The numbers in the rail summary spreadsheet show that rail transit often, but not always, uses less energy per passenger mile than buses. But this is deceptive because most rail lines are built in heavily traveled corridors, while many bus lines serve suburban routes and run nearly empty much of the day. The master spreadsheet shows fourteen different bus operations use less energy per passenger mile than the most energy-efficient rail operation. Thus, it is likely that many new rail lines use more energy per passenger mile than the buses they replaced.
The numbers in this week’s analyses also show that less than half of all U.S. rail transit lines use less energy per passenger mile than the average passenger car, and only three rail lines in the entire country use less than a Prius or other high-mileage auto. Thus, building rail transit provides no assurance of saving any energy.
My previous reports, Great Rail Disasters and Rail Disasters 2005 showed that San Diego and Boston are the only cities that have built new rail lines in the last 30 years that have seen an increase in transit’s share of total travel or commuter travel since 1980. If all rail transit does is divert riders of energy-efficient bus routes to less energy-efficient rail routes, then it is a complete waste of energy.
Meanwhile the energy cost of building rail transit can be huge, especially if tunneling is required. Even if rail operations save energy, it can take decades for that savings to make up for the energy cost of construction. Since rail lines have to be largely rebuilt every 30 years or so, any energy savings that does not repay the construction cost within 30 years is likely to be a net loss.
A few new rail lines, such as the San Diego light rail, do seem to save a small amount of energy, though it is likely it will take years if not decades for that savings to cover the cost of construction. The high dollar cost of rail transit, combined with the high risk that there will be no real savings, eliminates any notion that rail can be a cost-effective way of reducing energy consumption or greenhouse gas emissions.
If saving energy and reducing CO2 emissions are worthy public goals, then there are many transportation policies that can achieve these goals with greater assurance and at a far lower public cost. Here are three ideas.
1. A Transit Strategy — From an energy standpoint, the bus systems in many cities perform at a mediocre level. But some systems use less than half as much energy per passenger mile as automobiles. The big difference is average bus loads: by carrying an average of 15 to 30 passengers at a time, instead of the national average of just 10, bus systems in Los Angeles, New York-New Jersey, Providence, and elsewhere manage to save lots of energy.
In this regard, several people have brought to my attention a 1977 study by the Congressional Budget Office titled Urban Transportation and Energy. The study found that express buses did a far better job at saving energy than rail transit, partly because a much larger share of people riding express buses would otherwise drive their cars than the people who ride rail. “Rail rapid transit offers hardly any aid to the nation’s efforts to save fuel,” said the study. As such, “expenditure of federal funds on these systems for purposes of energy conservation appears to be misguided and possibly even counter-productive.” The study is titled Urban Transportation and Energy.
Increase bus loads: The best way to increase bus loads is to provide the best service to areas where most transit customers live. The transit industry has a goal of providing service within a quarter mile of every suburbanite in every urban area, which guarantees lots of empty buses. Agencies should focus instead on the urban core, where transit-dependent people tend to locate, and provide corridor and limited services in the suburbs.
Buy smaller buses: When they must serve routes that won’t attract as many riders, transit agencies should reduce the size of their buses. Because the federal government pays much if not all of the cost of new buses, transit agencies tend to buy buses that are larger than they really need. Smaller buses would use less fuel and could be used on routes where average loads were less than 15 people at a time.
It is worth noting that by far the most fuel- and greenhouse gas-efficient transit services in the National Transit Database were van pools, which consumed an average of 1,510 BTUs and emitted 0.24 pounds of CO2 per passenger mile. Compare that with any of the modes listed in the table on Tuesday’s post. The Congresional Budget Office study also found that van pools were the only form of public transit that did even more to save energy than express buses.
Use alternative fuels: Larger loads and smaller buses could do far more to reduce the amount of energy used by public transit than building rail lines. If the goal is to reduce greenhouse gases, using alternative fuels makes a lot more sense than relying on electric power, which usually means coal. Biodiesel, for example, is estimated to produce only a third of the net CO2 emissions of regular Diesel.
2. A Highway Strategy — The Texas Transportation Institute estimates that congestion costs more than 2.3 billion gallons of wasted fuel each year. Relieving this congestion by fixing bottlenecks, using congestion tolls, and adding new capacity will do far more to reduce energy than rail transit. Moreover, new highways can largely pay for themselves, especially if tolls are used, while rail transit requires huge subsidies.
Some people fear that new roads will simply induce more travel, and the energy costs of that travel will cancel out the savings from congestion relief. As previously discussed here, the induced-demand story is as much a myth as the claim that General Motors shut down streetcar systems in order to force people to buy cars. Besides, increased mobility leads to increased wealth, and increased wealth will help us cope with any global climate problems that arise in the future.
3. A Transportation Strategy — This analysis compared transit systems with the average passenger car, which consumes about 3,445 BTUs per passenger mile. But many cars are well above (or below in this case) average.
Vehicles that get 30 miles per gallon or better, such as the Ford Escape Hybrid, Honda Fit, Toyota Corolla, or Camry Hybrid, use less than 2,800 BTUs and emit only 0.43 pounds of CO2 per passenger mile (assuming an average of 1.5 people per car). The Toyota Prius and Honda Civic Hybrid consume less than 2,000 BTUs and emit only about 0.30 pounds of CO2 per passenger mile. Only two commuter-rail lines in the New York region and one light-rail system (San Diego) do this well.
The EPA estimates that switching to hybrid-electric vehicles can reduce energy consumption by 30 to 40 percent and greenhouse gas emissions by 29 to 35 percent. Other technologies on the horizon can do even better.
Spending billions on rail transit is unlikely to coax more than 1 or at most 2 percent of travelers to switch from autos to transit. Relatively minor incentives will be needed to persuade 1 or 2 percent of Americans to change from the car they have to a Prius or another car that gets 30 to 40 miles per gallon or better, and the result will do more to reduce energy use than rail transit.
In fact, no government incentives may be needed at all. During the 1970s and 1980s, high fuel prices led Americans to buy cars that were more fuel efficient, with the result that the average car on the road in 1990 consumed about a third less energy per mile than in 1973. After 1990, average miles per gallon flattened out, but cars got bigger, so ton-miles per gallon continued to increase.
If gas prices stay high, we can expect fuel economy to increase again. In fact, since 2002, it has grown at an average of 1.1 percent per year. Within a decade (which is the time it takes to plan and build a rail line), the average passenger car will probably use less than 3,000 BTUs and emit less than 0.47 pounds of CO2 per passenger mile.
This means it won’t be enough for a rail line to reduce energy use to a level below the average automobile of today. To really save energy, it will have to reduce energy use to a level below the autos of the future.
There may be places in the world where rail transit works. There may be reasons to build it somewhere in the United States. But saving energy and reducing greenhouse gas emissions are not among those reasons. Regions and states that want to be green should explore other alternatives such as the ones described here.