Engines idling in traffic jams wasted an estimated 2.3 billion gallons of fuel in 2003, according to the Texas Transportation Institute’s 2005 Urban Mobility Study. Using the EPA's estimate of 1 gallon of gasoline producing 20 pounds of CO2, that would mean 46 billion pounds of CO2 needlessly went into the atmosphere. To address this concern, many carmakers are seeking to equip their vehicles with automatic shutdown and restart systems. Most hybrids already take advantage of this technology.
Drivers of non-hybrid vehicles will still be forced to idle their engines in traffic jams, but they can help by turning off the engine when waiting at the curb to pick up the kids or during other temporary stops off the roadway.
It’s also a good idea to skip those remote cold-start devices. While it’s great to get into a car that’s already cozy on a frigid day, the warm-up idling wastes fuel and dumps needless CO2 into the atmosphere.