Quote:
Originally Posted by Abner
So a bus that gets 8 mpg would actually use less fuel than individual cars with an average of only four passengers on board? Or is there more to it than that?
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I found this amazing chart on a blog, exactly the info I was looking for. Since it was already on a blog, I'm hoping it's fair game. Props to the Sightline Institute.
http://www.cooltownstudios.com/mt/archives/001295.html
The chart is for Carbon Footprint, which I'm assuming correlates farily well to fuel per passenger mile. Your assumption is correct, a bus is very sensitive to passenger load, and a carpool does beat out a 1/4 full bus, but not a 3/4 full bus.
So what is the effect of a 2nd gen hybrid bus? By raising fuel economy from 2mpg to 8mpg, fuel efficiency is quadrupled and the carbon/fuel footprint of a transit bus is cut 75%.
So the 1/4 full hybrid bus goes from 0.8 to 0.2, beating out the carpool. The 3/4 bus goes from 0.25 to 0.0625, 2nd only to walking. And of course, all the compounding variables and economies of scale all work in the bus' favor for adding passengers.
EDIT: Photobucket's being flaky, just follow the link if you get the red x of death.