Article: Colorado: Investigation Forces Yellow Light Changes
Investigative reporting forced Denver, Colorado to lengthen the yellow at four city intersections where red light cameras are to be installed. In late March, the Rocky Mountain News uncovered
how these intersections had quick, three-second yellow times that fell short of recognized engineering standards. Drivers will now enjoy up to two additional seconds of warning at some intersections by the time automated tickets start landing in the mail on June 10.
"We want this program to be above reproach," Denver traffic engineer Brian Mitchell told the Rocky Mountain News.
The city will split $75 with Australian camera operator Redflex for each ticket the company is able to issue. But the number of those tickets will now be reduced significantly. At the posted 45 MPH intersection of northbound Quebec Street and 36th Avenue, the yellow increased from 3.0 to 5.0 seconds. Yellow rises from 3.0 to 4.0 seconds at both eastbound Sixth Avenue at Kalamath and westbound Eighth Avenue at Speer Boulevard. Yellow increases just half a second at eastbound Sixth at Lincoln Street to 3.5 seconds.
Boosting the duration of the yellow signal has proved to reduce accidents and violations. In nearby Fort Collins, for example, the installation of a red light camera at College Avenue and Drake Road did nothing but increase the accident rate by 45 percent. Immediately after increasing the yellow light duration
by one second, however, the accident rate dropped 30 percent -- from 2.8 to 2.0 accidents per million vehicle entries.Investigative reporting in Dallas, Texas
found the city's most profitable photo enforced intersections had yellow times shorter than the bare minimum recommended amount. After the city raised times in response, several of the cameras became unprofitable and were removed from service. Source