Malaysia's Smart Tunnel Transforms into a Giant River

A highway where cars used to zoom by transforms into a massive river in the face of torrential rain. This is the story of the SMART Tunnel in Kuala Lumpur, Malaysia. This city is situated at the confluence of two rivers, which meant that whenever it rained heavily, water would flood the urban areas. However, building a separate flood tunnel would incur enormous costs, and the roads leading into the city were perpetually choked with traffic. They needed to manage floods and ease traffic congestion, essentially facing the challenge of excavating the same land twice. So, engineers decided not to build separate channels for water and vehicles. They integrated both functions into a single tunnel. A massive stormwater tunnel, 9.7 kilometers long, was constructed, with a 3-kilometer section featuring a two-tiered roadway built within it. During normal times, cars travel on both levels. When moderate rain occurs, water is diverted solely through the bottom-most drainage channel, leaving the roadway fully operational.