In order to calm vehicular traffic movements in dense pedestrian areas, urban planners and local authorities around the world are increasingly adopting the ‘shared space’ concept developed by Dutch traffic engineer Hans Monderman.
The introduction of these open space environments over recent years has changed the way our urban landscapes are designed. A central goal of the concept being to remove the traditional segregation of vehicles, bicycles, and pedestrians in public spaces and encourage natural human interaction.
The removal of road markings and traffic signs, the elimination of curbs, the expansion of sidewalks, and the addition of street furnishings are all transformational characteristics. Some of these areas have even been dubbed as “naked streets” because of the removal of street signs and pedestrian barriers.
Shared Spaces Around the World
In Holland, the birthplace of the modern day shared space concept, these areas are called “woonerfs”, where pedestrians and cyclists actually have legal right-of-way over motorists. By 1999, Holland had over 6000 woonerf concept areas.
Leonard Circus, London regulated and calmed the downtown area’s traffic conditions, while achieving a greener and more attractive environment at the same time!
The entire shared space area was repaved on a single level with unglazed brickwork, broken by an irregular pattern of panels using contrasting grey granite, York Stone and Italian porphyry.
The apparently random planting location of eleven various deciduous and evergreen tree varieties was, in fact, dictated by the need to avoid a very dense network of underground utility ducting and cabling.
Stratacells were used to protect the utilities and maintain the load-bearing capability of the road, while ensuring a greatly enhanced uncompacted soil environment.
New Zealand has also been viewed as a leader in the movement, with the multi award winning Auckland waterfront revitalization adopting the open space approach.
John Potter of Boffa Miskell, the landscape architectural firm that worked with Auckland City Council, spent some time with our Australasian partner Citygreen to discuss the project. He described the shared space as a scheme that “reclaimed the streets as high quality spaces that attract more people, more street-based activity, and fewer vehicles.”
Incorporating mature trees in the woonerf projects were vital. The biggest challenge with implementing the trees was ensuring the provision of adequate uncompacted soil volume for root development.
The landscape architect worked with the city’s arborist to determine the growing medium required and used StrataCells to construct tree pits to meet the requirements, while providing structural support for the overlying pavement which is subject to pedestrian and vehicular traffic.
Boffa Miskell also specified StrataCells on Auckland’s St Patrick’s Square project which won the NZILA George Malcolm Supreme Award and the Landscape Design Category gold award in 2010.
The recent revitalization of the West Don Lands in Toronto has successfully integrated a shared space woonerf.
This 80-acre waterfront beautification showcases modern community development where design excellence and sustainability come together. James Roche, the then director of Design & Construction at Waterfront Toronto, summarized the nature of the woonerf as “a more public streetscape which allows for the blurring of public and private.”
Unlike most infrastructure development which focuses on vehicle-centric design, shared spaces work to achieve a different goal. Michael Ormston-Holloway of The Planning Partnership, a landscape architect involved in the West Don Lands project, explained the uniqueness of the shared space was “compounded by a mandate from the city to have highly mature trees with canopy cover over the street.”
Incorporating trees into the West Don Lands woonerf however, proved to be a challenge due to limitations in vertical space for the tree rootballs. The design called for slightly raised planters to accommodate this challenge.
Bollards are commonly used in shared space areas
Aside from spatial constraints, getting city approval for the elimination of curbs and the use of pavers in the roadway proved difficult. However these issues were resolved through working with city officials and selecting appropriate heavy-duty pavers with contrast/tactile pavers at curblines.
Load-Bearing Soil Cells
Load-bearing soil cells, such as the GreenBlue StrataCell, are structural support modules that come in units which assemble to form a skeletal matrix underground that provides uncompacted soil volume for healthy tree root growth, without compromising the integrity of the paved surface.
These soil cell systems feature almost five times more available growing medium compared to the traditional rock/soil method.
Many landscape architects and related specifiers, as well as local authorities and third party research institutions, have conducted trials involving the use of soil cells vs structural soil. Time and time again such tests have determined that soil cells are the best option for encouraging the mature growth of street trees.