If you build it, they will come
In the 10+ years in which Palo Alto has been investing heavily in Safe Routes, they have doubled their bike to school rates - up to 50% of middle-schoolers and 40% of high schoolers ride bikes to school. The National Safe Routes Partnership cites a study of more than 800 schools in DC, FL, OR, and TX that found that Safe Routes to School interventions resulted in an average 31% increase in walking and bicycling to school over a five-year period, with up to 43% for comprehensive approaches with infrastructure and multi-year programs.
There is a percentage of the population who will ride their bikes regardless of the conditions: those cyclists are "Strong and Fearless" and "Enthused and Confident". Those two categories make up 15% of the population in San Mateo County. The other 85% are "Interested but Concerned" (60%) and "No Way No How." (25%). It's the 60% of the "Interested but Concerned that we are focused on getting out of the woodwork to ride. If we can truly improve our infrastructure (build it), they may very well come. See chart.