The study, conducted by Mkhail Chester and Arpad Horvath from the University of California, Berkeley, compares the “full life-cycle” emissions of different modes of transportation in the US. They take into account all the pollution generated by the fuel consumption, maintenance and a number of processes involved in making the transportation means.
To be short, the study discovered that cars produce most of the pollution, except off-peak hours, when buses go almost empty. When they do that, they’re more polluting than SUVs. The finding also underlined that electric trains and cars can contribute to emissions if the electricity is generated by burning fossil fuels. Passengers on the Boston light rail, an electric commuter train, were found to emit as much or marginally more than those on mid-size and large aircraft. This is in part because 82 per cent of electricity in Massachusetts is generated by burning fossil fuels.
As you may have seen above, the study relies on data gathered specifically for the U.S., but in Europe, a large percentage of the electricity is generated from nuclear power or renewable resources, so those figures can’t be entirely true for that matter. Another aspect that we should look at is that U.S. cars have much bigger engines, their mileage is low, compared to European cars, that have engines reaching up to 60 mpg (some diesels).
So… true or false? It all depends on which side of the ocean you look – it might be an important signal for the U.S., anyway.