It is legal in Seattle for a cyclist to ride on the sidewalk, but it’s also the law that cyclists must yield the right-of-way to pedestrians, take it slow and use a bell or voice before overtaking or passing any pedestrian. Two things to consider are how wide the sidewalk is, and how many people are out walking.
Bicyclists may also ride in a “bus only” lane.
Cars cannot legally drive in a bicycle lane except to turn, and then they must yield the way to bicyclists in the lane.