> Can’t you pay to be in the HOV lane?

On a few of them, but not the ones I commute on and am talking about. If you do use one of the 'pay' lanes, it becomes free if you switch your fasttrak device to '3+' setting, and given the frequency of visually obvious violations in the ones you can't pay for, I would be surprised if many people are actually paying for the ones you can pay for.