Many narrow or crowded downtown streets operate informally as shared streets during rush hour or at lunchtime, but are not regulated as such. A commercial shared street environment should be considered in places where pedestrian activity is high and vehicle volumes are either low or discouraged. Commercial shared streets can be designed for narrow or wide cross sections, but become increasingly complex and difficult to maintain as a shared space as width increases.
From 1960–80, many neighborhood main streets and downtown retail corridors were converted to pedestrian-only usage. these conversions were often called “pedestrian malls.” in an era of declining downtown retail revenues due to competition from shopping center developments outside of historic cores, many of these conversions were unsuccessful or suffered from poor maintenance and a lack of programming or policing.1
Commercial shared streets differ from this earlier generation of pedestrian malls in both their regulation and implementation. Shared streets maintain access for vehicles operating at low speeds and are designed to permit easy loading and unloading for trucks at designated hours. they are designed to implicitly slow traffic speeds using pedestrian volumes, design, and other cues to slow or divert traffic.
The street illustrated below depicts a 22-foot shared way within a 30-foot right-of-way.
A commercial shared street environment should be considered in places where pedestrian activity is high and vehicle volumes are either low or discouraged.
Cambridge Shared Streets
The City of Cambridge converted Harvard Square’s Winthrop Street into a shared street in 2007, and Palmer Street shortly after. Previously, each travel mode had a designated space, and the street was cramped and poorly maintained. Conversion to a shared street allowed for more efficient use of space on a small street, accommodating pedestrians, bicyclists, outdoor diners and motorists. Shared streets in Cambridge have transformed the public space, integrating and balancing commercial uses, street performers, restaurant activity, and transportation into an aesthetically-pleasing design.
Prior to the project, Winthrop Street had narrow sidewalks and uneven pavers that created an inhospitable environment for pedestrians. Furthermore, the street failed to meet accessibility standards of the Americans with Disabilities Act. With vehicle volumes under 1,000 ADT but high pedestrian traffic, the street already implicitly functioned as a shared street; the City’s project formalized it.
Cambridge used standard color, interlocking concrete pavers, which facilitated easy maintenance. On Palmer Street, the use of in-ground lighting has proven more challenging to maintain. Similarly, bollards installed to protect buildings on Palmer Street have suffered some wear-and-tear from truck traffic.
Snow removal and stormwater management
In Cambridge, property owners are responsible for removing snow from sidewalks, and the City removes snow from the street. After conversion to a shared street, these delineations are less stark. In Harvard Square, property owners have proactively shouldered the additional snow removal responsibilities, but shared residential streets may prove more challenging. Stormwater management is also a consideration, because removing a curb changes runoff flows. To prevent puddling near buildings, shared streets in Cambridge grade towards a small gully in the center of the road.
Multiple government departments have worked collaboratively to realize Cambridge’s shared streets. The Community Development Department managed the design process and community involvement through a citizen advisory committee. Public Works is responsible for reviewing the project design regarding long-term maintenance and accessibility issues. The Traffic, Parking and Transportation Department oversees traffic and parking regulations, ensuring that deliveries are still feasible. Champions at the Harvard Square Business Association, the Harvard Square Design Committee, and the Historic Commission have also contributed to the success of the shared streets.
Cambridge plans to convert two dead-end residential streets with very limited sidewalk widths into shared streets. Residents are requesting additional street trees, but the sidewalk is not wide enough to both replace trees and maintain the sidewalk. Converting to a shared street will allow the city to preserve street trees and accessibility.
- The first pedestrian-only outdoor mall opened in Kalamazoo, MI, in 1959. For case studies of early pedestrian malls, see:
Roberto Brambilla and Gianni Longo, For Pedestrians Only: Planning, Design, and Management of Traffic-free Zones, (New York: Whitney Library of Design, 1977).
- The San Francisco Better Streets Plan provides guidance on “channels” and “runnels” that may be suitable for center street drainage.
“Channels and Runnels,” San Francisco Better Streets: A Guide to Making Street Improvements in San Francisco, accessed May 21, 2013, http://www.sfbetterstreets.org/ find-project-types/greening-and-stormwater-management/stormwater-overview/channels-and-runnels/.
- “Transit Mall Case Studies,” (San Francisco County Transportation Authority).
- Department of Transport “Shared Space.” Local Transport Note 1/11. London: 2011.
- Dickens, Liz, Emma Healy, Catherine Plews, Kayleigh Uthayakumar, and Stuart Reid. “Shared Space: Qualitative Research.” MVA Consultancy Ltd, 2010.
- Niagara Frontier Transportation Authority. “Experience of Other Communities with Pedestrian Malls.” Appendix A. Buffalo: 2009
- Pojani, Dorina. "American Downtown Pedestrian ‘Malls’: Rise, Fall, and Rebirth." Territorio (2008): 173-190.
- San Francisco County Transportation Authority. Transit Mall Case Studies. San Francisco: 1-17.
- Schmidt, Jessica. "Revisiting Pedestrian Malls." Prepared for the ITE 2010 Technical Conference and Exhibit, Savannah, Georgia, March 14-17, 2010.
- Shore, Fiona, Kayleigh Uthayakumar, Stuart Reid, Steven Lowe, and Sally Watts. “Shared Space: Operational Assessment.” MVA Consultancy Ltd, 2010