19 April 2012

Traffic light phasing.....is it that dificult?

| cranky
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Spurred by a related thread, it is apparent that little thought (or even malevolent thought) has been applied to the phasing of these devices. There is no doubt these lights are linked, as the results are always the same.

I have a couple of favourites. Traffic turning right from Yamba Drive heading north into Hindmarsh heading east are always stopped immediately at the Palmer Street lights. These should be reset to stop traffic once Yamba traffic is given the green. ie, only stopping the far fewer vehicles turning left onto Hindmarsh east from Yamba heading south.

Another is the traffic given a green to turn right onto Athllon Drive fom Beasley Street (Mawson) are always stopped at the next intersection, Mawson Drive. These should be reset to turn red when any traffic from Beasley Street (Torrens) turning left onto Athllon is given the green. This traffic is allowed to turn left at any time.

Disproportionate timing is also comment worthy. Monaro Highway/Mugga Lane morning timing is approximately 2.5 minutes/20 seconds. Traffic heading south on the Monaro turning right into Mugga Lane can take 3 or 4 changes to get through. Yes, there is a shedload of traffic heading north on the Monaro, but another 10 or 15 seconds per cycle would certainly help the turners. Long Gully onto Yamba in the afternoon has similar timing, but giving huge green times to Yamba heading south, when there is little traffic.

I’m sure other RAers have their own examples.

Mr Gill, are you there?

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The phasing of traffic lights anywhere in Canberra is beyond the skills and capability of Roads ACT. There are that many examples of this you may as well place all sets of lights in the same basket. Great peak hour examples are yamba dr past the hospital in peak hours, stop at every set of lights, northbourne ave closer you get to the city particularly in the morning. Also the number of lights where you’re turning right where there is a huge gap in traffic where the lights actually will wait for the on coming traffic to come before going red for them belconnen way onto Gungahlin drive is a good example. I’m sure they will continue with the “oh but it’s all too hard” story until they’re blue in the face instead of investing in some proper technology and people to do it.

Reminded me of this: Link

I am surprised nobody has mentioned the ‘Magic 7’. the run of soul-crushing red lights that start at the intersection of Erindale dve/Drakeford Dve and end at Sulwood/Drakeford..Cop all 7 in a row and you have added 15-20 minutes of frustrating hell to your journey.

Woody Mann-Caruso8:06 pm 19 Apr 12

Traffic light phasing…..is it that dificult?

Paging Dr Dunning and Dr Kruger…

but these changes would certainly speed up the flow of higher volumes of traffic.

What makes you think this is desirable? What effects will it have at the next intersection, and the one after that, and others that might lie on intersecting roads?

It’s a network. You can’t just stuff around with one bit without risking buggering up the rest of it.

cranky said :

Traffic turning right from Yamba Drive heading north into Hindmarsh heading east are always stopped immediately at the Palmer Street lights.

Not if you plant it, I’ve found. Dawdle around the corner and up to them, and yes quite often you’ll get stopped. Put your foot down (it is 80 after all) and get moving and you often miss them and are free to head up the hill while everyone pulls up behind you.

That said, I travel there every day (not in peak time mind you) and I do probably get the Palmer Street lights one day out of five.

I think some have gone off a bit half cocked regarding my original post.

Beazley/Athllon -Exiting Mawson, these lights allow traffic to go straight ahead or turn right. Oncoming traffic from Torrens has a red, until given their turn to either travel straight ahead into Mawson, or turn right towards Tuggers. I am suggesting that the Mawson Drive lights be coordinated with this second change, allowing ex Beazley traffic a straight run, and will have turned green for the oncoming northbound Athllon traffic once released from Beazley St lights. This does not inconvenience anyone, as traffic turning north onto Athllon from Torrens is permitted to turn left at any time.

Similarly the Yamba/Hindmarsh lights. If the lights were delayed so that the often quite heavy traffic turning onto Hindmarsh from Yamba were able to clear the Palmer St, the only traffic affected on Hindmarsh are the far lower volume traffic heading south on Yamba and turning east onto Hindmarsh.

I am not trying to ensure I have a dream run, but these changes would certainly speed up the flow of higher volumes of traffic.

For a serious traffic light blackspot, try leaving the Monaro Highway at Fyshwick (heading north), to turn right into Newcastle Street. Every effort has been made to impede this traffic flow. Primary reason is permanent very long greens for traffic heading south on Newcastle and turning north onto the Monaro. These lights need a serious re-phasing. Traffic heading east along Newcastle from Dairy flat get priority meaning Monaro/Newcastle traffic moves from one red to another turning red as they approach.

remember when considering phasing of lights that, while you’re cursing the changes in the direction you’re travelling, traffic is flowing the other way and is likely also affected by phases of lights elsewhere in the flow of that mass of cars, buses, bikes, trucks, etc…

what would be useful are more practical ‘turn left when you want’ signs at red lights and taking those away from intersections where you can’t bloody see the traffic coming and need a light to tell you it’s safe [unless you take to streetscapes with a chainsaw…]

The mugga lane one is interesting. I took that way once and found nearly all the traffic went to Fyshwick like me, they just decided to try and dodge the potential backlog of traffic.

That said I note in my suburb we get an extra large volume of traffic driving through the suburbs and school zones just because the roundabout on isabella/drakeford/tharwa drive intersection is clogged. That intersection needs lights ASAP.

Airport to Majura Road is painful. If there’s trucks in the queue to turn right from Pialligo, you might have to wait 2 goes of the lights. And you’ll seldom make the right turn into Majura, which seems to come on at about the same time as the right turn from Pialligo. It takes about 10 minutes to get from the airport road to Majura Road, all of 100 metres.

zorro29 said :

(worst example is the intersection near the hospital – giving the right turning traffic 2 goes causes kms of traffic back past Bunnings in the mornings when there is seldom ever a line of traffic waiting to turn right).

would love it if the traffic flowed well!

I think traffic turning right getting a second go is more to do with the traffic turning left onto Belconnen Way from Haydon Drive. They have a green light for the entire time, and there is normally traffic flowing through there for the entire green light. Yes, it holds up Belconnen Way traffic, but it’s not like a little side street joining Belconnen Way – if Haydon Drive traffic had a shorter green light, it’d just clog up that road.

Although I agree there are some lights that could be fixed, I don’t think the OP’s examples are very good.
It pretty much reads like “I should get green lights wherever I drive”.

Holden Caulfield12:25 pm 19 Apr 12

I have to say commuting along Limestone (entering from Wakefield) tends to work pretty well. Usually have to stop once at Ipima Street intersection, then generally get green all the way beyond the War Memorial.

If you enter from a different intersection than Wakefield (Ipima, for example) you end up being out of sequence and will most likely have to stop once or twice before AWM.

I fail to believe any sequence of lights can be more poorly synchronised than the Barry Drive-Cooyong St-Coranderrk St run. You don’t expect to get them all green, but one stop, instead of three or four, should be possible, surely.

TAMS explains it here using Drakeford Dr as an example.

http://www.tams.act.gov.au/move/roads/traffic/trafficsignals#How

Looks like it does depend on the time of day. The direction of co-ordination can change outside of peak hours depending on traffic flows.

stormboy said :

Selfish much?

Why would the lights be co-ordinated to benefit a lower volume of cars entering an arterial corridor than on the arterial corridor itself? I am sure that the same thing happens when you turn right off Melrose onto Hindmarsh eastbound, but getting greens at the subsequent lights would be nice don’t you think.

It might depend on the time of day, but when I drive straight down Hindmarsh in the afternoon it usually goes: 50/50 at Hindmarsh/Botany, red at Hindmarsh/Athllon, 50/50 at Hindmarsh/Ainsworth, red at Hindmarsh/Yamba, green at Hindmarsh/Palmer. But yes, it would be nice to get greens at the subsequent lights.

couldn’t agree more…Belconnen Way and Ginninderra Drive are my favourites…

in a number of European countries (notably Austria), if you drive on the speed limit, you will get all green lights…that seems to be a way of encouraging people not to speed and reducing congestion

whereas here, if you drive on the speed limit, you’re usually rewarded with the next red light. it really annoys me on belconnen way that the flow-through traffic isn’t given right of way (worst example is the intersection near the hospital – giving the right turning traffic 2 goes causes kms of traffic back past Bunnings in the mornings when there is seldom ever a line of traffic waiting to turn right).

would love it if the traffic flowed well!

Selfish much?

Why would the lights be co-ordinated to benefit a lower volume of cars entering an arterial corridor than on the arterial corridor itself? I am sure that the same thing happens when you turn right off Melrose onto Hindmarsh eastbound, but getting greens at the subsequent lights would be nice don’t you think.

I’ve thought about it long and hard, and can see why it happens at some points.

For the Monaro Highway, if traffic is stopped for too long, even another 15 seconds, then the back ups could potentially be another 20 or 30 cars heading north, that could lead to problems with the Isabella Drive Roundabout (more problems then there already is.) So it is given that a majority of people will get the right of way, 50 cars as opposed to 5 cars, it is a big difference.

The Hindmarsh/Palmer Street intersection, this would be done as less cars are able to turn onto Hindmarsh drive, then can travel along Hindmarsh drive, those lights need to turn green at some stage to allow the traffic leaving Palmer street, if turned green when Hindmarsh traffic was on it, it could potentially block the Hindmarsh/Yamba Drive intersection.

Beasley street to Mawson Drive, this would be the same as the other two examples, it appears that you are driving to where a minority of people are going, trying to go against where a majority of people are going.

Say for some unknown reason, you left Mawson, did not get stuck at Mawson Drive, turned right onto Hindmarsh, did not get stuck at Palmer street, turned right onto the Monaro Highway, and managed to get through on the first of second phase of the lights, you would have saved approx. 16 minutes in that one trip, say there was unexpectedly 10 cars doing the same route, that is I guess a net savings of 160 minutes.

But because of that, 60 cars are stopped for 3 minutes at Palmer Street, 40 cars stopped at the Monaro Highway, and 15 cars were stopped at Mawson drive, to allow you and 9 other people to travel this route unimpeded, you have stopped 115 cars, effectively costing 345 minutes. Which is over double the time it saved you.

While I see your point, changing the light pattern for the minority of road users does not equate to a better driving experience for the majority.

I am saying this and I live in a land locked suburb with 2 exits, I can’t easily get onto the GDE, I have to navigate Haydon Drive (aka Traffic light central), I work in Braddon at times not conducive to public transport travel and have to deal with the fact that I am driving with the minority of people.

My advice to you if find a rat run that works, I took one yesterday and beat a fire engine with lights and sirens up the length of Northbourne.

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