The Physics of Feeling: Measuring Vibrancy in Urban Places

Why Measure Vibrancy at All?

Vibrancy is usually treated as intuitive: something you recognize when you experience it. A lively street, a crowded plaza, a place that feels active and welcoming. But in practice, the word gets used in many different ways. Residents, business owners, property owners, planners, and policymakers may all talk about vibrancy while picturing very different outcomes. For some, it means economic activity. For others, it’s cultural expression, social life, or a sense of belonging.

When places are at an inflection point, when investment decisions are being made and long-term futures are being debated, that ambiguity becomes a challenge. Without a shared understanding of what vibrancy actually looks like on the ground, it becomes difficult to align priorities or evaluate whether interventions are working. Shared ambition requires shared language.

Vibrancy also plays a quieter but equally important role in how places endure change. Neighborhoods and districts with a mix of activity, social presence, and informal stewardship tend to recover more quickly from disruption: whether economic shocks, public health crises, or shifts in how people work and move. Places without that underlying vitality are often more fragile, even if they appear successful by conventional measures.

Recent disruptions made this especially visible in many urban centers. Areas that once performed well by standard indicators struggled when a narrow set of users or activities disappeared. Metrics like foot traffic counts, sales volume, or rent levels told only part of the story. They captured intensity, but not resilience. That is, how adaptable a place actually was when conditions changed.

The goal of the Vibrancy Index is not to replace those measures, but to complement them. It offers a way to look more holistically at how places function socially, spatially, economically, and emotionally, translating an often elusive quality into something observable, discussable, and measurable.

The Ground Plane, Where City Life Happens

At the heart of vibrancy is what urban designers call the ground plane: the layer of the city where daily life unfolds. It includes sidewalks, storefronts, building entrances, plazas, lobbies, cafés, and the spaces that connect them. This is where people meet, pause, watch one another, and make quick, often unconscious decisions about whether a place feels welcoming, interesting, or worth spending time in.

When the ground plane works well, it supports a wide range of uses and users throughout the day. When it doesn’t, even well-located neighborhoods can feel hollow or incomplete. Understanding how this layer performs is essential, not just in downtowns, but in commercial corridors, neighborhood centers, and mixed-use districts of all kinds.

The ground plane is where the relationship between buildings and public life becomes visible. It reflects not only design decisions, but patterns of use, management, and care over time. Small changes at this level – open doors, active edges, places to sit, reasons to linger – can have an outsized impact on how a place feels and functions.

What is the Vibrancy Index?

Developed in 2025 by SF New Deal and Gehl, the Vibrancy Index is a diagnostic tool designed to assess the health of urban environments at the ground-plane level. It combines direct observation, surveys, and spatial analysis to understand how people use a place, how it supports everyday activity, and how it is experienced by those who spend time there.

The framework is anchored in a simple idea:

Vibrancy emerges from the ongoing interplay between energy and novelty—activity, diversity, and cultural expression—and belonging and care—the stewardship, inclusivity, and connection that sustain places over time.

To make this measurable, the Index evaluates four interconnected dimensions:

1. Public Life, or how people use space and interact with one another
2. Public Space, including comfort, accessibility, and the quality of the physical environment
3. Economic Vitality, focusing on the diversity and resilience of ground-floor uses
4. Identity, reflecting cultural relevance and emotional connection to place

 The Index provides a way of making patterns visible and grounding conversations in shared observations. Rather than reinforcing headlines or assumptions, the Index shifts the conversation toward specifics. It allows different stakeholders to engage with the same evidence, even if their priorities differ.

The Index in Practice

The Vibrancy Index is designed to be applied in many neighborhood contexts. In our initial pilot, Downtown San Francisco was used to test and refine the approach, specifically Union Square Plaza, Powell Street between Market and Geary, and Maiden Lane between Stockton and Grant.

Applied to Union Square, the Index produced a baseline: a snapshot in time that helps distinguish between what is functioning well, what is under strain, and where targeted change might have the greatest impact. 

Built Form as a Source of Friction

One of the clearest challenges identified in the Union Square pilot relates to the physical configuration of the built environment. Storefront occupancy emerged as the lowest-performing metric, driven largely by vacancy in larger ground-floor spaces.

Overall vacancy at the time of the study in the area was 42 percent, but that aggregate figure masks an important pattern. Large and extra-large storefronts were far more likely to be vacant than smaller ones, which showed considerably higher occupancy rates.

This points to a structural mismatch. Large-format retail spaces, designed for a previous era of demand, can be harder to adapt quickly. When vacant, they often create long stretches of inactive frontage that reduce visual interest and limit opportunities for interaction at street level. Smaller spaces, by contrast, tend to support a greater diversity of uses and operators, contributing to a more fine-grained and adaptable ground plane.

The takeaway is that a mix of scales matters, especially when it comes to sustaining everyday street life.

Identity and Emotional Attachment

The strongest-performing dimension in the pilot was Identity. Despite widely circulated narratives about decline, survey responses suggested that many people still feel connected to Union Square. Deeper examination of the data across different audiences revealed subtle but crucial differences for neighborhood residents, city residents, regional residents, and tourists. The Index revealed both a clear directional pattern about sense of belonging and more granular nuanced insights about how different users perceived area relevance. 

This highlights an important distinction. Social and cultural activity can sustain a place’s emotional core even when physical conditions lag behind. Programming, informal use, and collective presence appear to be maintaining a sense of continuity, even as the built environment presents challenges.

The heartbeat is there, but it is operating within constraints.

The Role of Small Businesses and Fine-Grain Activation

The pilot found that 38 percent of businesses in the study area were independently operated. In a high-profile commercial district, that number suggests room for growth.

Independent businesses often contribute disproportionately to vibrancy. They add uniqueness, respond quickly to local conditions, and help create reasons to return. Observations from initiatives like SF New Deal’s Vacant to Vibrant program reinforced this pattern, showing how even temporary or small-scale storefront activations can increase dwell time and street-level engagement.

Stickiness Matters

An encouraging finding from the pilot was how people behaved once they arrived. Average dwell time was strong. Observations also showed that roughly one in three people chose to linger in public space rather than simply pass through.

Even with lower overall volume than in peak pre-pandemic years, the social mechanics of the place were functioning. Where investments in activation and public space had been concentrated by the City and collaborating stakeholders, people were sitting, watching, talking, and spending time together. That “stickiness” is a critical ingredient of vibrancy—and a strong foundation to build on. 

Using the Index Going Forward

The Vibrancy Index is a shared reference point: a way to align conversations, test assumptions, and track change over time.

By grounding discussions in observed conditions and lived experience, this tool can support more thoughtful, phased approaches to change. It can help cities, property owners, and community partners move beyond surface-level activation toward strategies that strengthen the underlying systems that make places resilient.

Downtown San Francisco served as a proving ground, but the ambition is broader: to offer a way of understanding vibrancy that is useful anywhere people are working to build places that are not just active, but durable, inclusive, and alive over time.