Designing for Car-Free Cities

Vision

The United States is estimated to have as many as two billion parking spaces to serve about 250 million cars, and parking represents the primary land use in many cities. As Americans living in cities continue the decade-long trend of driving less and owning fewer cars, one of the great challenges in coming decades will be the redevelopment of today’s parking garages to support more sustainable ways of living. Through research, case studies and digital tools, The End of Parking R+D project proposes to distill design strategies and principles to adapt existing parking structures to other uses and to integrate future adaptability in new structures.

Research

This R+D effort explored strategies and principles of designing for future uses through graphic study of a conventional parking structure undergoing adaptive reuse. The team reviewed existing literature on trends in future mobility and their impact on parking space demand, as well as parking structure planning and design strategies for future adaptability. The exploration also identified case studies of projects in North America that have attempted to convert existing urban parking garages to other uses (including the University of Washington Children’s Center at Portage Bay, a renovation within an existing parking garage), and projects that are designed to adapt to other specific future uses (including the Puyallup City Hall Block with future housing planned over the parking structure, and the Lloyd Crossing Sustainable Design Plan which emphasizes long-term adaptability and flexibility of systems).

These design and construction approaches were analyzed and organized into a comprehensive framework that included the following primary considerations: type of parking structure, the horizontal depth and size of the structure in relationship to the block and street orientation, and the typical floor-to-ceiling height. Other considerations include floor plan arrangement, vertical circulation and ramp configuration, material and construction method, land use and mobility network context and adaptability to surrounding urban form including remediation of the building façade, navigating setbacks between the right of way and the building footprint and the inclusion of active uses along the building frontage.

Observations and recommendations were compiled within a graphic toolkit of design strategies and principles for future-proofing parking structures. Key vignettes and areas of focus included removable vertical circulation and ramps, flat floor plates, structure that adapts to multiple uses, adequate floor-to-floor height, vertical expansion and additional load carrying capacity, adaptability of the building façade, phasing and additional service capacity. The toolkit is intended to be an accessible tool and reference for designers, as well as urban property developers and investors whose existing properties and new developments may currently require parking structures, but foresee a reduction in parking demand in the future and are interested in an adaptive reuse strategy to meet sustainability goals and optimize property utilization.

Looking Forward

The graphic toolkit and research findings will be published and circulated to serve as an accessible reference for designers and developers planning parking structures that will preserve long-term value and contribute to resilience in cities.

This exploration also highlighted additional areas of study and tools that could be developed to further facilitate decision making between replacement or adaptive reuse of an existing parking structure, and designing for an adaptable new parking structure. The R+D team is also interested in exploring strategies for phased transformation of parking structures—identifying short-, medium- and long-term uses appropriate to the type and configuration of the parking structure.

Examining how innovations in urban mobility and commerce may potentially impact cities, communities, public space, streets and the relationship of buildings to the public will inform the design of these spaces in the future. Developing conceptual design principles and strategies that integrate mobility while supporting urban vitality, livability and character will be key to advancing more sustainable and equitable cities.