sidewalk vs. bikelane

Sidewalks are for walking. Bike lanes are for bikes. Why is it that this is so hard to understand?

Bike lanes are also safer for bikers and pedestrians alike. You are more likely to be hit by a car when you ride on the sidewalk than when you ride on the street going in the right direction. Just saying. So please let me walk on the sidewalk without having to jump out of the way.

Thank you.