What are you talking about, "bike lane"? That's the Uber and Lyft drop-off lane.
The separated lane along the Drag sucks (which is the one in the photo) for the reason you mentioned -- cars will turn across it, and people will wander across/along it.
The two-way separated lane on Rio Grande is great. My only complaint is that I occasionally come face-to-face with a car that decided they wanted to use it.
There's one of those bike signals on Rio Grande and 24th does make that light slow, and people ignore it a lot (partly because it's West Campus and that's what kids so.) It's also very short, at least when going north. It's green for long enough to get across the street, and that's about it. Once it turns yellow, cars to the right of the bike lane get the left-turn green. It just miss that light and have to wait a long time roughly every day.
I think better than the signals may be the "I see you" signal on southbound Rio Grande and MLK. There's a blue light that will light up when it detects you, so you know you'll eventually get a green. Going the other way, and at many other intersections, at certain times of night, I know that I have three options:
1. Wait for a car going the same way as me shows up and is detected,
2. Bike up onto the side walk so I can press the pedestrian signal, or
3. Run the light because it doesn't know I'm there and it will let me wait indefinitely until one of the above occurs. (Or morning rolls around in 8-12 hours, I guess?)
I'd trade all these new bike signals for more of those detectors/blue lights. Maybe all the intersections will detect me if I stop in just the right spot, but I don't know what spot is for any given light.