Re-thinking design strategies for street-level frontages

A vibrant street-life is valued for many reasons, ranging from recognised social benefits [1] to the production of economic activity [2]. The relationship between a building or land and the street or road onto which it faces is referred to as the 'frontage'. Since the 1960s, there has been a strong focus on the relationship between the design of frontages and street-life intensity. Jacobs [1] promoted the importance of visual connections between the street and the building interior, coining the influential phrase ‘eyes on the street’ or passive surveillance as a means of supporting street-life vitality by improving public safety. In addition to advocating for transparent and permeable building facades, commentators also sought to eliminate the blank frontages of institutions and shopping malls that ‘turned their back on the public realm and internalised public life' [3].

From these origins, the concept of ‘active frontages’ has evolved and, when assessing the design of buildings at street-level, active frontages are promoted as ‘best practice’. While active frontage definitions vary in detail, a concise description is: an interface that provides interaction at the boundary between the public realm of the street and privately owned property.

In Melbourne, the early adoption of active frontage policy was influenced and informed by the work of Jan Gehl, who has conducted public-life studies globally, including in central Melbourne [4]. Gehl developed an evaluation scale grading frontages to identify features that contribute to a healthy street live (i.e. active, open, permeable, good quality materials) or kill street life (i.e. inactive, closed, flat building surfaces with little detail).

Today, when implementing active frontage policies, a ‘default’ approach is often adopted, applying built-form active frontage controls in line with Gehl's evaluation scale by requiring (or recommending) a specified minimum percentage of street-level frontage to be clear transparent ‘shopfront’ glazing or building entry. Further, there is an aversion within active frontage policy to permit any form of frontage ‘blankness’.

While acknowledging the positive origins of active frontage policy in seeking street-life vitality and public safety, questions arise about this reliance on transparent shopfront controls which have limitations, especially in areas beyond main shopping strips. Questioning the status-quo of prescribed transparent frontage controls is particularly relevant in a time of disruptions to traditional ‘bricks and mortar’ retail, accelerated by the impacts of the Covid-19 pandemic - vacant shopfronts don’t provide ‘eyes on the street’.

Street-level urban affordances

To better understand the impacts of active frontage controls (particularly those promoting frontage transparency) on street-life vitality, I conducted urban research using a conceptual framework informed by Affordance Theory, which offers a pathway for understanding relationships between environments and occupants. An 'affordance' is what the environment offers a particular user- either favourably or unfavourably. The term was coined by Gibson, an environmental psychologist who provided an oft-quoted example: the surface of a pond affords support to a water-bug but not to a human [6]. Unconventional affordances may be possibilities that vary from the original design intent, for example, steps used for sitting or walls for leaning. In addition to physical affordances, affordances are also linked to sensory experience and perceptions.

When considering urban affordances, ‘the task for urban design is one of maximising affordances’ [7]. Active frontage controls that prescribe extensive transparency aim to afford street-life vitality and public safety; however, there is the potential for such controls to actually erode or limit (rather than maximise) affordances, resulting in:

• Exclusion: active frontages can be used as ‘soft controls’ to attract preferred street-level users while eliminating ‘undesirable’ behaviours. However, security for some can come at the expense of eroding affordances offered to others, resulting in inequitable access to the street-level public realm.
• Uniformity: Jacobs observed that street-life vitality is impacted not only by the concentration of people in the street, but also by the diversity of street-level building uses, users and activities [1]. By requiring a formula-based uniformity of activity and built form, active frontage controls can encourage homogenisation and ‘generic' design approaches, limiting affordances that better support diversity.
• Elimination: policy that seeks to eliminate all areas of ‘blankness’ in public space can restrict sites affording non-commercialised activity, including self-expression and urban play [8]
• Inflexibility: active frontage controls can limit frontage adaptability, eroding affordances for new and innovative uses. The inflexibility of built form and use is linked to environmental unsustainability as a sustainable city is resilient through adaptability to change [9].

Researching active street-level frontage controls

Examining the questions ‘do we need active everywhere?’, and ‘how much blankness is too much?’ through a lens of affordance theory, my research questioned whether active frontage controls that require expansive frontage transparency are always effective in affording street-life vitality, and what other forms of street-level frontage control may also support this.

My research included fieldwork in Forrest Hill, South Yarra - a former light industrial area located 3km south-east of Melbourne [10]. Since 2004, more than thirty office and apartment towers (ranging from 15 to 50 storeys) have been built, with more under construction or in the pipeline. This area was selected for analysis as the focus of the research was to understand the relevance of active frontage controls requiring transparent shopfronts outside of main retail strips.

The research included exploring synergies between active frontage codes and affordances to understand how the built environment outcomes and building occupancy/uses may support or restrict urban affordances (both ‘intended’ and ‘unconventional’) that contribute to a diversity of street-level use, users and experiences.

As a starting point, I analysed and recorded frontage types, referencing a frontage classification system [11] that provides a more nuanced understanding of interfaces than Gehl’s graded scale, but adapted to suit the focus of my study. In my typology (see Figure 1), a 'transparent active frontage' relates to the standard policy definition where 60%-80% of a frontage is clear glass or entry. The alternative 'non-standard frontage' type has less than 60% glazing, or may be blank - but only if the blankness demonstrates a considered design treatment. Whereas monotonous lengths of blank frontage are classified as 'impermeable/blank frontage'.

I then studied street-level behaviours in relation to these different frontage types. Observations at 'transparent active shopfront' locations of head-turning and pausing activities (indicating interest in a frontage) revealed that pedestrians paid little attention to the standard 'transparent active frontages'. Further, during periodic walk throughs of the wider case-study precinct, lingering stationery activities (indicating opportunities for social interactions) and unconventional affordances (indicating diversity of behaviours) were generally observed next to 'impermeable/blank frontages' or 'non-standard frontages', rather than in front of transparent active frontages'. A sample of recorded behaviours relating to blank frontages is illustrated in Figure 1. Affordances may be transitory and fleeting, therefore those observed provide a limited sample of what may potentially be occurring in these street spaces, however, these observations provide an interesting snapshot of the relationships between frontage types and physical affordances.

Pedestrians’ sensory perceptions relating to frontage types were also investigated, with participants making smartphone video/audio recordings ‘capturing’ their street-level experiences during accompanied walk-alongs. Somewhat predictably, standard transparent shopfronts (unless occupied by a busy café) "felt dull and boring", contributing to a perceived "non-vital atmosphere", whereas some non-standard frontages elicited more positive responses.

The Forrest Hill case is an exploratory study; further refinement of the methodology is required and additional case-studies would allow for comparison. However, while acknowledging these research limitations, the findings provide useful insights applicable to other emerging mixed-use neighbourhoods in Melbourne and beyond. For example, suggesting that frontage transparency and physical porosity need not always be continuous; non-standard and considered blank frontages can also play a role in affording street life. The research also offers a method for future research to better understand sensory and physical affordances relating to street-level frontage design.

Alternative street-level frontage design strategies

To understand different design possibilities for street-level frontages, informed by the Forrest Hill case and my experience in architecture practice, I developed three affordance-based urban design strategies that more successfully afford a diversity of use, users and sensory experiences than the existing transparency controls:

1. Establish street-level interfaces which afford a diversity of use and users
2. Enable a variety of engagements between users, and between users and the street-level frontage
3. Enrich street-level sensory experiences

There are a range of local and international exemplars of alternative frontage design that demonstrate tactics to support these strategies:

Building on these tactics, design principles were developed for alternative frontage designs (Figure 2) and applied to a speculative re-imagining of frontages in the Forrest Hill precinct (Figure 3). Close-encounter frontage design tactics including considered materials and detailing, and integrated façade lighting that supplements general street lighting can afford enlivened street-level atmospheres that are less intimidating and encourage more ‘eyes on the street’.

My research findings suggest that façade transparency is not the only form of frontage design that can support street-life vitality. 'Non-standard' and 'considered' alternative frontages can also play a key role. While resisting frontage blankness is a legitimate response to the loss of interaction between the public and private realms, blankness can actually provide spaces for lingering activities and spontaneous urban life. Long non-transparent walls and the voids of poorly designed carpark entries and services enclosures can be deadening; however pockets of well-designed, ‘considered’ blankness can actually contribute positively to street-life vitality, if part of a mix.

This research does not promote the de-regulation of street-level interfaces but rather challenges the status-quo application of such controls. We need controls that protect our cities from poor urban development and active frontage controls have an important role to play in this. Using insights gained from this research I advocate for a more critical approach to the design codes that impact frontages. I suggest a more flexible framework that allows (and encourages) innovative strategies for the design of street-level frontages to be tried and tested, thereby enabling a more diverse and vital street-life.