Is a pedicab really more virtuous environmentally than a taxi?

I ask because I came across an interesting challenge to the notion that taking short trips in a car is bad for the planet. This challenge comes from Chris Goodall, the author of

<a href="http://tierneylab.blogs.nytimes.com/2008/02/25/how-virtuous-is-ed-begley-jr/?em&amp;ex=1204174800&amp;en=86d915153b1a4e7c&amp;ei=5087%0A">http://tierneylab.blogs.nytimes.com/2008/02/25/how-virtuous-is-ed-begley-jr/?em&amp;ex=1204174800&amp;en=86d915153b1a4e7c&amp;ei=5087%0A</a>;