The 21.5km long North-South Corridor (NSC) runs along the existing road corridor between ECP and Admiralty Road West. It will have grade-separated carriageways on the viaduct and tunnel and will largely be dual 3-lanes; except for the stretch of CTE and PIE where it will be dual 4-lanes. The NSC, also feature bus priority and active mobility measures. The tunnel section of the NSC is 12.3km long. For operation of the tunnel, five facility buildings will be provided at Ang Mo Kio Town Garden West, Marymount Road, PIE (Thomson Flyover), Kampong Java Road and Nicoll Highway. The remaining 9.2km is elevated viaduct and at-grade roads.

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