Auckland motorists are inching towards congestion charges.
According to a joint Auckland Council-government report, the Congestion Question, charging motorists "shows real promise" to help throttle back use of the city's increasingly clogged roads.
The parties have accepted the report's recommendations to look further into how it might work and pricing.
By August, the researchers hope to have identified, designed and assessed how much and where motorists could be charged.
No ball-park figures were mentioned in the report but automatic number plate reading was likely to be the best way to charge people.
The authors says congestion is now spreading throughout Auckland's day - 33 per cent more of main roads are now congested than in 2014.
That meant increasing travel times, unreliability (people now need to add up to 55 per cent more time to their journey to get there on time) and ultimately cost.
There were more than 700 new cars on Auckland's road every week and without congestion charging, in 2046 many motorist driving to work in the morning won't be able to go above 30 per cent of the speed limit, the report said.
"Without some form of congestion pricing, congestion will continue to increase and overall network performance will deteriorate further.
"The result is that Aucklanders access to jobs, education and other opportunities will become more difficult and the benefits of growth will be limited."
The researchers looked at Stockholm and Gothenburg's cordon charge, London's congestion zone and Dubai's corridor charge, as well as Singapore's experience, where a congestion zone was introduced in 1975.
However, they noted there were major differences between those cities and Auckland.
A decision on congestion charges could be made by next year and if it proceeds could be introduced within five to 10 years.