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Calculate your commuting emissions with Metro's new tool

Earlier this fall, WMATA's sustainability team developed a greenhouse gas (GHG) emissions savings calculator and have launched a draft version on their blog, PlanItMetro. You can use it to compare their carbon footprint when taking transit or driving.

Photo by Leonski Oh Leonski on Flickr.

The tool is simple and intuitive to use, similar to WMATA's trip planner. Enter your origin and destination and the calculator will give you options for how to arrive at your destination via transit or by driving, and will tell you the total amount of CO2 emissions for each option. If your trip involves walking, the calculator will even give you an estimate of the calories you expended in the process.

Check out a sample entry I did for a trip I used to make from my old place in College Park as a student at the University of Maryland to the Coalition for Smarter Growth office near Union Station. By taking the Metro rather than driving, I reduced my carbon footprint by 61% and burned over 90 calories in the process.

Metro's carbon footprint calculator.

A map of transit versus driving routes.

The transit emissions the tool calculates represent your slice of the total emissions pie of Metro's fleet divided by all Metrorail or Metrobus riders. Since we have already invested in these transit systems, every additional person who boards a bus or train improves the efficiency of the overall system, while avoiding the emissions they would generate by driving.

But it's also instructive to see the significant emissions our transit vehicles emit. Reducing transportation emissions by using cleaner fuels for Metrobus and Metrorail should be a goal for our transit system as well. Public concerns over natural gas have been increasing, given the devastating environmental impacts of fracking. Recent studies suggest that natural gas' net climate impact may be even worse than coal.

Metro wants to move from using traditional diesel or natural gas vehicles to diesel hybrid buses. Today, the bus fleet consists of 41% hybrids, which will rise to 62% by 2018.

The emissions figures from riding Metrorail are based on the amount of electricity the system uses from Maryland's and Virginia's electricity grids. Maryland and Virginia currently both generate over half of their electricity from fossil fuels.

Maryland must generate 20% of its energy from renewable sources by 2020, and passed a major offshore wind bill last year. Virginia is lagging behind Maryland, having only adopted a voluntary renewable portfolio standard. Someday, if we have a clean grid, Metro could also consider running trolley buses on clean energy like in Seattle and San Francisco.

If we are to lower emissions at the rate and degree scientists say is necessary to avert climate disaster, we will have to find a way to dramatically reduce our transportation emissions, which make up 30% of the Washington DC region's carbon emissions. Tools like WMATA's offer the opportunity for individuals to understand the environmental impact of their commutes and the benefits of walking, bicycling, and transit use.

Still, behavior change is difficult, and studies have found that carbon calculators tend to reach a limited and self-selecting audience. So how can WMATA improve the tool to maximize its impact?

One idea would be to illustrate the meaning of "kilograms of CO2" in easily understandable ways by comparing it to gallons of gas, the cost of gas, or home energy use. WMATA could potentially use data from this tool from the EPA, which compares kilograms of CO2 to a wide variety of everyday energy uses.

It would also be great if the tool incorporated more options, especially biking to transit stations. In testing WMATA's calculator, we also found that it didn't offer biking or bikeshare as options where those appear to be a convenient alternative.

In addition, the emissions savings from one trip may not be a huge motivator, but what if you could see the impact of riding transit and ditching your car for a whole year? Driving represents by far the biggest share of the typical American's carbon footprint, so switching to other modes over the long term is one of the most important actions an individual can make to fight climate change. The following chart shows the major contributors to the average household's carbon footprint.

Graph from NRDC and UC Berkeley.

Finally, WMATA's tool could work in concert with the Housing + Transportation Cost Calculator pioneered by the Center for Neighborhood Technology and adopted by the federal Partnership for Sustainable Communities to show how transit-accessible neighborhoods can not only reduce your carbon footprint, but your living expenses as well.

What ideas do you have to improve WMATA's greenhouse gas tool? Let us know in the comments.

Tyler Grote is an organizing intern with the Coalition for Smarter Growth. He is a recent graduate of the University of Maryland, where his interest in the Purple Line and the redevelopment of College Park spurred a passion for smart growth in the DC region. He is looking to use his experiences in smart growth to start a career in the world of urban planning and policy. 


Add a comment »

Does Metro count to carbon released from the sighs of all those passengers in delays to to broken down this, sick passenger that?

by Randall M. on Jan 3, 2014 1:42 pm • linkreport

I'd much rather have a bus burn national gas -- and emit co2 -- than a diesel or even the alleged "diesel hybrid". I say alleged because you can still smell them, and that is a good marker for funky emissions.

by charlie on Jan 3, 2014 1:53 pm • linkreport

The tool needs to include the total emissions of producing and delivering the fuels. Needs a total system option with emissions of building the vehicles and rails or roads, or at least the unit emissions for capacity expansions.

Factoring in all sources, do off peak drivers emit more or less than peak rail transit riders? That is a real choice some people face as off peak rail is too inconvenient, especially on Commuter rails or if there is a bus connection

by JimT on Jan 3, 2014 2:51 pm • linkreport


Both are using similar fuels, so we could probably assume that the associated cost of producing/delivering the fuel is about the same, so the carbon costs of each would still be proportional to the answers given by the tool.

Not sure what you mean by "do off-peak drivers emit more or less than peak rail transit riders"? Peak rail transit is highly efficient per person (more efficient than at off-peak times because there are more people). Off-peak driving is maybe a little more efficient than peak driving because of less congestion. Transit still wins.

The reality is that for the individual, taking transit is ALWAYS going to result in fewer carbon emissions because the transit is already running and your additional transit trip adds ZERO GHG. Your car trip adds GHG because otherwise your car would not be used.

by MLD on Jan 3, 2014 3:02 pm • linkreport

it should also show an estimate of the difference in travel time.

by sk on Jan 3, 2014 3:22 pm • linkreport

It does vary with time.

Peak rail has great efficiency for passengers per car.
Off peak(summer afternoon) uses peak electricity which would be natural gas.
Off peak(winter evening) uses baseload capacity electricity, which around here is mostly nuclear or hydro.

Also the marginal costs are nothing for Metro, they will run the trains whether you personally ride or not, so if you drive, you do not save metro from emitting. On the other hand if you ride metro, they will not emit any more because of you.

There are greenhouses gases produced in the production of petroleum products, most notably in natural gas with methane leakage. The transport however is not really that significant. Even from saudi arabia, an oil tanker is a pretty efficient way to move a massive quantity of bulk a very long way and the amount of energy used to move it(and thus CO2 emitted) is very small compared to the energy in the oil.

by Richard on Jan 3, 2014 3:26 pm • linkreport

Interesting! I live only about 2 miles from work and while I can drive directly the public transit options take me somewhat out of the way. I've thought that extra distance justified driving, but not according to this tool! Will have to rethink. (And yes, I bike in milder weather)

by Emily on Jan 3, 2014 3:45 pm • linkreport

@mld: what I meant was that (for example) 10,000 more people driving during peak might require another lane on some highways, which uses alot of energy. If they take the train, they might require a third track whose construction roll require alot of energy. While one person might seem to have zero capital cost, is that really so?

by JimT on Jan 6, 2014 5:30 pm • linkreport

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