This note presents the scope and contents of a special collection in the Journal of Transport and Land Use, devoted to the theme of “Modeling Choice Behavior of Cyclists and Pedestrians in Urban Activity Space.” The aim of the special issue is to explore the significance of active transport modes—specifically, cycling and walking—in promoting sustainable urban mobility. In the face of increasing urban mobility demands and the pressing need to meet environmental and climate goals, this collection of studies presents new analytical and empirical insights into the factors influencing cycling and pedestrian behaviors. The research highlights the interplay between infrastructural support, socioeconomic conditions, and user perceptions, providing recommendations for policymakers and urban planners. By examining diverse contexts, from university settings to micromobility patterns in urban centers, the findings presented in this special issue highlight the potential of active transport modes to foster healthier lifestyles and reduce reliance on motorized vehicle use.