Texas

[bwana39]

I ran into this while checking out the nature of the construction along IH 35 & 410.
https://www.txdot.gov/projects/projects-studies/san-antonio/i35-nex-i410-south-fm1103.html

From what it says is that 19.5 miles of IH 35 will have elevated express lanes that are not tolled and most of all allow all vehicles to use two lanes of it while only one will serve the HOV vehicles.

Whats the catch?   

Pretty sure the only catch is the obvious one - there will be limited to no local access to interchanges.

Austin has been this way for decades. A high (through) set of freeway lanes and a lower set of freeway lanes  with local access.