(WYTV)- If you drive a four door sedan, you’ve noticed that while the front windows disappear down into the doors completely, the rear windows on both sides mostly likely do not.

You can’t roll those back windows all the way down.

Is this some sort of safety feature? Little kids are always, or at least they should be…backseat passengers so maybe their windows don’t go all the way down as another way of keeping them inside the car, they can’t squeeze out the top of the window.

No, that’s not it. It has nothing to do with safety.

A website called Gear Patrol explains it this way: the real reason the rear windows don’t disappear into the doors is because there’s no place for the glass to go when the window rolls down. If you look at a four door car from the side, you’ll see that the front doors are rectangular, and the front windows can slide right down.

But the rear doors are usually curved or slanted forward to make room for the back wheels. This shape interferes with the path of the back windows: The glass sheets can only slide down so far before they’d hit the wheel wells.