I-35 expansion using MoPac also
Make I-35 one way from Kyle to Georgetown. And MoPac one way the other direction from Kyle to Georgetown. That way you can keep up with the growth in traffic as Austin grows and expand both roads without buying more real estate downtown.
During rush hour 1/2 of both roads are pretty much empty while the other half is bumper to bumper. This change would handle the growth and alleviate congestion for 20 years, and allow Austin to grow gracefully. 183 would need to be expanded between the 2 roads also.