Related by context. Frequent words. (Click for all words.) 55 GHG reduction 55 tailpipe emissions 54 greenhouse gas 54 emission 53 greenhouse gas emission reductions 53 GHGs 53 CAFE standards 52 emissions 52 greenhouse gas emissions 51 carbon emissions 51 greenhouse gases 51 emission reduction 51 carbon dioxide emissions 51 polluter pays 50 carbon emission 50 CO2 emissions 50 carbon dioxide emission 50 CO2 emission 50 greenhouse gas emission 49 exhaust emissions 49 emission reductions 49 greenhouse emissions 49 greenhouse gasses 49 speed limiters 48 CO2 48 reduce carbon emissions 48 reducing carbon emissions 48 corn ethanol 48 GHG 48 VMT 48 scrappage 48 GHG emissions 48 carbon dioxide CO2 emissions 47 C# emissions 47 biodiesel blends 47 carbon 47 alternative fuels 47 carbon emitting 47 pollutant emissions 47 greenhouses gases 47 greenhouse gas GHG 47 reducing CO2 emissions 47 fossil fuel 47 cleaner fuels 46 PHEVs 46 diesel 46 renewable fuels 46 Fuel Economy 46 gas guzzlers 46 rebates 46 curbing greenhouse gases 46 reduce greenhouse gas 45 hybrids 45 Pavley 45 technologically feasible 45 biofuels 45 Co2 45 congestion pricing 45 CARB 45 incentives 45 emit greenhouse gases 45 CO2 emitted 45 Waxman Markey 45 gas guzzling vehicles 45 greenhouse gas GHG emissions 45 Waxman Markey bill 45 nitrous oxide emissions 45 Average Fuel 45 fossil fuels 45 nonpolluting 45 ZENN 44 carbon dioxide 44 renewable energy 44 diesels 44 FFVs 44 Greenhouse Gas 44 cleaner burning 44 gas guzzling SUV 44 particulate emissions 44 TerraPass 44 gas guzzler 44 NOx 44 EVs 44 environmentally friendlier 44 bio fuels 44 zero emission 44 ethanol 43 Fuel Efficiency 43 BlueMotion 43 ethanol blends 43 Emissions 43 PZEV 43 emit carbon dioxide 43 internal combustion engine 43 global warming gases 43 reducing greenhouse gas 43 Greenhouse Gas Emissions 43 renewables 43 biofuel 43 tailpipe 43 HCFC