The project aims to alleviate chronic flooding and traffic congestion on Nguyen Trai street, a crucial arterial road in Hanoi's southwest. This 3,4 km long route, connecting Nga Tu So overpass to Tran Phu street in Ha Dong ward, experiences peak hour traffic density 3,3-5,6 times its design capacity. This often results in gridlock and severe flooding, particularly in the section from the University of Social Sciences and Humanities to the Nguyen Trai - Nguyen Tuan intersection, which frequently becomes impassable during heavy rains.

The Hanoi Department of Construction has outlined a comprehensive traffic diversion plan and safety measures to ensure smooth progress during the sewer line's installation. The construction will be carried out in distinct segments, employing both fixed and mobile barricades to minimize disruption while ensuring efficient progress.

The first major segment, stretching approximately 800 m from Royal City to the Nguyen Trai - Vu Trong Phung intersection, will utilize fixed barricades. Contractors will work on 20-30 m sections at a time, involving an excavation width of 4,6 m and a barricade width of 5,6 m for the new box culvert. To maintain traffic flow, an average of 5-12 m of road width will remain open per side for vehicles traveling from Nga Tu So towards Ring Road 3. Each segment will be fully completed and the road surface restored before work begins on the next.

Nguyen Trai street was congested during the rain on 14/10/2025. *Ngoc Thanh*

Two additional sections will employ mobile barricades and a "roll-on, roll-off" construction method, primarily during nighttime hours to mitigate traffic impact. The 317 m segment from the Nguyen Trai - Vu Trong Phung intersection to the pedestrian bridge in front of the University of Social Sciences and Humanities will involve 10 m long, 4 m wide segments, leaving an average of 16-18 m of road width open. Further down, the 149 m section from the pedestrian bridge to the Nguyen Trai - Nguyen Tuan intersection will see 10 m segments with a 2 m excavation width and 3 m barricade width, maintaining 17-20 m of road width for traffic.

Construction for these two sections, from the Nguyen Trai - Vu Trong Phung intersection through the University of Social Sciences and Humanities to the Nguyen Trai - Nguyen Tuan intersection, will be conducted nightly from 22h to 5h the following morning. The contractor will ensure the road surface is restored after each segment before moving to the next phase.

The area in front of the University of Social Sciences and Humanities (Nguyen Trai street) was deeply flooded during heavy rain on 7/10/2025. *Hoang Giang*

Nguyen Trai street is a vital connection to National Highway 6, leading to Hoa Binh, Son La, and Dien Bien. The new sewer system is expected to significantly improve the resilience of this critical urban artery against the impacts of heavy rainfall.

*Vo Hai*