The Missouri state Senate yesterday voted to require local jurisdictions to adhere to minimum standards for yellow warning time at intersections. State Senator Jim Lembke (R-St. Louis), an opponent of the use of red light cameras, introduced amendments to an omnibus transportation bill designed to limit the desirability of photo enforcement. His colleagues went along with language mandating that signals on all roads adhere to the bare minimum "nationally recognized engineering standards."

Modifications to the bill must be approved by the House before becoming law, but the Missouri Department of Transportation (MoDOT) has already begun increasing yellow signal timing with very positive results. In Arnold, the first city in the Show Me state to use automated ticketing machines, yellow timing was increased from 4.0 to 5.0 seconds at three intersections along Missouri Route 141 on February 24. Smaller changes were made on April 15, including a boost from 4.0 to 4.4 seconds at northbound 141 and US 61/67, a 4.0 to 4.5 second change at northbound US 61/67 at Rockport School, and from 4.0 to 4.7 seconds at southbound Vogel Road at Richardson Road (4.3 seconds at the northbound approach).

The impact of the longer yellow at red light camera monitored locations was felt immediately. In January, before any signal timing had been changed, American Traffic Solutions recorded 875 alleged violations in the city of Arnold. At the end of April, that figure fell 70 percent to just 266. Jefferson County Councilman Bob Boyer obtained the ATS statistics after learning that MoDOT had extended the yellow times.

"This recent bit of information goes further to prove the point that there are other safety measures that can be implemented if safety, not money, is the focus," Boyer said.

Longer yellows have a significant impact on red light camera intersections because the vast majority of straight-through red light "violations" happen when a driver misjudges the end of the yellow light by less than 0.25 seconds -- literally the blink of an eye (view chart). In most cases, a yellow shortened by one second can increase the number of tickets issued by 110 percent, according to a Texas Transportation Institute report. Former Arnold Councilman Matt Hay, founder of WrongOnRed.com, believes city officials exploited bad engineering practices to make money.

"The preliminary data completely validates WrongOnRed's position that longer yellows have the greatest singular impact in reducing red light running," Hay told TheNewspaper. "The city of Arnold took no efforts or measures to actually reduce red light violations, and in fact, was more than willing to allow short yellows, dangerous intersections, and physics to ensure they had a steady flow of cash from unsuspecting motorists who fall victim to the trap."

A copy of the latest violation report is available in a 50k PDF file at the source link below.