Auckland's Northern Busway is being hailed in a Transport Agency report as a major growth stimulant for the central business district.
The report by agency consultants says the busway is largely responsible for a 15 per cent increase in those crossing the harbour bridge, which would become substantially more congested without the $300 million facility.
An estimated 43 per cent of the approximately 7500 passengers who crossed the bridge on buses in morning peak periods in 2010 were believed to have been former car commuters, making buses responsible for 33.1 per cent of travel from North Shore to the city.
Labour transport spokesman Phil Twyford, who obtained the report ahead of publication, said it showed the busway had been a remarkable success and would add weight to a campaign for a similar public transport highway from West Auckland.
"It has prevented total gridlock on the bridge and Northern Motorway," he said yesterday.