Mr Greening, a former Manurewa Local Board member, studied congestion and how to battle it after getting stuck in jams caused by what he says was a failure to make the Southern Motorway wide enough to cope with traffic joining it at Manukau from the Southwestern Motorway.
Dismissing self-driving vehicles as a bit too futuristic to solve Auckland's transport crisis in time, he became keen on the Tango after seeing video footage of one dragging off racing cars and of two models driving side by side in a single US freeway lane before and after passing another motorist from both sides, in a rapid scissoring manoeuvre.
He followed that up with a visit to the US last month to meet Commuter Cars president Rick Woodbury, who offered to bring a demonstration model to New Zealand at the Seattle-based company's expense.
Mr Greening says that even if the cars are required to drive in formation in this country, as are motorbikes following a two-second separation rule, using 15,000 of them on Auckland's motorways to displace normal gas-guzzling cars at peak times would free up enough space to allow all traffic to flow freely.
Although he acknowledges the Tango will be a tight fit for its driver, who has an option of carrying a back-seat passenger, he says it is remarkably stable and encompassed by a roll cage tough enough to protect occupants from collisions with other vehicles to a combined speed of 322km/h.
He estimates the cost of building 15,000 cars at $435 million, but says that figure is nowhere near as scary as the $68 billion of spending on transport projects and operating costs deemed necessary to cope with up to a million more Aucklanders by 2041.
"We're not saying [to the council and Government] we want you to give us a cheque for $435 million now, because that's what it will cost to build this amount of cars, but we want to do a year-long pilot with three to five vehicles to demonstrate to the public and see what type of reaction we would get."
Auckland Council infrastructure chairman Mike Lee is nervous about a funding pitch Mr Greening wants to make for council's 2014-15 annual plan, saying he should concentrate on getting private sector support.
"Good luck to him, but we have a substandard public transport system and we need to put all our efforts into getting that right before we go off on a tangent into bubble cars or whatever," Mr Lee said.
"If we had a top-notch public transport system and we had extra money to flash around, maybe you'd think about it. But we need to redouble our efforts into things like the City Rail Link, rail to the airport - electric bubble cars are not going to solve problems of mass transit around Auckland."
