A growing number of cities have constructed separate lanes for bicycles along their busiest roads. The lanes are protected by low concrete barriers, so that people on bicycles are no longer obliged to share the carriageway with cars and buses travelling at speed. Since the first of them opened, considerably more residents have chosen to cycle to work in the morning, and the number of collisions involving cyclists has fallen in every district where the barriers were installed. Shopkeepers along the route report an increase in customers as well, although they had originally opposed the scheme.