It is very easy to find a taxi in Chicago as they are everywhere. You just have to raise your hand, and one will stop. If you are in a distant neighborhood, however, it is better to call a company and book one. Asa convenience, if you are in a restaurant you can ask the management to call one for you. It is easy to recognize them. They all have a big banner on the top of the car to do some advertising or a smaller one with the word “taxi” on it. Moreover the taxi cars are all almost the same old car! You can also recognize them as companies have special colors for their car: yellow cab, beige and green car, and so on.
Nevertheless it is really difficult, especially at night, to know if a taxi is occupied or not as the drivers do not always (and most of the time never) put the light on to specify that they already have a customer. Just keep your hand raised until one stops.
As soon as you get in a cab in Chicago, you are charged $2.25. Then, every 1/9 of mile costs you $0.20 and every 36 seconds the rate increases of $0.20. If you are two travelers, you will pay $1 more and each additional passenger from two of them will pay $0.50.