when do we say in the street and when on the street.
It depends upon the context. In AmE, we use "in" when referring to some particular object (human or otherwise) on the pavement. For example: "John Doe was hit by a car when he was standing in the street begging for money." Or: "Construction was completed on Telegraph Road two months ago but there are still orange traffic cones left in the middle of the street."
Americans say "on" when referring to a location, such as "I live on Main Street" or "The post office is on Evergreen Road."![]()