The affordability question is also relevant at the top-end of the market. A survey of cars' carbon dioxide emissions found that luxury car brands such as Rolls-Royce and Lamborghini were the highest polluters, based on grams of C02 per kilometre travelled — more than double that of the cleanest fossil-fuel brand Citroen.
If a driver has the budget to fork out for a Rolls or a Lamborghini, they are unlikely to be swayed by the potential $3000 penalty. Of course, this is an extreme example and these cars make up a small percentage of vehicles on our roads.
However, further down the price ladder the question remains whether the penalty will be stiff enough to deter customers. Will the country's army of SUV drivers be willing to forsake their vehicles, capable of comfortably transporting the family and assorted sports gear, buggies and bicycles?
The sweet spot of the scheme will be for those who have a genuine choice about whether to opt for a high-emission petrol car or a cleaner alternative, and where the financial incentive will make a material difference to them.
Another difficulty is that the policy does not apply to the more than 3.2 million vehicles already on our roads. About 74 per cent of annual sales are of vehicles already registered, according to Associate Transport Minister and Green MP Julie Anne Genter. There is also the issue of whether there will be an adequate network of charging stations to serve an increase in electric vehicles.
The new policy is best seen then as a good step towards transforming New Zealand's fleet and reducing transport emissions.
Plastic bags are now disappearing from our supermarkets and pantries after the ban introduced this month, and most Kiwis are fine with that. We are likely to show the same level of acceptance as high-polluting petrol cars slowly drive off into the sunset.