. >> reporter: david kidwell is an investigative reporter.has been following the troubled history of chicago's red light program. since 2003, the city's nearly 400 red light cam ares have brought in $500 million in traffic fines, money the city desperately needs. >> the city of chicago's bond rating is darn near junk rating right now. ending the red light camera program only creates more problems for the government of the city in terms of making up very, very critical shortfall in the amount of money they have to run the city. >> reporter: and kidwell's investigation also exposed other issues at intersections in chicago with red light cameras. one of the biggest problems is the yellow-light intervals are too short. the city's yellow lights are set at 3 seconds. kidwell uncovered evidence that many of the intersections had so-called yellow light intervals of less than 3 seconds. this man is better known to thousands of chicagoans as the red light doctor. he is able to capture the exact duration of a yellow-light interval. today his research sh

. >> david kidwell is an investigative reporting for the chicago tribune. he has been following the troubled history of chicago's red light program. since 2003 the city's neerl cits nearly 500 red light cameras have brought in $500 million in fines, an amount the city desperately need. >> ending the red light camera program only creates more problems for government of the city of chicago in terms of making up very, very critical shortfall in the amount of money they have to run the city. >> and kidwell's investigation also exposed other issues at intersections in chicago with red light cameras. one of the biggest problems is that the yellow light intervals are too short. federal guidelines say yellow lights should last at least 3.2 seconds. the city of chicago's department of transportation says its yellow lights are set at 3 seconds but kidwell uncovered evidence that many of the red light camera intersections had so-called yellow light intervals of less than three seconds. that means millions more revenue for the city. >> there's probably between half mil