Did you know that if you drive a car with a rear-impact sensor not only will it detect when you are about to hit something or someone, but it will do the complimentary - it also will sound when someone gets too close to you.
I found this out from my neighbor who owns such a car and was sitting at a railroad crossing when the car behind her decided that if they creeped right up to her bumper, the train just might move on the tracks faster and they might be able to cross the tracks quicker. All of a sudden, her sensor starts beeping and she had no idea why! She finally figured it out and scooted forward a bit, but so did the sensor-offending car behind her. Only when the train cleared the tracks and traffic resumed, did it stop.
Okay, since I've been informed I have been on the lookout for these cars - not to harrass them, but only becuase they have a distinguishing characteristic on their bumper. Today, I wasn't paying attention, but my Dearest was.
We were turning off the freeway/expressway/whatever you call the Interstate and into a left turn lane that had quite a few cars in it already. Our van wasn't quite in the lane and had it's right rear end jutting out into the lane next to us. I could clearly see the rear bumper of the car in front of the car in front of us through it's windshield, but they were not inclined to move forward. Since they were not creeping forward, I creeped a bit to get the rest of our van into the lane and not disrupt traffic in the lane next to us. This is when my Dearest noticed that this car in front of us had a rear-sensor. He said, "Hey, they have a sensor in their bumper! If we get closer, they will start beeping and move forward!" We started laughing uproariously at the though and idea. Ethan asked us what we were laughing about and we explained to him about this feature. Isaac then asked, "May we do that, please?"