Introduced in 2012, the second version of the Clean Air Vehicle decal scheme introduced a two-tier system allowing plug-in hybrids, CNG and fully electric vehicles to use California’s High Occupancy Vehicle lanes without having two or more passengers – said to cut commuting time by 36 minutes.

This had originally set a target of 40,000 green decals for plug-in hybrids, but this original allocation ran out in April. A further 15,000 green decals were authorised in July, with the last of this second batch issued in September. An additional 15,000 will now be issued from January 1st, but the Department of Motor Vehicles is already accepting applications.

The white decals, which are available for CNG and fully electric vehicles (including hydrogen fuel cell vehicles), are available in unlimited numbers and offer HOV lane access until January 1 2019 – the same expiry date as the scheme for plug-in hybrids.