Motorway On Ramp Signals: “Consistent Increases”


Do the onramp signals make any good difference to traffic flows?

It cost $68.7m to roll them out on the entire Auckland motorway over seven years so are we getting our money’s worth?

A new report from NZTA says there are “consistent increases of some 15% in peak periods and a corresponding 15% in speed together with improved consistency and better safety.”

It says that, at most locations, “more drivers are now using individual onramps compared to the same period before ramp signals were installed, with peak period increases of between 100 and 140 vph.”

It admits there are “still periods when all the network is overwhelmed by the sheer volumes of traffic, but even then the ramp signal operations enable to onset of severe congestion to be avoided for up to 30 minutes and recovery achieved earlier than before.”

I don’t drive enough on motorways to know.

Most times I encounter the signals turned off and the most recent occasion when the signals were on, when I heading north over the bridge, the signals just seem to aggravate the slow traffic build-up.

So I’d be interested to know the experiences of those who do encounter them more regularly.

Ramp signals are presently operating at 58 sites on the motorway network

The signals will also be on the SH20 Mt Roskill, SH18 Greenhithe and SH20/1 Manukau extension projections and are being investigated for SH20 between Queenstown Rd and Puhinui Rd.




  1. Jon R says:

    It would be interesting to find out where were the points on the motorway that they measured the “15% in speed”. As we have found out before by previous Transit reports (when they say speed decreased and argued for more lanes and motorway spending) often the increase, or decrease, has been from questionable survey points.

    Since the introduction of these “gross waste of transport funding”, which have not worked overseas, I have not remarkably noticed any change. Did the 15% increase in speed include the 15 or 30% slower journey to the motorway as the local roads are all choked due to the tail backs like lights cause?

  2. Christopher says:

    I’ve definitely noticed a change. Previously I could count on severe congestion at peak times; with the on ramp signals, there is congestion but it flows much much better and smoother.

    I support the on ramp signals.

  3. max says:

    NZTA argues that their primary function is to keep the motorways running. I do certainly believe them that they managed that, and they have a case for it (after all, motorways are our long-distance routes - or should be), so increasing their capacity is good (it may keep us from having to build even more of the bloody things).

    As for local congestion. Sure it will increase at least at some points, but again, I suggest NZTA will hardly be lying when they say X vehicles passed this point, being Y more than the last time we measured this on-ramp.

    As we should know by now, transport system congestions isn’t something we can prevent, only manage. Widening the belt only gets you more obesity. So the question is really - where do we want to have gridlock - is congestion on local roads acceptable if it keeps the motorways flowing better?

  4. Richard says:

    The way to improve flow on the motorways is to remove half the interchanges not add traffic lights. Interchanges should I understand be no more than at least five to ten kilometres spacing not 2-300metres as we have in Auckland central.

    As stated by Max motorways are for long distance travel not for going from Khyber Pass Road to Gilles Avenue. It was ludicrous to leave the Wellington St. on ramp once the Port/Western on ramp was completed…they run into each other almost!!! It’s no distance to go from Wellington St. to the on ramp at Fanshawe St. DAFT

    Our motorway system is a far bigger mess than the track layout at Newmarket Station.

    Thirty years ago ramp lights were installed at Esmonde Road on ramp as a trial. They were removed in a matter of months and were seldom operating..WHY? They caused mayhem on the nearby urban streets. It was felt more important to have a slight holdup on the motorway and keep unrelated urban traffic flowing on the streets. Today the RTA are a rule unto themselves, only care about the motorways and cars, raising two fingers to everybody else.

    RTA must start looking at the total picture, their silly ramp signals money would have been better spent fixing potholes and footpaths damaged by illegal parkers

  5. joust says:

    What follows is completely subjective and I have no idea what the overall flows have been and how they might affect my observations.

    I regularly enter SH20 in the mornings southbound. The signals have only recently been turned on. Both I and 1-2 others I’ve spoken to at work tend to agree they’ve helped a bit. It seems to have meant the speed of the left motorway lane and the merging lane can be kept a little bit quicker with just 2 cars than letting a whole green-light change worth slug of say 30 vehicles all flooding the ramp at once. The problem before was on the long merging lane was 5-6 cars would all be finding and taking gaps along the length of the ramp. slowing down both lanes while they do it. Now it seems like the 2 released from a green flash at the signal have joined the motorway by the time the next 2 are leaving the gate. Or perhaps thats the intention at least. I’ve seen that when the speed of the motorway drops to about 7-8kph they don’t seem to make much difference as its too crowded to get any speed up.

    There’s always somewhere else the money could be spent. If this does in fact give us the kind of benefits that are being claimed then we’re enhancing our original investment in the motorway. Getting it working better.

  6. max says:

    Richard - the motorway ramp signals are paid from NZTA money (who are notably more flush than local Councils) because they are parts of the motorway system.

    NZTA doesn’t care about local road potholes, though to be fair, they pay the local councils big subsidies for such work. Part of the issue is that in Auckland, the motorway system and the local roading system are almost one and the same.

  7. Joshua says:

    In the end the Motorway is carrying the major flow, by freeing up this flow you are actually decreasing congestion of the system (local and motorway roads together), overall having these lights are better for the environment and better time savings. People do notice it more when the congestion happens on the On-ramps and local roads rather than on the motorways though.

  8. Terrence says:

    I get on at Esmonde Rd going through the city daily and anyone who gets on there knows that it takes a good 20-30minutes just to get onto the motorway after 7am. This is without the ramp signals on. I have lived over the shore for about 9 months and I have only ever seen the ramp signals come on no more than 5 times. Gotta wonder why they were ever installed? My read on this is that they have installed them willy-nilly without researching the traffic because if they did they would realise that the signals cannot handle the volumes of traffic. Esmonde needs to feed into the motorway with its own lane but this was no doubt not done due to budget constraints when they bus lanes were created.


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