KEY POINTS:
Holidaymakers and commuters were caught in traffic jams in and around Auckland yesterday, particularly past Orewa and at roadworks on Hillsborough Rd's junction with the Southwestern Motorway.
Motorists going south from Auckland on State Highway 1 past Mercer or the Maramarua Highway to the Coromandel Peninsula or the Bay of Plenty also faced delays, especially after lunchtime, when rain made surfaces slippery and triggered a rash of minor nose-to-tail collisions.
Northbound vehicles, many packed with Christmas presents and holiday provisions, took 40 minutes or so to travel 3km through the Orewa bottleneck to the Hibiscus Coast.
And some motorists took about two hours to reach Snells Beach from Auckland, about double the normal trip time.
Even those going across Mangere Bridge found themselves bumper-to-bumper in residential streets used as detours for motorway traffic through Hillsborough.
Carlton Rd and Littlejohn St were full of traffic for much of the day because of the closure of State Highway 20 to eastbound vehicles between Hayr Rd and Queenstown Rd.
The northern approach to the motorway was also jammed along the other end of Queenstown Rd - a main route to the airport from central Auckland.
Transit NZ is keeping the end of the motorway open to westbound traffic for now, but the closure of exits in both directions to Hillsborough Rd means drivers can expect a slow grind up the hill from Onehunga Bay until the end of next week.
A giant temporary roundabout is being built at the motorway's intersection with Hillsborough Rd.
Transit has taken out newspaper advertisements urging motorists to turn off through Onehunga or Queenstown Rd to avoid the jams, but a high demand for electronic message boards at other trouble spots meant its contractors were unable to obtain any for the Southwestern Motorway.
The agency timed its construction of the 130m-diameter roundabout for the holiday period, expecting 25 per cent less traffic this week than the 40,000-plus vehicles which pass through the intersection on a normal business day.
Transit is hoping the roundabout will be complete by the end of next week.
It will manage traffic while an interchange for its $195 million motorway extension through Mt Roskill is built over the next two years.
Another Northern Motorway traffic diversion will be in effect until January 14.
Transit says drivers should use the Greville Rd or Tristram Ave southbound ramps to reach the motorway during closure of the Constellation Drive entry point while a trench is dug for a high-voltage power link.
* Two cars collided head-on north of Paekakariki last night, putting seven people - including an 11-year-old girl - in hospital and closing State Highway 1.
Three of the injured are said to have life-threatening injuries.
The 11-year-old was taken to hospital by Westpac Rescue Helicopter, and another patient was airlifted by the Square Trust Rescue Helicopter. It is understood the other victims were taken to hospital by ambulance.
The crash happened about 5pm.
