The Rise of the Woonerf

The urban landscape has been changing slowly in the last couple of years with the introduction of shared spaces, aimed at removing the traditional segregation of motor vehicles, pedestrians and other road users.

The concept of the Woonerf (or more commonly known in the United States as the Home Zone) was developed by Dutch traffic specialist Hans Monderman. One of the major characteristics of shared spaces is the removal of road markings and traffic signs to encourage natural human interactions when using the public space. Several towns and cities around the world have adopted the shared space concept and implemented it in a way that would suit their area.

In Australia, the Bendigo City Council in Victoria unveiled a $16 million urban make over of its city centre in 2007, dubbed as “naked streets” by commentators.

Traffic signs and road markings were taken out, footpaths were expanded and filled with street furniture and public art, kerbs were eliminated and replaced with paving marks for car parking spots.

In Germany, the town of Bohmte ditched its traffic light in 2007 in a $1.66 million project. These zones translated as “traffic calming area” restricts the maximum speed of motorists to 7kmh under the country’s traffic law.

In New Zealand, several of Auckland’s streets have been turned into shared spaces, including Elliot and Darby Streets, Lorne street, and the Fort street areas.

John Potter from Boffa Miskell, lead supplier of professional design services for the Auckland Council, said the recent completion of shared space “has effectively reclaimed these streets as high quality spaces that attract more people, more street-based activity and fewer vehicles”.

After conducting trials involving the use of structural soil and tree cells, they decided to use the Citygreen® modular Stratacell™ system. Boffa Miskell also specified the use of Stratacells on the St Patrick’s Square project in the Auckland CBD, which won the NZILA George Malcolm Supreme Award and a Gold award in the Landscape Design Category in 2010.

Stratacells are structural soil cells that come in modular units, which can then be assembled to form a skeletal matrix that supports pavement and traffic loads. This structural cell system features almost five times more available growing media compared to the traditional rock/soil method, therefore facilitating healthy root growth.

“We were looking for a system that would enable us to provide a significant volume of planting medium to support tree growth whilst also providing structural integrity to the overlying paved surfaces. This system has subsequently been used on the Auckland City Centre Shared Space projects plus other significant projects in the area,” John said.

The project’s biggest challenge with the incorporation of trees into the streetscape was “ensuring the provision of an adequate volume of growing medium for root development”.

“Boffa Miskell worked with the Auckland Council Arborist to determine the growing medium volume required, and Stratacells were used to construct a tree planter to meet these requirements whilst providing structural support to the overlying pavement, which is subject to both vehicular and pedestrian overrun. A Citygreen aeration/manual irrigation system was also incorporated into the tree pit design,” John added.

In the Netherlands, the shared space is called a woonerf – a street where pedestrians and cyclists have legal priority over motorists as stated under article 44 of the Dutch traffic code. By 1999, the Netherlands had over 6000 woonerfs with Makkinga and Drachten as its pioneer towns.

Canada has also followed suit with the transformation of the West Don Lands’ sustainable riverside community. James Roche, director of Parks Design and Construction, led the Waterfront Toronto project in the West Don Lands, which featured a woonerf. James says that through the very nature of the woonerf design, including the materials and detailing, “a more public streetscape is established” which “allows for the blurring of the public and private”.

Incorporating trees into some areas proved to be a bit of a challenge “due to the limitations in vertical room for rootballs of the trees”. “The design calls for slightly raised planters to accommodate rootballs,” James said.

Aside from the spatial challenges, getting city approval for the use of pavers in the roadway and for having no curbs also proved to be difficult. “These were resolved through working together with city agencies, selecting appropriate heavy duty pavers, and using high contrast/tactile pavers at curblines,” James added.

Although the project turned out great, James says there are still some things he would have done differently; “I would have pushed the design interface between the buildings and public space, allowing for larger moments within the woonerfs, wider spaces, perhaps at entrance ways to the residence. Maybe create larger entry plazas, further enhancing the notion of a pedestrian street.”

Studies in Europe have shown that woonerfs are significantly safer than traditional streets. It also doesn’t compromise travel time because drivers are able to maintain a constant speed similar to the average speed traveled in normal start/stop traffic.

In the United Kingdom, several areas have been dubbed as “naked streets” by the press because of the removal of traffic signs and pedestrian barriers. They are called home zones but are not protected by law like woonerfs are.

Although the United States was slow to embrace the concept at first, several states have taken on home zones. By 2008, the concept was being adopted in various cities including Miami, Seattle, Portland (Oregon), San Francisco, Santa Monica, and more.

With the continued development of urban shared spaces, Citygreen has positioned itself very well in becoming a favoured system to use in future projects.