More than 100,000 zero-emission vehicles now travel the roads of California, according to a survey from the Plug-In Electric Vehicle Collaborative.

The organization teamed up with the California Air Resources Board to keep track of the number of clean vehicles sold in the state starting in December 2010. The study included battery electrics, plug-in hybrids, and hydrogen fuel cell vehicles.

California is the largest U.S. market for plug-in EVs. There are several initiatives supporting the adoption of EVs and infrastructure as a way of reaching state goals for reducing emissions.

Two years ago, Gov. Jerry Brown set the goal of reaching 1.5 million zero-emission vehicles in the state by 2025. Zero-emission sales now make up only a small portion of the 15 to 16 million vehicles sold annually, according to the Los Angeles Times.

Gov. Brown and the California Public Utilities Commission are in the process of constructing at least 200 public fast-charging stations and another 10,000 plug-in units at 1,000 locations across the state. NRG Energy Inc. is funding the $120 million settlement.