Carpool to work! You can cut your gas consumption by half or more. Or, use no gas at all: Ride a bike
Why leave the carpool lanes empty while you sit alone in your car stuck in traffic? See if your employer has a carpooling program. If not, discuss the possibility with your human resources officer and canvass fellow employees about carpooling.
If carpooling isn't a great option for you, check bus routes, trains, walking paths and bicycle routes. It's best to allow yourself more than one option for commuting given inclement weather or the chance of missing an infrequent bus.
For bicycle commuting, see if your workplace has an indoor bicycle lock up. If none exists, talk with your employer about providing one. Remember that even cycling at the mellow rate of 5 miles per hour, you'll burn about 175 calories in an hour. Compare to that to your car, which releases over 25 pounds of the heat-trapping pollutant carbon dioxide for every gallon of gas burned (not to mention other air pollutants that contribute to smog and harm your health).
For more information on ensuring your safety while bike riding, see "Shifting Gears: Tips for Safe Bike Commuting" at NRDC's Simple Steps.