Chicago Bicycle Program posted these photos on its Facebook wall, announcing the installation of a bicycle radar sensor on Dearborn St:
"Did you know that Dearborn has Bike Radar? Two sets of radar sensors were installed just north of Polk St to detect southbound bicycles as they approach the light. The sensors communicate wirelessly with the stoplight and once a bicycle is detected the signal will change to a green bike light!"
Here it is one of the newly installed bicycle signal in Chicago: