Can We Retrofit Suburban Arterials?

Problem, research strategy, and findingsThe multilane arterial roadway is a central feature of post–World War II (WWII) suburbs that challenges efforts to create more transit-oriented regions. Retrofitting suburbs is an important planning goal, but research examining the urban form of arterials and their potential for transformation has been scarce. We analyzed four suburban corridors in the Toronto (Canada) region developed during different periods of suburbanization. We found that the walkability of corridors declined as modernist planning ideas were more fully implemented, and then walkability increased as new urbanist ideas began to influence planning in the 1990s. Over time, however, the retrofit potential declined across all corridors studied, with patterns of lots and development becoming ever more static. Understanding these patterns is important to developing successful strategies for retrofitting suburban arterials.Takeaway for practiceArterial roadway corridors present potential to bring transit-oriented, walkable urban places near large areas of automobile-dependent suburbs and should be a primary focus for retrofitting research and practice. We present here a set of metrics that rely on readily available data, are not complex to carry out, and produce mapping and visualization that is legible and allows comparison across corridors. We suggest that local governments should be routinely studying and evaluating the potential for retrofit and intensification of all such corridors within their jurisdiction. Planners should seek to develop approaches to managing future corridor development to permit greater adaptability in response to future economic, transportation, and climate changes and vulnerabilities.