How green are trains and public transportation? It depends.
Most of us assume that some things are givens when it comes to environment-friendly transportation choices. Among those assumptions: Taking the subway is better than driving an SUV, riding a train tops hopping on a plane, and a hybrid car is much preferred over a conventional gasoline-powered vehicle.
But that’s not always true.
Environmental engineers Mikhail Chester and Arpad Horvath of the University of California found that instead of taking a train into the city from suburbia, there are times when “people would be better off traveling through town in a gas-guzzling, high emission SUV. Ouch!
But it gets even worse: Taking the commuter train across Boston results in higher greenhouse gas emissions than traveling the same distance in a jumbo jet, says New Scientist.
How could that possibly be?
Part of it comes down to how the power that fuels the transportation is generated. Boston’s electric commuter trains use electricity that comes mostly from burning fossil fuels.
“Including these additional sources of pollution more than doubles the greenhouse gas emissions of train travel. The emissions generated by car travel increase by nearly one third when manufacturing and infrastructure are taken into account. In comparison to cars on roads and trains on tracks, air travel requires little infrastructure. As a result, full life-cycle emissions are between 10 and 20 per cent higher than ‘tailpipe’ emissions.
Occupancy also matters when it comes to measuring greenness – almost-empty buses at off-peak hours were less efficient than even SUVs and pickup trucks.
This way of measuring the environmental impact of transportation should be taken into account when planning new initiatives, say the researchers.
Of course, none of this is to deny the long list of benefits of buying a hybrid vehicle (or even taking the train or bus). But it does point out the complexity of many environmental issues.
1 Comment June 11, 2009
