The Texas Dept. of Transportation has awarded a $746-million contract to British-based Balfour-Beatty to construct 2.5 miles of its massive Interstate 35 Capital Express Central project.

This upgrade will start south of downtown Austin during the first half of 2025 and finish by 2033. It will reconstruct a bridge over the 417-acre Lady Bird Lake on the Colorado River, add two high-occupancy-vehicle management lanes in each direction, and build an interchange for access to future light rail routes, as well as a walkers-only bridge and enhanced bike and walking paths.

Balfour Beatty said in a release that the nearly 60-year-old bridge will be constructed from a barge, since it requires “complex engineering and marine expertise.” Mark Johnnie, chief operating officer of the contractor's US civil construction unit, said it will bring in “specialized overwater bridge replacement capabilities.”

At peak, the project will employ around 150 people. Divided into six segments with construction extending to the middle 2030s, the upgrade is set to ease congestion on a roadway traveled by roughly 200,000 vehicles daily.

When completed, parts of the interstate will include more than 20 lanes. When the project is completed, improvements will include removing the current I-35 decks to lower the roadway. adding to non-tolled HOV-managed lanes in each direction and building east-west cross-street bridges and pedestrian and bicycle paths.

Opposing the plan is Rethink35, which argues that more cars on the road will worsen city air quality and worsen health risks. One group proposal is for the state to buy out the SH-130 tollway, which it says is underused. 

The transportation agency said its 2023 project environmental Impact study concluded that work completion would not increase pollution or affect health issues along the interstate.