Originally enacted in $1963,$ CAA has been amended many times to tighten emissions standards. The California Air Resources Board $($CARB$)$ often adopts stronger fuel economy standards than those of CAA and often sets the precedent for the rest of the country on how to mitigate vehicle emissions. For example, CARB's Advanced Clean Truck Rule seeks to cuts pollution by requiring medium$-$ and heavy$-$duty truck makers to sell an increasing number of emission$-$free electric trucks in place of diesel and gasoline vehicles. By $2035,$ zero$-$emission truck$/$chassis sales will need to account for SS percent of Class $2$b$-3$ truck sales, $75$ percent of Class $4-8$ straight truck sales, and $40$ percent of Class $7$ and $8$ truck$$tractor$$sales$.$