"This “Guide Map of the City of Detroit for Bicyclists, Showing Pavements” was copyrighted during the bicycle boom of the 1890’s... The map’s title points out its most striking detail: the color-coded mish-mash of various pavement types, ranging from unpaved to wood to brick to asphalt. Even though the League of American Wheelmen had formed over a decade earlier, this map was published in the heyday of the Good Roads movement, when cities across America were responding to cyclists’ demands for better rights-of-way by paving their thoroughfares. While most of Detroit’s streets were paved with wood (tree trunk slices laid out like flat, disc-like cobbles), its large radial avenues and other high-traffic roads had been upgraded to granite or asphalt by 1896... the 1896 bike map includes other notable features that help explain what was important to the city’s Gilded Age cyclists. Along with the numerous freight railway lines (indeed, today’s Dequindre Cut greenway shows up on the map as a railroad track), Detroit’s equally numerous streetcar lines are denoted for cyclists’ convenience. Likewise, the locations of passenger ferry service across the Detroit River are also indicated... outside runs.."
http://thehubofdetroit.org/detroit%E2%80%99s-grand-bicycle-map-tradition/
