15 November 2012

The complexities of mass transit and energy policy

...many studies of energy efficiency by mode often make questionable and — depending on the author’s point of view — self-serving assumptions. The main trick is to look at autos with but one passenger and compare them to transit vehicles in which every seat is full...

But in the real world, this is emphatically not the case.  At any given time, the average auto has somewhere around 1.6 passengers, and the average (typically 40-seat) bus has only about 10. Rail vehicles typically have more passengers (on average about 25), but then again they are also typically much larger...

It is not clear that moving around large and largely empty vehicles is much of an improvement over moving around smaller ones. In fact, it may be worse...

Pumping up ridership by adding transit service will probably do little good, and may even be counterproductive. The reason is that new service promises to reduce transit’s already less-than-spectacular load factors and result in largely empty vehicles. Why? At this point we have picked all the low-hanging fruit in terms of transit markets....

On the other hand, if we can persuade travelers to leave their cars and ride existing transit service, rather than new service, the environment will benefit greatly. Given its current low load factors, transit generally has plenty of capacity to absorb new customers with practically zero additional energy expenditure. Strategies to pursue this would involve economic incentives to influence behavior. These might include pull strategies designed to lure riders onto transit, such as fare cuts, or push strategies designed to get them out of cars onto transit, such as increasing gas taxes, congestion tolling, or charging market rates for street parking...

So there it is: to benefit the environment, probably the best thing to do is be very skeptical about adding new transit service and even to discontinue some service we are currently providing (sorry, liberals). Simultaneously, we should raise fees and taxes for driving (apologies to you conservatives).
I heard part of this essay on the radio last night while driving to pick up Chinese take-out, and found the rest of it this morning at Freakonomics.  It's a complex matter that's not reliably represented by excerpts, so please view the original for details and caveats.


  1. ...many studies of energy efficiency by mode often make questionable and — depending on the author’s point of view — self-serving assumptions

    I had to chuckle a bit hearing this coming from The Freakonomics camp, considering it's basically in the business of making money off this kind of contrarian pro-industry pop science.

    Time and again, the critics say, Dubner and Levitt raise provocative, if unoriginal, arguments only to move on to the next provocation without bothering to mention substantial, even overwhelming, evidence to the contrary. Among other things, readers are told that solar power contributes to global warming, that the climate models that predict warming have all been doctored to achieve matching results, and that carbon dioxide does not “necessarily” warm the earth and may have had little to do with recent warming trends - all arguments that the majority of climate scientists reject as wrong. What’s more, some of the researchers Dubner and Levitt cite charge them with mischaracterizing their research. In short, the authors’ critics charge them with letting their own particular bias - for clever and scandalously counterintuitive answers to big questions - blind them to the weight of the evidence.

    “At a minimum, they’re guilty of extremely shoddy scholarship and overcredulity,” says Gavin A. Schmidt, a climate scientist at NASA’s Goddard Institute for Space Studies. “At the worst, they think just being contrarian is much more important than being right.”


    Pumping up ridership by adding transit service will probably do little good, and may even be counterproductive.

    Ridership has steadily increased where I live despite little or no service expansion, and in many cases reduced bus runs and lines. Anybody who actually rides transit often can tell you that the choice between owning a car and taking transit comes down to how reliable, extensive, and often transit runs.

    At least he was on to something with congestion taxes.

  2. Taxation with representation is no longer a safeguard is it. What keeps me off of mass transit is two things: racism and germ load. I've been called some rather despicable racial epithets while riding a bus and every time I get sick, it's because I rode in a small container with a bunch of other walking exhaling petry dishes. --A.

  3. I want to know where these near-empty buses and trains are. I'm in Chicago, and more than a million people work in the Loop, and precious few of them drive, because there aren't enough parking spaces. Not to mention the fact that you can pay $20 a day to park a mile away from your job, as long as you're in before 8.

    All that means that the trains are full, the buses are full, and if it's raining you can try to push your way on but good luck.

    So are they selectively looking at systems in small towns at buses in the middle of the night? It all sounds very fishy to me.

    1. If you had read the article, you would have noticed the comment that -

      "the places where land use and demographic characteristics are congruent with high transit use—such as CENTRAL CHICAGO..." (caps added)

      No one argues against the efficacy of mass transit if densely populated urban areas. If you want to know where you can ride a near-empty bus, visit a mid-size or smaller city. I see near-empty buses frequently even in Madison.

  4. The line of thinking in the freakonomics article has been rebutted before - but here's a couple good explanations from a high-quality transit writer:


    and similarly:


    1. It doesn't appear to me that either one of those posts actually rebuts the argument offered at Freakonomics, which is basically "to benefit the environment, probably the best thing to do is be very skeptical about adding new transit service and even to discontinue some service."

      Neither of the posts at HumanTransit says that the environment benefits from more mass transit. What he is saying (twice) is that communities have an obligation to offer public transit as a service (for those who do not have automobiles),and it is not done because "the outcry would be tremendous, the politics toxic."

      That's a separate argument about a different justification, not a "rebuttal" of the premise that mass transit may not be optimal for the environment.

      Correct me if I'm wrong.

  5. But here's a counterargument:

    "A private car, in contrast, spends the vast majority of its much shorter life sitting in a garage, driveway, or parking lot - all of which require vast amounts of energy to build and almost none of which is cleanly produced and transmitted over a grid."

    - from one of the followup posts at the original source.


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