When Sharrows Don’t Work [BikeNoob]

I’ve run across several streets with “sharrow” markings lately. Sharrows are generally a great idea. They signify the sharing of traffic lanes between bikes and cars, and thereby let cars know that bikes may be around, may be taking the lane, and that it’s all right to do so. However, one recently added sharrow in Austin isn’t working.
Here’s a good example of a proper sharrow. It occupies the right lane, leaving the left lane open for motorized traffic. But bikes and cars can share the sharrow lane.