The funding and timeframe for the Matakana Link Road has been confirmed, with construction expected to start in 2019.
The road will create a link from SH1 north of the showgrounds, near the end of the Puhoi to Warkworth Motorway, through to Matakana Road, meaning traffic heading east can bypass the Hill Street intersection.
Auckland Transport and the NZ Transport Agency (NZTA) have signed an agreement to deliver the project by 2022, just before the new motorway opens, and planning and consenting work is already underway.
NZTA will provide early funding to build the road if Auckland Transport funds are not available.
But Fix Hill Street Now group member Grant McLachlan says the link road won't address the core issue.
"Local traffic will more than double at the intersection by the time that the link road is complete," Mr McLachlan says. "In the meantime, construction traffic for these other projects will make congestion exponentially worse."