Hmmm- I see I-35 southwest of Bexar County.
More lies, the land and the highwat will belong to the state.
It is a private toll roadsystem which will be operated by private consortiums, i.e. Cintra-Zachary in Texas.
Neither your map nor your link says that.
The state will own the right of way and lease it out to the Cintra-Zachry consortium, which will put up the money to build the road and maintain it, while collecting tolls to make up for the expense and get some profit as well, for a term of 50 years. The state will own the road; Cintra-Zachry will merely build and run it.