I can't even sit in the back seat w/o feeling sick.

I have this motion sickness when I try to read, watch, etc. in a moving vehicle. I have to close my eyes (sleep is even better if possible and faster). I hate commuting.

I'm in the back seat with no air circulation, and I'll get sick almost immediately. Front seat in the same situation, and it takes several minutes. Driving, and I can go for an hour or so.

Open a window and things change. I can probably read a book in the back seat for 30 min, but if I need to change focus to horizon-book-horizon, I'll get sick faster. Same with interior-exterior-interior.. I've only ever been sick from video games once when I first played Descent, and with the invention of "Mask poor action scene with wobbly camera", I have felt a few small familiar headaches.

Why women are more susceptible to motion sickness?

Well, she says motion sickness is tied to puking up bad things we eat, well, women were the ones doing most of the picking up and tasting back in ancient times.

Why is a passenger more susceptible than the driver?

The driver is focused outside. They "become" the car. Every jiggle of the wheel, every push of a pedal, the car becomes an extension of the body.