To understand why this was built, you're going to have to listen to a awesome podcast called 99% Invisible, episode name Arsenal of Exclusion. It talks about how infrastructure can be used to funnel and control human behavior. In the case of this useless protected bicycle lane, it is used to encourage people on bicycle to not ride down S Flores, but to choose S Main instead and connect with the protected bicycle lane that was build behind the new grocery store.
In the end, by not putting it down on S Flores, the people who live in the new apartments along S Flores will choose to drive to the new HEB grocery store instead of doing the environmental thing to do which is to ride your bicycle or walk. If you don't think that putting bicycle lanes where they're not needed don't have an effect on the rest of us, just look up into the sky, we're not in compliance anymore.
Now it's not completely useless after all, it provides space for joggers and people walking who live in the King William area. Only time will tell if this useless bicycle lane becomes a parking lane during fiesta. Then the rubber barriers will be destroyed and thus the joggers will loose out on their new jogging strip.
In the Netherlands and Denmark, they don't put protected bicycle lanes down streets like Arsenal, instead they lower the speed limit to about 20 mph. The Author of Copenhagenize.com, came out with a chart on where to put bicycle lanes. It clearly shows in kilometers per hour on where to put the bicycle lanes. (Image 43-2) By using this chart, it clearly shows that a street like Arsenal don't need a protected bicycle lane, speed limit is just too low.
43-1: The protected Bicycle lane on Arsenal between the San Antonio River and S Main Looking East.
43-2: The chart that Mikael Colville-Andersen created can be found on his blog: http://www.copenhagenize.com/2013/04/the-copenhagenize-bicycle-planning-guide.html