Modeling Equity Gains from Opening Limited-Access Green Spaces: A Framework Using Mobile Signaling and Optimization

Rapid urban expansion has intensified green space scarcity and inequality in high-density areas. This study evaluates the role of limited-access green spaces (LAGSs) in reducing such inequity and the benefits of their potential opening. Previous studies focused mainly on residential LAGS due to data and user identification challenges, largely overlooking occupational LAGS. To address this gap, we incorporated both types of LAGS using large-scale mobile signaling data to accurately identify users. We employed the Mann–Whitney U test to assess accessibility disparities among vulnerable groups and applied the nondominated sorting genetic algorithm II (NSGA-II) algorithm to simulate equity improvements under various LAGS opening scenarios. Results show that including LAGS increased green space accessibility by 60.10% and reduced the Gini coefficient from 0.600 to 0.501, indicating markedly enhanced equity. However, vulnerable groups such as the elderly and low-income residents still experience lower accessibility. Optimization simulations suggest that selectively opening LAGS in selected subdistricts can achieve near-optimal equity gains with controlled costs, markedly outperforming the pre-optimization scenario. This study underscores the critical role of LAGS in alleviating green space shortages and spatial injustice in dense cities, demonstrating that integrating these spaces can substantially improve accessibility without requiring additional land resources.