Here's an interesting video on the history of cycle tracks, or separated bike lanes, in The Netherlands. Turns out that Napolean may be to thank as cycle tracks were created from excess width in the roads that the Emperor had constructed in the 1850s when France ruled The Netherlands. Fourty years later, this excess width in the poorly maintained roads were paved with bricks and provided a smoother surface for cyclists than the adjacent cobblestone surface which was used by carriages.
To prevent carriages from using the smoother brick surface, the lanes were physically separated with rows of trees in the rural areas and concrete islands in the cities. This gave rise to cycle tracks.