Back in 2008, there was a regulation that was created to help remove massive rigs or vehicles from California roads to help reduce the cancerous emissions from Diesel fuel and others.
The mission is to have clean air in the sunshine state as the Senate Bill 1, was signed into law. What it means: Any diesel vehicles weighing over 14,000 pounds and built before 2010 are banned from operating on California roads as of Jan. 1, 2023.
According to CARB, "Diesel exhaust is responsible for 70% of the cancer risk from airborne toxics [...] therefore, by January 1, 2023, nearly all trucks and buses will be required to have 2010 or newer model year engines to reduce particulate matter (PM) and oxides of nitrogen (NOx) emissions."
Plans for cleaner Cali., air with a zero-emission vehicle world is aimed for 2045.