A couple of weeks ago on our youth conference, I was sitting next to a woman, chatting about riding in such a large bus.* I mentioned that I liked riding so high up off the ground, and that I've always wondered what the inside of those big 18 wheeler cabs looked like. As fate would have it, we looked ahead to see that we were about to pass another 18 wheeler, and since we were riding slightly higher than the cab, we both waited in anticipation to check out the inside.
As we drove past and peeked in, we - both of us - let out a loud, shocked, high pitched, involuntary "Ewwwww".
The only thing either one of us had seen in our brief glance, was the driver. Really BIG driver. - - - And the only piece of fabric anywhere near the top half of his body was the skinny little seatbelt strap.
Fortunately there was no time on our way past to see the answer to your next question. Yes, I know what it is, and NO, I don't know and I prefer not to speculate.
*Our very nice driver made it clear that he would prefer the bus to be called a "coach". OK- but that just has me thinking I'm riding in a giant pumpkin.