With the complete lack of competent and high quality public transportation options in California, I'm not sure "targeting the fleet" would be where I spend mos

With the complete lack of competent and high quality public transportation options in California, I'm not sure "targeting the fleet" would be where I spend most of my effort. Any vehicle that is tooling around empty is polluting. You've just moved the pollution from the vehicle to whatever source is powering the grid. Even if it was fully renewable that still would not a good excuse to entirely ignore efficiency in these "full vehicle for a single rider" transportation options.