Rising gas prices and concerns about greenhouse gases have stimulated calls to build more rail transit lines in urban areas, increase subsidies to Amtrak, and construct a large-scale intercity high-speed rail system. These megaprojects will cost hundreds of billions of dollars, but they won’t save energy or significantly reduce greenhouse gas emissions.

Although media reports suggest that many people are taking public transit instead of driving, actual numbers show that recent increases in transit ridership account for only 3 percent of the decline in urban driving. Also, contrary to popular belief, rail transit does not save energy. Many light-rail operations use more energy per passenger mile than the average sport utility vehicle, and almost none uses less than a fuel-efficient car such as a Toyota Prius. People who respond to high fuel prices by taking transit are not saving energy; they are merely imposing their energy costs on someone else.

Rail transportation is also much more heavily subsidized than other forms of travel. Where highway subsidies average less than a penny per passenger mile, and subsidies to flying are even lower, Amtrak costs taxpayers 22 cents per passenger mile and urban transit costs 61 cents per passenger mile.

Even if rail transport did save energy, spending more money on rail will get few people out of their cars. People who want to save energy should plan to buy more fuel-efficient cars and encourage cities to invest in traffic signal coordination, which can save far more energy at a tiny fraction of the cost of building new rail transport lines.