To dream of a sidewalk curb represents a need to slow down or be more patient. Restrictions and limitations on how fast or aggressive you are being. An obstacle or person that must be respected as you try to achieve your goals. A need to more careful or “cut down” on something.
Alternatively, a curb may reflect a need to be careful around other people achievements or sense of security. Not interfering or invading others rights or personal space. Feeling that you finally have to notice other people, too.