98Phase Zero approaches The Alliance proposes a holistic approach to advancing sustainability and circularity in urban development. APPROACH 1 Stakeholder co-creation and participatory decision-making Engaging diverse stakeholders early in the deci- sion-making process is essential for aligning priorities, preventing harmful development patterns and ensuring urban development reflects local needs and values. This requires a shift from traditional, top-down planning towards a circular, community-driven approach that pri- oritizes inclusive participation. Currently, a key barrier to effective co-creation is a gap in practitioner expertise on how to facilitate mean- ingful engagement (rather than a gap in community knowledge). Insufficient stakeholder participation – par - ticularly in Phase Zero – often results in environmentally and socially harmful development patterns that are diffi- cult to reverse later. To enable meaningful, evidence-based decision-mak - ing, Phase Zero must prioritize robust engagement strategies that empower communities, policy-makers, professionals, investors and developers to collaborate effectively. For the public sector, this means integrating partic- ipatory decision-making into early policy and planning frameworks, ensuring that infrastructure investments and land-use strategies reflect local needs. For the private sector, this involves embedding community engagement into feasibility assessments and project design from the outset, and aligning business objectives with long-term urban resilience. LIBERTY BANK BUILDING IN SEATTLE The Liberty Bank Building in Seattle exemplifies com- munity-led development at Phase Zero, demonstrating how early community engagement can shape culturally responsive urban development. Built on the former site of the first Black-owned bank in the Pacific Northwest, the project was co-created with local residents to address displacement and preserve the neighbourhood’s cultural identity. Through deep engagement led by Africatown Community Land Trust, Capitol Hill Housing (now Com- munity Roots Housing) and other partners, the project integrated affordable housing, Black-owned businesses and public art celebrating the area’s history. Designed by Mithun, The Liberty Bank Building demonstrates how Phase Zero can build trust, ensure planning reliability and meet local needs.APPROACH 2 Cultivate cross-sector leadership to mainstream Phase Zero To integrate Phase Zero into urban planning more widely, both public- and private-sector actors can cul- tivate leadership at multiple levels and cities can create an enabling environment for end-of-life re-use, regen- eration and sustainable land management. Meanwhile, regulatory changes are not a prerequisite for implement - ing Phase Zero. Supportive policies and incentives can help scale its adoption, making it easier for stakeholders to prioritize sustainability from the outset. The public sector plays an important role in provid- ing guidance and creating conditions that encourage Phase Zero. Governments can explore ways to embed early-stage sustainability assessments into urban development processes and ensure projects start with comprehensive stakeholder collaboration. Integrating Phase Zero principles into zoning laws, land-use planning and infrastructure strategies can help align developments with long-term sustainability, resilience and equity goals. Additionally, economic incentives – such as tax benefits, expedited permitting or funding support for projects that prioritize circular materials and sustainable design – can encourage wider adoption. While Phase Zero does not require regulatory change, an enabling environment can provide clarity and consistency, making it easier for cities and developers to integrate sustainability objectives. At the same time, the private sector can play a key role in advancing Phase Zero by aligning investment strategies with sustainability and resilience priorities. Investors and developers can integrate Phase Zero principles into funding criteria, prioritizing projects that maximize circular material use, adaptive re-use and low-carbon construction. ESG-driven financing models offer a pathway to direct capital towards developments that incorporate sustainability from the outset, while industry standards that promote early-stage collabora - tion, life cycle sustainability assessments and adaptive planning can further reinforce Phase Zero as a core business practice. By considering project costs, busi- nesses can explore how to maximize the use of circular materials and resource-efficient design, extending the life cycle of materials and reducing waste.Collaboration across sectors can further accelerate the adoption of Phase Zero. Public-private partnerships (PPPs) provide an avenue to align private-sector devel- opment priorities with public policy goals, promoting co-investment in urban sustainability initiatives. While Phase Zero can be implemented without regulatory change, a shared vision, supported by clear incentives and industry leadership, can help normalize it as a standard practice. With efforts to streamline regulatory pathways, support circular and sustainable business models and encourage innovative design approaches, Phase Zero can evolve from an emerging best practice into a widely adopted approach. 99BILLHORNER BRÜCKENSTRASSE RAILWAY The renewal of the Billhorner Brückenstraße railway overpass in Hamburg, Germany exemplifies the Phase Zero approach at a project scale, demonstrating early collaboration between public- and private-sector stake- holders. The project partners, Deutsche Bahn and the City of Hamburg, aligned project goals, planning prin- ciples and frameworks, ensuring both time and cost savings while enhancing sustainability. Early-phase coordination allowed for assessments on structural repairs and new construction, along with urban environment considerations, creating a shared vision for future development. This effort helped define spatial, ecological and aesthetic requirements, ensuring long-term value. By establishing a common understanding and focus- ing on governance, functionality and context, the project sets a strong example for replicating Phase Zero in other urban development projects, streamlining processes and promoting long-term sustainability.Kevin Scott (@k7scott)

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