Unraveling the origin of exponential law in intra-urban human mobility

TL;DR

This paper investigates the exponential distribution of intra-urban travel distances, proposing a model that links trip length to population density decay, providing insights into urban mobility patterns.

Contribution

It introduces a new model explaining the exponential law in intra-urban mobility based on population density decay, improving prediction of individual urban travel flows.

Findings

Trip lengths follow an exponential distribution in urban areas.

Population density decreases exponentially from city center.

Trip length and population density share the same decay rate.

Abstract

The vast majority of travel takes place within cities. Recently, new data has become available which allows for the discovery of urban mobility patterns which differ from established results about long distance travel. Specifically, the latest evidence increasingly points to exponential trip length distributions, contrary to the scaling laws observed on larger scales. In this paper, in order to explore the origin of the exponential law, we propose a new model which can predict individual flows in urban areas better. Based on the model, we explain the exponential law of intra-urban mobility as a result of the exponential decrease in average population density in urban areas. Indeed, both empirical and analytical results indicate that the trip length and the population density share the same exponential decaying rate.