I had an incident where I was almost hit by a bus. I was in the bicycle lane and the bus just passed me (it was not even by me all the way) when it veered into the bike lane to make a stop at a bus stop. I was stuck inbetween the bus and the curb, so I had to stop until the bus took off again.
I think that bus drivers don't always remember how long their buses are and they forget that when they pass a cyclist, then they have to make sure they do not cut them off when the veer over to make a stop. I did not do anything on this occasion because I was only in danger of being forced to the curb, but if I were actually hit by the bus, or the bus actually forced me off the road, then I would note the time, bus number and street stop, and report that to the transit authority. This was in Portland, so I would think that something would get done, but that may be just wishful thinking.
All in all, I find sidewalk riding harder and less safe than road cycling, but that may be because I ride fast and I am used to cars passing me on the road. If a person is riding slow and is used to dodging things in their path, then a sidewalk may be the better option. For me the sidewalk is only used if I make a mistake in finding the place where I want to be and do not want to ride around the block.
For someone riding a sidewalk, remember that they are designed for pedestrian use, and if you are riding a bike on it, you should keep your speed slow and keep a sharp eye out for obstacles, pedestrians, other cyclists, cars, dogs, trees, cuts for driveways, pavement cracks, and any other thing that may crop up with a sidewalk. In other words, ride as if you are walking.
BR
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Cat 2 Track, Cat 3 Road.
"If you’re new enough [to racing] that you would ask such question, then i would hazard a guess that if you just made up a workout that sounded hard to do, and did it, you’d probably get faster." --
the tiniest sprinter