The Kallang-Paya Lebar Expressway (KPE) is a 12km long strategic road link between the existing East Coast Park Expressway (ECP) in the south and Tampines Expressway (TPE) in the north-east. The KPE comprises 9km of underground road and 3km of surface level road, together with major interchanges with the Pan-Island Expressway (PIE), ECP and TPE. It is currently the longest underground tunnel in South-East Asia.

The C422 design scope involves the 1.64km section of the KPE between the ECP and PIE, and all elevated slip roads, at-grade highway, ventilation building and landscaping. There are a total of 3 elevated slip roads at the KPE-PIE Interchange. The scope also includes significant temporary works such as temporary vehicular bridges, diaphragm walls, temporary steel shoring and traffic diversion during construction.