Given Maurice Williamson's minor faux pas while I was in Ireland, I thought I should put in my rather short (you'll be relieved) free and rank on what I think of what the Nats have said on this:
1. I'd welcome opening up investment in roads to the private sector, but the more the private sector can carry the risk (and any profits) the better. Think, for example, if the Auckland Harbour Bridge was privatised, even by lease to avoid Treaty of Waitangi/Public Works Act issues, including SH1 from Spaghetti Junction north and from Constellation Drive south (both being where other state highways intersect). The new owner could toll it, could investigate, design, build, finance, operate the second crossing. If very clever it could even work with the state to refund road user charges and fuel taxes paid for using the motorway (or the state could pay the equivalent to offset the tolls to the company). Let it be the example to New Zealand of how the private sector can build, operate, own and manage a highway - see how the tolls will go up at peak times which is exactly when the second crossing is needed, so exactly the users who should pay for it. See how the tolls will be marginal at off peak periods, see how private bus companies can take advantage of a less congested crossing to provide more services for those who wont pay the toll. Oh and while we're at it, see how the Victoria Park Viaduct widening/tunnelling can be financed the same way.
2. Tolling for new road capacity is good, but the scope to do this in New Zealand is limited due to the nature of its road network, the volumes of traffic involved and the ready availability of other routes. However, it could be considered as a means of moving away from fuel tax.
What I DO want to ask Maurice Williamson is:
Will National abolish the regional fuel taxes?
Will National abolish automatic inflation based indexation of fuel excise duty and road user charges?
Will National consider shifting from taxing motorists and property owners to pay for roads, to motorists paying to use the roads?
The first would be consistent with how National voted in Parliament, as would the second. The third would be consistent with National's policy when it was voted out of office. It's technically and economically feasible to go down this path, and a sensible way forward would be to commercialise road management, and then consider how to privatise it.