Hiking with Tobler: Tracking Movement and Calibrating a Cost Function for Personalized 3D Accessibility

Abstract

This paper analyzes the author's travel trajectories to calibrate a bespoke walking cost function based on Tobler's Hiking Function (THF) and uses it to estimate personalized accessibility on a 3D network in Hong Kong. Compared to the THF, the calibrated cost function reflects slower walking speeds on flatter ground and higher speeds on more sloped terrain. This latter effect is likely due to the presence of staircases that enable increased walking speeds on steeper slopes. Accessibility results using the calibrated function are slightly lower than those from the THF and highlight the importance of slope-aware cost functions in modelling walkability.