Retrofitting Suburban Corridors for Active Transportation: Engineering Challenges in Post-Auto-Centric Design

Abstract

Suburban corridors, designed for automobile dominance, pose significant engineering challenges when retrofitted for active transportation, such as walking and cycling. This study investigates these challenges through a mixed-methods case study of Roswell Road in Sandy Springs, Georgia, retrofitted between 2015 and 2018 to enhance pedestrian and cyclist infrastructure. Using archival analysis, field observations, quantitative data (crash rates, usage volumes, traffic flow), and stakeholder interviews, the research identifies physical, socio-economic, and policy barriers and evaluates retrofitting outcomes. Results show a 38.9% reduction in pedestrian crashes, a 41.7% reduction in cyclist crashes, a 66.7% increase in pedestrian volumes, and a 15–20% revenue boost for local businesses, with minimal traffic disruption. However, limited right-of-way, utility conflicts, and bike lane connectivity gaps increased costs and highlighted equity concerns for low-income communities. Community engagement and adaptive signal timing were critical to success, though maintenance costs and inconsistent infrastructure distribution remain challenges. The findings underscore the need for innovative engineering solutions, robust public engagement, and equitable design to transform suburban corridors into safe, accessible spaces. Recommendations include standardized guidelines, sustainable funding models, and integration of smart technologies. This study contributes to post-auto-centric design by offering practical insights for planners and engineers to create sustainable suburban environments.