Keeping your eyes on the road is the safest way to drive, but even the best drivers can't always be 100% vigilant. Fortunately, modern car technology helps to watch your back, or rather your front in this case, with pre-collision warnings and automatic emergency braking systems that can predict and sometimes even prevent fender benders. But how does this technology work? Now, an automatic emergency braking system needs a few things to work.
First, it needs brakes that can be controlled electronically. You also need some sort of a way to detect other cars on the road. This is usually a radar distance sensor. And finally, you need an electronic brain or an ECU that's smart enough to control it all. As you're driving along, the radar sensor is constantly bouncing radio waves off of the cars ahead to detect their presence.
And based on the time and fractions of a second that it takes those waves to bounce back, the ECU is determining how far ahead the next car is and how quickly that distance is changing. So the system now knows how close you are and how fast you're going, and if you're too close to the car ahead for the average human reaction time to be able to safely brake in an emergency, it may issue some sort of an alert, usually a beep or a chime or a flashing dashboard light. Now, if you ignore that alert, or if the distance is closing quickly enough that the system thinks that a collision may be imminent, it may even engage the brakes automatically to lessen an impact.
At low enough speeds, which varies from car to car, but is often somewhere below 30 to 35 ish miles per hour, some systems can even completely stop your car, preventing an impact altogether. Now some cars can make use of a camera instead of, or in the most advanced systems in addition to, that radar sensor. And that often comes with the advantage of also being able to detect pedestrians or cyclists.
We'll explain how that tech works another time.