Decongesting Ngauranga

The Akatarawa Motorway opens the way for a radical re-organisation of freight transport in the Wellington region.
Right now, just about everything must travel through either the Ngauranga Gorge, or the Wellington Motorway, or both.
Very little freight travels into or out of the region by rail, because very few freight forwarders possess depots that allow them to efficiently transfer freight between trains and local delivery trucks.
Long-haul trucks operate from depots at places such as Ngauranga and Seaview. Many of them use the Ngauranga Gorge every day. On top of all that long-haul traffic, local delivery trucks and vans operate from the same locations. Those serving areas along State Highway One, from Tawa to Waikanae, further increase traffic in the gorge. Other local delivery trucks radiate out from Ngauranga and Seaview along the already-congested Wellington Motorway.
We can reduce inner-city traffic by locating freight depots on the outskirts of the city. This means that only trucks and vans with freight for the inner city need to use inner city streets.
Depots for the northern suburbs would be located at Waikanae and Upper Hutt. Waikanae is especially attractive because it is on the North Island Main Trunk railway, so freight forwarding depots at Waikanae would be able to transfer freight between trains and local delivery trucks, as well as between long-haul and local delivery trucks. This would shift a significant amount of long-haul freight from road to rail.
Upper Hutt would suit freight forwarders who, for whatever reasons, cannot use rail.
Local delivery trucks would radiate out from both locations to serve areas north of Ngauranga. Organised properly, none of these trucks or vans would go anywhere near the central city, and only goods vehicles with freight for Ngauranga would use the Petone to Ngauranga motorway.
Ideally freight for the southern and western suburbs would go to depots south of the central city, to minimise congestion from that side. That requires improvements to the Ngauranga to Airport Corridor. That is outside the scope of this blog, though I should say that I see no reason we can't extend the North Island Main Trunk railway and the motorway through to the airport.
In any case, I'm convinced that the Akatarawa Motorway, combined with a six-lane motorway and a wide, two-way cycle road between between Petone and Ngauranga, will open the way for a radical revamp of Wellington's freight distribution system which would reduce congestion and make driving and cycling between the Hutt Valley and Wellington far more pleasant than it presently is.