Red Light Camera Countermeasures Test

Do license plate covers, photo spray and radar detectors really work?

by Radartest staff

Last updated: 2014

Redflex speed camera on US 60 in Mesa, AZ
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 consortiums 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.

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 Max and the Escort Passport 9500ix. Active devices include a solenoid-activated plate-flipper that flattens the plate on command. 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.

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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.)

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. 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 uniform angle found in all red light and speed cameras. To make the State's case, they only need a clear view of the plate and, in some states, of the driver's face.

Obscuring the plate is patently 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 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.

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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 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 We Tested Them

Violation photo taken by red light camera
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.
'B' violation photo taken by red light camera
Red light camera "B" photo taken in mid-intersection. The light had been red for 1.75 seconds by this time.

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 two fun cars.

On Track Manufacturing Cruiser Shield on 2008 Subaru WRX
Subaru WRX with 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.

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. 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.

From the camera manufacturers' own equipment specifications we duplicated their powerful strobe flash, polarizing filter, shutter speed, lens focal length and other parameters.

Multanova 6F photo radar in Ford Freestyle van
We installed our $40,000 Multanova speed camera system in a Ford Freestyle van. The strobe flash was mounted near the front bumper.

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 Photoshop, it's certain that the image-enhancement tools available to camera vendors are at least as effective.

The Contenders

Original Protector
On Track Manufacturing

On Track Original Protector on Colorado license plate
Red light camera photo of the Original Protector license plate cover
Original Protector on Colorado license plate
Photo radar camera photo of the Original Protector plate cover

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.

PhantomPlate Reflector Cover over Michigan license plate
Red light camera photo of Reflector license plate cover.
PhantomPlate Reflector Cover over a Michigan license plate
Photo radar's camera photo of Reflector license plate cover.

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.

  • Stealth factor: High
  • Effectiveness vs. photo radar: None
  • Effectiveness vs. red light/speed cameras: None

Photo Blur
On Track Manufacturing

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.

Photo Blur license plate cover
Red light camera photo of Blur license plate cover
Photo Blur photo radar license plate cover
Photo radar camera photo of Blur license plate cover

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.

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: Low
  • Effectiveness vs. photo radar: Poor
  • Effectiveness vs. red light/speed cameras: Poor

Super Protector
On Track Manufacturing

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.

On Track Super Protector license plate cover
Red light camera photo of Super Protector plate cover
On Track Super Protector license plate cover
Photo radar camera photo of Super Protector license plate cover

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.

One red light camera vendor, American Traffic Solutions (ATS), has such a rig, hanging the camera high over the intersection. 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.

  • Stealth factor: Low
  • Effectiveness vs. photo radar: Poor
  • Effectiveness vs. red light/speed cameras: Poor

Overhead Protector
On Track Manufacturing

On Track Overhead Protector on Colorado license plate
Red light camera photo of Overhead Protector license plate cover
On Track Overhead Protector license plate cover
Photo radar camera photo of Overhead Protector license 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.

  • Stealth factor: Low
  • Effectiveness vs. photo radar: None
  • Effectiveness vs. red light/speed cameras: Poor

TollFree Protector
On Track Manufacturing

On Track Toll Protector license plate cover
Red light camera photo of the Toll Protector license plate cover
On Track Toll Protector license plate cover
Photo radar violation photo of On Track Toll Protector plate cover

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.

  • Stealth factor: Low
  • Effectiveness vs. photo radar: None
  • Effectiveness vs. red light/speed cameras: Poor

Anti Photo Radar Club
Car-Kor Enterprises

Car-Kor Anti Photo Radar Flap
Car-Kor Anti Photo Radar Flap at a 35-degree angle
Car-Kor Anti Photo Radar Flap photo from our photo radar unit
Car-Kor Anti Photo Radar Flap photo from Multanova photo radar camera.

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

PhantomPlate, Inc.

PhotoBlocker anti-red light camera spray

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.

PhotoBlocker spray applied to California license plate
Red light camera photo of PhotoBlocker-coated California plate
PhotoBlocker spray applied to Michigan license plate
Photo radar photo of Michigan plate coated with PhotoBlocker spray

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 powerless to interfere with the camera.

California license plate coated with PhotoBlocker spray
California plate coated with PhotoBlocker spray.
California license plate coated with Ace Hardware clear spray
California plate coated with Ace Hardware clear spray.

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.

  • Stealth factor: High
  • Effectiveness vs. photo radar: None
  • Effectiveness vs. red light/speed cameras: None


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 website 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 different results.

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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 Max. In one 18-month-long comparison test, we found the best of these radar detectors to warn of cameras with a commendable 95-percent accuracy rate.

Judging from the generally lackluster performance of these plate covers and sprays, our tests show that the best red light camera defense remains one of the Escort or BEL (Beltronics) GPS-enabled radar detectors.

Non-GPS Escort and BEL models can be linked to the innovative Escort Live system, using an iPhone or Android smartphone's GPS to protect from red light cameras while also eliminating false alarms.

Ranked in descending order by their radar performance, the best radar detectors among GPS models are the Escort Passport Max followed by the Escort Passport 9500ix and its clone, the BEL (Beltronics) Pro 500. The best of the non-GPS models is the Escort RedlineXR, followed by the Escort Redline, the BEL STi Magnum and the Escort Passport SmartRadar. (The last model has integral Escort Live; the user supplies the smartphone, either Apple iPhone or Android.)

Not inexpensive, perhaps, but any of these can pay for itself in a single missed encounter with the unblinking eye of a photo-enforcement camera.

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