Seyed Hassan Ameli

Many of the larger US metropolitan regions promote polycentric development as a way of fostering livability, accessibility, and sustainability. Polycentric urban structures can increase transit ridership, promote active transportation, and decrease vehicle miles traveled (VMT) and CO₂ emissions. Although many regions include ambitious polycentric aspirations in their plans, only a few follow up with rigorous implementation and see their efforts come to fruition. The topic of implementation is also widely omitted from scholarly inquiry. This research aims to explore three examples of successful implementation of urban polycentricity: Portland, Oregon; Seattle, Washington; and Denver, Colorado. Each region employs a very distinct polycentric development model, but each relies heavily on its regional governance organization for direction, guidance, and even command in the implementation process. To understand specific strategies and methods used by each region, the authors conducted interviews with metropolitan planning organizations, central cities, and transit agencies in the three regions and used qualitative techniques to analyze the interview transcripts and collected documents. As regional governance organizations play a crucial role in implementing regional plans, their policies and practices were also investigated by the authors. Based on collected data and insights, we conclude that the three regions are great examples of an advanced implementation of polycentric development. This research can be helpful to other US metropolitan regions that wish to promote polycentric development. The lessons learned from the three case studies can provide guidance and possible paths to successful implementation.

This paper describes a before-and-after case study of a protected intersection in Salt Lake City, Utah. The intersection was completed in late 2015 and represented one of the first examples of a protected intersection design in North America. We analyzed bird’s-eye view video data that was recorded before the intersection was implemented and compared it against video data recorded from the exact same location after implementation. In order to examine changes in intersection usage and behavior, we operationalized safety in terms of the frequency of nonoptimal behaviors demonstrated by active transportation modes. We found that active transportation usage of the intersection has increased since the new configuration, with most of that growth attributable to e-scooter users. There was minimal change in the rates of nonoptimal behaviors by pedestrians. Bicyclists showed mostly decreased rates of nonoptimal behaviors, suggesting improved safety for this mode. E-scooter users, however, demonstrated nonoptimal behaviors at very high rates as compared with other active modes. This case study gives evidence that a protected intersection can have positive effects on active transportation volume and safety in a U.S. context.

Compact development can result in many benefits for communities and residents. Areas can connect compact developments through high-quality transportation options, creating a network of centers, or a “polycentric” region. This development pattern is very popular in Europe and is linked to significant benefits. Salt Lake County has organically developed several small centers, and with the right strategies could continue to fuel this kind of growth. The metropolitan planning organization (MPO) for the region, the Wasatch Front Regional Council, has been planning for polycentric development since the Wasatch Choice for 2040 Vision was released in 2010. Our research is aimed at exploring the academic literature and empirical evidence surrounding polycentric development, analyzing more than 120 regional transportation plans (RTP) to see how they promote polycentric development, defining types of centers in a hierarchy of centers, quantifying the transportation benefits of polycentric development, examining a case study of best practices, and, finally, outlining context-specific strategies for Salt Lake County and the Wasatch Front. The resulting report will enable the county and MPO to make informed decisions about its future growth patterns, set realistic—yet visionary—goals, and improve the overall health of its residents and communities.