Dear Car Talk:
I see that new cars have a small rectangle on the grill of the car. Some are clear and some are solid.
To my eye, it seems to ruin the appearance and pattern of the grills.
I was wondering what purpose they serve. -- John
They keep you from crashing into a parked UPS truck, John,
Those are sensors for the safety systems that come on more and more new cars. The newer ones are Lidar sensors that use laser-based radar to detect other objects in the road, be they cars, pedestrians or bicycles.
The Lidar sends out pulses of light, and by measuring how quickly they bounce back, it can tell when there's an object in front of the car and how quickly your car is closing in on it.
For instance, let's say you're traveling on the highway, and you're going 65 mph in traffic. The Lidar will know that the car in front of you is also going 65 mph because your distance from that car will remain the same. Everything is fine.
But, what if the car in front of you suddenly slows down or stops? The Lidar-based system will immediately detect that you're getting closer and closer to that car, and it will go on alert. If it sees that your foot is still on the gas, not the brake, it'll conclude that you haven't noticed the stopped car in front of you, and that's when things get interesting.
Normally, the first thing the system will do is warn you with a light. If you ignore that, it'll add an audible alarm. And if you still can't be pried away from texting your takeout order to the local Chinese restaurant, and the system calculates that you're going to crash into the object in front of you, it will actually apply the brakes to slow the car and either avoid the crash or lessen its severity.
Pretty cool, huh? These systems vary from car to car and come under the generic names "forward collision warning," and "automatic emergency braking." Some work at slow speeds only, while the better ones work at high speeds, too. And some can detect non-car objects like pedestrians and bikes.
While they're not perfect, they are, generally speaking, wonderful technological advances that will soon be in all new cars. Plus, they're already saving lives, and sheet metal.
At some point, someone will invent a sensor that can be better camouflaged into the front of the car. But until then, I say, who cares? I'll take an ugly rectangle on my grill if it means saving that grill from getting mangled ... with my own grill right behind it.