Construction on the $1.6 billion North Tarrant Express Project, which has slowed and frustrated millions of drivers along Interstate 35W through Fort Worth for the past several years, is all but complete.

Officials behind the project are expected to announce that “substantial completion” is set for Thursday at a news conference.

The 10.1 mile project runs from Interstate 30 interchange with I-35W near Downtown Fort Worth to North Tarrant Parkway at the U.S. 287 interchange.

As recently as 2012, that stretch of highway was named by the Texas Department of Transportation as the most congested highway in the state.

Since then the interstate has been rebuilt, with added frontage roads and bypass lanes, as well as two managed TEXpress Lanes in each direction.

Approximately 135,000 vehicles travel through this section of I-35W every day, according to Robert Hinkle with NTE Mobility Partners, the company that has worked on the project on behalf of the Texas Department of Transportation.

“(Interstate) 35 is a big deal,” Hinkle said. “There are hundreds of thousands of people who move up and down that corridor every week, and not just people in Tarrant County. They're coming from the border of Mexico moving to the border of Canada, because it is an interstate, it is a NAFTA route and there is a lot of trade out there.”

Substantial completion of the project means that all of the road work on the main highway is complete, and all lanes will officially be open to traffic.

There will still be some significant construction through the area for the next several months because work still needs to be completed on a handful of ramps and connectors, which were not part of the original plan, according to Hinkle.