Does rail transit reduce CO2?

An interesting new Cato study from Randal O’Toole says no:

Rail transit may use less energy, per passenger mile, than buses. But the introduction of rail transit rarely leads to a reduction in bus operations. Instead, buses that once followed the rail corridors are converted to feeder bus routes. So the incremental effect of rail transit on a transit system’s overall energy use can often be to increase consumption per passenger mile.


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. Three emit less greenhouse gases than a Prius, but several emit more greenhouse gases than light trucks.

Since auto efficiency will continue to improve as fuel prices rise and since rail lines have a working life of several decades, the difference is only likely to become greater. O’Toole suggests that improvements in fuels, vehicles, road innovations, and relatively inexpensive bus transit would be much more cost-effective for reducing greenhouse gas emissions than expanded rail service. Some of these improvements would be surprisingly cheap:

San Jose coordinated 223 traffic signals on the city’s most-congested streets at a cost of about $500,000. Engineers estimate that this saves 471,000 gallons of gasoline each year, which translates to a 9.2 million pound reduction in CO2 emissions. That works out to a cost of just 5.4 cents per pound.

At the margin, of course, if your city already has a rail line you’ll reduce your personal carbon footprint by using it. But if it doesn’t, reducing greenhouse gas emissions is probably not a good reason to spend millions of dollars building one.

Consider this my obligatory Earth Day post.


5 thoughts on “Does rail transit reduce CO2?”

  1. Thanks, Jacob. Nothing like a little despair for Earth Day.

    Unless you somehow contend that fuel efficiency is going to reach such levels that we aren’t going to wreck the planet, I find this post hideously depressing.

  2. Are you serious? Do you seriously think the market is going to lead to some solution like solar power for the problems like global climate change?

    I ask that not in a spirit of challenge but of honest inquiry. I visited that A Better Earth site of yours once or twice, and all I found was criticism of government-based approaches to environmentalism. I was hoping that someone would be proposing some market based solutions. I’d be willing to listen to that. And maybe I wasn’t searching that hard, but all I found were critiques explaining how government approaches won’t work….but offering no alternative.

    Which, as I said, just leads me to despair.

  3. Maybe I misunderstood your point there. No, I don’t think solar is the key to everything, but I do think it’s a promising technology.

    I often criticize government approaches to environmental problems, but mainly because I think they’re too often compromised by other interests. Our extremely wasteful ethanol subsidies are just one example.

    That said, I’m quite open to a tax on carbon emissions applied at the source of power generation. CO2 is a classic externality. If the problem is big enough, it certainly makes sense to tax it early in the supply chain and then let the market figure out the most efficient ways to cut back on emissions. So a role for government, sure, but in a way that takes advantage of economic discovery.

    I’d also like to see better pricing for energy related goods. For example, more toll roads, variable electric pricing, and rewarding small-scale producers of renewable energy who put excess power into the grid. There are lots of market approaches whose use could be expanded.

  4. Actually O’Toole’s conclusions are badly flawed because his figures on cars’ energy efficiency included both urban driving and the much higher-efficiency highway driving (the study doesn’t say so – I had to email him to find out). A valid comparison between transit and cars must be made on urban driving alone. Based on O’Toole’s distorted figures, transit is already more efficient than cars, so imagine how much better transit actually is.

    Nor does O’Toole take into account the many ways that transit makes possible a greener lifestyle by facilitating dense urban development that requires fewer and shorter trips overall. For a full critique see here.

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