Inferring commercial vehicle activities in Gauteng, South Africa

Abstract

To address the underreporting of freight from a transport geography point of view, we present a novel analysis of the time and spatial characteristics of disaggregated commercial vehicle activities. The activities were extracted from raw global positioning system (GPS) data collected in South Africa over a sixmonth period for more than 30,000 commercial vehicles. The analyses of the activity chains provide useful characteristics such as activity and chain durations, number of activities per chain, and the spatial extent of the activity chains. Key results indicate that about 60% of activity chains have between 5 and 15 activities per chain while 25% of the chains have 4 or less; 89% of the chains have a duration of 24 hours or less; and approximately 75% of all activities start between 08:00 and 17:00. The paper’s contribution is twofold: it firstly demonstrates a methodology to extract and evaluate vehicle activities and activity chains from raw GPS data. Novel results and characteristics about transport geographies in Gauteng, the economic centre of South Africa, are presented. We also report on the sensitivity of the analyses to certain parameters. Secondly, we introduce new metrics to evaluate a geographical area’s economic productivity based on commercial activity.