Cameras that for years generated just a few tickets daily suddenly caught dozens of drivers a day. One camera near the United Center rocketed from generating one ticket per day to 56 per day for a two-week period last summer before mysteriously dropping back to normal. Tickets for so-called rolling right turns on red shot up during some of the most dramatic spikes, suggesting an unannounced change in enforcement. One North Side camera generated only a dozen tickets for rolling rights out of 100 total tickets in the entire second half of 2011. Then, over a 12-day spike, it spewed 563 tickets — 560 of them for rolling rights. Many of the spikes were marked by periods immediately before or after when no tickets were issued — downtimes suggesting human intervention that should have been documented. City officials said they cannot explain the absence of such records.
