Almost as soon as I boarded at 21st Street, the driver encountered a parked car in what is supposed to be a bus-only lane. The street was jammed with traffic, making it hard to change lanes. Pedestrians passed us as we inched toward 17th Street, where a tide of humanity flooded the crosswalks and kept cars from turning right. After several light-cycle changes, the bus plunged forward half a block, only to be thwarted by an Uber pickup. Another half block on, at 15th Street, everything came to a halt: A VIP party bus lazed idly in front Del Frisco’s, one set of wheels straddling the left lane, making it impossible for anyone to squeeze past.