Aftermarket companies offer three types of backup systems: rearview cameras, sensor systems, and wide-angle lenses. Use to decide which best suits your needs. For wired camera and sensor systems, we recommend professional installation.

No matter what type of system you choose, consider the following when deciding on a specific model:

Know how the device mounts on your vehicle

Camera and sensor systems that are mounted on the vehicle's bumper or bodywork might require drilling. They might not be the best choice if you lease your vehicle.

If you have a trailer hitch, you can consider a model that mounts in the hitch receiver. But you would have to remove the system to use your trailer.

Other camera and sensor models mount on the license-plate frame. But some states prohibit frames because they can obscure the plate.

Within types, features vary

That is especially true with the sensor models we tested. The ultrasonic systems were generally the most sensitive, but their performance was adversely affected by rain, snow, or other inclement weather.

The microwave-based sensor systems we tested were not affected by weather but are less sensitive as a group. They also don't warn the driver unless the vehicle or object behind it is moving.

The display quality of the camera-based models is very good, although it doesn't match that of the larger screens on some carmakers' integrated navigation systems. All of the system displays turn on when the vehicle shifts into reverse.

All the systems we tested are potentially useful. They're a good complement to looking around the vehicle before entering, and checking the rear window and rearview mirror just before and while moving in reverse.