Work is to start today on the Chom Chao flyover, the sixth of its kind at the busy Chom Chao roundabout in Phnom Penh.
Prime Minister Hun Sen will attend the groundbreaking ceremony.
The project comprises three flyover sections and an underpass, according to City Hall. As planned, the construction will take 30 months to complete.
According to the master plan, the main flyover connects Russian Federation Boulevard to National Road 3 and it is 408 metres long and 15.8 metres wide.
The second flyover connects Russian Federation Boulevard to Veng Sreng Street and is 40 metres long and 5.25 metres wide. The third flyover connects Veng Sreng Street to National Road 3 and is 60 metres long and 5.25 metres wide.
The single-way underpass connects National Road 4 to Russian Federation Boulevard and is 470 metres long and 8.5 metres wide.
Once completed, the flyover and underpass will have a 100-year lifespan. The Overseas Cambodia Investment Corporation has been awarded the contract.
City Hall spokesman Met Meas Pheakdey declined to provide the cost of the project. The flyover would contribute to traffic flow and ease congestion, he noted.
It was an important junction connecting Phnom Penh to National Road 3 and National Road 4 in term of the transport of goods to the deep seaport in Preah Sihanouk province, he added.
Currently, there are five flyovers in Phnom Penh, with four already in operation and one in temporary operation.