For Bus, a total annual riderrship number is used and then apportioned based on vehicle type VMT. The average of 16 persons per bus mile includes a lot of late night and weekend hours. Also, passenger average trip length using federal data is notoriously weak given small samples. Finally, the census data they quote is not real census data, because of data suppression a lot of data is lost. The average commuter rail trip of 11 miles is way off base, unless they are talking about only NYC residents commuting to NYC. Because of these issues, I think the Prius/Bus comparison is actually much closer then shown here.

Also, I’m usually a big fan of Streetsblog, including Brad’s contributions. My one bit of constructive criticism here: lots of people get confused about the various environmental and other impacts that mode choice can have. They especially confuse energy efficiency, petroleum dependency and emissions. I think this post would have been more informative if you’d pointed out, as the study did, that emissions are just one of the wide range of consequences. To put it in perspective.

I’m also sorry to hear that you’re so constrained by federal funding. As I’ve written before, in New Jersey we have private bus companies that have been brought up to a competitive position by some basic infrastructure subsidies. The small van lines were using cutaways for a while, but most of them seem to have switched to some kind of tour minibuses that are bigger than the cutaways but smaller than the full size NJ Transit buses. I’m probably jeopardizing my transit geek cred by not being able to quote model numbers off the top of my head. They deal with the scheduling issues by simply waiting until they’re full to leave Manhattan – and I know that a lot of small-city minibuses in the US would never get anywhere on that system.

My main point is that they seem to deal with most of those challenges you describe and bring in a profit. Of course, they don’t have to worry about federal funding, and they don’t seem to be required to take wheelchairs. I honestly don’t know how they do in terms of emissions. Thanks again.

Minibuses do emit less CO2, but there are many more factors to consider. The intermediate step before fuel cell is either diesel-electric hybrid heavy duty bus (they get around 5 MPG versus a conventional diesel heavy duty bus getting around 2-3 MPG) or CNG.

But that changes if more people ride them.

Thus, for those who had ECON 101, is the difference between the AVERAGE carbon emissions and the MARGINAL carbon emissions. Until they reach overload, mass transit systems have near-zero marginal costs and emissions.

Transit agencies in other (less urban) parts of the country run these huge buses all over the place with 1-2 (or zero!) passengers. It’s pretty ridiculous.

A disappointing set of facts in the report is page 31, which gives the emissions per passenger-mile of the different types of buses. Diesel is 0.52 pounds of CO2 per passenger/mile, hybrids are 0.42 and CNG are 0.58.

Of course, emissions are only part of the story. Fuel efficiency is another. From a fuel efficiency standpoint, it looks like it’s still a good idea for the MTA to continue converting the bus fleet to hybrids, and to promote BRT. As the report says:

While this report addresses CO2 emissions specifically, modal shifts away from cars and onto public and non-motorized transportation will confer myriad additional benefits: improved air quality, reduced congestion, safer streets, and a more active, healthier population. As the City considers policies and programs promoting modal shifts (congestion pricing, transit, bicycling and walking improvements, etc.), the CO2 emissions reductions quantified here should be considered as just one element of the overall public benefit.

And what about those buses in San Francisco that run on the overhead wire? The technology for electric must be out there, we would just need the power source?