I've noticed these small (about 1 inch) sized caps (or what look like caps) on the back of bumpers on expensive/luxury cars like Cadillac and Lincoln. Usually there are about 4-6of them. What are these for?? Do they serve a purpose??

If you dont know what I'm talking about, I'll try to find a picture.

 

They are proximity sensors...

Part of an option that let's you know when you are going to bang into something when you are backing up.

Nice feature on a luxury vehicle, or van or something where it is hard to tell how must distance you have left, but it would be nice if they could "pretty it up" somehow, especially on the luxury cars...

 

reversing sensors

 

They work at >110GHz...the high resolution needed for the relatively short distance being measured.



They'll be standard equipment on all cars in a few years...just like airbags are now and spare tires are being phased out ...what took so long?

 

they are getting rid of spare tires??

 

They'd like to. Spare tires (along with jacking hardware) add a lot of weight, cost, and take up valuable storage space underneath. Problem is, you need some kind of contingency plan in case of a flat. Cars with very low profile tires can stiffen up the sidewalls and use them as runflats, but regular cars don't work out as well with that option. Also, runflat tires are heavier (which is doubly bad because it's unsprung weight) and if the owner decides to buy some other kind of tire, then they're really screwed if they get a flat.

 

Those buttons are a signal to the world "WARNING, DRIVER DOESN'T KNOW HOW TO BACK UP."

Can you believe some people get these things on 12 foot long Mini Coopers?

 

The sensors are a nice idea. But why cant they be hidden behind the bumper?? They're really ugly.