These are some newer type, Green Lane, bicycle lanes that we have on our bike commute to my third grader's elementary school. They continue past the elementary school to get you down safely to Zilker Park, or at least the big hill at the top of Robert E. Lee. The intention is to separate bike traffic from motorist traffic, even if it is primarily a psychological barrier (cones, flags, green colored lanes in intersections, etc.).
This design also helps to decrease the chance of a right hook. Maybe. Attention, avoidance, care are the best ways. And I still split lanes, sometimes, when it makes sense, as discussed, and other alternatives are lacking.