Background Land use density and land use mix are the two most studied characteristics of the built environment and generally, it is believed that higher land use density and higher level of land use mix are associated with more walking, especially for utilitarian purposes. However, although a large number of studies including population density and land use mix have been conducted over the last two decades, overall, the result is still not very clear. Methods I developed a simple computer model to simulate the influence of land use density and land use mix on walking. It includes a hypothetical city with a grid space and a number of households and non-residential places located across the city. Eventually, we varied the contexts to explore the corresponding results of the walking trips and walking distance across the population. Results Only at a very low level, increased land use density may increase walking trips. At the same time, increased land use density may decrease the total distance of walking trips. A higher level of land use mix is associated with higher walking trips. However, a higher level of land use mix level may be not associated with a higher total distance of walking trips. The relationship between land use and walking is significantly modified by other factors. Conclusion The relationship between land use and walking is complicated because multiple factors at multiple levels could contribute to this relationship and the conclusions from the most existing practical studies may apply only to a specific population in a specific context. Computer models will be supplemental because they provide a method to disentangle the complex relationship by separating and removing confounding factors and focusing on the interested factors.

The authors have declared no competing interest.

This study did not receive any funding

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