'Bike Route' Designations

I live in corktown and recently we got all kinds of bike lanes and routes and such like this.

My question is, on my street bagley, we do not have bike lanes but we got signs indicating it's a 'bike route'. What exactly does this mean and how is it different form a normal street? It seems they did this on streets that were not wide enough for striping.

Another thing I noticed is it seems that the signs are black if there are lanes and green if there are not lanes. Is this true? Is there meaning behind this?

In other cities the routes get numbers designated to them so you can follow a given route, but so far these 'bike route' signs seem kind of random and like they don't serve a propose. Can anyone shed some light on this?

-dh

You are correct. The black signs are for roads with painted bike lanes, the green ones are "bike routes." Bike routes basically aim to detour cyclists onto less busy streets that parallel busy ones. These side streets don't need a dedicated painted lane since the cyclist can easily share it with cars. Ultimately, they do nothing since any side street is a de facto bike route, and if a cyclist wanted to take a quieter side street he/she would.

They actually do follow logical routes that you can find online [[I think MDOT's website), but I agree, at street level, they pretty much seem haphazard.

I think of those signs as helping car drivers more than bikers. They're often put on common bike routes and if nothing else, can help remind a driver to look out for bikes in that area.