The North Texas Tollway Authority’s board of directors chose an alignment for the phase 4B/5A extension of the Dallas North Tollway that straddles the Collin-Denton county line and extends 11.9 mi from FM 423 in Collin County to FM 121 in Grayson County.

NTTA has continued to extend the original Dallas North Tollway for several decades as communities to the north have grown and requested expansions. When complete, the 4B/5A extension will be a limited-access toll road with six main lanes and four frontage road lanes. It’s expected to cost $864 million.

“The alignment was chosen based on a variety of factors such as environmental impacts, socioeconomic impacts, design and cost factors, as well as input gathered from meetings with the public and elected officials,” NTTA spokeswoman Susan Slupecki tells Texas Construction.

As part of NTTA’s public participation process, the NTTA conducted eight work-group meetings with public and elected officials beginning in October 2009. About 700 people attended public meetings held in March in Collin and Denton counties, and more than 300 comments were received during the public meeting process, Slupecki says.

The chosen alignment will bring economic development opportunities for the region, Slupecki says. And because the alignment follows an existing county road it will ultimately require less right-of-way, she adds.

NTTA followed long-established procedures to study the three possible alignments, as well as a no-build alternative. The alignments were comparable in cost and other characteristics.

The extension project is divided into two sections. Phase 4A will extend from U.S. Hwy. 380 to FM 428. Phase 4B/5A will extend north of FM 428. The alignment selected by the NTTA board is part of Phase 4B/5A.