Though dairy farms, air travel and oil and gas refineries have come under fire in California’s fight against climate change, they are not the biggest culprit.

That dubious honor lies with the passenger vehicle. The tailpipes of the cars and pick-up trucks that flood California’s freeways every morning and afternoon generate more than one-fourth of the greenhouse gas emissions in the state, according to air quality regulators.

Emissions from cars outstrip all other single sources of greenhouse gases in California, including the freight and shipping industry, oil and gas production, and all the state’s commercial and residential real estate combined.

On Monday, Southern California transit agencies will celebrate Earth Day by urging commuters to help the environment by leaving their cars at home and riding the bus, the train or a bicycle for free.


Los Angeles County’s transit agency, the Metropolitan Transportation Authority, is waiving its $1.75 fare all day. Rides on Metro’s 2,200 buses and six rail lines will be free starting 4 a.m. Monday, the agency said.

“What better time to turn over a new leaf than on Earth Day?” said Los Angeles County supervisor and Metro board chair Sheila Kuehl in a prepared statement. “If you make Metro part of your daily commute moving forward, you’ll save half a ton of CO2 emissions over the year.”

The fare gates at Metro’s 93 rail stations will be unlocked to allow passengers to board without swiping a fare card. Bus drivers will not be checking for fares, officials said.

Southern California’s commuter rail system, Metrolink, will also be free Monday. Commuters coming to downtown Los Angeles from the far reaches of Ventura County, Riverside or San Bernardino counties could save more than $25 on a round-trip fare.


If 1,000 commuters on Monday took the train instead of driving, Metrolink said, they would reduce greenhouse gas emissions by more than 23,000 pounds — the equivalent of the carbon removed by a forest the size of 10 football fields.

In Los Angeles, the Transportation Department will offer free fares on Commuter Express, DASH, Dial-a-Ride and a new on-demand shuttle service on the Westside. City officials said they hoped to eliminate 500 vehicle trips.

“Small changes like walking, biking, and taking transit every once in a while make a big difference for our future,” said LADOT general manager Seleta Reynolds in a prepared statement.

Half-hour rides on Metro’s bikeshare system will be free all day Monday. The green and black bikes are available in downtown, Chinatown, Westlake, Echo Park, University Park, Venice Beach, Culver City and Mar Vista.


Users can waive the $1.75 fee for a half-hour ride by entering the code 4222019 when checking out a bike. The code will work for an unlimited number of rides.

Other regional carriers, including Pasadena Transit and San Bernardino County’s Omnitrans system, will offer free fares, too.

laura.nelson@latimes.com

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