One-way traffic refers to a system of vehicle movement where all vehicles are required to travel in a single direction on a particular road or street. This arrangement helps to reduce congestion and improve safety by minimizing the chances of head-on collisions. One-way streets are often marked with specific signs and road markings to guide drivers. In urban planning, one-way traffic can enhance the flow of vehicles, making it easier for drivers to navigate busy areas. Cities like New York and San Francisco utilize one-way streets to manage traffic effectively, allowing for smoother transit and better organization of roadways.