Montgomery County, Maryland's inspector general in June confirmed that local officials increased the amount of revenue generated by the county red light camera program by using illegally short yellow times (view report. The Maryland Drivers Alliance revealed last week that the number of violations at Georgia Avenue and Seminary Road dropped in half as soon as the yellow was increased from 2.9 seconds to 3.5 seconds to meet the state's minimum requirement for a 35 MPH road.

The drivers rights group turned its attention to the intersection after a camera run by Xerox Corporation (now Conduent) issued a ticket to Peggy Lucero, a motorist who fought the accusation in court. The ensuing media attention forced the county to increase the yellow time to 3.5 seconds on the left turn approach in December 2016.

According to county records, the result was an immediate 52 percent drop in the number of violations at the intersection from January through May 2017 (longer yellow) compared to January through May 2016 (shorter yellow). A few miles north at Georgia Avenue and Norbeck Road, the yellow times did not change. Violation here stayed within two percent of what they were in 2016.

The violation data are a somewhat imprecise measure, since the yellow time was only increased on the left turn approach of the intersection in question. The Maryland Drivers Alliance has been trying to obtain more precise figures about violations and signal timing, but Montgomery County officials have refused to hand anything relevant over. An ongoing Maryland Public Information Act (MPIA) lawsuit is asking a circuit court judge to compel disclosure.

"Were the Montgomery County Police to release the detailed violation data which is in dispute in my MPIA case, I am confident it would prove a causal link beyond any doubt," the Maryland Drivers Alliance's Ron Ely told TheNewspaper. "Perhaps that is why they don't want me to have that data."

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).