News & Discussion: Roads & Traffic

[English Electric]

Rundle/East intersection had major issues with fitting the amount of pedestrian traffic during events like Fringe.
Hundreds at a time were trying to squeeze on the island and would spill well in to the roads surrounding it in every direction.
At intersections like that with such large volumes of foot traffic the islands seem to be incompatible.

Fair enough at that particular intersection - I've seen the situation with crowds during events in the east Parklands, and this was probably the correct approach to take there.

But at other main road intersections, like Dequetteville / Rundle Rd, or Hutt / Pirie / East Tce - at at other intersections out in the suburbs - there is hardly ever going to be large, sustained volumes of pedestrians, but the same strategy seems to be followed to remove slip lanes and make any turning traffic wait whenever there is a red light.

[SRW]

Tbh in most instances I feel they should be removed as policy as drivers seem to rarely give way to pedestrians even when so signed. I have nearly been collected by cars turning at speed multiple times, and I'm sure it's not an isolated experience. However, I don't think it is policy as a slip lane was reinstalled at Dequetteville/North Tce during the O-Bahn works. I'd rather drivers be allowed to stop and turn left on red when safe as in the States (on the right, obvs).

[SBD]

Tbh in most instances I feel they should be removed as policy as drivers seem to rarely give way to pedestrians even when so signed. I have nearly been collected by cars turning at speed multiple times, and I'm sure it's not an isolated experience. However, I don't think it is policy as a slip lane was reinstalled at Dequetteville/North Tce during the O-Bahn works. I'd rather drivers be allowed to stop and turn left on red when safe as in the States (on the right, obvs).

Rather than make an exception to allow drivers to drive through red lights sometimes, an alternative could be a vehicle detection loop and just turn the red light off at times when drivers are allowed/expected to use their own judgement. There are a few intersections around that sometimes show green and red right turn arrows, but at other times, there is neither a red nor a green arrow so turning is permitted when the green circle is lit and no oncoming traffic.

[claybro]

Tbh in most instances I feel they should be removed as policy as drivers seem to rarely give way to pedestrians even when so signed. I have nearly been collected by cars turning at speed multiple times, and I'm sure it's not an isolated experience. However, I don't think it is policy as a slip lane was reinstalled at Dequetteville/North Tce during the O-Bahn works. I'd rather drivers be allowed to stop and turn left on red when safe as in the States (on the right, obvs).

Rather than make an exception to allow drivers to drive through red lights sometimes, an alternative could be a vehicle detection loop and just turn the red light off at times when drivers are allowed/expected to use their own judgement. There are a few intersections around that sometimes show green and red right turn arrows, but at other times, there is neither a red nor a green arrow so turning is permitted when the green circle is lit and no oncoming traffic.

I think generally they are trying to take "judgement" options away from drivers where possible, and probably with good reason given what happens on the roads. The situation mentioned above with "options" for turn right of arrows sometimes lit, and the sometimes not allowing for turning with care on the green circle causes confusion, particularly with younger drivers. Some people, when no green arrow is present, will sit back behind the line, not proceed into the intersection, seemingly waiting for the green arrow, or an act of God to allow them to turn. The then hurriedly turn after the light has gone amber even when no oncoming traffic is present, holding up everyone behind them. Common sense driving seems to be a thing of the past, and so the nanny state as usual is stepping in to protect us from ourselves.

[rhino]

Common sense driving seems to be a thing of the past, and so the nanny state as usual is stepping in to protect us from ourselves.

Cause and Effect - the fact that we have a nanny state is the reason Common Sense seems to be a thing of the past. The fact that we are allowed to blame someone else in court for our own stupidity causes us to take no responsibility for our actions. The fact that we have a GPS has resulted in most people having no idea where they are spatially, what is around them but out of sight, or how they got there. And to fix this problem, we always choose a method that exacerbates the problem.

[SBD]

Tbh in most instances I feel they should be removed as policy as drivers seem to rarely give way to pedestrians even when so signed. I have nearly been collected by cars turning at speed multiple times, and I'm sure it's not an isolated experience. However, I don't think it is policy as a slip lane was reinstalled at Dequetteville/North Tce during the O-Bahn works. I'd rather drivers be allowed to stop and turn left on red when safe as in the States (on the right, obvs).

Rather than make an exception to allow drivers to drive through red lights sometimes, an alternative could be a vehicle detection loop and just turn the red light off at times when drivers are allowed/expected to use their own judgement. There are a few intersections around that sometimes show green and red right turn arrows, but at other times, there is neither a red nor a green arrow so turning is permitted when the green circle is lit and no oncoming traffic.

I think generally they are trying to take "judgement" options away from drivers where possible, and probably with good reason given what happens on the roads. The situation mentioned above with "options" for turn right of arrows sometimes lit, and the sometimes not allowing for turning with care on the green circle causes confusion, particularly with younger drivers. Some people, when no green arrow is present, will sit back behind the line, not proceed into the intersection, seemingly waiting for the green arrow, or an act of God to allow them to turn. The then hurriedly turn after the light has gone amber even when no oncoming traffic is present, holding up everyone behind them. Common sense driving seems to be a thing of the past, and so the nanny state as usual is stepping in to protect us from ourselves.

I'd rather live with people exercising judgement by waiting for the other green light than have them exercising judgement on when it is OK to go through a red light.

I also don't like slip lanes that look like "turn left any time with care" and then suddenly realising there is a red light on it instead of that sign.

[claybro]

I'd rather live with people exercising judgement by waiting for the other green light than have them exercising judgement on when it is OK to go through a red light.

I also don't like slip lanes that look like "turn left any time with care" and then suddenly realising there is a red light on it instead of that sign.

Which is completely understandable given the standard of some driving on the roads, but if Adelaide is going to use directional traffic lights to control absolutely every aspect of intersection movements, the powers that be better get much better at synchronising and timing issues.

[ChillyPhilly]

I'd rather live with people exercising judgement by waiting for the other green light than have them exercising judgement on when it is OK to go through a red light.

I also don't like slip lanes that look like "turn left any time with care" and then suddenly realising there is a red light on it instead of that sign.

Which is completely understandable given the standard of some driving on the roads, but if Adelaide is going to use directional traffic lights to control absolutely every aspect of intersection movements, the powers that be better get much better at synchronising and timing issues.

I'm an advocate of improved light sequencing, synchronisation and frequency. One thing that we should have more of in Adelaide is right turn control at intersections. At many, right turn arrows start red then go blank, allowing for those turning to complete the turn if there is no oncoming traffic. However, the choice of intersection where this happens and in particular the direction of these right turns, makes little sense and is virtually redundant as maximum two vehicles get through.

[rev]

I'd rather live with people exercising judgement by waiting for the other green light than have them exercising judgement on when it is OK to go through a red light.

I also don't like slip lanes that look like "turn left any time with care" and then suddenly realising there is a red light on it instead of that sign.

Which is completely understandable given the standard of some driving on the roads, but if Adelaide is going to use directional traffic lights to control absolutely every aspect of intersection movements, the powers that be better get much better at synchronising and timing issues.

I'm an advocate of improved light sequencing, synchronisation and frequency. One thing that we should have more of in Adelaide is right turn control at intersections. At many, right turn arrows start red then go blank, allowing for those turning to complete the turn if there is no oncoming traffic. However, the choice of intersection where this happens and in particular the direction of these right turns, makes little sense and is virtually redundant as maximum two vehicles get through.

The problem with that is the timing of when the red arrow turns off. What's the point of it during peak hour traffic periods? As you said, max two vehicles will get through.

[SBD]

Which is completely understandable given the standard of some driving on the roads, but if Adelaide is going to use directional traffic lights to control absolutely every aspect of intersection movements, the powers that be better get much better at synchronising and timing issues.

I'm an advocate of improved light sequencing, synchronisation and frequency. One thing that we should have more of in Adelaide is right turn control at intersections. At many, right turn arrows start red then go blank, allowing for those turning to complete the turn if there is no oncoming traffic. However, the choice of intersection where this happens and in particular the direction of these right turns, makes little sense and is virtually redundant as maximum two vehicles get through.

The problem with that is the timing of when the red arrow turns off. What's the point of it during peak hour traffic periods? As you said, max two vehicles will get through.

Right turn from southbound Main North Road into Regency Road gets two turns per cycle (evening peak anyway). There's a green arrow which goes red before northbound traffic is let through. Later, the red arrow goes out, and one or two more cars (or more depending on the timing of gaps in northbound traffic) get through. It seems to work there.

[rev]

I'm an advocate of improved light sequencing, synchronisation and frequency. One thing that we should have more of in Adelaide is right turn control at intersections. At many, right turn arrows start red then go blank, allowing for those turning to complete the turn if there is no oncoming traffic. However, the choice of intersection where this happens and in particular the direction of these right turns, makes little sense and is virtually redundant as maximum two vehicles get through.

The problem with that is the timing of when the red arrow turns off. What's the point of it during peak hour traffic periods? As you said, max two vehicles will get through.

Right turn from southbound Main North Road into Regency Road gets two turns per cycle (evening peak anyway). There's a green arrow which goes red before northbound traffic is let through. Later, the red arrow goes out, and one or two more cars (or more depending on the timing of gaps in northbound traffic) get through. It seems to work there.

That's not the case everywhere though.

Another example. Torrens Road/South Road-T2T intersection..
The distance to turn from Torrens Road onto South Road is now quite large. The time the green arrows stay on is so small, only 2-3 cars manage to get through, 4 if all the drivers are switched on and get a move on and the last guy runs through the yellow as it turns red.
During peak hour, when there's cars banked up in the right lane, because there's cars waiting to enter the turning lane, that's not sufficient and causes congestion.
The turning lanes will never be a couple hundred meters long, so there will always be a spill of cars waiting to get into the turning lane during peak hour.
Why don't they change the sequence so when the green light comes on for traffic going straight, the green arrow turns on and stays on, then they both go yellow/red together. Wouldn't that help traffic flow smoother with less delays?

[SBD]

The problem with that is the timing of when the red arrow turns off. What's the point of it during peak hour traffic periods? As you said, max two vehicles will get through.

Right turn from southbound Main North Road into Regency Road gets two turns per cycle (evening peak anyway). There's a green arrow which goes red before northbound traffic is let through. Later, the red arrow goes out, and one or two more cars (or more depending on the timing of gaps in northbound traffic) get through. It seems to work there.

That's not the case everywhere though.

Another example. Torrens Road/South Road-T2T intersection..
The distance to turn from Torrens Road onto South Road is now quite large. The time the green arrows stay on is so small, only 2-3 cars manage to get through, 4 if all the drivers are switched on and get a move on and the last guy runs through the yellow as it turns red.
During peak hour, when there's cars banked up in the right lane, because there's cars waiting to enter the turning lane, that's not sufficient and causes congestion.
The turning lanes will never be a couple hundred meters long, so there will always be a spill of cars waiting to get into the turning lane during peak hour.
Why don't they change the sequence so when the green light comes on for traffic going straight, the green arrow turns on and stays on, then they both go yellow/red together. Wouldn't that help traffic flow smoother with less delays?

They do have different sequences in different places, I guess they are set according to the anticipated traffic flows, but I have no idea how often they can be reviewed or how complex they can be for different times of day.

Your example is close to how the Main North Road and Curtis/Craigmore Road intersection works. There are left turn slip lanes on all sides.
* Northbound goes green, including north-east right turn arrow (this phase is skipped if no cars queued to turn)
* Right arrow changes to red, southbound gets red arrow and green circle
* northbound goes red, south-west arrow goes green (this phase is skipped if no cars queued to turn)
* all MNR gets red, Curtis eastbound gets green, including arrow
* Curtis gets red, Craigmore westbound gets green including arrow
I don't know if the east/west phases merge if nothing is queued to turn either side as I don't think I've ever seen it.
RIght turn lane from northbound has recently been extended, so doesn't block through traffic as much now. Right turn from Curtis (eastbound) has two lanes but still fills up.
As well as the general timing constraints, I think there may be a monitor to watch the queue for the railway crossing further back Curtis Road as I don't think the right turn arrow lights on MNR if the road is full.

Main North and Womma/Tolmer Roads is different.
* Both Main North right turn arrows go green
* There are sensors in both right turn lanes; as they empty, the arrow goes red and opposing straight on gets green (these seem to change in either order, depending on traffic)
* Main North has green both ways
* Womma gets straight and right
* Tolmer gets straight and right

[claybro]

Which highlights another problem which in my experience is unique to Adelaide, the length of time a particular light stays green. If we are to use turning arrows for absolutely everything well and good, but please extend the length of light cycles. The constantly changing lights causes major delays as cars just get up to speed, only to reach a red light. The light sequences in Adelaide certainly seem to me to be shorter than the other capitals. Not sure if there are any figures of this, just an observation, but I am not the only person to notice this.

[Norman]

Which highlights another problem which in my experience is unique to Adelaide, the length of time a particular light stays green. If we are to use turning arrows for absolutely everything well and good, but please extend the length of light cycles. The constantly changing lights causes major delays as cars just get up to speed, only to reach a red light. The light sequences in Adelaide certainly seem to me to be shorter than the other capitals. Not sure if there are any figures of this, just an observation, but I am not the only person to notice this.

I think the timing of Adelaide's traffic lights are pretty much right. Maybe you're used to the ones in Perth, which I thought took way too long to change in my opinion.

[Llessur2002]

Which highlights another problem which in my experience is unique to Adelaide, the length of time a particular light stays green. If we are to use turning arrows for absolutely everything well and good, but please extend the length of light cycles. The constantly changing lights causes major delays as cars just get up to speed, only to reach a red light. The light sequences in Adelaide certainly seem to me to be shorter than the other capitals. Not sure if there are any figures of this, just an observation, but I am not the only person to notice this.

I think the timing of Adelaide's traffic lights are pretty much right. Maybe you're used to the ones in Perth, which I thought took way too long to change in my opinion.

Plus, shorter cycles are much more convenient for pedestrians - it's a bit of a balancing act.