The Jinzishan interchange (formerly, the South Outer Ring interchange project), another key traffic project within the urban area, is scheduled to be under the first phase of its enclosure construction on October 8. Workers will have one lane of the South Outer Ring Road closed by then. 

The total investment in Jinzishan interchange is about 1.802 billion yuan. Preliminary construction of the interchange will run from October of this year and continue until October 2021. With an approximate 24 months of construction time, the plan calls for the interchange to be completed and open to traffic by 2021. 

This project will feature a diversion from the South Outer Ring Road, the construction of submerged tunnels, and eight ramps. The total length of the diversion is 2.679 km, and the two-way six-lane urban expressway standard has been adopted. The designed speed of the main line is 80 km/h. 

"The underground tunnel is about 800 meters long and 40 meters wide. When completed, it will be the widest tunnel in Zhongshan," said Hu Jian, chief engineer of the project. 

Hu added that the first phase of the project will be the largest in terms of workload. In addition, this phase will last about one and a half years.