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We look at ways to fix Warkworth's infamous Hill Street intersection



Ideas have been flowing, and designs have been presented to help find a solution to fix Warkworth's infamous Hill Street intersection.


Many people have their opinion on what will work to permanently reduce the congestion issues, but only some are achievable.


A trial is currently underway by Auckland Transport (AT) and the New Zealand Transport Agency (NZTA) which stops cars from leaving the Hill Street set of lights and turning right onto Elizabeth Street.


We have spoken to Warkworth residents and NZTA about what they think will fix the issue permanently.


Fix Hill Street Now Action Group member and former infrastructure analyst Grant McLachlan has been keeping a close eye on the intersection.


He believes the best way to lay out the intersection is in a "pill" shaped roundabout.


"Due to the intersection acting as a regional distributor of local and through traffic, the design spreads out the existing five intersections into one large roundabout," he says.


"To avoid congestion of the Sandspit and Matakana Roads, we've used the natural topography to allow for an underpass for eastbound Sandspit Road traffic, and a better confluence of the two roads for westbound traffic."


He states; With this in place the intersection will have better entry and access for all eight points of the intersection.


In the design, Elizabeth Street has "an inviting town entrance and easier exit onto the intersection. Kowhai Park is reconfigured with better vehicle and pedestrian access, and there is pedestrian underpasses for Sandspit and Brown Roads," he says.


"The traffic light phases at Hudson and Whitaker Roads currently control the waves of traffic at Hill Street, which allows the roundabout to flow. In the future, the design also can accommodate an overpass if traffic growth requires grade separation."


McLachlan strongly believes the whole intersection can be phased in with minimal disruption as the majority of the design is outside the current intersection footprint.


Qualified industrial designer Erin Hearne uses the intersection daily to take his daughter to and from school.


He says; He is not a road engineer, but is a long term and very experienced road user, who has a very clear understanding of what works and why it works.


His design is a roundabout concept where the traffic keeps moving, heavy traffic flow is favoured and the environment impact is lower.


"Compared to the "pill" or "elongated roundabout" proposal this has a much lower environmental impact. It also has no property reclaimed to implement my concept, and the road north and south of the intersection along State Highway 1 (SH1) can be widened to four lanes with no private property impact," he says.


In his design he has also included footpaths, cycleways, pedestrian overbridges and concrete dividers between lanes to enforce correct traffic code.


"This is a comprehensive view of how an intersection like this can be managed in a modern format for all users."


Hearne says there are three main components to his proposal. These are the Matakana Link Road, the widening of SH1 between Hudson Road and Whitaker Road, and the Hill Street Roundabout as you can see in the picture.


In sequence of construction, Hearne believes the Matakana Link Road needs to be completed first as "this would allow Matakana and Snells traffic access to SH1 and beyond while the roundabout was being constructed".


He then says; The bridge south of Hill Street on SH1 needs to be widened to allow for four lanes north and south, "eliminating the current choke point and increasing traffic flow capacity".


Lastly he says the widening of SH1 to four lanes off Hill Street needs to continue to Hudson Road and then the roundabout needs to be completed.


"For this concept of mine to be successful, all three components of my proposal must work together as a united solution. If one component is left out, this proposal will fail," Hearne says.


"Naturally, there would be disruption to traffic to implement this or any other viable solution. However, with night works and patience, we could have a long-lasting solution that benefits all road users."


The NZTA has been looking at many ways to deal with the issues and say they understand the frustrations of both local communities and people passing through Warkworth using SH1.


Their Auckland and Northland Highway Manager Brett Gliddon says they are committed to looking at short term solutions to help improve the operation of the intersection.


"Within five years there will be a world class motorway which is costing hundreds of millions of dollars to improve transport choices in the region, and which will remove the current frustrations," he says.


It is said the Puhoi to Warkworth Road of National Significance will be open in 2021. This will mean traffic will bypass Warkworth and the intersection by using the new motorway or by accessing Warkworth from the north where the new motorway will end.


"When both the RoNS and Matakana Link are finished it will have a combined effect of removing more than 8,500 vehicles a day from the intersection," Gliddon says.


The construction on the Matakana Link will be an alternative to the Hill Street intersection for traffic heading to and from Matakana, and the eastern beaches is expected to begin in the second half of 2019 at a cost of up to 40 million.


The Western Collector will also provide an additional local route to SH1 for local traffic.


"A section bridging the Mahurangi River is being built now and will be finished early next year. When all of this work has been done we will upgrade the Hill Street intersection based on the traffic flows at that time."


Gliddon believes while roundabouts can be a good solution, at a complex intersection there are some key design features needed to make them work which includes flat topography and equal traffic flows from each direction.


"Roundabouts need to be built on flat ground to counter trucks tipping over and because this area is hilly and one of the designs goes over a stream, it would require a significant amount of earthworks to level it out, which would be disruptive" he says.


"Traffic using roundabouts can experience significant delays where the approaches to roundabouts carry differing volumes of traffic, so where one or two approaches carry much more traffic than others. "


He also explains "roundabouts can be difficult to provide a safe environment for pedestrians or cyclists particularly multi-lane roundabouts at busy times".


It is said the NZTA will continue to work with AT to look at the long term solutions at this intersection.


#design #NZTA