Ramp signals – those traffic lights on motorway on-ramps that are designed to limit the number of vehicles that enter the motorway and thereby help keep traffic flowing, have long been a controversial transport initiative. They were first introduced on Auckland’s motorway system between 2006 and 2009, and are now present on nearly all busy on-ramps.
NZTA’s explanation of ramp signals focuses entirely on how they help limit congestion on the motorway network:
Ramp signals are traffic lights, which have been installed at the end of motorway on-ramps to manage traffic flow onto the motorways during peak periods and other busy times. These signals operate automatically when they are needed to improve traffic conditions on the motorway.
Ramp signals are widely used internationally and have been shown to improve motorway traffic conditions, resulting in more consistent travel times, safer merging and fewer accidents.
Electronic sensors built into the road detect when traffic conditions change, allowing the system to automatically activate and adjust each ramp signals timing sequence in response to current motorway traffic conditions.
And it does seem as though ramp signals have been fairly successful at this job:
Auckland motorway data gathered since the introduction of ramp signals has shown the following results:
- 12% improved travel speeds across the motorway.
- 18% increase in throughput onto the motorway.
- Reduced merging incidents: around 32-34% outbound and 17% inbound
- Faster response times to incidents by Emergency Services due to improved traffic conditions.
- Motorway incidents being cleared up to 15 minutes faster.
Large volumes of vehicles entering a section of motorway will cause traffic to slow and create a ripple effect on the motorway. Ramp signalling provides a smoother flow for traffic entering the motorway, by breaking up these large volumes into more manageable numbers.
Accidents that occur on Auckland’s motorway, happen during peak hours when traffic is stop-start which adds to the congestion and reduces overall efficiency of the network increasing journey times.
Of course nothing comes or free and this “improvement” to motorway travel speeds and throughput comes at a cost, which is much longer queuing time to get onto the motorway in the first place. In many places the queue is simply shifted from the motorway to the on-ramp and the local roads feeding into the on-ramp. When the signals were introduced this ‘shifting the problem’ seemed fine for NZTA, because the queues on local roads were Auckland Transport’s problem.
So if all we cared about was to keep the motorways flowing, then ramp signals are a reasonably good way to help with achieving that goal. Of course this is absolutely not all that we want to achieve from the transport system, and it seems to me that ramp signals have quite a few perverse outcomes that call into question whether they are fundamentally flawed. Let’s run through a few big issues:
- Ramp signals prioritise longer trips over shorter trips, thereby incentivising more vehicle travel.
- Ramp signals push traffic queues off motorways and onto local roads, where the queuing cars disrupt public transport, walking, cycling and where the pollution from these queuing cars is much closer to people and therefore more likely to harm their health.
- Ramp signals can discourage use of the motorway network, resulting in more traffic on local roads to avoid the congested onramps.
It’s this last issue I’m going to look at in more detail – with a particular focus on how ramp signals in spaghetti junction create a stupid incentive for people to drive right through the city centre.
The ramp signal in question is where the SH16 ramps from the Northwest Motorway and the Port join with the Northern Motorway. This site is particularly notable in that the motorway picks up a lane here so it’s not like traffic is even merging with the traffic from further south on SH1. You can see in the afternoon peak how that leads to massive queues:
The implication of all this is that drivers get put off using the motorway for this cross-town trips and instead drive through the city centre or through other roads such as Ponsonby Rd.
Making a change where this ramp signal was removed would, of course, mean that other parts of the motorway may end up a bit more congested – especially trips travelling from south of Grafton Gully through to the Harbour Bridge and beyond. But this comes back to the fundamental question of what’s best for Auckland as a whole. Given the council’s goals in making the city centre more people friendly, getting as much traffic as possible out of the city centre is a key part of that and will very good for Auckland. As for those long distance trips, let’s not forget we’ve just spent billions building an alternative state highway route through the region.
Processing...
To remove that signal safely they might have to close Wellington St ramp.
Win-win.
Isn’t the problem they could not keep Wellington Street shut after the Vic Park project?
Besides, how would removing the ramp traffic light change anything? from my journeys around the network there is huge demand from the city and also from west on this part that creates the queue.
Is not the answer to keep increasing the price of car parks in the City centre to encourage more trips by bus ?
NZTA argued for it to stay because cars. They built the thing with a huge retaining wall at significant expense, but then wanted to keep it shut because traffic was better without it.
But politicians said, WTAF you just spent millions building this thing and now you want to keep it closed?! You’re just wasting our money.
They then offered it to AT to use as a bus ramp to save face. AT said “err, we don’t run any buses there, its a bad place to run buses… why didn’t you put the bus lane in Saint Mary’s Bay like we asked for”.
So they put the traffic back in.
The pressure was from Herne Bay residents due to traffic redirecting to Curran St ramp.
The answer to that is to traffic calm our local areas (where the people are) so it is not more attractive to drive across them than wait in the queue closest.
As well as providing the alternatives of course.
Yes, SH16 to SH1 is a spectacular fail by NZTA and it is quicker to bypass the motorway at Newton Rd or go through the city and re-enter at Fanshawe St. It is jammed up back down past, if not well past the Western Springs side of Newton Rd after 2.30 PM nowadays thanks to the ramp lights and from at least 7.00 am.
They should close Wellington St onramp permanently or at least make it available only during off peak.
Alternatively you can exit (Southbound) then re-enter (Northbound) at Gillies.
Removing the SH16 ramp signal will make no difference due to congestion. It will still clog back and it will be slow.
Given that the research showed the ramp signals do cause queuing in local roads, isn’t it logical that removing them will decrease queuing?
Before reopening Wellington St onramp the traffic flowed a lot better as in it actually flowed as this has it’s own lane, there’s no merge, but the instant they reopened it and operated the lights things turned bad
It’s quite incredible how NZTA turn suburban streets into car parks by doing this.
Isn’t the purpose of ramp signals is to decrease the flow rate onto the motorway? If they don’t cause queuing aren’t they kind of pointless?
Well I could see why – if your goal is to improve traffic flow – that you would give them a trial. It’s conceivable that the benefits of steadier motorway flow could create a situation where queues were created, but that they flowed so steadily that overall even the queues were shorter, or at least, no longer.
That’s not what they found, though. Not in the original trial. And not subsequently.
Research overseas also shows clearly that door-to-door journey times are worsened by these ramp signals for shorter trips, and improved for longer trips. They are simply another way that sprawl is subsidised.
“They are simply another way that sprawl is subsidised.” Yes, hadn’t thought of that aspect.
I bought my place in Great North Rd (Chinaman’s Hill) 10 years ago. The traffic was not too bad. Now it is horrific. I blame the queuing for the Harbour Bridge in the left lane of SH16 means that drivers can no longer exit at Newton Rd. Indeed I used to take the motorway if heading to Newton Rd, now it is no longer an option in peak times.
So all that traffic has been diverted to local roads making these unsafe, especially for pedestrians and cyclists. Unintended consequences…
Yes, and Motions Rd too. Pt Chev Rd reached record traffic volumes, but is possibly at its capacity now – unless the peak hour just gets longer.
That’s what sprawl and road building does – it makes homes for people in places where they need to rely on cars, and it ruins the neighbourhoods for people closer in.
It would’ve been far better to build extra homes on Great North Rd (especially along towards Pt Chev) and in the Western Springs Precinct where the carparks are spreading all the amenities apart than for us to have to put up with this sprawl-induced traffic.
I dug out the original trial into the first ramp signals, in Mangere. Low queueing levels on the local roads was not adopted as a performance measure. They did note, however:
“In general the amount of time where queuing exists has increased as a result of ramp metering.”
So the conclusions were it was deemed a success, but they did note:
“The local road interface needs to be well managed.”
Despite saying that these signals operate automatically, it appears the south bound ramp signals at Greville Rd and Constellation Dr switched off during the weekend.
This results in the motorway traffic coming to a full stop immediately after the ridge of the hill. I wonder how many nose to tail car accidents have been caused by this stopped traffic hiding behind the hill.
I would like to see these ramp signals operating automatically during the weekend as advertised.
Motorways don’t work very well when they take all the congestion they cause, I suppose.
Thats some Dali Lama level pithy insight Heidi.
Of course all of this madness could be made redundant if all future motorway spending went toward building Auckland an extensive fast PT system. Auckland is what it is, created by motorways, spread out and yet integrated so there’s no going back.
But that’s too damned hard and far too easy to find reasons why not, North West LR comes to mind. So we will need to not only keep using motorways but adding to them and keep kicking that can down the road and leave it another generation to sort. After all, as our Transport Minister surrendered and said, “money does not grow on trees”!
It seems money must be buried deep, since we keep on digging ourselves deeper into the hole.
Its like our politicians have given up hope and since we’ve invested SO much money on motorways, well then, we may as well stick with them, even though their failings are blatantly obvious twice daily and even though each kilometre of tarmac laid to improve things only makes things even worse.
We are in a twilight world of knowing this but yet fence sit and do nothing about moving forward.
Well NZTA have just had their second m’way turned down under this govt, first east-west in AKL, now P2G in Welly…. the ocean liner is starting to turn…
The delay and throughput studies they did after the ramp signals went in excluded the delay on local and arterial roads and only counted the delay on State Highways. Why? Because if they had included the big delays they caused then it would have shown ramp signals were a stupid idea. But like the left turn gives way to all traffic rule we will have to wait for a generation of decision makers to die before anyone can put it back how it was before.
I drive to the Curran Street on ramp each morning specifically to avoid that on ramp signal. I personally think it’s dangerous having cars queue down SH16 when there is traffic travelling much faster in the other lanes. Personally I think it should be switched off as soon as the tail reaching SH16.
It is insanity isn’t it, have an NZTA sponsored motorway blockage that has a stationary tail in an 80 km zone. Potentially lethal!
The tail blocks newton offramp too, so people undercut on the shoulder full speed, up to the nice and hazardous left turn slip lane.
NZTA only cares about “its” motorways. It doesn’t give a shit about AT’s local roads.
So they are maximising the flow for their domain and little else. Overall throughput of people and freight within Auckland? They couldn’t give a stuff.
However, there are cases where NZTA’s on-ramp signals on local roads do cause massive tail backs onto the adjacent motorway. Such occurs at Ellerslie Panmure roundabout – where the northbound “on-ramp” ramp signals in the AM peaks cause tailbacks right around the roundabout that invariably means off-ramp traffic on the southbound motorway lane to queue right back onto the motorway.
So NZTA presumably has to keep the northbound on ramps traffic flowing on more than they otherwise might to help minimise the tailbacks [adding to the congestion on the northbound lanes]. So hoist by their own petard in that case it seems.
And of course, this means that anyone who might want to use streets around the EP roundabout to travel soley on local roads knows (or will soon find out) that they must avoid EP roundabout.
This no doubt means lots of motorway bound (or existing) traffic abandoning the motorway altogether if normally using EP, – and using Market Road, Racecourse or Greenlane, [or MT Wellington when coming from the south] then performing local road travel to their destinations.
Hardly managing the system for the best overall outcomes. But NZTA get to keep “their” precious motorway lanes flowing for a few more seconds.
Far better to bring in proper variable priced congestion charging. Because simply rationing access to the motorways doesn’t in itself encourage much use of other modes for the occupants of private vehicles. Other than their “waiting” time.
However if they could know ahead of time what the cost to use the motorway they might simply vote to use PT or other modes to get to their destination.
But they need to know this before they leave. Because once they are in their car on the road. They are committed to driving the entire journey.
And we don’t everyone to do this switch, a small percentage being incentivised to switch can make a huge, long term difference.
So ramp signals are meant to be the start of this pricing process.
Not the end game in themselves a a feeble attempt to throttle traffic that they’ve turned into it seems.
I’d say remove those lights and replace them with toll gantries/cameras. I’m quite sure the flow both on and off the motorways would improve significantly, particularly if the cost to drive a km on the motorway was proportional to number of cars on given stretch.
Well, most onramps have two signal lanes that merge into one. Why not remove the ramp signals altogether, have one general vehicle lane and one bus/t3 lane.
NZTA’s 2018/19 Statement of Performance Expectations lists “Three Big Changes We’ll Make”, and one of those is “People-Centric Approach … We aim to put people and place, rather than vehicles and networks at the centre of our decision-making”
And critically, for the children walking along Wellington St for school, it says:
“In urban areas, we will manage demand on overcrowded roads by incentivising a shift from single occupancy vehicles to a broader variety of affordable and attractive travel options such as, buses, trains, ferries and active and healthy modes like walking and cycling. This means doing the basics well, for example by providing high quality and safe routes to and from schools and making the connections between modes easy and seamless.”
Go to it, NZTA. Here’s a really cheap action you can take that will immediately put people and place before vehicles and networks, and incentivise walking and cycling by taking away the fumes and congestion caused by all that queueing traffic.
If the Government / NZTA / AT / Auckland Council want to reduce traffic congestion, particularly on the motorways, *and* increase revenue for transport projects, they should replace all the on-ramp signals with tolling.
Ramp signals just cause congestion in local streets which adversely affects not only motorists but cyclists, pedestrians and residents who live nearby on the surrounding local roads with the noise and fumes from queued traffic.
Introducing tolling on all the on-ramps across Auckland’s motorway network would be a pro-active measure which will seriously make Aucklanders think about whether they need to make a journey in a car on the motorway if there is going to be a direct cost involved. This would help to free up the motorways for those that really need to use them and to encourage people to seriously consider alternative travel options such as public transport, cycling, walking or whether they need to make the journey at all.
Tolling just the motorway on-ramps (and not the beginning of the motorways so as not to unfairly penalise those vehicles travelling right through Auckland from outside the region and outside the reach of the Auckland public transport system), will create a fairer user-pays system for the motorway, where people who use it pay for it, just like public transport users pay to use public transport system.
A motorway toll will still likely be cheaper than a public transport fare and for those who don’t wish to pay for their travel there is still the option of driving on local roads, or cycling or walking (or using the train where fare evasion if rife..). But by introducing a direct charge to use the motorway, this will likely have a big impact on both reducing the amount of traffic on the motorways *and* encouraging more people to use public transport – win-win!
All combined this creates a fairer system and provides a new source of revenue for the Government.
Tolling all onramps, including those at the ends of the motorways, is critical to such a plan. How much demand for greenfields housing comes on the back of having priority through the motorway system?
What must be avoided with a tolling system is people ratrunning through the local streets. I’d say any arterials crossing a cordon should be tolled, too, to prevent this, and all roads smaller than an arterial should be rerouted to provide filtered permeability for walking, cycling and buses only, over the cordon line.
The sooner they convert the ramp meter toll system to monetary tolling the better. The current system is already tolling it just charges time and petrol rather than money.
While I agree some care needs to be taken to look at and respond to adverse impacts it might have in other areas, the reality is that the current ramp metering already induces a lot of rat running. Drivers cut through local roads to try and jump in further up the queues and or to dodge from a more congested interchanges to a less congested ones. The current approach also has major adverse impacts on users of the local road network (not just cars, but pedestrians, buses and bikes too).
The biggest flaw in this is the likely increase of traffic on non-tolled suburban roads. If we are going to toll to reduce congestion then we need to toll all roads.
Jezza,
I don’t believe using alternate routes to avoid a toll will be a big issue. It certainly doesn’t seem to be with people avoiding the Northern toll by cutting through Orewa.
Logic also says people won’t queue endlessly to avoid a couple of dollars toll.
It seems way too expensive to toll every on ramp. Major cities like Sao Paulo only have a couple of toll points on a stretch of road. In most cases the short trip is not captured, but the medium and longer trips are tolled the most. I think that such an approach here would be the most politically acceptable, first given that it would affect a fewer number of people, and second that it would penalise the longer trips that are more hard to justify.
For me the important counter balance is to put the revenue directly into public transport fare reduction. First, this would appeal to the existing users of public transport, and second it would provide a cheaper option instead of driving.
There are definitely people who cut through Orewa, last I heard it was about 25 % that take the free route.
If you are correct and it makes no difference in driver behaviour then it means tolls are effectively useless as a tool for managing congestion.
John, absolutely they will take the ratruns instead. Google is already directing them there if it’s quicker. I’m sure once there are tolls, they’ll be able to choose the relative weighting they want Google to give to price and to time.
These ratruns are through residential areas and town centres that should have a nice atmosphere but are ruined by the traffic. It does matter.
There needs to be large park and rides built with new rail stations on the outskirts of the city where the rail lines and motorways into Auckland intersect with each other at Kumeu and Drury.
Agree about the trains being a free-loaders paradise. Proper Transport Police are needed along with more gating.
It’s important the park and rides are not built at the train stations. They’re planning for growth in both Kumeu and Drury. The last thing such townships need is cars driving through to parks that are in the prime, connected spot, putting anyone approaching the station by foot or cycle in danger, and spoiling any chance of a well-laid-out township.
Any park and ride facilities should be in the middle of farmland and connected by a shuttle bus.
Disagree.
It is important to have park and rides at strategically located rail stations such as Kumeu and Drury where they will be visible and easily accessible to people driving in from further afield outside the urban area where there isn’t public transport available.
Pedestrians and cyclists could still be catered for and easily access these new rail stations with good design which accommodates all users.
At Drury the undeveloped land under the power pylons next to the motorway / Great South Road / Flanagan Road would be perfect for a park and ride as it is in full view from the motorway and Great South Road and quick and easy to access.
All that achieves is reducing the number of people that are in walking distance of the station, which will result in more people driving meaning more parking is required. Far better to build higher density housing instead.
If there is going to be PNR around Kumeu it should be an extra station on the western edge of Huapai. This parking should be charged at a rate that ensures the cost of providing this extra station and parking is recovered.
“Pedestrians and cyclists could still be catered for and easily access these new rail stations with good design which accommodates all users.”
It’s not something NZ has shown itself to be capable of doing. It’s also a fundamental design error. The Dutch Cycling Embassy says that before you attempt to put in a cycling network, you need to reduce traffic volumes. Providing parking does the opposite – it creates traffic, and it creates it in the centre of the town.
Your suggestion, essentially, favours the status quo bias towards amenity for drivers.
If a shuttle bus from a less-convenient location is unappealing, the park and rides will need to be at their own station; I’d say the daily cost of parking to cover the cost of a station would be exorbitant. Which indicates the level of subsidy that giving that prime land around a station over to parking involves.
I think most people would rather see a large park and ride built at Drury on the land under the high tension power pylons beside the motorway, as such a location would not be suitable or desirable for intensified housing.
People catching the train south of Drury wouldn’t be so keen as it would just be an extra stop for them.
Robin, you’re probably right. The key probably lies in the fact that Drury shouldn’t be getting more housing. If it does, though, it needs to be designed as a great place to live, without a hole of a park and ride in the middle.
We do need to create a fairer system. What you propose here might have the opposite effect however, as it will only benefit those with access to frequent public transport and this will be at the expense of those who don’t. It further privileges the already privileged.
A much better plan to get to a fairer system (that we both agree is necessary) is to expand the frequent public transport network so that everyone within the urban boundary has access to it, and to fix the many current fare inequities at the same time.
Great plan, Just need some way to find the money for extra expansions and subsidies. I know.. Road pricing!
“A much better plan to get to a fairer system (that we both agree is necessary) is to expand the frequent public transport network so that everyone within the urban boundary has access to it, and to fix the many current fare inequities at the same time.”
I absolutely agree with you. Such a plan would address congestion and a range of other issues. What is abundantly clear is that neither central nor local government are progressing at sufficient (any) speed to make a difference.
As Felix says where is the money going to come from for both opex and capex?
There is an easy starting point. Tourism leaders are starting to question the quality of our tourism. Does the FIT pay the full costs of the increasing amount of infrastructure that NZers are funding to allow them to travel wherever? Clearly the answer is no, otherwise there would not be a problem.
Maybe visitors to Auckland who use our roads should pay for the cost of this? The Queenstown Airport levy is $8 on all taxis using the airport. What about a similar amount in Auckland for taxis and ubers? Also, what about a daily tax on rental cars? And a vehicle drop off fee? Surely there are a range of revenue raising options that arguably should fall on the Airport to address the carbon unfriendly travel options that they are not addressing.
Auckland Airport’s planning that is affecting that part of the city is frankly a disgrace. From the Herald a couple of days ago, “the number of car trips to and from the airport is expected to increase from 90,000 a day now to more than 127,000 per day in 2044.” Really – you have to be joking? What are the airports plans to put these people on light rail? What is the Council’s plans (a 24% owner) to put them on light rail?
In respect of that light rail can I respectfully suggest that the reason that Phil Twyford cannot fund it is that he is not looking hard enough?
The whole gist of Matt’s post is to discourage rat running to avoid the motorway. Tolling the ramps would just add to this. Though I must confess I was advocating this a while back.
No!!!!!!
See comment above re Great North Rd traffic.
This would make the traffic past my front door even worse.
We need congestion charges in the city itself. I don’t want to see cars diverted off the motorways.
Can anyone prove they don’t work?
Can anyone prove that any noticeable amounts of traffic from east actually uses Quay/Fanshawe to head north in the evening peak?
I just see lots of anecdotal opinions, but few facts.
18% increase in capacity is a significant amount considering the minor costs of putting in some lights. If that data is true.
I’ve always wondered if they turned them off for a week and measure the congestion for local and highway to see if it works or not. Or let people decide what they prefer. I personally think that it would be very noticeable increased congestion on the motorway and many on-ramps would still be clogged up anyway.
The outside motorway lane stops moving when a dozen cars pile on and try to merge at 30km/h. You see this any time the onramp lights aren’t on just before or after the peak.
And is congestion on local roads a bad thing if it brings down speeds which is inherently safer than fast moving local traffic?
If I have to choose between spending tax money on on-ramp lights or more crazy expensive motorway widening to increase capacity by 18%, I know which one I will choose.
Just look at the South Western southbound connection to the Southern at Manukau, the queues in the afternoon tail back beyond the Puhinui Road interchange and similarly jam up all this interchange – and there are now plans to put bus lanes along Puhinui Road through all the middle of this..
The Redoubt Road southbound on-ramp at Manukau also often has horrific queues in the afternoons, which tail back and jam up Redoubt Road.
Get rid of the ramp signals and replace with tolling.
Why would you expand the motorway? You say it as if it is inevitable. Spemnding more money on motorways only encourages people to use the motorway.
Making driving unattractive is exactly what should happen – especially where that is a result of not widening the motorway and therefore having money to spend on PT and cycling.
But road pricing is a no brainer as well.
Tolling, for those with money trees, is what you put up when there is a good alternative in place such as a modern relatively reliable quick public transport system.
With the exception of rail catchment areas, Devonports regular ferries and some suburbs handy to a Northern busway, we don’t have that alternative.
So why add to the misery for no gain?
You’ve just answered your own question there Waspman.
Most of the routes the motorways through Auckland run, and in particular where the congestion is on the motorways, there are good public transport options already in place e.g. Southern Motorway and Southern Line, Northern Motorway / Upper Harbour Motorway / Harbour Bridge, and Northern Busway / Waitemata Harbour ferry services.
Building large park and rides in strategic locations on the outskirts of the city where the rail lines and State Highways intersect at Drury and Kumeu (along with extending rail services to Kumeu / Huapai with a ADL DMU rail shuttle between Henderson and Huapai) and *not* tolling the beginning of the motorways, will ensure those on the outskirts of the city and beyond the urban area and the reach of public transport are not disadvantaged.
Adding even just a small toll to the motorway system will highly likely have a big effect on reducing demand and congestion on the motorways and encouring people to seriously consider public transport or cycling.
When something is free it tends to enduce demand that might not otherwise be there with a direct cost. This is one of the reasons why public transport is not free – the system wouldn’t cope with the demand (not to mention the increase in ‘problem people’ who would then be attracted to it for entertainment and vandalise it and cause anti-social issues, such as has been seen on Auckland’s trains since the introduction of the HOP card ticketing system when travelling without paying became very easy when onboard staff numbers were reduced on a largely ungated network with no proper effective Transport Police).
It was pretty easy to travel without paying before Hop. I used to get 11 or 12 rides out of most 10 trip tickets, just because the clippers didn’t manage to get to me before my station.
I don’t see why those who choose to live on lifestyle blocks should be able to avoid paying motorway tolls, it is creating a perverse incentive if those who travel the furthest pay the least.
Jezza, I also struggle that everyone else should pay for their (life stylers) park and rides. What incentive is there to live anywhere near good public transport options?
Absolutely choose where you want to live, but don’t then expect others to pay for that choice.
Ever thought that “choice” is governed by what can be afforded? And I’m not talking niceties like home ownership here either.
Going by that theory If they choose not to live in Remmers, well they’re idiots aren’t they?
There are plenty of areas in South & West Auckland that have good transport links that will get even better with the CRL.
But people would rather live miles out than live in those areas. I refuse to have my tax dollars subsidise their wasteful, inefficient choices.
Well… it is called “drive ’til you qualify”, not “catch the bus ’til you qualify”.
Or “choice” if you’re neoliberal.
Better lane management of the motorway approaching spaghetti junction from the West would help. NZTA currently have two lanes dedicated for the port exit, but the demand isnt there. Those two lanes narrow to one anyway, as you hit spaghetti junction, so why not just have one lane? That would free a lane, meaning it would be possible to have two lanes exiting north – it wont stop the bottleneck at ‘X’ but it will reduce the tailback making it safer for other vehicles in other lanes.
There is enough room to take one of those lanes and make two from SH16 onto SH1 south bound. The right one could use the existing right lane on SH1 and the left one merge with the middle lane.
This should ease the tail back on SH16.
Those tail backs cause so many near accidents when people virtually stop in the next door lanes while they try to merge late into the slow moving tail backs.
If they implemented the “Access For Everyone”, it would be a problem if there is a long ramp signal queue when cars wants to get to other side of the city via the motorway.
You can’t get to the other side of the city using motorway.
So how once the city has been separated into disjoint sections?
The same way you do today, on arterial roads. Just not by rat running through city streets.
However there is very little traffic from one side of the CBD to the other, mostly just couriers doing a circuit. Almost all of the traffic is into the CBD or out again, either from motorways or arterials. That doesn’t change, except you might have to pick a different motorway exit.
Not sure I’d be against motorway ramp signals. Motorway accidents are probably more nasty (statistically more DSI) than on local streets, perhaps they are not though? In some cases, at least, worsening of the queues and start stop, differences in traffic flow on the motorway can be very dangerous due to the higher speed. Of course in most situations everyone is in a vehicle, whereas local streets we have peds & active modes to consider. Anyone got insight into this? Interesting they say “Motorway incidents being cleared up to 15 minutes faster” were they not also changing methods and response times to do this in other ways anyway I heard.
Well, our motorways are considered the safest roads, I believe. And our fatalities per km walked are four times that of Paris. The fatalities per km cycled are eight times that of Vancouver… so yeah, attempting to retain higher safety on our motorways at the expense of vulnerable people walking and cycling is dubious ethically…
Motorway collisions are less dangerous. You’d probably survive a nose-tail at 100km/h, you’d probably die in a ped-car at 50km/h.
Thanks Heidi & Sailor Boy, yes I think you are right.
There seems to be an attitude on here that we can either have ramp signals or not have ramp signals. Everyone has neglected to mention that we can have different ramp signals.
On the Oteha Southbound on-ramp the signal phases of the intersections under the motorway lead to short platoons of vehicles and large empty gaps. The ramp signals change that platoon to a trickle, which makes the lane changes that occur at the top of the hill much safer when motorway traffic is doing 100km/h of peak. That’s a case of ramp signals working really well.
At the same ramp at 8am traffic on the motorway is stationary. The tailback from the ramp signals reaches as far as East Coast Road. Motorway traffic speeds up after the onramp joins as an additional lane, leading to dangerous lane changes. The ramp singals create danger, prioritise longer trips, and resul in pollution in residential areas. This is a case of ramp signals working poorly.
We should change the programming of the ramp signals: they should only come on to regulate entry to the motorway if traffic is free flow.
Good point.
I have always hated these. In my old neighbourhood, it was impossible to get anywhere quickly during morning peak, even when not going on the motorway, because the queues backed up for several kilometres. Even PT was affected as there weren’t bus lanes.
Are Articles on Ramp Metering Fundamentally Flawed ?
The fundamental purpose of ramp meters is to improve traffic flow on the network as a whole – a locked up motorway quickly turns into a locked up local road network and the whole network grinds to a halt.
This is not intuitive and the common perception is that ramp meters are just “shifting the problem”. Possibly the real issue is that the benefits to local roads aren’t necessarily communicated clearly to the general public ..
If this was the case we would have seen a significant reduction in queuing to get on the motorway around 2006 – 07 when they were introduced across the city. This was not the case.
I would be very interested in seeing that study – there is precious little evidence out there around these issues …
look what aunty google randomly showed me when i was looking for something else entirely lol
https://www.geekzone.co.nz/forums.asp?forumid=162&topicid=230640
Some classic stuff in there. Would be great if induced traffic was understood. This one was a killer:
“On ramp lights do work. They inconvenience a few for the benefit of many. The statistics proved (according to a friend who used to work for the Auckland Motorway Alliance) that after they were implemented the average journey time on the motorways was reduced and the number of journeys completed per hour increased, cementing their future on Auckland’s motorways.”
Average journey time on the motorways was reduced = success
The number of journeys completed per hour increased = success
Whereas walkability on local roads isn’t a KPI for the AMA…
I personally dislike Ramp Signals, and 99% of drivers do not seem to understand the Merging part, you can sit in traffic on an on-ramp, take Greenlane interchange to travel a South, after waiting some considerable time to pass through green light, what do people do, get to the end of the ramp, slam on the brakes, flicker to get into next lane (hence making motorway traffic slowdown/stop to let them fit in’ all the while the merging lane ahead remains empty, if one follows to end a seamless entry is made. I also think that only one lane at a time should get the green light ie alternate lanes, stops the whacky races and ridiculous drag race that happens once green light appears.