Car-Free Downtowns: Green-ness and/or Economics or Both?

Kat Martindale sent me a link to this story about Sydney’s bid to take cars out of the CBD. Like the Times Square plan, this makes perfect sense from an economics standpoint: the land is too valuable to have space taken up through space-intensive modes like cars. Other very large, very congested cities who don’t regulate often go the same way through individual market sorting, with people taking to foot, bicycle, and scooter to slither through the cars sitting in gridlock.

Oddly, we may not know ultimately the environmental effect of these car-free zones. WHAT? ARE YOU STUPID, Dr. Schweitzer??? Anything that gets rid of cars is good, right? Well, we don’t know that these types of car-free zones actually get rid of cars and trucks, or whether the zones simply divert vehicles elsewhere, re-routing them and thus adding to VMT, idling, or just slower speeds–all of which can add emissions as easily as they can subtract them. Eliminating car trips isn’t as simple as disallowing them in various parts of the city. There will be local benefits to air quality and a bunch of other things, but we don’t know what happens for global or regional emissions.

There’s a nice manuscript, by researchers I respect immensely, on how Paris’ car suppression strategies have had mixed results for air quality:

Bouf, Dominique and David A. Hensher, The dark side of making transit irresistible: The example of France, Transport Policy, Volume 14, Issue 6, November 2007, Pages 523-532, ISSN 0967-070X, DOI: 10.1016/j.tranpol.2007.09.002.

Link in ScienceDirect.