More than one out of ten of Montgomery County, Maryland's intersections has a yellow warning time so short that they are in violation of state policies. That was the conclusion of the county's inspector general in a preliminary inquiry report made public on Wednesday. The official investigation followed a complaint from the Maryland Drivers Alliance, which last year noticed that the county had been issuing tickets at intersections where the yellow timing was just 2.9 seconds long, in violation of federal law. The short yellow problem was found to be more widespread than expected.

"According to the Montgomery County department of transportation, at the time of our review, 13 percent of the county-operated signals have a yellow signal duration of less than 3.5 seconds and need to be retimed," county inspector general Edward L. Blansitt III wrote. "We did not test or verify the accuracy of the information provided by MCDOT."

The county operates 836 traffic signals, and it is required to abide by the State Highway Administration (SHA) policies at 547 of those locations owned by SHA. The state in 2003 required all yellow signals to be no less than 3.5 seconds in duration, but the county ignored the rule, claiming it had never been formally notified of the requirement, which must have "slipped through the cracks." County officials insisted that they did not know about the 3.5 second policy until 2015, but the inspector general noted another complaint it received claimed red light cameras were strategically placed at those locations with short yellows.

A fraction of a second difference in yellow time can have a significant influence on the number of red light camera citations issued. In most cases, a yellow shortened by one second can increase the number of tickets issued by 110 percent, according to TTI (view report).

"The intersection at Georgia Avenue at Seminary Road saw a major reduction in red light running violations for the first two months after they increased the yellow times compared to the same months last year," the Maryland Drivers Alliance's Ron Ely told TheNewspaper. "It would be sad if an apparent lackadaisical attitude in applying SHA standards established 14 years ago increased the risk to the safety of motorists and pedestrians."

The inspector general urged county officials to be more diligent in abiding by the timing rules.

"The Montgomery County department of transportation should develop a formal schedule with a defined completion date for yellow signal retiming," the inspector general recommended. "The schedule should include a mechanism for routinely reporting progress to SHA."

A copy of the report is available in a 300kmb PDF file at the source link below.