I tend to avoid SIDEWALKS as possible, since it's usually faster and smoother on a street surface. However, here in the suburbs, there are a lot of 4 and 6-lane 'arterial' roads with 45mph limit (55mph operating speed) and curbs on both sides, so no shoulder.
The speed and volume of traffic and lack of an 'out' on these roads does not permit reasonably safe cycling except in the wee hours of the morning, so I ride the sidewalks there. Typically pedestrian traffic is very low on these roads so it's not a big deal.If I am on a sidewalk, I will slow and yield the pavement to oncoming pedestrians. I use a bell when overtaking pedestrians (or the occasional rider) I also give as much room as possible. If the road's clear, I 'll jump the curb, and overtake in the traffic lane, and get back to the sidewalk at the end of the block.