vehicles and global warming

[misisgreen]

Transportation sources (cars, trucks, etc.) emit approximately 29 percent of total U.S. greenhouse gas (GHG) emissions in 2006. Transportation is also:

the fastest-growing source of U.S. GHGs, it produced 47 percent of the net increase in total U.S. emissions since 1990.
the largest user source of carbon dioxide (CO2), the most common greenhouse gas.

[rohitkumar]

Transportation is the major cause of Global warming as it causes about 30 to 50% air pollution. Trains, buses causes less air pollution than automobiles. Vehicles on road produces the most carbon dioxide in air. But what is the solution of reducing the global warming cause by automobiles. Is stop using car is solution? I think no, Instead of petrol & diesel engine vehicles using, using CNG & electric automobiles helps in reducing the global warming.