The goal here is NOT to serve the public by improving traffic flow.
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The goal is to reduce (and eventually kill) use of the evil automobile. One way to do that is by CREATING choke points (like those created by the bike lane) so that people get frustrated and abandon using their cars – at least in that area of town. Create enough choke points and (according to plan) people will eventually throw up their hands in frustration and abandon their cars and use public transportation.