A new national ticketing system for buses, ferries and trains will open the way for more road tolls and could introduce congestion charges for motorists - for the first time.
A business case for the $1.4 billion system - being built by a US transport and military contractor - raises this possibility several times.
Waka Kotahi has signed up Cubic to roll out the new system across 13 regions by the end of 2026.
It could provide a platform for "park-and-ride, road tolling and congestion charging", the business case - released under the Official Information Act (OIA) - said.
It focused mainly on the benefits of boosting patronage, unjamming roads and relieving motorists of costs such as for repairs and parking. However, it also repeatedly noted the expansion options.
"There are a range of other transport-related services that could be serviced ... examples include tolling, congestion charging, park-and-ride and so forth."
It "would enable transport accounts not just for ticketing but for all transport payments such as ... congestion charges for drivers who enter congested areas at peak times".
The new system, like those in Queensland, London, Chicago and Sydney, is "open loop" - meaning you will not need to top up separate branded Snapper, Hop or Metrocards. Instead, you pay by hovering a smartphone or debit or credit card over a reader. Each customer would need only one account.
The simplified approach would allow the linking of link fare levels to "future congestion charging regimes", the report said.
Currently only three roads are tolled, but Waka Kotahi is already spending millions on back-office systems to enable more.
Both tolling more roads - each of which would require ministerial sign-off - and new congestion charging would be politically charged.
The 228-page business case was done in August, and does not put a timeframe around any of these options.
It said it was "guaranteed" the system would deliver the lowest possible fare to customers, and caps on fares, because it charges a person's account at the end of a day when all possible concessions can be factored in.
The business case, and several other reports released under the OIA, show Waka Kotahi had high hopes for the ticketing system helping unjam the roads, especially in Auckland.
It foresees $500 million of decongestion benefits from 2026/27.
"The key benefit is increased patronage, which lead to decongestion benefits from fewer private vehicles, and public transport user benefits from not using a vehicle, such as reduced petrol and maintenance costs, reduced parking charges."
Canterbury aims to run a pilot first-up in mid-2024.
Cubic offered to experiment in Wellington earlier, but its proposal was not costed or detailed enough, Waka Kotahi said; instead, a stopgap expansion of Snapper cards on to the train system has gone ahead at a cost of $25m.
Benefits of a national system outweighed the costs by 1.7-to-one compared to separate regional upgrades, the business case claimed.
At $1.4b in capital and operating costs over 14 years, the total for the new ticketing system compared to $1.1b for the region-by-region upgrade, and $700-800m for the third option, "do nothing".
Nothing for free
The business case briefly touched on making public transport free, at a cost of $385m a year.
"In those countries and cities that have introduced free public transport, there has been little reduction in private vehicle use," it said.
Services typically did not improve due to lack of money, it said, dismissing the idea.
Climate change is touched on in the business case, but not in depth.
The national ticketing solution is a long time coming. Stopgap solutions have been used since 2013 to keep the country's 16 different systems going.
"Outdated and inefficient" systems - such as in Canterbury, and for trains in Wellington - turned customers off, the report said. They virtually all need updating within five years.
Wrangles with Auckland Transport (AT) have held up a national system for years. The business case stressed Waka Kotahi was keeping Auckland on board and "AT is increasingly supportive".
Auckland stands to gain the most if the new system boosts patronage as forecast. A mere 0.5 percent boost in customers nationally would be worth $236m in benefits.
Overall, it was forecast the ticket system would increase passenger trip numbers by 2 percent in 2026/27, and by up to 5 percent by year 10.
That would play a part in the forecast overall rises in patronage for Auckland, from 48 million trips a year now to 198 million by 2035; in greater Wellington from 18 million to 58 million; and in Canterbury from 7 million to 17 million.
A group of nine smaller regions - that have been instrumental in getting this far with national ticketing - would grow from 7 million trips now to 19 million.
One drawback is the national ticketing system will concentrate customer information in one place that could be hacked or compromised by security gaps.
"One central, account-based system poses wider and more significant digital risks than the current regional closed-loop solutions," the report said.
Auckland's Hop, Wellington's Snapper. Christchurch's Metrocard and the regions' Bee Card are closed-loop, proprietary systems.
A plus was all the "rich data" the new system would provide to planners and policymakers.
It would also boost tracing and tracking attempts during disruptions such as Covid, the report said.
"Richer data ... can enable faster contact tracing, which could mean more localised lockdowns, reducing the economic impact and enabling faster recovery."
Data "capture" could also enable future services like ride-sharing and the development of "smart" cities, it said - where cities focus on using information and communication technologies to increase efficiency and provide services.
In the US, privacy campaigners have expressed alarm "the development of smart cities creates growing incentives for companies like Cubic to aggregate our data and then sell it".
Waka Kotahi told RNZ only "very limited" personal information would be gathered by the system, "eg name, contact details".
The system would "meet the requirements and expectations in respect of data sovereignty and Māori data sovereignty".
It had adopted privacy-by-design approach and would do a privacy impact assessment at the delivery phase.