Compressed natural gas, hydrogen, electric, and plug-in hybrid electric vehicles meeting specified California and federal emissions standards and affixed with a California Department of Motor Vehicles (DMV) Clean Air Vehicle sticker may use HOV lanes regardless of the number of occupants in the vehicle. DMV issues Red Clean Air Vehicle stickers to applicants that have not already been issued a White or Green Clean Air Vehicle sticker, with the exception of the instances mentioned below. Stickers are valid through the following dates:

Stickers issued for Model Year 2004 or earlier vehicles, regardless of the issue date, expire January 1, 2019;
Stickers issued before March 1, 2018, expire January 1, 2019;
Stickers issued between March 1, 2018, and January 1, 2019, expire January 1, 2022;
Stickers issued on or after March 1, 2018, for a vehicle that had previously been issued a sticker between January 1, 2017, and March 1, 2018, expire January 1, 2022; and
Stickers issued on or after January 1, 2019, expire January 1, 2023.

DMV may issue stickers on or after January 1, 2020, only for applicants that have a household income at or below 80% of the state median income, which will expire January 1, 2024. The California Department of Transportation must publish a report between January 1, 2023, and June 1, 2023, detailing the number of stickers issued under this program.

Vehicles with stickers are also eligible for reduced rates on or exemptions from toll charges imposed on HOT lanes. For more information and restrictions, including a list of qualifying vehicles, see the California Air Resources Board Carpool Lane Use Stickers website.

(Reference Senate Bill 957, 2018, and California Vehicle Code 5205.5 and 21655.9)