What defines the linear city? Examining accessibility premises with novel flow-based linearity indices

This study re-examines the widely held assumption that the linear city model enhances both efficiency and equity of accessibility. From a space syntax perspective, we introduce two flow-based linearity indices: the Morphological Linearity Index, which captures how strongly path-implied trips align along a single axis, and the Structural Linearity Index, which captures how strongly paths converge on shared street segments. We then relate these indices to accessibility measures that are likewise derived from network configuration alone. Applying these indices to 60 South Korean cities, we find that corridor-centered structures alone do not guarantee efficient or equitable accessibility. Networks with higher morphological linearity show lower mean detour rates yet no corresponding reduction in average trip distance, a directness-distance trade-off that can offset net efficiency gains. Higher structural linearity is associated with both greater detour rates and longer trip distances, suggesting that corridor-centered designs can undermine overall accessibility. By translating the “linear city” into measurable indices, this study provides an operational basis for evidence-based road network planning and assessment.