Golden, Colorado-based Proterra, Inc. — the makers of electric commercial vehicles, systems and charging stations for them— raised $30 million, the company announced today. The investment was led by Kleiner Perkins Caufield & Byers (KPCB) and joined by GM Ventures, Mitsui & Co., Vision Ridge Partners and 88 Green Ventures. According to a press statement today, Proterra will use its new funding to: complete federal testing of its buses; supply vehicles and systems to pilot fleets; and increase the number of buses and systems its Greenville, South Carolina plant manufactures each year. The plant is supposed to have the capacity to produce 400 buses annually, when fully operational.