From the 26th of March 2012 the Fanshawe Street on-ramp which feeds the Northern Motorway from Beaumont and Fanshawe Streets will allow vehicles in the afternoon to join the Northern motorway on both sides of the tunnel.

So if you are driving along Fanshawe Street between 3.30 and 7pm weeknights and you wish to get on the motorway you can make two choices, you can join the motorway on the left and carry on to the Harbour Bridge and use the clip-ons (left two lanes) or you can join on the right side and carry on over the bridge in the centre lanes.

If you take the Stafford Road off-ramp, you will probably continue to use the left land ramp, if you carry on all the way to Tristram you will probably start using the right hand lane.

Yep, it is odd. But there is a reason. The Harbour Bridge currently has a moveable barrier, and during weekdays this barrier machine moves the bridge lanes around in three different configurations. In the morning peak it is five lanes heading south, during the day it is four lanes in each direction and during the afternoon peak it is five lanes north, this is because the demand on the Bridge changes throughout the day.

Part of the Victoria Park Tunnel project is improving the St Mary's Bay section by widening it in both directions. However, this posed a problem. You could not widen the northbound lanes in St Mary's Bay without widening the Harbour Bridge when it is not in the afternoon layout. As this was not possible, the Barrier Machine operation has been extended all the way to the Fanshawe Street on-ramp to provide five lanes through St Mary's Bay when needed.

Above: Barrier Transfer Machine going through St Mary's Bay.

In the afternoon, Fanshawe Street on-ramp must supply two lanes, any less and Fanshawe Street would be worse than it currently is. Also, why build a tunnel if you cannot provide another lane? So, with five lanes through St Mary's Bay in the afternoon and five carrying on over the Bridge the existing two-left-hand lane on-ramp at Fanshawe Street and new third lane from the tunnel would have been fine. But during the day when Fanshawe Street contributes less traffic - you are effectively knocking out the new tunnel lane as it has to close before the Bridge. During the morning peak you are effectively ruining 66% of the tunnel by forcing them all into the three left hand lanes.

Therefore if you can drop Fanshawe Street on-ramp down to one lane outside of peak times you can retain three uninterrupted lanes out of the tunnel and during morning peak you make no difference to the current layout coming out of the tunnel. Then during PM peak you can have two lanes from Fanshawe (one on the left and right) and three directly out of the tunnel uninterrupted.

Above: The PM peak lane is the right hand lane, the left hand lane is the always open Fanshawe Street on-ramp @ one lane.

The Barrier Machine will no longer park at the southern end of the bridge, instead it will do the current barrier run over the bridge and park underneath the existing Victoria Viaduct. In the afternoon when it reaches its home by Fanshawe Street a hydraulic gate will open the PM peak lane to traffic, which can begin entering from Fanshawe Street and Beaumont Street (if they are in the respective right hand lanes on those streets).

Vehicles will continue along that new PM peak lane into St Mary's Bay in a newly opened fifth lane onto the existing fifth lane on the Harbour Bridge.

The PM peak ramp and fifth lane through St Mary's Bay and the Bridge is only open between 3.30pm and 7pm Monday to Friday. At other times vehicles will use the existing left hand on-ramp at Fanshawe Street which will be reduced to one lane.

Above: An overview of the intersections and on-ramp layout. Click here to see a larger version of this, along with St Mary's.

As long as a right hand lane that enters on a motorway with existing traffic does not have to merge with an existing lane it is to motorway standard.

The only thing that is encouraged is that people entering on the right hand lane don't plan to exit the motorway until Esmonde or further north. If you exit at Onewa and Stafford off-ramps it is recommended that you continue along the left-hand ramp.

Currently there is too much demand on the left two northbound lanes of the Bridge, as a large volume enters at Fanshawe and Curran Street a lesser volume utilises the centre three northbound lanes in the afternoon. It is hoped that having three lanes from the tunnel, with its left hand lane feeding the left lanes of the Bridge, its two right hand lanes and the right hand Fanshawe on-ramp lane feeding the centre lanes of the bridge - that a better split will be achieved, providing better throughput in the section.

Firstly wait until the lane opens on the 26th of March before you try and use it. But in the mean time, as you a driving past figure out how you might access it in the future and let other people you know who take the route aware of the upcoming change. There probably will be delays on the days following the opening as the existing left hand lane will only provide one lane of access and most people will probably be unaware that you can access the motorway on the right hand side.

Otherwise let plenty of people know about this.

Some people using the ramp.

Monday the 26th of March was a great day for commuters on the Southern Motorway heading northbound in the afternoon, they had a dream run to the Bridge. Not so much for the commuters coming out of the CBD when trying to access the motorway from Fanshawe Street on-ramp.

Traffic at seven in the evening was backed up to Queen Street (and hardly moving) and Victoria Street was back to Hobson Street. The traffic crept towards the Fanshawe Street on-ramp before it was shuffled into one lane to enter the motorway. Where was the second lane? It was to the right of the existing ramp and it was empty. Why? Nobody really knew it even existed.

The PM peak lane is perfectly fine and will work well in time because people will realise they will be able to use the ramp on either side. But the confusion will last a few weeks before the section flows as well as it ever could in the past. This website made quite an effort to market the change because I knew that the change was significant enough to cause a big problem. The problem? Who is going to use an on-ramp they have never seen, when for a long time they have been using the traditional left hand side ramp.

This has allowed another project to get affected by the first day having teething probelms. But it didn’t need to happen that way. Why was it not advertised extensively that the PM peak lane for motorists was about to open, why did they not delay it a week after the Give Way rule change? Why did they not have a couple of people in high-vis jackets down at the ramp showing people they were allowed to use the ramp?

Lessons: when something is significantly changed, let the people who use it on a daily basis know about it, then it should work. Also, have some sort of signage...

Day two, better.

Some works were done to make the lane markings better at the ramp and two large (temporary) electronic signs were erected down at the ramp saying "PM Peak Lane OPEN" which seemed to get more drivers confidence high enough to use the new ramp. Good to see.

By Benjamin Paul | Contact