DNT Extension Phase 4


Initial planning is underway for a proposed 13.7-mile extension of the Dallas North Tollway (DNT) northward from U.S. 380 to FM428 (Phase 4A) and from FM 428 to the Grayson County line (Phase 4B). The extension will be a limited access toll road with six main lanes and six frontage road lanes.

The NTTA Board of Directors chose an alignment for the Phase 4 extension that straddles the Collin-Denton County line from FM 428 in Collin County to the Grayson County line. The county alignment provides a greater economic development benefit for most of the region, requires less right of way and follows an existing county road system.

Initially, there was an additional section identified as part of this extension. It was referred to as Phase 5A and would have extended the DNT from the Grayson County line to FM 121 in Grayson County.

Per state law, the Grayson County Regional Mobility Authority has primacy on any toll project within Grayson County, including portions of the DNT which may extend into Grayson County.

Planning and environmental study completed.

Design of southbound frontage roads for Phase 4B is currently underway.

Design of the DNT main lane extension over U.S. 380 is underway.

Estimated Cost
To be determined.

Construction Date
To be determined.


  • NTTA began preliminary route studies, schematic design work, environmental documentation, and public involvement for Phases 4A, 4B and 5A of the DNT extension project in November 2007.
  • The road that will become the DNT Phase 4A (U.S. 380 to FM 428) northbound frontage road opened to traffic in 2008 as a bi-directional, two-lane facility.
  • On March 16, 2009, the NTTA Board approved an expansion of the DNT 4B/5A (FM 428 to FM 121) study area to the west and north. The expansion captured more of Denton and Grayson counties and a small portion of southeast Cooke County, which enabled NTTA to identify and preserve right of way for the DNT corridor.
  • The NTTA Board selected a “county line” alignment on July 21, 2010, for the DNT Phase 4B/5A extension, from FM 428 in Collin and Denton counties to FM 121 in Grayson County.
  • On June 15, 2011, the NTTA Board approved the schematic design and environmental evaluation for the DNT Phase 4B/5A extension project.
  • At the February 2013 Board Meeting, an interlocal agreement with Denton County to advance the DNT Phase 4B southbound frontage road project was approved.
  • At the October 2014 Board Meeting, Burns & McDonnell Engineering, Inc. was approved to perform design engineering services for the DNT 4B southbound frontage road. Design is underway and construction is anticipated to begin spring 2018.
  • In early 2017, the NTTA staff determined that it is no longer necessary to include “Phase 5A” as part of the project name.
  • The NTTA Board of Directors approved a request to advertise for design and engineering services for the DNT extension over U.S. 380 at their July 2017 meeting.
  • At the Dec. 2017 meeting, the NTTA Board of Directors awarded a contract to Brown and Gay Engineers to provide design and engineering services for the DNT main lane extension over U.S. 380.

Page Updated
September 2018

Project Information
Email: dnt45@ntta.org
Public Involvement: (972) 628-3134