They can also struggle to turn the steering wheel correctly.  I remember sitting at a red light watching an obese woman tring to make a left turn.  This was several years ago, and I'm not sure why the scene has stuck with me as vividly as it has, but my god what a tough time she was having. It was a minivan with next to no room between her gut and the wheel. Her arms were pumping in short intervals moving the wheel portions of the needed rotation with each monumental bit of physical exertion. She must've been sweating at the end of it. It was tougher than walking to the car. And to think she may have had to do this multiple times in one route!?!    Did she have her seat that far forward because her short arms required it?  Maybe, or maybe it was a unique case where she was transporting something large in the back. Either way, I still remain shocked years later at the thought of this woman driving around barely able to turn the steering wheel...nothing about that is safe.