The NEWS says the California port situation is caused by a driver shortage.
Not so fast: It is in part caused by a California Truck Ban which says all trucks must be 2011 or newer and a law called AB 5 which prohibits Owner Operators.
Traditionally the ports have been served by Owner Operators (non union). California has now banned Owner Operators.
Long term, truckers in California are not investing in new trucks because California has a law that makes them illegal in 2035.