Two issues contribute to the issue. One, CA has flat outlawed any truck older than a 2011 (i.e. pre-DEF). Historically, new trucss go on the long haul (OTR) circuit, and when they get to about half a million miles or so, they tend to go to local companies for pickup and delivery work, containers, agriculture. construction, etc. There they spent the rest of their life running a few miles a day. CARB eliminated more than half of the trucking fleet with that regulation. And right now, you can't buy a new truck. I've been trying to order a new Kenworth, and it looks like it might be 2013 before I get it.
Second, AB5, which prohibits owner operators. This is a common legal construct in trucking where the driver owns the truck, but "leases on" his truck to a corporation who handles registration, insurance, dispatch, billing, etc. Doing the union's bidding, AB5 outlawed this arrangement, and many, many truck owners simply "moved" to Nevada, Oregon, Arizona, etc, and continued driving outside of CA.
