, its camera works at a shallower angle and it easily outwits this plate cover.
- Stealth factor: Poor
- Effectiveness vs. photo radar: Poor
- Effectiveness vs. red light/speed cameras: Poor
Overhead Protector
On Track Manufacturing
$29.95
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Red light camera photo of Overhead Protector license plate cover
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Photo radar camera photo of Overhead Protector license plate cover
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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 the high-def cameras.
- Stealth factor: Poor
- Effectiveness vs. photo radar: None
- Effectiveness vs. red light/speed cameras: Poor
On Track Manufacturing
$69.95
Red light camera photo of the Toll Protector license plate cover
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Photo radar violation photo of On Track Toll Protector plate cover
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The Tollfree Protector claims to defeat red light cameras and also toll booth cameras, which typically operate at a much sharper angle than red light cameras.
It works well against toll booth cameras: we were delayed each time we exited Sky Harbor Airport while 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.
- Stealth factor: Poor
- Effectiveness vs. photo radar: None
- Effectiveness vs. red light/speed cameras: Poor
Anti Photo Radar Club
Car-Kor Enterprises
$29.95
Car-Kor Anti Photo Radar Flap at a 35-degree angle
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Car-Kor Anti Photo Radar Flap photo from Multanova photo radar camera.
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Anti Photo Radar Club by Car-Kor Enterprises. Iffy protection from a device that practically begs an officer to make a traffic stop.
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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 chosen 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."
- Stealth factor: None
- Effectiveness vs. photo radar: Marginal
- Effectiveness vs. red light/speed cameras: None
PhotoBlocker
PhantomPlate, Inc.
$29.95
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.
Red light camera photo of PhotoBlocker-coated California plate
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Photo radar photo of Michigan plate coated with PhotoBlocker spray
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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 entirely unaffected.
Curious about the magic contents in this skinny spray can that weighs-in at 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 to be powerless to interfere with the camera.
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California plate coated with PhotoBlocker spray.
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California plate coated with Ace Hardware clear spray. Results were indistinguishable from those of the Photo Blocker spray. The only difference was the latter's $26.46-greater price tag.
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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 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.
- Stealth factor: High
- Effectiveness vs. photo radar: None
- Effectiveness vs. red light/speed cameras: None
Conclusions
It's worth noting that the CEO of North America's largest manufacturer of license plate covers admits privately that he's never hired an experienced product-evaluation outfit to test his wares. That's one way to sidestep potentially unflattering publicity, but it doesn't add much to the knowledge base.
Clearly our test results differ substantially from those depicted on vendors' Web sites. For example, the Photo Blocker Web site, displays several videos where TV news reporters breathlessly report stellar performance. Trouble is, each of these tireless warriors for truth cluelessly followed the same recipe for success. They used a highly reflective plate, snapped photos from directly behind it, at point-blank range, and used super-powerful lights. Had any of them bothered to conduct a real-world test—perhaps even using a red light camera—we suspect they'd have experienced very different results.
We've also tested GPS-based active countermeasures ranging from simple red light camera detectors (Whistler RLC-100, Cheetah C-100) to sophisticated GPS-enabled radar detectors like the Escort Passport 9500ix. In one 18-month-long comparison test, we found the best of these devices to warn of cameras with a commendable 95-percent accuracy rate.
Basic red light camera detectors must tread carefully lest they infringe on Escort's GPS patents. This renders several of the most valuable features off-limits to the competition. And our test of the camera location databases that are key to these devices revealed a wide variation in accuracy, significantly reducing the level of protection offered by some.
Another drawback of the standalone red light camera detectors is their lack of protection from radar and lasers. After 22 years spent monitoring the photo-enforcement industry, we know that when the cameras go up, photo radar won't be far behind, making radar/laser protection a must.
While it's possible to use both types of product in parallel, the added complexity of operating two windshield-mounted devices at once tends to limit their attractiveness. That in mind, and judging from the lackluster performance of the plate covers and sprays, it's apparent that the best defense remains the GPS-enabled radar detector. Pricey perhaps, but the only proven protection against the unblinking eye of the photo-enforcement camera.
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