I didn't even realize that the Chicago taxi cabs had been redesigned recently, but apparently in 2001 the lights on top of the cab that indicate whether or not the cab is available were changed. A veteran driver took an informal survey of his riders, and found out that they nearly all thought that the pre-2001 design was easier to see. So now what does he do with this information? Well, now that Mayor Daley is interested in putting rooftop advertising on Chicago cabs, obviously the lights are going to have to be redesigned again, so why not return to a design that people prefer?