https://www.siliconvalley.com/2020/01/13/californias-hydrogen-highway-never-happened/

California has been dreaming of a clean, modern hydrogen highway since 2004, when former Gov. Arnold Schwarzenegger ordered preparations for a traffic jam of zero-emission, hydrogen-fueled cars, buses and trucks.

That revolution, part of the battle against climate change, never materialized. The technology remains expensive and hasn’t gained wide traction, ceding the green-transportation crown to battery-powered electric vehicles, which are more widely available and support an ever-growing recharging network.