Big transit projects have a big carbon footprint

toronto street car
CC BY 2.0 Toronto streetcar/ Lloyd Alter

The late Toronto Mayor Rob Ford liked driving his SUV and didn’t like stupid trolleys in his way. So when it came to a fully-funded ready to go plan for Light Rapid Transit (LRT) he had a simple idea and said on March 22, 2012:

People want subways, folks. They want subways, subways. They don’t want these damned streetcars blocking up our city. That’s what they don’t want….I’m not going to support the LRTs, I’ll tell you that right now. I’m going to do everything in my power to try to stop it.

Now it is March 2017, and Toronto doesn’t have the LRT that might have served much of the east end of the city by today. It is still arguing about a one-stop subway extension that will cost over three billion dollars and make residents’ bus rides longer than it is now, and will take probably another decade to build. Everybody knows this, but everyone wants the votes that elected Rob Ford, who attracted the same kind of dedication and belief among his followers that Donald Trump does among his. As was often said about Justin Trudeau’s father: He haunts us still.

The biggest living supporter of the subway, besides Mayor John Tory, is an environmentalist, Glenn De Baeremaeker, who used to fight developers and save parks, and who cycles to City Hall year-round. He should have a look at a new study by Shoshanna Saxe, an associate professor of civil engineering at the University of Toronto, which demonstrates that subways are not necessarily the greenest form of transportation.

Saxe studied in London and studied the 1999 extension to the Jubilee line. It carries a lot of people, 175 million trips per year. She then looked at the last subway built in Toronto, the Sheppard line, did a life-cycle analysis and found that it generated 168,000 tonnes of Carbon Dioxide, all from the concrete, reinforcing, and equipment needed to build it.

She then looked at the savings in carbon that came from increased density and fewer people driving. This was a subway built for political reasons, rather than on the basis of good transit planning, so it is really not used by very many people. And thanks to induced demand, the roads are just as full as they ever were. So in the end, the payback period for all that carbon dioxide is between 11 and 35 years, probably closer to the latter.

She note that surface transportation has serious advantages in carbon footprint and concludes:

Concrete and steel, two major components of metro construction, are both GHG intensive materials. Leaner structures and/or smaller, simpler stations would reduce the capital GHG. At grade, track and stations require capital GHG investment an order of magnitude smaller than that required for tunnels and underground stations. Where possible, at grade track and stations should be considered.

She does not do an analysis of how much CO2 might have been saved if the investment had been made in a much larger LRT system that served more people and replaced more buses. Or how the induced demand might have been reduced if the LRT ran down the middle of the road, eating up a lane or two.

Nor has the City of Toronto or environmentalist Glenn De Baeremaeker done this analysis for the new one stop Scarborough subway, comparing its environmental costs and benefits against a 24 stop LRT system. It’s all just about emotion, saying “The city will not be one until people in Scarborough perceive they are getting their fair share. And nothing demonstrates this more than the subway.”

But as Saxe concludes, if we really want to get people out of their cars we have to give them good alternatives, but we have to deal with induced demand. “policies can include efforts to make driving more expensive (fees) and/or to make it slower (reductions in speed limit or traffic lanes).”

Embodied energy, embodied carbon, and the payback period are always controversial issues, and many would say that even a payback of even 35 years is pretty short for investment in transit. But it should still be a factor in the choices that are made. Saxe tells Ben Spurr of the Toronto Star:

“We should be thinking about greenhouse gas emissions and the impact at all the stages of design. We should be thinking about them during construction, we should be thinking about them as we do our transport and land use planning. And this study puts the numbers underneath it to help us think about it in a constructive way.”

Toronto Light RailTTC/Public Domain

I have always made the case that where one is not talking about New York-style densities, surface transportation is better for cities than underground. Without even thinking of the carbon footprint, I have written:

Doing the right thing for Scarborough is not pumping people downtown a few seconds faster. It is getting the largest number of people from place to place within Scarborough, for setting up the best conditions for transit-oriented development, and for letting people see what is going on around them instead of being dumped into an expensive pipe.

But that kind of thinking is political suicide in car-oriented suburban Toronto (or Caronto as it is often known) so we get a one-stop subway extension instead. Again, the environment and any planning logic is sacrificed for political expedience.

Big transit projects have a big carbon footprint
This should be taken into account when doing transport and land use planning, according to Engineering Professor Shoshana Saxe

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