Two to three percent of cars in regular use statewide are unregistered, often due to emissions problems. Many of them are “gross polluters” with five to twenty times the emissions of a typical car.

Exhaust from fewer than a million of these older, very dirty cars could be creating 30 percent of actual statewide vehicle emissions. Unregistered vehicle emissions are not included in state air quality models, so they should be considered unique and additional potential emissions reductions that can be used to meet air quality standards.

Most of these unregistered, dirty vehicles reside and drive in disadvantaged community census tracts.

"The country demands bold, persistent experimentation. It is common sense to take a method and try it: If it fails, admit it frankly and try another." -- Theodore Rooselvelt


2023 Cal-ITP Report

2022 CCFR Report

UCLA Luskin Center for Innovation Reports