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What You Need to Know About Backup Cameras

How They Work and What's Coming Next

If your car doesn't currently have a backup camera, also called a rearview camera, it's likely that your next new vehicle will. As of May 2018, federal law has required that all new passenger cars, trucks, vans and other vehicles weighing less than 10,000 pounds be equipped with rearview monitoring technology. And in most cases that means rear-mounted video cameras.

Rearview mirrors have been a fundamental piece of motor vehicle equipment for more than a century. But as useful as mirrors are, they have a couple of significant drawbacks: They don't help you see what's directly behind your car below the level of the rear window, and they don't provide a wide-angle view.

According to the latest available government statistics, those shortcomings result in about 210 deaths and 15,000 injuries every year from backover accidents involving light vehicles. Tragically, 31 percent of those fatalities involve children under the age of 5. And the statistics don't begin to take into account those incidents in which a driver backs into something or runs over a bicycle, toy or other object.

Advantages of Backup Cameras

Clearly, the most obvious benefit of a rear-facing camera is that it helps avert injury-causing and potentially fatal backover accidents by expanding your field of vision, particularly below the rear window or trunk level. Cameras also increase your ability to see beyond the width of a mirror's image, helping to eliminate blind spots. But in addition to helping protect people and property behind a vehicle, cameras have a number of other benefits as well.

For example, backup cameras can help you park more quickly and safely. Rear-facing cameras give the driver a much clearer and more accurate view of obstacles behind the car, and most backup systems include a warning tone that lets you know when you're getting too close to an object.

Almost all backup cameras feature on-screen guidelines: two parallel lines that help direct you into or out of parking spaces more easily. Some also feature a middle line that can help you keep the vehicle centered in the space. Modern color displays allow the system to change the color of the guidelines from green to yellow to red as you get closer to an obstruction. And that, combined with an audible warning from rear-facing sensors, can be very useful in preventing backover accidents.

If you tow a trailer, a backup camera can be especially helpful. The camera gives you a close-up view of the trailer as you line it up with your vehicle's hitch, while line color and audible sensors keep you posted on distance.

How Backup Cameras Work

On the face of it, the idea is simple: When you put your car into Reverse, a camera mounted at the rear of the vehicle turns on and sends an image to a monitor to show what's behind you. But the reality is a bit more complicated. Backup camera systems, even at their most basic, are fairly sophisticated pieces of technology, and they're getting more high-tech all the time.

The complexity begins with the image that is captured by the camera. Rather than transmitting the picture that a typical camera might see, backup camera systems are actually designed to send a mirror image to the monitor so the orientation is correct when you look at it. If you were looking at a direct feed of what the camera sees, the image would be reversed, and you'd steer left when you wanted to go right. The system is designed to correct this so the view on the display makes sense.

Manufacturers generally install backup cameras in the vehicle's rear trim pieces. They're fairly unobtrusive, so they can be a bit hard to see, but you might find them hidden in the bumper, near the license plate, in the trunklid or in the tailgate of an SUV or pickup truck. The cameras are usually aimed at a downward angle to provide the best view immediately behind your car. They also have wide-angle lenses, so you're getting a more comprehensive image than you'd get with a rearview mirror.

Monitors can be mounted anywhere in the driver's field of vision, but they're generally found in the center area of the cockpit. Since most newer vehicles have an existing screen for the entertainment system, climate control, navigation and other functions, that display is often used for the backup camera system. Other versions use a portion of the rearview mirror as a monitor, which has the advantage of situating the display where drivers are accustomed to looking when backing up. But this type of monitor is much smaller and provides a less detailed image than one with a larger screen.

Although some of the early experimental systems, and a few aftermarket models, use monochrome cameras and monitors, virtually all of them now feature color displays. Some of the latest models use high-resolution cameras to deliver what automakers describe as a high-definition display (although it might not be quite as crisp as your new flat-screen TV). And vehicles — including the BMW 7 Series, the Cadillac CT6 and the Mercedes-Benz S-Class — now offer night-vision capability in their backup systems, according to those brands.

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Backup Cameras Aren't Perfect

Although backup camera systems have many advantages and can enhance both safety and convenience, some issues can affect their operation. Knowing what to expect can help you prepare to use and maintain your rear monitoring system effectively.

The most common problem that owners experience is poor image quality, and the most likely cause is simply a dirty lens. Since many cameras are mounted low on the back of the car, they're subject to being obscured by mud, snow, dirt or other debris. Luckily, the fix is easy: Clean the lens with a soft cloth (to prevent scratching the lens).

If you have a wireless system — most often found on aftermarket models — there could be an interference or pairing problem with the signal. Interference, although rare, could be caused by using other wireless devices while the camera is in operation. For the camera and monitor to work together in a wireless system, they need to be "paired" so they can communicate with each other. Incompatibility could particularly be an issue if you purchased the camera and monitor separately.

Another cause of poor image quality, or the lack of an image altogether, might be a defect or malfunction in the camera, monitor or other component of the system. There could be numerous causes for this problem, and a qualified technician should diagnose and repair it.

It's important to keep in mind that backup cameras aren't a guarantee of safety when you put your car in Reverse. As noted by the National Highway Traffic Safety Administration: "Rearview video systems are not a replacement for mirrors or turning around to look; rather, they're an added safety tool for revealing hidden dangers."

Although information is still being collected by a number of government and private organizations, a NHTSA study using data from 2008 to 2011 showed that even though the number of vehicles with backup cameras more than doubled over that period, the number of injuries was reduced by less than 8 percent. On the other hand, the fatality rate from these types of accidents fell by more than 30 percent. It must be noted, however, that the NHTSA investigation is several years old, and it relied on a relatively small sample size. As newer information becomes available, we'll learn more about the efficacy of backup camera systems.

Finally, backup cameras are only effective if you use them. A study conducted at the University of Massachusetts found that just 20 percent of the drivers in its sample group looked at their rearview monitors when backing up. And the study also found that 46 percent of the group who failed to watch the monitor did look at it when an alarm sounded, indicating that the vehicle was getting close to an object. Since most modern rearview systems do have alarms, it's likely that your next vehicle will remind you to keep an eye on your monitor.

Adding an Aftermarket Backup Camera

If your existing car doesn't have a backup camera, adding one is fairly easy, and you don't necessarily have to spend a lot for it. Retailers such as Amazon, Best Buy and Crutchfield sell aftermarket systems starting at less than $10 for a bottom-of-the-line stand-alone camera for vehicles that have existing in-dash displays. Complete setups with a camera, transmitter and display can run from less than $100 to more than $500.

With some aftermarket systems, you mount the camera in a license-plate frame. So installing it is simple, and the only tool you need might be a screwdriver. Other cameras mount in a rear trim piece or bumper cover, so you might need to drill holes and use more tools to get the job done. And there are some systems that use two or more cameras, which add to the complexity of the installation.

Then there's the issue of a monitor. If you have an existing screen, there are cameras available that can send the image directly to that display. But if your car isn't currently equipped with a monitor, you'll need to buy a system that includes one. There are several options, such as dash- or console-mounted displays and replacement rearview mirrors with monitors built into them. And since most new products feature wireless backup cameras, you won't have the problems of fishing cables through your vehicle's interior. To make installation easier, some aftermarket suppliers post videos on their websites to help DIYers with step-by-step setup instructions. If DIY isn't for you, many auto-parts retailers will handle the installation for you.

Future Camera Technology

In many ways, the future is already here. For example, many automakers now offer a 360-degree camera system — also called a bird's-eye view system — that uses images from four exterior cameras to create an accurate overhead picture that's very useful when maneuvering in tight spaces. This technology usually is available as an option or as part of a technology package.

Through the years, several concept cars have been displayed with sideview cameras that eliminate mirrors, but the 2019 Lexus ES 350 sedan is the first production vehicle on the market with this feature. The advantages, according to Lexus, include better forward visibility since the cameras are smaller than mirrors; less wind noise; and better side and rear visibility with fewer blind spots. For now this technology will only be available in Japan, where sideview cameras are legal.

Mitsubishi Electric is testing what it says is the industry's highest-performing automotive camera, which combines with proprietary artificial intelligence (AI) capability to detect and differentiate objects as far away as 100 meters. This system uses AI to mimic human visual behavior and focus rapidly on objects to let the driver know if it's "seeing" another car, a pedestrian, a motorcycle or some other object.

And, of course, cameras will be an integral part of autonomous vehicle design. For now, the semi-automated systems available on many cars still require the driver to remain alert, and some are using in-cabin cameras and sensors to be sure someone is paying attention. Cadillac's Super Cruise technology, for example, uses an infrared camera to monitor the driver's head and eye movements. If driver focus wanders too long from the road, warnings sound, and if that doesn't work, Super Cruise will gently bring the car to a stop. BMW is introducing similar technology on the 2019 BMW X5 SUV. The BMW system uses an optical camera to track driver attention, and combined with a suite of other tech features, it will allow hands-free and pedal-free operation under certain conditions.

As autonomous vehicles are developed more fully, cameras will be combined with sensors and computer modules in increasingly sophisticated active systems. They'll help cars find their way, remain oriented with lanes, maintain distance from other vehicles and objects, read road signs, avoid accidents and tie-ups, and adjust the car's controls to suit the weather and traffic conditions. Many of these functions are currently available in such features as adaptive cruise control, adaptive headlights and lane keeping systems, but autonomous vehicles are expected to bring together these and many other technologies into a fully self-driving car.