Bicycle Austin forum

<i>The problem with this is that you're isolating one outcome without looking at the possible affects of more people bicycling on other outcomes. Would bicyclists tend to be more environmentally conscious in other aspects?</i>

This would seem to be the key.  A "cycling culture" would have systemic effects that don't come across in a simple, person-to-person comparison using just one variable : e.g., in a city built to a cycling-commuter friendly scale (i.e., denser) and with light rail connecting the suburbs to the urban centers, even the non-cyclists would burn less fuel when commuting.