Not even a $2.86 billion rail tunnel will stop morning traffic in downtown Auckland from grinding down to half its current speed within a decade, according to a major study recommending the project.
But without it, there will be inadequate road capacity to meet demand after 2021, and relying solely on more buses to improve public transport will hasten gridlock, say consultants hired by Auckland Transport to answer Government questions about a 3.5km rail tunnel from Britomart to Mt Eden.
Even so, the Sinclair Knight Merz consultants are recommending extra buses and underground trains to ensure enough people can be brought into central Auckland and its fringes to fill extra jobs predicted for the country's commercial capital.
That option - costing about $3.3 billion after inflation - is expected to slow traffic entering the city between 7am and 9am on weekday mornings to about 6km/h by 2021, compared with 16km/h now.
Although a rail tunnel for extra public transport would offer motorists a slightly higher speed of 8km/h, Auckland Transport chief executive David Warburton says an integrated solution involving more buses would be the only way of bringing enough people into the city centre.