High-Speed Rail and CO2

Photo: Shi Yali

One of the less-publicized components of the stimulus package was an $8 billion commitment to develop a high-speed rail (HSR) network in America. This is no more than a down payment, given the very large sums needed to build HSR (University of Minnesota transportation scholar David Levinson estimates that the proposed California segment alone will cost $80 billion, or more than $2,000 per Californian; given my state’s financial problems, this is going to require a very large bake sale).
Since this policy appears to be a personal favorite of the president and other officials, the needed funding may well materialize down the road. But it is worth asking whether the touted benefits will too.
Backers cite many gains to be reaped from HSR, including relieving crowding at airports and on highways; cutting the need for expensive new air and road infrastructure; preventing road fatalities; reducing travel times and costs; promoting economic development (particularly in areas not well covered by air service); improving travel reliability; boosting productivity; spurring technological advances; stimulating the economy/creating jobs; and, because HSR will run on electricity and may require less energy to move each passenger, reducing greenhouse gas emissions.
This is a long list and the blog is a short medium. So for now let’s just consider the final point about HSR’s environmental benefits. Under some conditions, there is no doubt that an HSR system would reduce greenhouse emissions. Unfortunately, a study undertaken by the consulting firm Booz Allen Hamilton for the U.K. Department for Transport raises some troublesome questions about whether these conditions can be met in reality.
Booz Allen considered two potential U.K. HSR lines (London-Manchester and London-Edinburgh/Glasgow). They found that the CO2 emissions required to move HSR passenger seats were about the same as those required to move automobile seats — hardly a slam dunk for rail. In fact, intercity bus came out considerably cleaner than HSR on a per-seat-mile basis.
HSR would emit less on a per-seat mile basis than air travel. But the major caveat is that all of these figures consider emissions from operations only, without taking into account the very large amount of pollution that will be created in the construction of the HSR system.
When the emissions spewed by all those earth movers, tunnel boring machines, bulldozers, trucks, cranes, etc. are taken into account, the carbon advantage for HSR vis a vis air travel largely evaporates.
What would the bottom line be if the proposed U.K. lines were built? It all depends on how many people shift from air to rail; the more HSR passengers the better. But the authors found that even if the mode split on the proposed London/Manchester line shifted from 50-50 air/rail (approximately the current distribution) to 100 percent rail ridership, emissions over a 60-year period would be lower if the HSR line was never built.
The picture for HSR is somewhat brighter for a proposed London/Scotland line, because that corridor currently has a low 15 percent rail share (meaning there’s more scope for people to switch to rail). But to make the rail line worthwhile, HSR would have to capture almost two-thirds of the air/rail split. This is not impossible, but it may prove difficult given that air travel has a considerable speed advantage over HSR and will continue to do so in the future. (For reference, even the California HSR authority, which strongly supports the program, forecasts that rail will attract only one third of the air/rail split in the California corridor).
There are, of course, many uncertainties involved in this type of analysis. Technological advances may make electricity production cleaner in the future (though airplanes’ fuel economy may improve as well). Obviously Britain is not the U.S. (although given its high population density and short distances, Britain may actually be a better place for HSR than most areas of our country).
Still, the results of this study deserve careful consideration. No one argues that futuristic rail isn’t a great way to get from Main Street U.S.A. to Epcot Center (usually). But given the very severe budget constraints we are currently facing, a program as costly as HSR should be evaluated very thoroughly despite its considerable allure.
Hat tip: David Bayliss