Browsing by Author "Ter Huurne, Dominique"

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    An evaluation of TraClus-DL as a diagnostic tool for road transportation supply in the South-African local planning context: a case study of the town of Stellenbosch
    (Stellenbosch : Stellenbosch University, 2021-03) Ter Huurne, Dominique; Du Plessis, Danie; Bruwer, Megan; Stellenbosch University. Faculty of Sociology and Social Anthropology. Dept. of Sociology and Social Anthropology.
    ENGLISH ABSTRACT: Travel demand management (TDM), transportation systems management (TSM) and the integration of land use and transportation planning are important alternative relief measures to the increased provision of road infrastructure for South Africa’s saturated urban road networks. The optimal implementation of these strategies requires a comprehensive understanding of travel demand. In South Africa, the present origin-destination (O-D) data sources are transport demand models, household travel surveys and other O-D surveys (although not accessible to many municipalities). These are, however, cost- and data-intensive. This study evaluates commercially-available, historical O-D floating car data (FCD) as a plausible solution to this data-source problem. As an application to O-D FCD, the main aim of this research is to evaluate TraClus-DL as a diagnostic tool for road transportation supply in the South African local planning context. TraClus-DL is a density-based partition-and-group clustering method that identifies travel demand corridors. The town of Stellenbosch serves as the case study for this research. This study compares the complexity of the application of TraClus-DL to that of the standard South African road congestion performance measures. It visualises travel demand corridors for the AM and PM peak period, and then determines the efficiency of the transportation supply network by means of the collective distortion indicator (CDI), collective remoteness indicator (CRI) and dynamic time warping (DTW) trajectory similarity measure. Based on the output, the study then comments on the strategies for congestion relief proposed in the latest Spatial Development Framework (SDF) and Comprehensive Integrated Transport Plan (CITP) of the Stellenbosch municipality. Moreover, the research aims to recommend additional or alternative strategies for congestion relief in Stellenbosch in terms of TDM and TSM. The results show that commercially-available, historical O-D FCD is a valuable data source for assessing existing travel demand, and that TraClus-DL is a relatively simple tool to use. The visualisation of demand corridors alone was found to be useful for spatial and transport planning purposes. The CDI was likewise found to be adequate in terms of the network supply efficiency measures. The CRI and DTW results were only deemed valuable for comparative studies. The results of this research support the majority of the prioritised spatial and transport plans and proposals outlined in the SDF and CITP of the Stellenbosch municipality. The TraClus- DL outputs back the plans for transit oriented development and can, in general, inform the municipality where residential development can continue or be initiated and where it should be delayed until road capacities are increased or attractive public transport alternatives become available. The study recommends a prioritisation of the various routes of the proposed public transport networks, as well as the most feasible location for the central terminal. The most valuable application of travel demand corridors was found to be in analysing the desired function of roads and recommending the most effective use of the transportation supply network. Since many South African municipalities do not have a comparable alternative to TraClus-DL at their disposal, the combination of commercially-available, historical O-D FCD, TraClus-DL and, to some extent, transport supply network efficiency measures is seen to be of significant value to these authorities.
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    A quantitative measure of congestion in Stellenbosch using probe data
    (2014-12) Ter Huurne, Dominique; Andersen, Johann
    ENGLISH ABSTRACT: This paper aims to quantify and evaluate congestion in Stellenbosch, a historic university town located approximately 50 kilometres east of Cape Town, South Africa, using probe data. It is known that Stellenbosch experiences traffic congestion, but the scientific extent of this congestion has not been fully determined, as the present volume counts alone are not a sufficient form of assessment. Its residents complain about congestion suffered in town and express frustration. This, along with the fourth annual TomTom South African Traffic Index publication, which revealed that Cape Town (with a congestion index of 27%) is the most congested city in South Africa, instigated this study. Literature bares that the level of service concept (LOS) defined in the Highway Capacity Manual (HCM) has been widely used as a basis for congestion measures, although travel-time-based measures are suggested to satisfy the need for congestion information best. Travel time is well understood by both the general public and professional community, but the collection of travel time, travel speed, travel rate and travel delay data is historically deemed somewhat more complex and onerous than traffic volume counting procedures, and together with limited financial resources has restrained its application. The methodology applied in this study comprises the utilisation of TomTom Traffic Stats Portal that contains historic travel-time-based data from TomTom in-vehicle navigation systems and supporting devices. The platform and associated configuration is state-of-the-art and brings new light to travel-time-based congestion measures. The data was statistically analysed over various date and time periods, and standard congestion index concepts were applied. Congestion measures were considered along the major arterials leading into and out of Stellenbosch, as well as on part of its central road network. This paper shows that Stellenbosch evidently faces increased levels of congestion. Travel times on the inbound arterials are on the rise, and in-town traffic is becoming unsustainable.