Frustrated commuters are calling for a change in retail working hours after a motorway crash caused gridlock across Auckland.

Inner-city Auckland traffic was brought to a virtual standstill after a motorway crash - gridlock that the Automobile Association described as the worst it had seen.

Auckland's Southern Motorway has reopened all four southbound lanes after a serious crash this afternoon, but gridlocked traffic will still take some time to clear.

Motorists heading out of the city are being urged to be patient following a four-car crash on Auckland's northern motorway.

Holidaymakers driving home have been urged by police to "take it easy'' on the roads and plan the return journey to ensure they get home in one piece.

Fatal accidents, breakdowns and huge traffic backlogs have plagued the first four days of the official Christmas road toll period.

A new motorway is being constructed near Hamilton, coming into the city from the north; many kilometres are near completion.

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, a study says.

All northbound lanes on Auckland's southern motorway are now open after an overturned truck caused traffic chaos.

Rush-hour traffic in central Auckland will slow to walking pace in 10 years if the central city rail tunnel isn't built, a confidential report warns.

A tourist route where an American honeymooner died has been identified as one of the country's riskiest roads to drive on.

A police traffic officer has been charged with careless driving after he crashed his patrol car into a tree.

Former Cabinet minister Dover Samuels has defended a traffic ticket for driving in a bus lane, claiming country drivers don't know city rules.