Even the inner-city rail loop would, according to the study, see morning traffic slow to 8km/h by 2021. But that provides the highest speeds for cars within the city centre, and is also the only option to deliver increased capacity beyond 2030.
But given its shortcomings, the study says the best way to ensure enough people can be brought into central Auckland to fill the extra jobs associated with its growth would be to build the rail loop while also improving the bus service. This would have a price tag of $3.3 billion and, because of extra buses, slow morning traffic entering the city to 6km/h by 2021.
Mr Brownlee objects to the study's conclusions on two grounds. First, he says, an assumption of central city job growth of 46 per cent in the next 10 years, compared with an increase of just 18 per cent in the past decade, is too ambitious. Auckland, however, has routinely been plagued by under-estimations of its growth. Secondly, the minister says the study underplays the role of highway improvements, such as the completion of the western ring route in 2017, which will draw many thousands of traffic movements away from the central city.
Given that criticism, it is significant that the study is not simply the work of Sinclair Knight Merz. Senior officials from the Ministry of Transport, the Transport Agency and the Treasury were involved. Further input was provided by Auckland Transport, which commissioned the study after the Government and the council had arrived at very different conclusions about the rail loop's return on every dollar invested. Given all that, this study should be the definitive research, not yet another document destined to gather dust. Mr Brown's task now is to convince Aucklanders that the study is robust and its conclusions are right. If he can, the Government should stand to one side.