Accessory backup video systems for cars are widely available with several electronics manufacturers competing in the market. While the primary mission of these minicams is simply to provide a view to the rear while you're parking or backing up, they also offer a safety advantage because they can help you to see a child, pet, or hazard.
Our previous tests of a few aftermarket models found that performance generally tracked with price—another case of "you get what you pay for." That said, even the worst performers are better than a beeper-type parking aid at seeing objects or people behind the vehicle.