The proposed regulations are pretty complex, but it appears to also have a transitional strategy where PHEVs (plug-in hybrids) can count as ZEVs for this quota.

The proposed regulations are pretty complex, but it appears to also have a transitional strategy where PHEVs (plug-in hybrids) can count as ZEVs for this quota. During the transition years, the rules shift in terms of requiring more battery-only range from the PHEV to count as one ZEV, with a way to have lesser range PHEVs count as a fractional ZEV in the fleet. E.g. they require 70 miles of range for full credits, and partial credits for 43 miles of range. I can't speak to economic feasibility, but with the Toyota RAV4 being one of the most popular cars in the US and already being available as a PHEV, it doesn't seem that far-fetched to have these kinds of vehicles becoming a large portion of those sold.