"Higher levels of bicycle infrastructure are positively and significantly correlated with higher rates of bicycle commuting ... With growing concerns over traffic congestion and vehicle pollution, public policy makers are increasingly promoting bicycling as an alternative for commuting..." "Higher levels of bicycle infrastructure are positively and significantly correlated with higher rates of bicycle commuting ... With growing concerns over traffic congestion and vehicle pollution, public policy makers are increasingly promoting bicycling as an alternative for commuting..."

Further Reading:

Bicycle Commuting and Facilities in Major US Cities