Generalized noortman and van es’ empty trips model

Abstract

This paper presents a generalized Noortman and Van Es’ empty trips model that considers commodity groups and vehicle types. The model allows the analyst to quantify the contribution of empty trips by the various types of commodities. The model was validated using data collected in Colombia as part of the national Freight Origin-Destination Survey. The results reveal that not all commodities generate empty trips in similar proportions, and commodities that require specialized equipment are the ones with the largest proportion of empty trips generated. Moreover, the results show that the proportions of empty trips generated by a given commodity varies across vehicle types. The key contribution of the model is that it produces more precise estimates of empty trips as it includes the impacts of the cargo type in the generation of empty trips. The proposed model could be used by planners to identify key commodities that could be paired together with equipment that could be repurposed to reduce empty trips in their regions.