This is incorrect. I've been following this since it even got on the radar.
They were considering a SW school. It was never agreed upon. The district's enrollment is dropping. Bowie's enrollment has finally stagnated a bit. It still isn't as big as it was pre-Akins. SE Austin is growing more rapidly than SW Austin. The Bowie zone is full of environmentally-protected areas that will never get built on.
Also, much of the overcrowding came from Akins and Crockett kids transferring into Bowie. That has been curtailed the last couple of years. There's no longer any majority-to-minority transfers allowed (Hispanic kids going to a white Bowie).
Half of LASA enrollment was made up of kids from south of the river. Most of those from Bowie and Austin High zones. LASA is now moving farther south and will be even closer, and allow twice the enrollment it did at LBJ. I could see even more Bowie kids transferring out, which will relieve overcrowding.
Lastly, the entire Bowie campus is getting millions of dollars infused. Permanent capacity will be 2,900. Currently, it's ~2,450 and holds ~2,900 kids. Population projections see the Bowie zone topping off around 3,100 HS age kids in the next couple of years, then dropping back to around 2,900 again.
Personally, I'd rather continue building upon what Bowie has created. They've had decent success in both academics and extracurricular activities. They're the strongest HS in AISD. Building another HS out there would have diluted them and likely created 2 average 5A high schools.
As for the parking, yes it's a nightmare. Yes, the garage will cause a bottleneck for the students trying to leave. But they're also redesigning the traffic flow, and adding turn lanes onto Slaughter. We'll see how it works.