Public transit helps the poor, saves energy, and cleans the air, right? Not really. Transit is a subsidy to the wealthy as much as it is to the poor, and it really isn’t any greener than driving.
Some low-income people ride transit, but the people most likely to use transit to get to work are those who earn $75,000 and up. According to table B08119 of the Census Bureau’s 2015 American Community Survey, 6.6 percent of people who earn $75,000 and up take transit to work, as opposed to just 6.2 percent of people who earn $15,000 or less.
Nor is transit particularly green, at least, not according to the Department of Energy’s Transportation Energy Data Book. The average car uses about 3,100 BTUs per passenger mile while the average SUV uses about 3,500. By comparison, transit buses and light rail average about 3,800. While heavy rail averages just 2,150 BTUs per passenger mile, that is heavily weight by New York City. Outside of New York, the only heavy-rail lines more energy efficient than cars are in San Francisco and Atlanta. By operating mainly during rush hours, commuter rail does okay at 2,700 BTUs, but many commuter lines, including those in Dallas, Minneapolis, Nashville, and Philadelphia, are worse than driving.
Many of these numbers are heavily weighted by New York City, where 40 percent of all transit rides and 62 percent of all rail transit rides take place. Transit in New York City is pretty energy efficient, but outside of New York, the only urban areas with transit more energy efficient than cars are Atlanta, Chicago, Honolulu, Portland, and San Francisco-Oakland.
Counting all modes, from streetcars to ferry boats, the nation’s transit uses 3,700 BTUs per passenger mile, more than either cars or SUVs. If you want to save energy, you’ll do better by getting more people to drive fuel-efficient cars such as the Prius, which uses less than 1,700 BTUs per passenger mile.
For fossil-fueled transit, air pollution is roughly proportional to energy consumption, though Diesel-powered vehicles produce more nitrogen oxides while gasoline-powered vehicles produce more hydrocarbons. Electric-powered transit can actually be more polluting than petroleum-fueled transit if the electricity is generated by burning fossil fuels, because it takes 3 BTUs of fossil fuels to deliver 1 BTU of energy to electricity customers.
The average gasoline-powered car emits about 222 grams of carbon dioxide per passenger mile. The Washington Metro produces about 256 grams per passenger mile, while light rail in Salt Lake City produces more than 400. Electric-powered transit systems on the West Coast, which gets most of its electricity from hydropower, do better. But it makes more sense to make cars that are more energy efficient and use that hydroelectric power in places of fossil-fueled energy consumers, such as heating homes and offices, than it does to build more rail transit in California, Oregon, or Washington.
You might be able to personally save energy by riding transit. But most transit expansions actually use far more energy and emit more pollution and greenhouse gases than they save.