The $200 million project will add a fourth lane in both directions of the tollway from Denton Tap Road in Lewisville to US 75 in McKinney.
Four Lewisville intersections along the SRT are affected by the construction as crews work to widen overpass bridges. The North Texas Tollway Authority owns and operates the SRT.
At least three more intersections west of I-35 are slated to undergo the same overpass widening construction this winter, according to NTTA’s construction timeline.
The SRT’s annual traffic counts are expected to increase by nearly 39 million transactions between 2015 and 2022, according to NTTA projections.
“[We] welcome the increased capacity on the tollway,” city of Lewisville spokesperson James Kunke said in an email. “It will be a benefit to commuters on the tollway and also to Lewisville businesses located along the tollway that will enjoy better customer access when the project is completed.”
The project’s anticipated completion in late 2021 will mark the end of construction along the tollway for the foreseeable future, NTTA spokesperson Michael Rey said.
Construction crews began working on the 26-mile project in January. They are adding the fourth lanes in either the median or on the outside edges of the tollway.
NTTA staff have since met with business groups along the tollway to keep them up to date on the status of the construction project.
Starting in the spring, crews began widening overpass bridges. Three Lewisville intersections east of I-35 are being affected by the overpass work. Those intersections are Josey Lane/Main Street, Standridge Drive/Castle Hills Drive, and Hebron Parkway.
Kunke said the city is not conducting any additional construction projects along the tollway.
“[There] are no ramps or bridges being significantly affected in Lewisville, so we’ve not been directly involved with NTTA on this project,” he said in the email.
However, he said the city has coordinated with the NTTA to ensure the correct names of streets and business complexes are used on the detour and construction signs.
Construction affecting the three Lewisville intersections east of I-35 will continue through the fall, according to NTTA. Crews will begin working on the bridges at Lake Vista Drive, MacArthur Boulevard and Denton Tap Road in the winter.
Michelle Raglon, Texas Department of Transportation spokesperson, said the project will not affect the interchange between I-35 and the SRT.
The added capacity will help with the area’s growth. North Central Texas Council of Governments projects the region’s population will increase from 7.4 million today to about 11.2 million in 2045. The NCTCOG works with cities, counties and transportation agencies to better coordinate regional planning.
Meanwhile, the NTTA saw its annual transactions increase from 141.8 million in 2015 to 167.7 million in 2018. It projects those transactions to rise by 13 million over the next three years.
A transaction is recorded any time a vehicle passes through a toll, which means one vehicle could have multiple transactions during a single trip.
Rey said although transactions are anticipated to increase along the tollway, there are no future plans to add a fifth lane.
“To do that we would have to acquire right of way, and I don’t believe that’s in the plans,” he said. “That’s why we go to the middle of the roadway, which will essentially take up the remaining right of way.”
Adding more than four lanes can have a degrading effect on traffic, said Kevin Feldt, an NCTCOG program manager.
“You don’t want to go to five lanes in each direction or six [lanes] because you don’t get your return on investment from that,” Feldt said.
More lanes means vehicles changing lanes more frequently, which causes heavier congestion, he said.
Feldt said the NTTA raises its own project funds by selling bonds and collecting tolls.
“Unlike most other projects, NTTA’s projects are: ‘You bring your own money, you get your own project’ kind of deal,” Feldt said. “We view the NTTA project as cost- and revenue-neutral, in that they have the money to construct, operate and maintain their projects.”
Transportation planners should explore other solutions to improving regional mobility, Feldt said.
“It’s not just about the big roads that we have,” Feldt said. “We also need to think about our arterial network of roadways as well. And we need to think about public transportation projects as well.”
Cassidy Ritter contributed to this story.