The Pialligo roundabout is dead

Youami said: “Shame though as roundabouts control traffic flow a lot more efficiently than lights”

Hmmmm – That is interesting – Lights control intersections MUCH Better than roundabouts – Roundabouts just limit traffic flow to those to your right.

Many a fine morning – I have circled local roundabouts many many times, just to give the other poor bastards a chance of getting on…..

MrPC said :

Isabella/Drakeford once kept me stuck for a good 10 minutes southbound on Drakeford at 5:10pm, about two months ago. There was too much traffic coming out of Tuggers into the roundabout that those coming south off the Parkway just couldn’t get into the intersection.

Well, I got stuck at the traffic lights out the front of Flinders St Station in Melbourne for 30min at 5pm because of traffic lights. At high traffic times, sometimes road designs cant handle the load, no matter how well you design them. Thats just part of life.. Why completely redesign a road, because for a 10-min period everyday, some people have to wait upto 10min. The one thing you will notice though, is that even though you wait 10min, you are generally crawling along for that time. If you get stuck at traffic lights, you might move once or twice, but its more of a surge than a smooth flow.

MrPC said :

The only set of lights that I really want to see replaced just now is that useless set at Mugga Lane and Monaro Highway. I certainly wouldn’t replace it with a roundabout though, since even less northbound traffic on the Monaro would get through than does now.

Because, the round-about at Isabella/Monaro or Johnson/Monaro are so bad? What makes you think that a round-about at Mugga Ln/Monaro wouldnt flow as easily as the two roundabouts I mentioned? If you think these roundabouts cause backed up traffic, check some of the speed camera threads here and youll often see people caught speeding into the round-about because theyre still doing above 80 by the time they reach the entry lane.

Roundabouts generally do provide better traffic control, but only if drivers are sensible and educated enough to know how to use them. The biggest problem with roundabouts occurs when people dont understand how to use them, and either dont merge at appropriate speeds, stop before merging, turn from the wrong lane, etc.

The lights at the Monaro Highway/Mugga Lane are heavily biased in favour of Monaro Highway northbound morning traffic.

2 and a half minutes for the Monaro, 20 seconds for Mugga Lane. Probably a fair split, but causes a considerable bank up of Mugga Lane traffic.

Not helped by the goose travelling northbound on the Monaro who decided to do a ‘U’ey at this intersection. Mayhem ensued, at 80K’s.

Roundabouts are OK in balanced traffic flows, but crash in unbalanced and peak flows.

Where there is a dominant flow (such as along Majura Rd past Brand Depot because of course hardly anyone goes in there…) the roundabout just slows down the dominant flow, while the minor flow doesn’t get a look in – witness Kings Ave.

And lights can be adjusted for different time periods to give greater precedence to peak flows at peak times, yet still give the minor flows a chance.

Roundabouts are simply over-rated.

on roads like parkes way and morshead drive the fewer roundabouts the better, the ones at coranderrk st and kings avenue need replacing with over/underpasses and link roads as soon as possible. Maybe the Government will finally learn that merging lanes should be as long as possible to allow traffic to flow. I think pigs will fly first though.

Isabella/Drakeford once kept me stuck for a good 10 minutes southbound on Drakeford at 5:10pm, about two months ago. There was too much traffic coming out of Tuggers into the roundabout that those coming south off the Parkway just couldn’t get into the intersection.

Thank $DEITY I don’t have to use that roundabout in peak hour daily.

The only set of lights that I really want to see replaced just now is that useless set at Mugga Lane and Monaro Highway. I certainly wouldn’t replace it with a roundabout though, since even less northbound traffic on the Monaro would get through than does now. That one needs an overpass from southbound on Monaro to westbound on Mugga, and a give way sign from eastbound on Mugga to Southbound on Monaro.

There are a whole lot of roundabouts I’d like to see replaced by -anything- else. Three way roundabouts on main roads in general should be given bypass lanes in one direction and over/underpasses in the other, assuming we’re talking about the main traffic flow being straight ahead on the main road. We have plenty of bypass lanes, but that just creates worse problems for the traffic flow heading in the opposite direction, with no break from turning traffic.

I’d definitely give that sort of treatment to every roundabout between Pialligo and Civic on Morshead/Parkes. There are too many roundabouts between the Airport and the City. Up until the other day there were 7 roundabouts to contend with up until the big one at Corranderrk Street. That’s about 7 too many IMHO. At least they are looking at doing something at Morshead/Parkes/Kings. That still leaves 5, and 5 too many.

MrPC said :

They actually had to have a flagman there stopping the traffic from the airport/queanbeyan from entering the roundabout so that people that work at Snowtown or who otherwise need to get to the Airport could even enter the roundabout in the first place!

Actually, the flagmen were originally hired by Guideline after local residents and business-owners complained that they coudln’t get out of the road due to the traffic roaring in from the airport end, and the way traffic queued up across that roundabout. There were stories of cars waiting 15 minutes to get out, and traffic banked back up the raod.

The flagmen then started preventing traffic from queuing across the intersection so more directions could flow.

I am not a supporter of lights in general, but sadly this intersection needed the lights.

On the subject of poor planning, why were the Hindmarsh-Jerra Ave lights being switched on and off yesterday without any police to monitor the intersection? Given the traffic flow through there I would have thought it would have been prudent to have the police controlling traffic than a more laissez-faire approach

OYM said :

I’m not a traffic engineer

From my trip home today from the Fed Hwy via Majura and Monaro Hwy, neither is anyone in ACT roads. Interesting though the change in thinking. The Isabella-Drakeford intersection was changed from lights to a roundabout. Not sure that change was entirely beneficial in retrospect. Although any roundabout in a 80kph zone is good for some sideways drifting

Should’ve built an interchange – and learnt from the Glenloch mistakes.

It’s too low to the waterline to have built an underpass (with a river and a creek a few metres away) and it’s too close to the airport for a 3 stack overpass (to avoid the mistakes of Glenloch). You’d only be able to build a 2 level overpass there (if the money and inclination existed). 2 levels isn’t enough with 4 approach roads each having 3 possible routes. The best you could do is have an overpass for one priority flow and a roundabout underneath it, but if you did that, nobody would be able to get in or out of Pialligo during peak hour with all the rat runners from Queanbeyan plus the Airport arrivals turning right/north monopolising the hypothetical roundabout’s traffic flow.