Final answer:
The solid white line marks the outside edge of the traffic lane and indicates that crossing it is generally not permitted except under special circumstances, such as emergencies or when directed to do so.
Step-by-step explanation:
The line that indicates the outside edge of the traffic lane, which can only be crossed by traffic moving to or from the shoulder, is commonly known as the solid white line. This line delineates the boundary of the lane and the shoulder, and it is intended to signal to drivers that crossing this line from the traffic lane is discouraged except in certain circumstances such as emergencies or when directed by traffic signs or law enforcement. It is an important part of road safety rules and is typically found on the far right of the roadway for traffic moving in the same direction.