Mt. Juliet moves ahead on traffic signal technology

Traffic congestion around Mt. Juliet’s Providence Marketplace may not be as bad as some corridors in Nashville, but Wilson County resident J.M. Kuno is concerned volumes haven't peaked.

“Mt. Juliet is skyrocketing, building subdivision after subdivision, and what you see now is going to be worse,” Kuno said of the traffic at the corridor. “Let the north-south traffic run as long as you can to keep that flow going.”

The city has committed to a coordinated traffic signal system designed to optimize green-light time according to real-time traffic patterns during peak and non-peak hours.that will be installed next year for eight signals on Mt. Juliet Road.

Mt. Juliet will use an adaptive traffic signal system from Rhythm Engineering on lights from Graves Crossing to Pleasant Grove Road. Some aspects of the system may be operational within three months, and the entire system is expected to be active in six months, Mt. Juliet Deputy Public Works Director Andy Barlow said.

Franklin is also exploring an adaptive signal system for the Cool Springs Boulevard and Mallory Lane corridors with plans to request bids in the coming months, said Abby Gambill, traffic operations center operator.

Adaptive signal systems elsewhere

Chattanooga has had about an 8 percent improvement in traffic flow since its Rhythm Engineering adaptive signal technology became operational in 2013 for 14 signals on State Route 153.

The city shoots for a 12 percent improvement, but it has been worthwhile, according to Chattanooga Traffic Signal Systems Engineer Kevin Comstock.

“It’s pretty good considering the amount of traffic goes through that corridor,” Comstock said. “It takes some tweaking once in a while.”

But Idaho’s Ada County Highway District has sent notice to terminate its contract to Rhythm Engineering on its adaptive signal technology system, according to the district’s Assistant General Counsel Scott Spears. Spears did not comment on the reasons why the highway district is discontinuing the technology, though reports in Idaho cited sun glare, fog and other issues as having an impact on the video technology used.

Lexington, Ky., uses adaptive technology on 22 traffic lights — the majority installed earlier this year.

Noticeable travel time reductions haven’t occurred yet in Lexington, but the city continues to work with the vendor and is hopeful for improvement, said Director of Traffic Engineering Dowell Hoskins-Squire.

Vehicles pulling out from side streets and business parking lots without lights have been a factor on the system in Chattanooga, Comstock said.

“Every corridor is different,” Hoskins-Squire said. “It’s not just a buy-it-and-leave-it system.”

Mt. Juliet adds protections

Barlow, aware of reports in Idaho, says issues raised will be a discussion point with the vendor "to ensure we don't have any similar issues here," he said.

Mt. Juliet will use high-definition radar detection with Rhythm’s video system to provide “a dual-detection method, which should prevent any detection failure issues,” said Barlow.

Chattanooga uses sensors so video detection can be used as backup, Comstock said.

“It comes down to being educated with what you need in your area,” Gambill said.

Mt. Juliet’s adaptive signal system costs $585,000, with a grant covering $468,000. The city is responsible for the remaining $117,000 and about $68,000 for engineering and design costs.

Barlow would look to expand the technology to other signals on Mt. Juliet Road and other streets with positive results on the initial eight signals, he said.

Nashville seeks improvements

Nashville has put out requests for proposals to prospective vendors for a signal-timing optimization project at 19 corridors for 560 signals.

Metro also has a current project installing 200 traffic signal controllers and a new software network to allow for communication between signals to a central controller to provide improved options for signal-timing configurations.

Installation will continue throughout the next several months followed by plans to put in 400 new controllers during the spring and summer.

"We expect to gain significant improvement in traffic flow and circulation from these first two phases," Public Works spokeswoman Jenna Smith said. "We are also considering an adaptive traffic system now that the foundation is being laid with these current projects.”

Reach Andy Humbles at 615-726-5939 and on Twitter @AndyHumbles.

NASHVILLE CORRIDORS PLANNED FOR TRAFFIC SIGNAL ENHANCEMENTS

Metro has sent out bid requests to optimize traffic signals. Phase 1 has a projected installation by the end of 2016, Phase 2 by 2017.

Phase 1

Charlotte Pike (55 traffic signals)

Korean Veterans Boulevard/Shelby Avenue (21)

21st Avenue South (17)

West End Avenue/Harding Pike (50)

Nolensville Road (47)

Hermitage Avenue/Lebanon Road (32)

Gallatin Pike (73)

Metro Center/Rosa Parks Boulevard/Jefferson Street (26)

Phase 2

Downtown Nashville (99)

Hillsboro Road (22)

Harding Place (18)

Donelson Pike (7)

Bell Road (19)

Haywood Lane (5)

James Robertson Parkway (6)

Highway 70 South (14)

Franklin Road (15)

Dickerson Road (19)

Clarksville Pike (15)