In the metro areas in California they've been adding or replacing carpool lanes with these pay by the distance express lanes. To drive in them you need to get a little 'fastrak' box. Carpoolers still could use them, two people in a car get a discount, three or more are free. The more congestion the higher the rates get. The rates could get pretty expensive, I've seen it approach $0.50 between exits. That could add up to quite a cost for a daily commute. The notion kinda sits with me wrong, what I'm mostly seeing is a class separation where those with high end cars are driving past working class people. I suppose it's a better system than having everyone pay.
