carpool north and south

I have always wondered, but can't remember if I asked it here...

Does anybody know why Northern CA has smart carpool lanes and Southern CA has stupid carpool lanes? I guess the easy answer would be that someone or some committee somewhere decided So Cal was too stupid to handle smart ones... but there might be other answers, I dunno..

The lanes in NorCal are in effect during heavy traffic hours only, so regular drivers can use them in off-hours like 2 a.m. etc, and the SoCal ones are just brainlessly in effect all 24 hours ;P