Related by context. Frequent words. (Click for all words.) 69 CNG 59 CNG buses 57 bio diesel 57 diesel 55 biomethane 55 E# ethanol 54 flex fuel 54 alternative fuels 54 hydrogen powered 53 hybrid electric 53 diesel powered 52 biogas 52 biodiesel 51 cleaner burning 51 hydrogen fuel 51 electric hybrid 50 LPG 50 diesel engines 49 liquefied petroleum gas 49 cleaner fuels 48 hydrogen fueling 48 diesel engine 47 hydrogen 46 gasohol 46 liquid propane 46 PHEV 46 low sulfur diesel 46 zero emission 46 Hybrid Electric 45 hydrogen refueling 45 internal combustion engines 45 diesel fuel 45 Clean Cities 45 EVs 45 hybrid 45 bio ethanol 44 buses 44 ethanol blended 44 CNG stations 44 ethanol blends 43 Alternative Fuel 43 vanpool 43 natural gas 43 cogeneration 43 NGV 43 gasification 42 electric propulsion 42 Ford Escape Hybrid 42 internal combustion engine 42 liquefied natural gas 42 bio fuels 42 Alternative Fuels 42 liquid fuels 42 selective catalytic reduction 42 electric 42 PHEVs 42 cleaner greener 42 propane 42 diesels 41 gas 41 biofuel 41 renewable energy 41 coal gasification 41 cogeneration plant 41 liquified natural gas 41 unleaded fuel 40 hybrid powertrain 40 LNG 40 Hydrogen 40 Coulomb Technologies 40 Electric Vehicle 40 environmentally friendly 40 electric scooters 40 electric hybrids 40 LCVs 40 diesel locomotives 40 taxicabs 40 rotary engine 40 Fuel Cell 39 biodegradable bags 39 Enova 39 liquefied gas 39 hybrids 39 syngas 39 mass transit 39 Toyota Prius hybrid 39 combustion engines 39 fuel 39 powertrains 39 gas guzzler 39 EV charging 38 vehicles 38 cylinder diesel 38 turbo diesel 38 IdaTech 38 Electric Vehicles 38 Bus Rapid Transit 38 Escape Hybrid 38 carpooling 38 propulsion systems 38 biobutanol