11/13/2007Dallas, Texas Cameras Bank on Short Yellow Times
The top money-producing red light cameras in Dallas, Texas use short yellow warning times.
A local news investigation has found that the city of Dallas, Texas depends upon short yellow timing to maximize red light camera profit. Of the ten cameras that issue the greatest number of tickets in the city, seven are located at intersections where the yellow duration is shorter than the bare minimum recommended by the Texas Department of Transportation (TxDOT), KDFW-TV found.
The city's second highest revenue producing camera, for example, is located at the intersection of Greenville Avenue and Mockingbird Lane. It issued 9407 tickets worth $705,525 between January 1 and August 31, 2007. At the intersections on Greenville Avenue leadding up to the camera intersection, however, yellows are at least 3.5 or 4.0 seconds in duration, but the ticket producing intersection's yellow stands at just 3.15 seconds. The yellow is .35 seconds shorter than TxDOT's recommended bare minimum.
"For 30 miles per hour, if your yellow time was less than three and a half, you would not be giving that driver enough time to react and brake and stop prior to getting to the intersection," TxDOT Dallas District office transportation engineer supervisor Chris Blain told KDFW.
A small change in signal timing can have a great effect on the number of tickets issued. About four out of every five red light camera citations are issued before even a second has elapsed after the light changed to red, according to a report by the California State Auditor. This suggests that most citations are issued to those surprised by a quick-changing signal light. Confidential documents obtained in a 2001 court trial proved that the city of San Diego, California and its red light camera vendor, now ACS, only installed red light cameras at intersections with high volumes and "Amber (yellow) phase less than 4 seconds."
Dallas likewise installed the cameras at locations with existing short yellow times. A total of twenty-one camera intersections in Dallas have yellow times below TxDOT's bare minimum recommended amount. The Texas Transportation Institute study also found that shorter yellows generate a 110 percent jump in the number of tickets, but at the cost of safety. Increasing the yellow one second above the recommended minimum cut crashes by 40 percent.
Since the Dallas intersection ticketing program launched last December, it has issued $13.5 million worth of automated citations from sixty camera locations. Beginning in September, however, Texas cities must split camera ticket profit with the state. To make up for lost revenue, Dallas plans to install forty more cameras. View KDFW's signal timing chart, a 44k PDF file.