Slight humps at side roads mean that pedestrians can walk along the main road without breaking their stride. The gap in the double-yellows helps give a visual impression of continuity. A hump is cheaper than tightening the radius, because it avoids the need to alter drains. However it operates in the same way, because driving across a hump at an angle is uncomfortable, so cars slow down. Turning vehicles slightly disrupt the flow of traffic on the main road, reducing speed and making it more pleasant to cycle along.
The cycle lane is painted across the side road because this reduces accidents. It also gives a strong impression of continuity to the cyclist.