Light Rail Uses Twice the Energy as Driving

One of the justifications for diverting highway money to ridiculously expensive light rail systems is that light rail supposedly reduces energy consumption.  Really?  This is via the most recent report from the DOE's Transportation Energy Book, as highlighted by the Anti-Planner (click to enlarge):


The figures for cars are from tables 2.12 and 2.13 of the same report.  Even the best light rail systems are not substantially more efficient than cars, and this gap will likely continue to close, as it has for years, as cars get more efficient.

A Note on Freight: By the way, passenger rail promoters in the US always point to the Europeans as having a better rail system.  But while the Europeans put more of their passengers on rail than does the US, they put less of their freight there.  I would argue that the US system is much more "green", as the differences in energy use between a ton mile of freight on road vs. rail is much larger than the difference in energy use of a passenger mile on road vs. rail.  And besides, from a lifestyle standpoint, would you really want more freight on the roads?  (This is a real tradeoff -- unless one spends the absurd amount of money to build two separate systems, a rail network can be optimized for freight or passengers -- the two do not coexist very well on the same tracks).

Postscript: Just to head off the obvious rhetorical battles -- the incremental energy efficiency of moving one driver to a light rail rider of an existing system is very high.  The car consumption goes away and the train does not incrementally increase its energy use much with one more passenger.  So at the margin, it is correct when someone tells you that it saves energy to shift your commuting to an existing light rail line.  However, it does not make sense, from an energy perspective, to build a light rail line in the first place.  The investment is too high, the energy savings are negligible or non-existent, and the operating cost are so high that light rail tends to crowd out bus operations that help the poor.  As I have written before, for every light rail system I have checked, the cost to build the system is enough to buy every daily rider a Prius and the operating deficit enough to keep every one of these Prius's filled with gas.

Update:  I further understand that cars in the city likely have lower gas mileages than these averages, particularly for commutes that might be substituted by light rail.  But light rail is sold as if it is substantially more energy efficient, and it really would have to be orders of magnitude more efficient to justify the capital costs that are so much higher than for an equivalent capacity of roadway.  The efficiency is just not there.


  1. Frederick:

    Very good charts: Thanks.

    The problem is, I do not think that the progressive light rail folks are concerned so much with energy efficiency as they are concerned with making every one live a dense urban lifestyle. Exactly why utopian socialist thinkers have always wanted to have most of humanity grouped into urban living I cannot answer, but it does seem if you examine all of their solutions to the world problems, it involved moving people away from free living (guns, rural, self-reliant, self contained transportation, etc) to a more controlled environment (urban communal solutions to all problems).

  2. James:

    I'd be interested to see capital costs/maintenance costs of roads and highways included in these analysis.

  3. David:

    I'd also like to see the values for some of the heavy-rail systems (DC, SF, etc) considered too - I know that heavy rail is different from light rail in a lot of ways, and I'd be curious to see whether it compares to automobiles in a similar manner.

  4. Dr. T:

    Usually lost in these light rail scenarios are what happens after you get off. The station may be a mile or more from your final destination. Are there buses? Do you need to call a cab? Or, do you have to walk in Phoenix's heat or Seattle's cold rains? How much time and/or money did you lose by taking the "green" light rail system?

    I lived in the Hampton Roads Metropolitan Area when Norfolk and Virginia Beach were planning a multibillion dollar light rail line. The planned line was designed to do only one thing (although that's not how they promoted it): get poor workers from the "projects" in Norfolk to the hotels and restaurants on Virginia Beach. Virginia Beach has little parking, and the hotel and restaurant owners didn't want employees using up parking spots with their clunker cars. That's why they sought funding for the light rail boondoggle. They could have accomplished the same thing with less money by adding a few more metro transit buses (or, as "Coyote" notes, by giving all the poor employees Priuses).

  5. Not Sure:

    "How much time and/or money did you lose by taking the “green” light rail system?" - Dr. T

    Why People Don't Use Mass Transit- Steven Dutch

    Apart from the cost of wages, economic planners rarely acknowledge the value of individual time, but that has absolutely no impact on the reality that people themselves do put value on their time.


    There are plenty of good reasons to encourage mass transit, but arguments about the hidden costs of the automobile fall on deaf ears because people, unconsciously or not, factor time and convenience into their decision making. The average driver knows perfectly well why she drives.

  6. Danny J:

    I travel a lot on business. I have noticed that in cities where light rail exists, the trains almost always run close to empty (exception being Boston were light rail is used as part of the subway system).
    The whole light rail scheme just seems like a boondoggle to me.

  7. DAV:

    There's something about this graph that bothers me. I would think the goal is to minimize energy (measured in BTU's in this case). The graph does not show if this goal is being met.

    Comparing efficiencies to determine this is questionable if the efficiencies are unweighted. It matters little if one system is extravagant in energy usage if the others are not.

    One person riding a light rail would have a higher BTU per passenger mile than 100 persons riding the same rail. Kenosha, WI has a much higher BPPM than San Diego for the simple reason that San Diego likely has more riders.

    A light rail system has a higher energy overhead than a passenger car because of weight but it's possible to pack more people into a light rail than an automobile.

    So the real question is: knowing that increased ridership increases the efficiency of light rail, would a lower BTU expenditure be possible if ridership of current light rail systems were maximized as compared to other forms of transportation (also maximized)?

    The analyzis that produced this graph doesn't answer that question.

  8. epobirs:

    Dr. T,

    I've only had one occasion to use the rail system in Los Angeles County to commute to a job. This was an IT contract position with the Metropolitan Water District that has its HQ right next to Union Station. Driving to the rail station near-ish my home, although mostly in the wrong direction, was worthwhile mostly to avoid the hellish rush hour traffic to get to that part of the city. Costwise, it was a little less expensive than gas and parking.

    But when the job required me to go to a different MWD facility in La Verne, which despite being a good deal farther away was an easy drive with god traffic flow, the advantage of driving my own car immediately obvious.

    My work takes me all over the place but that contract was the only time the LA rail system was of any use to me.

  9. Brandybuck:

    The left likes dense urban areas because the left is urban. Urban versus rural is a dichotomy as old as Rome. Red state versus blue state isn't an accident.

  10. egk:

    The 'average' given in the table is not the average energy intensity of light rail travel in the USA. DoE tables show this to be about 3,450 BTUs per mile (the average on the table is the average of the 26 system averages, a meaningless number).