Thanks THC. Just a quick glance at it so far. Although they found a positive correlation between infrastructure and commuting, they specifically pointed out the results did not indicate a cause and effect relationship.

The data in table 2 is interesting and confounding. For example Fresno is ranked 5th in % of bicycle commuting but very low in infrastructure with zero bike lanes and only .13 'bike paths and lanes' per sq mile.

Clearly there are other factors at work. As they mention, Pucher identified 8 factors that affect cycling level:

1. Public and cultural attitudes, 2. Public image, 3. City size and density, 4. Car use cost and public transportation, 5. income, 6. climate, 7. Danger, 8. bicycle infrastructure