The immediate problem is the closure of a priority lane for buses and cars carrying two or more occupants along the on-ramp to the Northwestern Motorway from Great North Rd at Waterview, forcing traffic to queue along Great North Rd to Pt Chevalier.
Ritchies Transport chief Andrew Ritchie said that was causing delays of between 10 and 25 minutes in the evening travel peak.
Although the only westbound closure so far is that of the Waterview on-ramp priority lane, the agency intends shutting 640m of the bus shoulder lane on that side of the motorway from August 11. That is expected to stay closed for 2 years, although the agency hopes to open a wider and longer citybound bus lane in two years.
Labour's spokesman on Auckland issues, Te Atatu MP Phil Twyford, cannot understand why the Transport Agency is not allocating one of the motorway's three general traffic lanes in each direction to high-occupancy vehicles.
Transport Agency acting Auckland highways manager Steve Mutton said various options were being investigated, including Mr Twyford's suggestion.
Auckland Transport spokesman Mark Hannan said western bus timetables were being reviewed to take account of "running time issues across the day - not just at peak times".
Traffic light phases had been altered to manage vehicle flows to the Waterview motorway on-ramp.