The Interstate 99 Highway will be expanded to Houston from the existing state route between Houston and San Antonio, according to a state Department of Transportation statement.

The highway will be the second major expansion in the region in the past two years, with Houston, San Antonio and Austin also expanding the existing highway.

The state agency said Thursday the project will cost $2.2 billion and take two years to complete.

It’s a $6 billion project that will take a total of 15 years to build.

The extension will link Interstate 9 and the Texas Central Railway line, the two major corridors in the area.