Browsing by Author "Potgieter, Alicia"

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    Restricting freight traffic in urban areas: The economic and traffic impact of banning heavy vehicle movement in Stellenbosch during peak periods
    (Stellenbosch : Stellenbosch University, 2019-04) Potgieter, Alicia; Bruwer, Megan; Rouphail, Nagui; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
    ENGLISH ABSTRACT: Whenever new traffic regulations are proposed for implementation, it is crucial to investigate the effects that they will have on the operations of the transportation network. In this study, the potential impact of heavy vehicle restrictions in urban areas, as proposed by the South African Department of Transportation in 2015, was investigated. No evidence could be found to indicate that there had been any research performed into the effects of such restrictions before, or since, this proposal was made. Therefore, this study aimed to fill this gap. Although the regulations were proposed in an attempt to improve road safety, the focus of this study lies on the potential impact of the regulations on traffic conditions and the economy. Two main areas of research were addressed in this study; the first being the investigation of the current heavy vehicle movement patterns in Stellenbosch, and the second being the assessment of the impact of heavy vehicle bans on the traffic operations on the town’s road network. It was determined that almost no research had been performed in the past regarding the movements of freight vehicles in Stellenbosch and, therefore, this study aimed to fill this gap. Fleet management data from MiX Telematics and vehicle movement surveys were analysed for this purpose. From the analysis of fleet management data, the temporal and spatial distribution patterns of freight vehicles in Stellenbosch were determined. It was found that the majority of freight vehicles in Stellenbosch travel during the day and that the R44 and Bird Street are two of the most used roads for freight trips. The vehicle movement surveys found that the majority of freight trips in the town originate locally or in nearby towns. The potential impact of heavy vehicle bans on traffic conditions were investigated with the use of a microscopic traffic model constructed in PTV Vissim. The model examined the potential effects of the proposed bans on the transportation network of Stellenbosch in both the cases that latent demand was present in the town and the case where it was not. It was found that traffic conditions generally improved when latent demand was not present, but it worsened when latent demand was present. Even when traffic conditions improved, the changes were small, with no traffic condition improving by more than 10%. A high-level economic evaluation was performed in order to determine the economic impact of the proposed bans. It was found that passenger car drivers would experience economic losses if latent demand were present in Stellenbosch. In the absence of latent demand, passenger car drivers have the potential of saving R23 109.81 during the six banning hours, but it is believed that these benefits would be far outweighed by the cost of implementation of the bans and the losses experienced by the freight industry. The proposed heavy vehicle restrictions were not deemed feasible for implementation and more research would have to be performed into the effects of the bans on a national level.