Motorists will not be tolled on Wellington's $850m Transmission Gully motorway despite advice to transport planners that tolling is a smart way to go.
The Transport Agency's decision today follows more than a decade of to-ing and fro-ing over whether to toll the 27km four-lane highway.
The toll option was shelved in 2014, then revived, then shelved again around the time of the 2017 election.
It was reactivated in August last year, with the government ordering NZTA take a broader look at using tolling to manage traffic demand, even though legislation does not allow for this.
- Scroll to the end or click here to read the redacted NZTA document released under OIA
A key factor is the agency not wanting lots of drivers to avoid a toll by staying on the current SH1 coastal route through Paekākāriki.
This "would compromise the safety, environmental and access benefits which the new road will deliver for drivers as well as for communities along the coastal route", the director of regional relationships Emma Speight said in a statement.
The revenue over the lifetime of the toll was unlikely to make a meaningful dent in costs, she said.
The technological back-up is lacking too, and would have to improve too to cope with the likes of variable pricing, such as a lower after-dark toll to help reduce truck numbers on local roads at night.
An assessment in March this year said "smart pricing" on Transmission Gully could have countered drivers' desire to stick to the old road, and also helped counter an expected drop in commuters using rail.
However, Ms Speight said new modelling on Transmission Gully showed the toll would be ineffective in encouraging people to choose other modes of transport.
A 2016 review found basic tolling could be done on Transmission Gully at minimal cost in software and back-office systems.
It was estimated a $1.50 toll on cars and $3 on trucks would raise $3.5m a year.
The only other highway tolls, on three northern roads, were "providing significantly better value for money", it said.
NZTA's own reports over several years have generally backed the use of tolling.
"Tolling can also been seen as step towards a modern road pricing system: it gets people used to paying as they travel, and paying extra for certain benefits," a recent report said.
Past NZTA reports have pictured the country having a fully electronic national network, with a "suite" of toll roads including some busy city roads.
It has however taken six years for the agency to move from endorsing the principle of using tolls to manage traffic demand, to beginning a review of how it would do that, including addressing legislative and back-office barriers.
Read the OIA document (redacted by NZTA):