Reverse Park Assist System: What You Need To Know

According to the National Highway Traffic Safety Administration (NHTSA), more than 6,000 people are injured yearly by vehicles that are backing up. Of that number, 2,400 are children, and more than 100 of those children will die as a result of their injuries, according to the child-safety organization Kids and Cars(www.kidsandcars.org). A reverse parking-assist system, which helps the driver sense when objects are in the vehicle's "blind spot," can help prevent these type of accidents. Further, it is estimated that the majority of all reverse and parking accidents could be avoided with the use of a reverse parking-assist system.

What types of systems are available?
There are two common types of reverse parking-assist systems. The first is a simple audio warning indicating that the vehicle is approaching an object out of view. The second is a sophisticated camera and video-monitoring system that provide the driver with a view of the blind spot. Both types are available as options on new vehicles and from aftermarket providers. They can easily be installed in nearly any type of vehicle, regardless of the vehicle's age.

How do the systems work?
The most basic audible parking assist system uses ultrasonic technology to determine how close the vehicle is to an object. Similar to the way sonar works, an ultrasonic system bounces harmless high-frequency sound waves off objects. The sound waves echo back to the sensors, where they are interpreted to measure the distance of the object from the rear bumper. Warning tones inside the vehicle change pitch or frequency as the proximity to the object changes. Some systems integrate a series of LEDs (light-emitting diodes) into the dashboard or rear headliner for a visual alert to complement the audible warning.

A more advanced parking-assist system utilizes a small camera mounted in a protected area on the rear of the vehicle. A wide-angle view of the vicinity immediately behind the rear bumper is projected on a small display on the instrument panel or dashboard. Some of the most sophisticated systems will plot the vehicle's projected path as the steering wheel is turned, making the system invaluable for difficult parking maneuvers.

Are the systems reliable?
The ultrasonic sensors and cameras have both proven to be very reliable and effective in preventing injury and property damage. The two systems are unaffected by most weather conditions, though very heavy rain or snowfall can cause the ultrasonic sensor to indicate that an object appears closer than it really is (resulting in a harmless false alert). In extreme conditions, heavy dirt and grime on the ultrasonic sensors reduce their effectiveness, and the camera will provide a cloudy view to the driver if the lens is dirty. These situations are easily remedied by wiping clean the sensors and camera lens. A bumper-mounted rack or a trailer towed behind the vehicle can also cause the ultrasonic system to misread distances. Most systems can be defeated (turned off) to prevent this type of false alarm.

Do I need a reverse parking-assist system?
While nothing negates the driver's need to first look over their shoulders in both directions before engaging reverse, the most basic system is effective enough to safely alert the presence of an unseen object. As a complement to careful and sensible driving practices, reverse parking-assist systems are an invaluable safety feature. JD Power and Associates research also indicates that these systems are in demand. According to the JD Power and Associates 2006 U.S. Automotive Emerging Technologies Study,^SM 66 percent of survey respondents indicated they were interested in having backup sensors on their next vehicle and would pay $300 for the feature.