Modeling of Time and Distance Decay Functions for Modes of Transportation in the City of San Juan de Pasto - Nariño, Colombia

Abstract

The role of urban transport and its accessibility to key destinations are fundamental in urban planning and as part of the quality of life. This study focuses on the city of San Juan de Pasto, Colombia, aims to estimate the decay functions of time and distance for four modes of transportation: Bicycle, private vehicle, public transportation, and walking. The decay curves were modeled as exponential and Gaussian functions using empirical data collected from local mobility surveys. The findings indicate substantial distinctions in residents' propensity to make trips given the length and duration of trips, as well as the form of transportation.

Mean distances and shorter walking and cycling time were observed compared to private vehicles and public transport for longer trips. The results show that exponential functions better model travel behaviors on foot and in particular vehicles since they tend to detach from the access table with distance and time. In contrast, Gaussian functions were better suited to public transport and bicycles by capturing a gradual decrease in accessibility over greater distances. On the walking trip, they averaged 1 km or 12 minutes, and about 5 km or 20 minutes on the bike trip. It is therefore a matter of journeys of up to 15 km, that is, 25 minutes by private car or up to 10 km, that is, approximately 40 minutes by more public transport. Finally, an analysis of the decay functions of the travel series is presented, and it is shown that the exponential function optimally represents the data series, and that it is useful in particular for modes of transport that tend not to be motorized (walking and cycling) due to the advantages of its dispersion and better statistics. As required by the high variability of times and distances, motorized modes, such as the private vehicle, demand greater modeling efforts, for example, with the Gaussian function. Analysis of the beta parameters of decay functions provides us with additional information about transport patterns. The results highlight the importance of including the characteristics of each mode in the design of mobility policy, especially the infrastructure that encourages short-distance travel in active modes and that makes it possible to travel long distances in motorized modes. The opportunity to approach maximizes the efficiency of the system and the sustainability of urban transit systems