NPR has a news story that you can either read or listen to rightchea. The important part is where Tim Lomax from Texas Transportation Institute starts talking (that is, once you get past the factoid about the unused toll road circumnavigating the east side of the city is way underperforming projections and going bust. I'd suggest using one of those empty eastern corridors as a route for 35 and let 35's existing route be downgraded and function as part of the grid.).
Lomax says that no matter what is done, traffic will always be awful in Austin (lesson 1 - you can't fight congestion. A city as a fusion reactor for social and economic exchange brings people together.). Instead, Lomax says that behavior is what has to change. In his modeling, he said that things began to look less bleak when commutes to jobs dropped from the ~90% via private automobile to 60% (which would make it 2nd in the country for least auto-dependent behind NYC). Furthermore, the average commute per day has to drop from 20-some miles to about 5 to 7 miles. In other words, the only way to solve the ghost of traffic future is to relocalize and get people out of cars.
Here's the missing piece, however. It is precisely our infrastructural networks that nudge behavior either into or out of cars and further from or closer to where we work. Austinites drive more than New Yorkers because Austin has 6x the highway lane miles per capita, which limits route choice, advantages outer-lying real estate and relocation decisions, and subsidizes long-trip commuting.
While the market is dying for more real estate in walkable (or at least potentially/eventually walkable) infill locations, why not create some?