Natural gas powered cars...
Cost of building refueling stations and distance you can travel between fill ups are the 2 single issues that have slowed down a transition to CNG vehicles. Many companies are building their own refueling stations and converting their fleets to natural gas.
There are also opportunistic Natural Gas Producers with several different business models operating or planing to build future refueling stations, but the start up costs are very high.
Check out Clean Energy, t boone pickens company