Hanoi's four key interchanges with multiple ramps are expected to ease traffic flows in inner city. 

An interchange is defined as a road junction that uses grade separation, and typically one or more ramps, to permit traffic on at least one highway to pass through the junction without interruption from other crossing traffic streams.

The Mai Dich interchange seen above is situated in the west side of the city, connecting Xuan Thuy Street with Ho Tung Mau, Pham Hung, and Pham Van Dong streets (districts of Cau Giay, Nam Tu Liem and Bac Tu Liem).

The Mai Dich interchange has two ramps for cars, including Belt Road 3 and Mai Dich overpass which was completed in 2003. The work on this interchange also includes the elevated section of the capital city’s second metro line - Nhon-Hanoi Railway, which is set to open to traffic in April 2021.

The Cau Giay interchange has three ramps, two for vehicles and the other for the Nhon-Hanoi metro line. This is a crucial interchange because it links the western streets of Hanoi, as well as the Noi Bai International Airport to the city’s central area.

The Cau Giay interchange is named after the eponymous street that it cuts across. The ramp- Belt Road 2 elevated bridge, which went into operation in 2016, eases travel between Hanoi’s downtown and Vo Chi Cong Street (Hoan Kiem District), Nhat Tan Bridge (connecting Tay Ho District with rural district Dong Anh), and Vo Nguyen Giap Street (rural districts of Dong Anh and Soc Son). On top of it is the elevated section for Hanoi’s second metro line.

The Nguyen Trai - Thanh Xuan interchange has four ramps for both vehicles and trains. The heart of the interchange shows the tunnel heading towards the Thanh Xuan - Ha Dong area (see below). The tunnel is situated at Nguyen Trai Street (Dong Da and Thanh Xuan districts), topped by Belt Road 3 and the Cat Linh - Ha Dong metro line, Hanoi’s first.

When the first metro line was given a test run, locals in the area got to see what it would like when the four ramps of the Nguyen Trai - Thanh Xuan interchange all operated.

The completion of this interchange will help curtail traffic congestion in the areas of Tran Phu, Ha Dong, Nguyen Xien and Khuat Duy Tien.

The fourth interchange, Trung Hoa, sits on the axis of Belt Road 3. Work on three ramps has been completed. According to the city planners, this interchange will have an additional ramp for electric trains after 2020, when construction of the Hoa Lac - Tay train route begins.

Trung Hoa comprises the tunnel heading towards Tran Duy Hung Street (Cau Giay District) and Thang Long Boulevard, and the elevated Belt Road 3, topped by four traffic lines.

The Trung Hoa interchange connects Hanoi’s central area with the western side of the city, as well as major roads that link Hanoi with Hai Phong City and Lang Son Province. The interchange also eases travel between downtown Hanoi and the northern highlands province of Hoa Binh.