By Patrick Bedard
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Some things everybody knows, just knows. Like the WMD Saddam had in his back pocket. Everybody just knew he had ’em.
Everybody just knows that mass transit is cleaner than cars, too, and saves fuel. And once again, everybody’s got it wrong.
“Light rail” is the darling of transit boosters these days, operating or under construction in 26 American cities, including sprawling Phoenix and scattered Seattle-Tacoma. This is a system of self-powered cars. Depending on the design, it may run on its own exclusive right of way or on tracks through the streets. “Heavy rail,” either subways or elevated, always runs on its own right of way. “Commuter rail” uses passenger coaches pulled by locomotives, often on tracks shared with freight lines.
“Most light-rail systems use as much or more energy per passenger mile as the average passenger car, several are worse than the average light truck, and none is as efficient as a Prius,” writes Randal O’Toole in a new study from the Cato Institute titled “Does Rail Transit Save Energy or Reduce Greenhouse Gas Emissions?”
From several federal sources, O’Toole calculated the average energy used per passenger mile for various transportation methods. Ferry boats came out worst, sucking up 10,744 BTUs per passenger mile. A Toyota Prius was best at 1659 BTUs per mile. The average of all automobiles, which includes SUVs, vans, and cars together, is 3885 BTUs per mile, whereas passenger cars alone average 3445. The average light-rail system is slightly worse at 3465. Buses, at 4365 BTUs, are much worse; commuter rail and heavy rail are better at about 2600 but still no match for the Prius.
It turns out that light-rail cars aren’t light, weighing in at about 100,000 pounds, roughly four times the weight of a bus and 34 times the weight of a Prius. Another problem: With electrical power, there’s major shrinkage between the energy of the fuel going into a generating plant and the actual power out the far end of the transmission system to the railway—10,300 BTUs in for 3400 BTUs out, according to the U.S. Department of Energy. Yet another problem: To justify the political demands that come with the huge investment, light rail runs at a greater frequency than buses, and the trains are largely empty at off-peak travel times and toward the ends of the lines. Fully loaded rail cars are very energy efficient, but every mile traveled by a nearly empty car pulls down the average.
Ready for a radical idea? Forget building new light rail for commuters—few ride it anyway—and streamline the roads instead. Here’s why. New rail systems take at least 10 years to plan and build, then last 30 to 40 years before needing a major overhaul, so new rail planned today will, on average, be in the middle of its life in the 2030s. So it must compete with the cars on the road then.
This will be a tough league. Although rail systems are locked into today’s technology for years to come, cars respond very quickly to new mileage requirements. The average car sold in 2020 will get 35 mpg—it’s the law! As those new cars replace older models in the fleet, average mileage will improve, dropping the BTUs per mile from 3445 today to 3000 in 2020, and on to 2500 in year 2035, O’Toole calculates, even if the mileage law never tightens beyond what’s already on the books.
Looking at publicly available records, only one light-rail system in the country now, San Diego, beats 2500 BTUs per mile by more than one percent—well, actually, Boston beats it by 1.08 percent—but the point still stands: Unless there’s an unexpected move toward nuclear-sourced electricity, the cars of the future will outperform light rail on energy efficiency.
The CO2 situation is harder to predict. Will biofuels survive ethanol’s current bad press? Will the Chevrolet Volt and other plug-in hybrids actually happen? If they do, cars look even better because cars have one advantage that trains will never match. Cars don’t run when nobody wants the trip.