25 August 2009

Sustainability and the Streetcar

Many times in the streetcar debate, I hear the comment that separated-grade light rail would be a better option for Cincinnati. "We need to connect downtown to Kenwood and the Airport, not the Riverfront to Clifton", for example. I disagree. My feeling is that in a city like Cincinnati, where freeway traffic is not really a choke point in development, it is more important to build up the close-in neighborhoods before trying to connect to the suburbs.

So I ran across a study done last year for the city of Vancouver, by the University of British Columbia School of Architecture, in which they analyzed the different transportation modes. Here is the summary in PDF format. They judge these transit options based on 3 sustainability principles:

1. Shorter trips are inherently better than longer trips.
2. Low carbon is better than high carbon.
3. Which is most affordable long term?

Note that in this study, they use the word "tram" to describe a modern streetcar.

In the first sustainability principle, streetcars and electric buses score similarly:

Determining the carbon footprint takes more levels of deduction. First, how much energy is used per passenger mile:

Then they analyse the carbon emissions based on various sources of electricity. After that they extrapolate to this graph showing emissions when electricity is generated from coal. (They also have graphs using hydro power, but that is not very relevant to Cincinnati):

Then they get into capacity of the vehicles, the capital costs, and the operational costs. After combining all that info, they conclude with these graphs showing Total Cost per passenger Mile:

and current and future energy costs:

The study summarizes as follows:

"...Based on the three sustainability criteria, reducing trip length, greenhouse gas reduction, and lifecycle costs, trams represent the best investment. This investment is entirely dependent, however, on a long term commitment to balancing jobs and housing and a gradual reduction in the per capita demand for daily transportation of any kind. If most trips in the region are short then the rationale for investment in trams is overwhelming. If all trips are long then the rationale for the very expensive Skytrain system may still hold sway. Currently our region is at a tipping point between the two. Decisions made now about which mode to invest in could precipitate very different land use consequences, consequences lasting for decades. These arguments apply to every North American metropolitan area..."


John Schneider said...

Have you noticed how the anti-rail crowd always conjure up some statistics "proving" that buses and cars are always more efficient than rail, or use less energy per passenger mile than rail, or some other dubious measure?

The reason they can say that is simply because buses and cars make longer trips per passenger moved -- three to six times longer in this example.

So imagine a car that travels to downtown from West Chester. It makes one start during the whole trip and travels 18 miles or so. It's a lot of nonstop miles, so the numbers look pretty good. Now consider light rail running on the same route. It stops probably twenty times to board and de-board passengers, perhaps four or five times in downtown alone. People are getting on an off the whole time, and the average trip is fairly short, five miles, say. So even though you're serving many more people on lots of different types of trips, when you divide the total costs by the miles compiled on all those short trips,the average cost per mile in terms of dollars or energy expended looks high. But if you had six buses or 250 cars emulating the work of the LRT, the sum of their costs would be much, much higher and both would be much less efficient than rail.

Randy Simes said...

Fantastic information all around. Thanks for posting this, and thanks for the comment John. Both are very informative.