关键词: 城市交通, 系统韧性, 链路可靠性, 外卖配送, 降雨扰动

Abstract: The rapid growth of instant consumption has made food delivery an essential component of urban daily life. However, delivery operations that rely primarily on electric two-wheelers are highly vulnerable to rainfall, leading to substantial declines in delivery speed, increased delays, and reduced fulfillment reliability. Existing research offers limited insights into the resilience of food delivery systems under weather disruptions. This study develops a resilience assessment framework for rainfall-affected delivery operations based on link reliability and system-level recovery probability. A delivery-link resilience metric is created to measure the performance degradation and subsequent recovery at the task level, while a system resilience model incorporating link failure probability and recovery duration is established to quantify resilience under varying rainfall intensities. Using 6.243 7 million valid delivery trajectories and order records collected in Guangzhou, the empirical analysis reveals that average delivery speed under rainfall decreases to 10.8 km·h^-1, representing a 22.3 percent reduction compared with clear weather. Average delivery time increases to 13.2 minutes, an increase of 16.3 percent. Delivery-link resilience decreases by 16 percent in light rain, 18 percent in moderate rain, and 22 percent in heavy rain, with the reduction during the evening peak approximately 12.4 percent lower than in other periods. System-level resilience declines by about 1.4 percent for every 10 mm increase in rainfall intensity. Residential areas exhibit the highest sensitivity to rainfall, with resilience reductions exceeding those of other urban functional areas by more than 50 percent.

Key words: urban transportation, system resilience, link reliability, food delivery, rainfall disruptions