What defines a dual carriageway?

A dual carriageway is characterized by a two-way road that is separated into two distinct lanes for traffic moving in opposite directions, typically by a central median or barrier. This design improves safety by preventing head-on collisions and allows for smoother and more efficient traffic flow.

The presence of the median also permits vehicles to make safe lane changes and maneuver without the risk of encountering oncoming traffic directly. This separation is a key aspect that defines a dual carriageway, making it different from other types of roadways.

Alternative options like a one-way street or a two-lane road do not encompass the essential feature of separation for opposing traffic flows. Additionally, a multi-lane highway without separation would not meet the criteria of being a dual carriageway, as it lacks the protective median that is critical for this type of roadway designation.