Backup Sensors
Backup Sensors, or parking sensors, can be fairly useful tools. Their function is fairly simple and obvious: they detect an object behind you (while you’re backing up), and they alert you to its presence. How it actually works is a little bit more complicated, but we’ll get to that in a little bit. The point of backup sensors is to spare your bumpers from the little scratches that can accumulate over time as you slightly graze objects while parking. If the sensors sense anything, your car will give you an audio or visual signal that something is close to your bumpers.
Backup sensors work by sending out a constant barrage of ultrasonic proximity sensors. The sensors send out these ultrasonic waves about four times per second, and can be placed at the front and back of the vehicle, and will detect objects up to 8 feet in front of you. The alert you receive can be in audio o visual form. If it’s auditory (it is usually), you’ll usually hear a beep or tone, which will usually get louder or faster when you get closer to something. If it’s a visual alert (rare), it will usually light up your dashboard. This isn’t used as much because it’s easy to miss, especially if you’re looking over your shoulder while backing up.
The problem with backup sensors is that they only help avoid minor damage. If you’re going fairly slowly and don’t notice something behind or in front of you, they can help you avoid a few minor scrapes and dents. But if you’re driving with any speed, they won’t help at all. If you’ve got your foot on the gas pedal, and your sensor alerts you to something that’s four feet away, you’re not going to be able to make a full stop by then. Of course, it will be better than nothing, and even just slowing down can save you a lot of money. But it is a weakness of the system, and also why they usually only included on luxury cars; the cost/benefit ratio is stronger there.
Additionally, backup sensors have trouble detecting some objects, if they aren’t flat or large enough. They can also have trouble with short objects. Also, tall, thin objects, such as a telephone pole, can give them some issues. Now, the technology for these systems is fairly new, and the demand is fairly light, so there is still hope for the idea of backup sensors. But the technology as it exists today is pretty flawed, not to mention being pretty annoying. 99.9% of the time, we’re completely aware that we’re close to something. Having a constant, loud beeping sound whenever we get close to something is more irritating than helpful. And more to the point, the sensor won’t be able to tell you exactly when you’ll hit something, so it doesn’t really help you with precision parking. The only time they might help you is those very, very few times where you are unaware of being close to something, assume you haven’t tuned out the alert by then.
If you’re interested in buying a backup sensor, or a few of them, the cost can be fairly expensive. For a four-piece set, you can end up paying nearly $300 for a flawed technology that doesn’t always work. If you can afford that, fine. Having backup sensors on your car certainly won’t hurt, and who knows? Maybe it saves you more money than it costs somewhere along the way. Also, if you get your sensor just for the rear, that will effectively half the price. The backup sensor is one of those additions to a new car that can be helpful sometimes, but isn’t really worth buying on its own for most people.