A Recap Series

 

The Takanini Interchange

 

Time to do some recaps of a few posts I have done on Southern Auckland and both its urban development plus transport potential. In the first ‘Southern Auckland and Manukau – An Omnibus‘ post I recapped on the need for the Manukau South Rail Link (in spite of opposition from an unusual quarter) to allow high-speed, high-capacity and good frequency train services between Manukau City Centre and the rest of Southern Auckland down to Pukekohe. In the second “Southern Auckland and Manukau – An Omnibus” post I looked back at the evolution of my advocacy of bring Manukau into the 21st Century as a Super Metropolitan Centre – rather than some just other Metropolitan Centre as destined in the Auckland Plan.

In this post I will take a look at a pet peeve of Southern Auckland; that horrid stretch of State Highway One between Manukau and Takanini.

The Manukau to Takanini Motorway Saga

 

Situation: When the State Highway 20 Manukau extension was complete it was triumphed by the New Zealand Transport Agency that not only did the interchange have five years capacity in it before the State Highway One needed upgrading, but the local roads that have been so long congested would be free at last.

Reality: On day one the new State Highway 20 Manukau extension (so the SH1/20 interchange) reach capacity exacerbating the already congested State Highway One to the point NZTA had to put in ramp signals on the interchange. Couple of days later everyone else pretty much goes rat running again on the local roads to try to beat the interchange congestion so we are back at square one. Cue the slow clap.

The Problem: NZTA forgot (no other way to put it) to upgrade State Highway One from the Manukau Interchange down to the Takanini Interchange where the congestion is. Even before the Manukau Interchange was completed State Highway One was already congested as it dropped from three lanes to two lanes at the Hill Road off-ramp plus Takanini Interchange not being the best for efficiently taking traffic off the motorway causing further congestion. And all this just for the southbound side. Northbound you main problem rests back at the Takanini Interchange itself. Anyone who has entered the motorway from Takanini going north knows of the tight and uphill gradient of an on ramp which means both cars and trucks do not have the opportunity to apply power so they can get up to speed with the rest of the motorway traffic. What makes the northbound situation worse is the merging lane is very short so you still can not get to power and the speed needed to be with the already existing motorway traffic. Consequences? Congestion and a very hazardous situation with heightened risks of nose to tails.

 

The Numbers

Check page 28 of NZTA’s State Highway Traffic Data for the Southern Motorway (SH1) between Manukau and Takanini

Between the two sections going southbound some 56,800 vehicles (drops to 46,000 at Takanini with 12,800 vehicles using the off ramp) use a section of motorway that drops from 5 lanes to 2 lanes in the space of about one kilometre. Northbound some 11,300 vehicles enter the motorway at Takanini contending with that sharp hairpin and short merging bay onto the 2 lane section of motorway before hits three lanes some 200 metres further north. On these numbers alone you can see why we have the chronic congestion.

 

Solution

Simple really. Three lanes from Hill Road to Takanini Interchange heading south while the third lane heading north is brought right back to the on ramp itself so the existing motorway does not get caught by entering traffic. The Takanini Interchange itself will need upgrading with the southbound off ramp doubled in length to allow traffic to exit the motorway safely AND slow down as they prepare to enter the Great South Road. While the northbound side will prove interesting owing to the grade needed to get above the rail line although you could go underneath it if it weren’t for Papakura Stream just on the other side. That said bringing the third lane back to the on ramp and have it “separated” from the existing motorway traffic for about 300 metres so that the entering traffic can at least get to some decent speed before the changing lanes game would go some distance in removing the bottleneck we currently face.

It is also to note that until NZTA upgrade the Takanini Interchange, Auckland Transport will not proceed with upgrades along the Great South Road in the area which includes the addition of bus lanes for the new 33 Great South Road service from next year. So even public transport is “stuck” until NZTA decide to move…

 

2015/16

2015/2016 is when the upgrade to Takanini Interchange and the 3-lane-ing between Manukau and Takanini on the Southern Motorway is meant to happen. Looking at the 2012-2022 (draft) Regional Land Transport Program the upgrades were meant to be done already (check page 50 or 51)

When the 2015-2025 RLTP comes out it will be interesting to see where this necessary and vital upgrade gets placed. I hope like anything this upgrade will be completed by the end of 2016 not only for the South’s sake and sanity but also for the economy. Despite what some opposing quarters say this section of motorway is a vital inter city link between Auckland and the rest of the nation. Yes it carries 56,000 vehicles of which 8.2% (around 4,600) are heavy trucks but no amount of public transport investment on its own will fix this bottleneck. This upgrade is designed to keep traffic moving at whatever speed efficiently rather than the stop-start jerking motion we have now. Furthermore upgrading Takanini would allow traffic to leave the motorway more efficiently and safely than now. Also remember not everyone can take public transport and not all freight can be moved by rail in this “just-in-time” era.

Upgrading Takanini and having three lanes all the way to Takanini from Manukau for efficiency and safety sakes seems logical. Furthermore if State Highway One is flowing efficiently then the rat running we see back on the local roads should be minimised. That said the Manukau South Link and possible the Botany Sky Train might also go some distance in traffic relieve as well. And as I said earlier the upgrading of Takanini allows Auckland Transport to upgrade the Great South Road and get those much required bus lanes in for the 33 bus service due to start next year. Win-win-win for everyone all round.

 

Suppose the ultimate question is what will I be writing in 12 months time. Praising NZTA for getting the upgrade under way, or slamming them for more delays

 

The section of motorway in this post

Zoom in and have a look between Manukau Interchange and Takanini Interchange to see how bad that section of motorway it is