The Texas Department of Transportation's investigation into traffic flow on Main Street in Tomball revealed that a traffic light at the Cherry Street intersection was operating in "free mode," independently from other signals. The timing was corrected, and the light is now operating in coordination with other lights on FM 2920, said David Kauffman, director of public works.

"The engineers looked at FM 2920 all through Tomball and Cherry Street was where the big backup was, with cars waiting through two to four cycles to get through that intersection," Kauffman said. "Once that was corrected, we saw a significant and immediate improvement in traffic flow."

Kauffman said it is unclear what caused the light to reset and desynchronize from the others in the system, but lightning strikes have been known to have that effect.

The TxDOT study also concluded that restricting left turns at five Main Street intersections—Pine, Oak, Cherry, Walnut and Elm—would likely make congestion worse. The study looked at three separate scenarios: restricting left turns at all five intersections, restricting left turns only at the two signalized intersections (Cherry and Pine) and not restricting them at all.

In both instances that involve restricting turns, the city's Level of Service—the traffic signal industry's standard for rating efficiency—declines, Kauffman said. A rating of C is considered the acceptable standard.

"Restricting turns at signalized intersections showed a slight increase in congestion, dropping our LOS rating from the A–B range to the B–C range," he said. "Restricting turns at all intersections showed a significant increase in congestion, giving us a C rating or worse."

TxDOT's recommendation is in line with the Houston-Galveston Area Council's access management study, which suggests removing on-street parking on FM 2920 and creating a center turn lane. That sort of change is still several years out, Kauffman said. In the meantime, the city will continue to look for opportunities to provide off-street parking. Parking lots have recently been put in on N. Elm Street, at the corner of Main and Cherry streets and at the corner of Walnut and Fannin streets.

"It's one of those things that is going to be driven by demand as traffic volumes continue to increase," Kauffman said. "I think a lot of the concern drivers had was prompted by that one signal losing its programming. Knowing that our existing conditions give us an A–B level of service puts things in perspective."