Deputy Chief Engineer Jeff Ginn discussed four intersection design option changes with Southlake City Council during the Nov. 4 meeting. No decision was made; rather, it provided options for council to consider.
What’s happening?
The pause in construction is two-fold, according to Ginn. First was the wait time for new signal poles for phases 5 and 6 of the project near the SH 114 intersection. He also added that concerns have been raised about access to nearby businesses with the current plan.
Ginn said the project is 45% complete. Council awarded a contract to Tejas Cutters in May, according to previous reporting. Work started in July, and intersection improvements at North Carroll Avenue and Main Street, North Carroll Avenue and the fire station, North Carroll Avenue and the Southlake Department of Public Safety headquarters, and North Carroll Avenue and Carroll Pointe Shopping Center have been completed.
The remaining work includes phases 4-6, at Lake Wood Drive, eastbound SH 114 frontage road and westbound SH 114 frontage road, Ginn said. Phase 5 would add a left-turn lane at North Carroll Avenue to the eastbound SH 114 frontage road, while Phase 6 would add dual left-turn lanes onto the westbound SH 114 frontage road.
Current situation
With construction paused, Ginn said the city initiated a median access study to re-evaluate the intersection after a business owner raised concerns about access to the Landmark Office Building at 750 N. Carroll Ave.
The traffic study looked at the traffic count, crash data and signal warrant analysis. Ginn said the intersection of North Carroll Avenue and Lake Wood Drive had 58 conflict points.
The backstory
Ginn said North Carroll Avenue was widened into its current configuration in 2006. Studies were done in 2015 and then 2019 on the median improvements, but neither student's additional improvements were warranted, he said.
The earlier reports showed the median is wide enough for turning movements out of the driveway, but that, along with a left-hand turn into the shopping center with 7-Eleven, creates conflict points.
The previous two studies showed that only one of nine criteria was met for a signal at the location. The most recent study showed that seven out of nine criteria to warrant a signal were met, with traffic accidents being the leading concern.
He said adding a light at the intersection would result in a higher cost for the project.
Sorting out details
Ginn presented four options for the council to weigh.
- Option A: the original design that was included in the construction project. That does prevent access to the Landmark Office Building from northbound North Carroll Avenue drivers, who would need to make a U-turn, Ginn said.
- Option B: Ginn calls this a slightly modified version of Option A, maintaining the original intersection at North Carroll Avenue and Lake Wood Drive, but would improve the turning movements and U-turn movement by the 7-Eleven turn-in. It would reduce conflict points from 58 to 46.
- Option C: This introduces a traffic signal at Lake Wood Drive, and the left-turn median into Carroll Pointe Shopping Center would be extended to eliminate further conflict points, Ginn said. The cost of adding lights at the intersection would be $775,000, and the city would have to coordinate with TxDOT on signals. Part of the cost is $75,000 to relocate the driveway into the Landmark Office Building. The conflict points would drop from 58 to 25, Ginn said.
- Option D: The no-build option would retain the current intersection configuration, and it would remove $35,000 from the contract.
What else?
Tom Grant, an engineer with Kimley-Horn and Associates Inc., fielded questions from council about the possibility of traffic backed up to SH 114 and FM 1709/Southlake Boulevard with the addition of a traffic signal at Lake Wood Drive.
Grant said the city could work with TxDOT and get the signals tied together if council pursues that route. He said the city should avoid putting a pedestrian crossing there to avoid having queueing issues.
According to Grant, the traffic light at North Carroll Avenue and SH 114 would be the primary operating signal, and as it turned green, the Lake Wood Drive intersection would turn green as well.
