Twin

In the context of road construction and infrastructure terminology:

Twin: Refers to constructing a highway or roadway with two lanes on each side, often separated by a center median. This configuration allows for two lanes of traffic in each direction, providing increased capacity and potentially safer traffic flow by separating opposing directions of travel.

Dual: The British term for the same road configuration, also indicating a highway with two lanes in each direction, typically separated by a central reservation or median.

This setup is common in many modern highways and freeways to accommodate higher volumes of traffic and improve safety by reducing the risk of head-on collisions through the use of a physical barrier between lanes traveling in opposite directions.

See

• Big twins
• Doubles
• Flat twin
• Fore-and-aft Flat Twin
• Offset twin
• Parallel twin