The role of spatial scales in assessing urban mobility models

TL;DR

This study evaluates how different spatial scales impact the performance of popular urban mobility models, revealing that model effectiveness varies with scale and urban structure, with visitation models generally outperforming others.

Contribution

It systematically compares gravity, radiation, and visitation models across spatial scales, highlighting the importance of scale selection in urban mobility modeling.

Findings

Visitation model outperforms gravity and radiation models.

Model performance varies significantly with spatial scale.

Distance-based clustering can outperform administrative boundaries.

Abstract

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.