Tharwa Drive - worth the wait?

damien haas said :

I took the opportunity at last nights Gungahlin Community Council meeting to ask Tony Gill what variables were required for selecting a roundabout over traffic lights. He advises constant traffic from all directions. If there is a dominant flow from one direction, the roundabout doesn’t function properly. He also said a set of lights costs half a million dollars to install.

Money was always an issue with Tharwa Drive duplication…they never had enough. The road is still a disgrace. The first few hundred meters North bound from Lanyon Market Place is a pot hole highway. They obviously ran out of money and thought nothing of re-sealing that stretch. And what of the lanes going from 1.5 car widths on the straights to only 1 car width at the roundabouts. Those green lanes take up way too much of the vehicle lane space, everybody drives across the green strips. Needless top say, it was opened up to 80kmh, 2 weeks overdue.

I took the opportunity at last nights Gungahlin Community Council meeting to ask Tony Gill what variables were required for selecting a roundabout over traffic lights. He advises constant traffic from all directions. If there is a dominant flow from one direction, the roundabout doesn’t function properly. He also said a set of lights costs half a million dollars to install.

Horrid, i think that roundabouts actually make roads safer. They stop redlight running, and force drivers to remain aware of a requirement to look right. Good roundabout design can aid road safety and traffic flow. Where roundabouts fall down is in inappropriate location.

In terms of roads being efficient in moving volumes of cars, roundabouts are more efficient than traffic lights, up to a certain volume. After that, well congestion is congestion.

Roundabouts excel as they enable continuous flow, and dont lead to stop start driving. This is also more efficient for your vehicle.

In terms of considerations for road design, cars should be placed significantly higher than bicycles or pedestrians – on MAJOR roads designed for commuting traffic. Another prime consideration should be public transport access. Many roads in Gungahlin are unable to be serviced by certain buses in the Action fleet.

I was advised that some of the new 6 wheel buses purchased to replace the articulated buses, cannot service the ANU due to their inability to use roundabouts as they are too long. This will also restrict there deployment on school routes (which is one of the major uses of the present articulated buses).

Punter, civil engineering and logical thinking have no place on ACT roads.

Punter is depressingly correct- many an excellent cycle lane in this town is ruined by big roundabouts built along its route, meaning that far less people use it than otherwise might. And exactly the same problem applies to any adjacent walking/cycling paths as well. When will traffic engineers learn that roundabouts don’t make roads safer- that instead cyclists and pedestrians cop all the danger and inconvenience?

I was actually curious about this myself (as a cyclist), it seems unusual that a ramp has been placed before the roundabout (Mentone Veiw, northbound) but the green lane continues all the way to the roundabout itself. The way I would veiw to use this is to leave the road & re-enter after the intersection, as with Commonwealth Ave Bridge.

Seems like a redundant idea to me.

With regards to the actual width of the lane, I think this may be an oversight between the construction and the line markers. I imagine the construction crew have to do one thing & the line markers are bound to do another (I think there are a set of standards that line marking must adhere to).

I have not had to yet but I would imagine that it would be more difficult to negotiate the intersection in a car with a cyclist there. Having said that the idea of a roundabout is as a traffic calming device so people should slow down regardless.

As Grail points out #9/10 there is indeed a painted bike lane along the north bound side of this road at the roundabout intersection with Mentone View. The cycle lane becomes the green painted type as it approaches the roundabout right up to the entrance to the roundabout and there it ends. There is no cycle lane through the roundabout. The vehicle lane running along side the cycle lane has been reduced considerably to accomodate for the green cycle lane which raises 3 concerns if it is intended that cyclists continue through the roundabout. 1. The attention of a driver in this first lane is divided by any cyclists using the lane and any vehicles approaching from the right on the roundabout. 2. The reduction in lane width doesn’t allow a lot of seperation between cyclists and vehicles entering the roandabout at the same time. 3. As the cycle lane itself doesn’t continue through the intersection, rather it just ends which can lead to confusion as to who gives way to who once the lanes merge. I think there should either be a cycle lane through the roundabout in addition to the vehicle lane or a better option would be cyclists should leave the cycle lane at the side of the road to pass the roundabout on the shared path which is seperated from the road by a concrete barrier, and avoid vehicle traffic altogether.

I’m not having a shot at the cyclists vs cars debate which has raged here before (and is well overdone), rather, I’m making comments in favour of cyclist safety. I made this comment in another recent thread but it’s more relevant here.

I should have Googled before asking:

Generally the markings have been placed on cycle lanes on arterial roads and high traffic flow areas where the traffic speed is 60 to 80 km per hour to mark a potential area of conflict between a vehicle and a cyclist. The majority of treatments have been placed on exit ramps and left turn slip lane crossing areas , treatment has also been placed to mark a roundabout and across a high volume entry to an arterial roads both on a main cycle route.

Then there’s also this web site: http://www.austroads.com.au/abc/index.php?type=sep&id=36

So the take-home message is, “green lanes mean car drivers need to pay attention”.

I’m going to make some calls and figure out what the heck cyclists & motorists are supposed to make of those green lanes that start nowhere, end nowhere, and have no vehicular traffic crossing them.

goose said :

It will become a nice Saturday night drag strip for the try hards living in tuggies.

So nothing like that happens on the Barton Highway near Hall (on the specifically marked 1/4 mile & all)………….

Tis nice to have it finished but it has been as good as open for a couple of weeks anyway which happened to be only about a week after the other winge that was posted here.