The Tribune reported Thursday that its analysis of overturned tickets and interviews with experts suggested the Emanuel administration had made a subtle, but significant, change when it switched camera vendors this spring from the beleaguered Redflex Traffic Systems Inc. to Xerox State and Local Solutions. Hearing officers were suddenly throwing out hundreds of tickets that showed yellow light times at 2.9, below the 3-second minimum required by the city.



The city would not answer questions this week about whether it changed the yellow light standards, and Transportation Commissioner Rebekah Scheinfeld declined to explain the mystery in a recent interview with the Tribune, saying only that the tickets were valid because they fell within an acceptable standard for electrical deviations.



But in a broader review about problems with the red light program sparked by Tribune reports, the inspector general on Friday revealed that Scheinfeld's department had ordered changes early this year as the program was transitioning from Redflex to Xerox control.



"At the City's request Redflex categorically rejected any captured event with a recorded yellow light time below three seconds," Ferguson wrote. "However, after Xerox took over the operations of the RLC program, the City directed Xerox to accept RLC violations with yellow light times above 2.9 seconds."