Urban mobility models are essential tools for understanding and forecasting how people and goods move within cities, which is vital for transportation planning. The spatial scale at which urban mobility is analysed is a crucial determinant of the insights gained from any model as it can affect models' performance. It is, therefore, important that urban mobility models should be assessed at appropriate spatial scales to reflect the underlying dynamics. In this study, we systematically evaluate the performance of three popular urban mobility models, namely gravity, radiation, and visitation models across spatial scales. The results show that while the visitation model consistently performs better than its gravity and radiation counterparts, their performance does not differ much when being assessed at some appropriate spatial scale common to all of them. Interestingly, at scales where all models perform badly, the visitation model suffers the most. Furthermore, results based on the conventional admin boundary may not perform so well as compared to distance-based clustering. The cross examination of urban mobility models across spatial scales also reveals the spatial organisation of the urban structure.

翻译：城市移动模型是理解和预测城市内人员与货物流动的关键工具，对交通规划至关重要。分析城市移动所采用的空间尺度是决定模型洞察力的关键因素，因为它会影响模型的性能。因此，必须在适当的空间尺度上评估城市移动模型，以反映其内在动态。本研究系统评估了三种常用城市移动模型——即重力模型、辐射模型和访问模型——在不同空间尺度上的性能。结果表明，虽然访问模型的性能始终优于重力模型和辐射模型，但在所有模型共有的某些适当空间尺度上评估时，它们的性能差异不大。有趣的是，在所有模型表现不佳的尺度上，访问模型的性能下降最为显著。此外，基于传统行政边界的结果可能不如基于距离的聚类方法表现良好。对城市移动模型进行跨空间尺度的交叉检验也揭示了城市结构的空间组织特征。