Patrick James, October 5, 2009, GOOD - Cities Via Yglesias

According to Jan Garrard, a senior lecturer at Deakin University in Melbourne, Australia, the best way to determine how favorable a given city is for cycling is to measure the number of women bike-riders. From Scientific American:
Women are considered an "indicator species" for bike-friendly cities for several reasons. First, studies across disciplines as disparate as criminology and child rearing have shown that women are more averse to risk than men. In the cycling arena, that risk aversion translates into increased demand for safe bike infrastructure as a prerequisite for riding. Women also do most of the child care and household shopping, which means these bike routes need to be organized around practical urban destinations to make a difference.