Bike maps make for a fascinating study of cartographic "symbolization" -- the choices of the various lines and symbols, along with their sizes, colors, and types, that convey relevant geographical data on a map. Unlike most road (car) maps, you always need to consult the legend, and there are some common customs but no standardization. Bike paths are often green but may be red; dashed lines as opposed to solid ones could mean "trail" "future" or "caution"; and so on. The bike-relevant realities are complicated too, not just maps, but that'll be another post.
A lot of bike maps are found in pdf format on city (and state) web pages, which is great, because not so many years ago it was more voodoo to try and track them down, they would go out of print, be distributed through limited outlets (like bike shops), or you had to identify an obscure local official to call to get one. Yay for webbification of local government, easy searchability, and pdfs!
If any links get broken, be sporting and post a comment indicating the correct link. Here are bike map links (caution: most files big pdfs) for: Seattle (north and south), King County, WA, Portland OR, Vancouver BC, Eugene OR, San Francisco, Davis CA, Denver (back), Boulder, Minneapolis, Madison, Chicago, Philadelphia, New York City (Manhattan-Bronx-Queens, Brooklyn-Staten Island).
And for the next level entirely of bike route planning, check out the amazing, like-Mapquest-for-bikes-but-better, BikeMetro.com for Los Angeles and southern California.
