A lot of people champion bicycling as an eco-friendly way to get around. On a more practical matter, it can certainly save on gas and parking is often $20/ day in the heart of the city.
This photo shows one of the "bike lanes" that has been created in the city. This particular lane is on Wells Street, by the Merchandise Mart, with the "L" tracks above.
The lane is on the right side of the street. You can see who also shares this lane... the dreaded city bus. Anyone who has been in the city for five minutes knows that the bus can terrorize drivers. There are generally 2 types of bus drivers - those that just move forward and wheel out into traffic regardless of other cars (figuring, rightly so, that they are going to try to move out of the way so that they aren't crushed) and the "wimpy" kind that waits for people to get out of the way and takes about twice as long to get through city traffic. Cabs also frequent this lane, dashing back and forth trying to pick up passengers.
Really, they didn't add any space or amenities to "create" these bike lanes - they just painted lines on the street and said "let 'er rip". Doing a bike lane like this is kind of like trying to lose weight by erasing your weight on your drivers license and putting in a lower weight - pretty much wishful thinking.
The streets are already insanely crowded, even during the best of times. Thus adding bikes and having them share a lane with the already disrupting buses and often taxicabs is building a solution that is highly unlikely to work very well.
One time in Wicker park near North / Milwaukee / Damen avenue, I came across someone under the "L" tracks with a couple people nearby who looked like a bucket of red paint was poured over his head. Turns out that he was a bicyclist who got "doored" - this happens when someone opens a door without looking and the oncoming bike hits it head on and flies over it, with predictably nasty results.
There is NO doubt in my mind that riding a bike in the city is highly dangerous. I have seen many other accidents or near-accidents, and the problem has gotten exponentially worse with the profusion of drivers and cell phones. It even terrorizes me as a pedestrian (I walk to work, and I am on the damn sidewalk). In an accident, helmet or no, you are going to be on the losing side when a metal vehicle strikes an unprotected rider.
It is similar to the CAFE or fuel economy rules. The automakers responded by creating smaller cars to get better mileage, and smaller cars come out with a significantly higher death rate than larger cars in accidents (I know, SUV's have a rollover problem, but a bigger car has a much better survival rate than a smaller car). It is odd that liberals always are so willing to trade lives for oil, whether it is on bicycles or in cars. I am all for saving energy and giving people choices - God bless anyone who takes a bike or a small car - but it is a strange choice. Most of these same people travel far and wide to avoid chemicals on their food, wouldn't dream of smoking in front of their kids, and worry about pollution. All fine and good, but why then would they put their lives at risk in such a tangible way to bike through the city? I think that they are under-weighting REAL risks and over-weighting UNLIKELY risks.
Just my opinion... as someone who is too scared to ride a bike through city rush hour traffic, based on chronic near- death experiences he has witnessed...