Purpose of on-ramp lights?

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timbosan

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#1971114 8-Mar-2018 11:12

SepticSceptic:

gmball:

East bound North Western to Northern SH1 is what I encounter every morning. As as you rightly point out, that on-ramp becomes its own lane so there is no traffic merging onto the Northern.

I usually meet the on-ramp queue heading north at Western Springs, takes about 30 minutes to travel the 3km distance from there to the Northern motorway. I've followed many drivers who will actually drive into the city to enter at Wellington street which simply moves the bottleneck from a 5 lane motorway to a single lane central city street.

Would an alternative of travelling down Nelson, and then turning left onto Fanshaw be any better ?

I get off at Nelson street every day and even on my motorbike, getting from the lights at the top down to the Viaduct is very slow. There are 4(?) sets of lights down Nelson Street and its always heavy in the mornings. Plus with the recent changes to allow for the cycle lanes (great move by the way, I used to cycle down there before the lane was put in, and its scary!) and left turn only lanes, people are always swapping.

Plus you have 2 sets of lights on Fanshaw Street before the motorway.

So may not be much faster.

1eStar

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#1971215 8-Mar-2018 13:47

One of the reasons why ramp signals are active at end of SH16 and Wellington Street is to keep Vic Park Tunnel and the Harbour Bridge free flowing.

It's hard to see the big picture when you're stuck in a slow traffic queue...

kryptonjohn

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#1971237 8-Mar-2018 14:35

kryptonjohn:

Which reminds me of another annoying traffic management misfeature: dumb traffic lights on timers that make you sit and wait while *no* traffic is present on the green lighted lanes.

Yet AT want us to believe this:

https://www.stuff.co.nz/auckland/102023294/ask-auckland-australian-traffic-lights-system-keeps-the-citys-traffic-moving

I say BS. They might have smart lights at some intersections but there are most certainly others on a dumb timer. It's the only explanation as to why you sit on a red light when there's no other traffic.

SepticSceptic

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#1972041 9-Mar-2018 18:19

gmball:
SepticSceptic:

gmball:

East bound North Western to Northern SH1 is what I encounter every morning. As as you rightly point out, that on-ramp becomes its own lane so there is no traffic merging onto the Northern.

I usually meet the on-ramp queue heading north at Western Springs, takes about 30 minutes to travel the 3km distance from there to the Northern motorway. I've followed many drivers who will actually drive into the city to enter at Wellington street which simply moves the bottleneck from a 5 lane motorway to a single lane central city street.

Would an alternative of travelling down Nelson, and then turning left onto Fanshaw be any better ?

Worked a treat. Long queue at the on ramp from the North Western east bound to the Northern, potentially a good 30 minute wait for the poor buggers sitting there at 7pm this evening. Drove to the bottom of Nelson st, and along Fanshawe St, took less than 10 minutes.

Does seem ludicrous that this option is far more efficient than a motorway, I just hope that any congestion charges for entering the central city are many years away or abondoned completely.

Here's another one that only has 2 sets of traffic lights ( and a ramp light, but it's a quicker one)

From the western, take the link to southern, then off at Gillies ave, then loop under the m/way to get on again at Gillies Ave Northbound.

This is dependant on the volume of traffic on the south-bound southern M'way.

Here's another for the North Shore-ites queueing along Northcote road from Glenfield, etc to head south. Turn left @ Northcote interchange to head north, take the Tristram Ave exit, loop under motorway for the Tristram Ave on-ramp. Go south. Basically you are only queuing on the Tristram on ramp, rather than queuing along Northcote rd, and then queueing down the metered on-ramp.

This will probably now totally fcuk-up the Tristram interchange which is fubar at best during morning peak...... I've done my bit ....

cbdkid

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#1972203 10-Mar-2018 01:22

kryptonjohn:

kryptonjohn:

Which reminds me of another annoying traffic management misfeature: dumb traffic lights on timers that make you sit and wait while *no* traffic is present on the green lighted lanes.

Yet AT want us to believe this:

https://www.stuff.co.nz/auckland/102023294/ask-auckland-australian-traffic-lights-system-keeps-the-citys-traffic-moving

I say BS. They might have smart lights at some intersections but there are most certainly others on a dumb timer. It's the only explanation as to why you sit on a red light when there's no other traffic.

All the intersections in Auckland are actuated by stop line induction loops - none of them run on a 'dumb' timer. 99% of the sites are also connected to a central computer server which allocates phase times depending on vehicle demands.

Without knowing the specific corridor, the strategy and how the intersection has been set up, it can be confusing why you end up sitting on a red light even when there is little to no demand for the running phase. This can happen due to detector faults at the specific intersection, or just coordinated signals where a number of intersections are linked together with a common cycle time (the total amount of time that has been allocated for all phases to run in each cycle).

Sometimes you might even see a side road running for no apparent reason - this can also be a symptom of a faulty detector, or another input such as a pedestrian button (as most pedestrians run parallel with a vehicle phase). This is in essence a type of fail-safe so that when the traffic signal controller cannot determine whether there is vehicle or pedestrian demand (due to the faulty detector), the associated phase is then demanded once each cycle so you don't have motorists running reds or pedestrians running across the road.

It's definitely not a perfect system, but it does its job pretty well.

bmt

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#1972293 10-Mar-2018 12:16

Without you providing any evidence of that I'm going to have to disagree there. One intersection in particular I would go through every day on my way home from work, could be at different times of the day but it was quite clear it was on the exact same timer 24/7. Late afternoon with lots of traffic vs evening with no traffic, would still end up sitting there with nobody else around waiting for ages.

Eventually it was fixed and the phasing is much better now.

Dyson

Shop now for Dyson appliances (affiliate link).

cbdkid

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#1972318 10-Mar-2018 12:54

Which intersection? If there is a faulty loop the system is essentially blind as it doesn't know when to extend or terminate the phase. In that scenario an operator can code in a schedule in order to run either a fixed time phase or fixed percentage of a phase to be run everyday at the same time. You end up having to look at historical average phase times over the peak to determine the fixed time or percentage.

The schedule would remain in place until the detector loop was repaired whereupon the loop would be used again to terminate or extend the phase.

Linuxluver

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#1972647 11-Mar-2018 10:11

trig42:

And, just this morning - coming north over the Bridge. A bus was broken down at the top of the bridge in Lane 2. The information signs all stated that Lane 2 was blocked (even back on Fanshawe St, before I got on the Motorway, I saw a sign telling me), the flashy arrow trucks were on the bridge, the lane closed signal was above the lane. STILL, people changed into Lane 2, drove right up to the flashy lights, and cut back into Lane 1, slowing everyone down. Asswipes.

I know some pommy drivers who think this is really clever. (so you get ahead 8 cars, but actually, overall, go more slowly........okey dokey, then).

Hopeless.

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Linuxluver

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#1972649 11-Mar-2018 10:12

cbdkid:

All the intersections in Auckland are actuated by stop line induction loops - none of them run on a 'dumb' timer. 99% of the sites are also connected to a central computer server which allocates phase times depending on vehicle demands.

Without knowing the specific corridor, the strategy and how the intersection has been set up, it can be confusing why you end up sitting on a red light even when there is little to no demand for the running phase. This can happen due to detector faults at the specific intersection, or just coordinated signals where a number of intersections are linked together with a common cycle time (the total amount of time that has been allocated for all phases to run in each cycle).

Sometimes you might even see a side road running for no apparent reason - this can also be a symptom of a faulty detector, or another input such as a pedestrian button (as most pedestrians run parallel with a vehicle phase). This is in essence a type of fail-safe so that when the traffic signal controller cannot determine whether there is vehicle or pedestrian demand (due to the faulty detector), the associated phase is then demanded once each cycle so you don't have motorists running reds or pedestrians running across the road.

It's definitely not a perfect system, but it does its job pretty well.

Maybe that explains why they are putting new sensor loops under the Southern Motorway near Greenlane and elsewhere.......maybe variable-speed lanes are going to be introduced. We got a letter about "loop cutting"......and no explanation what that was. A quick Google showed it's laying sensors under the road.....

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I've been on Geekzone over 16 years..... Time flies....

cbdkid

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#1972765 11-Mar-2018 18:30

Linuxluver:

cbdkid:

All the intersections in Auckland are actuated by stop line induction loops - none of them run on a 'dumb' timer. 99% of the sites are also connected to a central computer server which allocates phase times depending on vehicle demands.

Without knowing the specific corridor, the strategy and how the intersection has been set up, it can be confusing why you end up sitting on a red light even when there is little to no demand for the running phase. This can happen due to detector faults at the specific intersection, or just coordinated signals where a number of intersections are linked together with a common cycle time (the total amount of time that has been allocated for all phases to run in each cycle).

Sometimes you might even see a side road running for no apparent reason - this can also be a symptom of a faulty detector, or another input such as a pedestrian button (as most pedestrians run parallel with a vehicle phase). This is in essence a type of fail-safe so that when the traffic signal controller cannot determine whether there is vehicle or pedestrian demand (due to the faulty detector), the associated phase is then demanded once each cycle so you don't have motorists running reds or pedestrians running across the road.

It's definitely not a perfect system, but it does its job pretty well.

Maybe that explains why they are putting new sensor loops under the Southern Motorway near Greenlane and elsewhere.......maybe variable-speed lanes are going to be introduced. We got a letter about "loop cutting"......and no explanation what that was. A quick Google showed it's laying sensors under the road.....

Could be to do with the variable-speed lane trial (although I had understood this was to be trialed elsewhere first). More likely it is due to loop faults along the Southern Motorway - these loops are used to measure occupancy/traffic flows, which is then fed back into the ramp metering system to determine the red times for the on-ramps feeding into the motorway. A common complaint is that the ramp meter is on when there is no congestion - however what cannot be easily seen by motorists is congestion further downstream of their current location.

Maintenance of these loops can also be quite difficult as it is usually completed after evening peak, however this gives you only a small window of opportunity given work needs to be completed by 10pm due to the excessive noise generated from cutting into the carriageway.

hsvhel

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#1972771 11-Mar-2018 18:58

They work a charm at rush hour for the East Auckland amateur traffic light drag racing association. But i find if you're lazy off the light its easier to merge......weird huh....

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