Masters Degrees (Civil Engineering)

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An analysis into the invigoration of a rail corridor through private sector investment and transit oriented development principles
(Stellenbosch : Stellenbosch University, 2021-12) Van Rensburg, Albertus Gerhardus; Bruwer, Megan; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
ENGLISH ABSTRACT: The steady decline in passenger volumes using the passenger railway network in South Africa since the implementation of the Transport Deregulation act in 1988 has escalated to a steep decline in passenger volumes since the early 2000’s. Train set loss, out-of-date technology, maintenance issues, operational inefficiency, a lack of skills development and safety and security issues have drastically reduced passenger utilisation across all public passenger rail networks in the country. The Passenger Rail Agency of South Africa (PRASA) has recognised the passenger decrease trend and is now actively trying to reverse the tide. PRASA unveiled a variety of key programmes in the 2020/2022 PRASA Medium Term Expenditure Framework (MTEF) Corporate Plan aimed at revitalising the national public passenger railway service by adding 3600 new rolling stock units to the current passenger train fleet and modernizing 135 stations along priority corridors (PRASA, 2018). The acquisition of new rolling stock and modernisation of stations are vital in reversing decades of neglect towards rail-based transport. This supply invigoration will need to be accompanied by a paradigm shift in how current and potential rail users view passenger rail transport if the demand for rail services is to be successfully and sustainably re-invigorated. This study analyses the ability of private sector investment and Transit Oriented Development (TOD) principles to re-invigorate passenger rail and provide the vital paradigm shift in how the public views passenger rail in South Africa. The analysis is conducted by assessing the anticipated effects of Stellenbosch Bridge on rail utilisation trends through a computer model of a section of the transport network. Stellenbosch Bridge is a proposed development designed using Transit Oriented Development principles located adjacent to a section of the railway line in the Cape Winelands. The proposed development will have direct access to the rail network, connecting Stellenbosch Bridge to surrounding suburbs, towns, and cities such as the Northern Suburbs of Cape Town, Stellenbosch, and Paarl. Stellenbosch Bridge provides an opportunity to assess the effects of a Transit Oriented Development on rail utilisation as it is located in a transit corridor which provides both road and rail movement alternatives. A variety of scenarios were developed to investigate the effects of revisions to passenger accessibility and the rail system itself, which are modelled by altering the way in which people view transport options in the study area. Analysis of the output is focused on the station usage rate and fluctuation in passenger volumes for each scenario set. A thorough study of the results produced by the simulation model allows the conclusion to be made that Transit Oriented Development principles and private sector investment can indeed re-invigorate rail and provide the required paradigm shift in how potential and current users view the passenger rail service.
An Analysis of flow characteristics of unconventional weaving traffic: Western Cape case Study
(Stellenbosch : Stellenbosch University, 2021-03) Masegela, Mathabo; Bruwer, Megan; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
ENGLISH ABSTRACT: The objective of this study is to analyse the characteristics of unconventional weaving behaviour of traffic within freeway sections and propose remedial measures. Thereby gaining a more detailed understanding of unconventional weaving behaviour, causes and possible solutions. Unconventional weaving traffic is defined as weaving that is not conventional according to the definition in the USA Highway Capacity Manual. It refers to excessive lane changing or weaving that occurs as a result of the geometry of the road, illegal behaviour, disregard of traffic marking etc. For purposes of this study the South African National Road N1 in the Western Cape between the R300 on-rampand the Okavango Boulevard was selected as the case study. The section of the road under consideration experiences a high number ofunconventional weaving manoeuvres resulting from the short distance between successive on-ramps (R300, Okavango), an observed general disregard of the lane markingsby numerous motorists(at the R300 on-rampdiverge point) and geometry of the section of road (particularly because no auxiliary lanesare provided). A regression analysis together with fundamental traffic flow diagrams are developed and applied to the base case and proposed remedial actions. The results indicate that weaving within the case study area can be improved by increasing the capacity of the R300 onramp and maintaining a lane balance. It is also observed that weaving within this section is not only related to the operations of the road but is also linked to human behaviour that may not be modelled.
Application of real-time traffic adaptive signal control on the R44 arterial, stellenbosch
(Stellenbosch : Stellenbosch University, 2019-12) Mohr, Wilko Stefan; Bruwer, Megan; Andersen, Johann; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
ENGLISH ABSTRACT: The ever increasing level of traffic congestion experienced within and surrounding the town of Stellenbosch, South Africa, has been one of concern for many years. A large volume of commuter traffic creates a major influx of vehicles into and through the town during the morning peak traffic hour and, vice versa, a large outflow during the afternoon peak hour. These extensive traffic volumes exceed the provided capacity, thus creating an imbalance relating to the capacity vs demand ratio. This in turn leads to extended travel times, increased vehicle delay and a general inconvenience to the typical road user. Considering this and understanding that congestion has a negative effect on the individual road user as well as on the economy in general, this research project investigates the potential feasibility of using a Traffic-Adaptive Signal Control (TASC) system to optimise and manage the flow of vehicles through a series of signalised intersections. Such a system relies on real-time traffic data input and a representative traffic model which simulates and tests several signalisation options and, based on the objective function of the optimisation method, results in a more suitable allocation of green-time shares within the network. This, in essence, optimises the flow of traffic on individual intersection level while at the same time coordinating the traffic flow on a network level. The main objective of this research project, therefore, was to evaluate the applicability of a TASC system on the R44 arterial surrounding Stellenbosch in order to address the question of how applicable and effective TASC is in a developing world environment as a means to alleviate transport related problems on a traffic corridor. PTV Epics and Balance, proven to be successful in developed world application, is one such TASC system and was used within this study to address the research question. In order to realise useful results, a calibrated and validated simulation environment had to be created. Modelling was firstly done within PTV Visum to create an underlying macroscopic model of Stellenbosch in general, after which another PTV Visum subnetwork model of the R44-specific study area was generated. The final model, a PTV Vissim microscopic model, represented the evaluative environment within which detailed results could be obtained for a number of different scenarios. These scenarios where firstly aimed at identifying whether the TASC system would bring any improvements at all and secondly under which level of TASC control, inclusive of different vehicle detection options, the best results were obtained. Different levels of TASC control refer to exclusive local optimisation, exclusive global coordination or a combination of both. Detection options included a suboptimal layout of the existing inductive loop detectors as well as more consistent TrafiCam x-stream virtual loop Results comparison over a range of traffic flow parameters showed that the TASC system did indeed enhance the traffic flow. This was most notably found to be true under condition of the consistent camera detection and, predominantly, by using combined local and global TASC control. Based on the findings, this study recommends, with further study and continued expansion, the implementation of the TASC system on the R44 arterial, Stellenbosch.
Calibration of Capacity Models to Predict Queues and Delays at Roundabouts in South Africa Operating Under Saturated Conditions
(Stellenbosch : Stellenbosch University, 2024-02) van Tonder, Inge; Bruwer, Megan; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
ENGLISH ABSTRACT: The investigation of operational conditions at roundabouts in South Africa by traffic engineers is complicated by a lack of local research and inconsistent geometric design of roundabouts. Particularly, there is little information about roundabout operations at or near capacity. Furthermore, no research has specifically considered methods to calibrate widely used international traffic models for South African traffic conditions. The research addressed this gap by leveraging data collected in association with the South African National Road Agency (SANRAL), employing advanced data collection methods using Unmanned Aerial Vehicles (UAVs) and models like HCM6 and VISSIM. This research focused on seven roundabouts in the City of Cape Town, Stellenbosch, Paarl, and George, which were identified to operate near capacity. The research design incorporated data collection using UAVs at roundabouts operating under saturated or near-saturated conditions. Data processing involved analysis using DataFromSky TrafficSurvey and software specifically developed for the South African National Road Agency (SANRAL) roundabout research panel. The Highway Capacity Manual (HCM) 2016 served as a significant reference, focusing on regression analysis and gap-acceptance models for roundabout capacity evaluation. The HCM6 uncalibrated and calibrated capacity models were compared with the field data. At single-lane roundabouts, the uncalibrated HCM6 capacity model presented closer to the field data, where the calibrated HCM6 capacity model overestimated the capacity indicating that the standard calibration factors proposed by the HCM2016 are not suitable for South African traffic conditions.. At double-lane roundabouts, both the uncalibrated and calibrated capacity models compared well with the field data. Microscopic simulation tools like VISSIM were used for assessing roundabout performance, considering parameters like driver behaviour, gap acceptance, and traffic assignment. Single-lane and double-lane roundabouts were calibrated and validated in VISSIM by using peak-hour entry volumes collected during separate peak-hour periods. After the calibration of the HCM6 models and the VISSIM models, the delay and queue lengths were determined using the respective models provided by each method. These results were compared to evaluate the similarities and differences in the output of the two types of roundabout analysis methods. Comparing the delay results from the HCM6 and VISSIM reveals discrepancies between analytical models and microsimulation. For instance, VISSIM includes elements that the HCM6 equations exclude, which could lead to more accurate estimations. The HCM6 model employs standardised equations and formulas to estimate delay and queue length, whereas VISSIM simulates actual vehicle interactions and traffic dynamics in a more realistic manner. However, the HCM6 models might rely on simplified assumptions and methods commonly used in practice. Examining queue length results across the models highlighted differences in how they handle lane utilisation and vehicle queues. VISSIM’s ability to simulate lane changes and dynamic traffic patterns might lead to more accurate queue length estimations compared to the other models that are hard to capture with static formulas. The HCM6 models, while convenient, might not fully account for complex interactions and lane-changing behaviours. In all of these cases, the comparison between HCM6 and VISSIM results shows how each model’s approach impacts the prediction of roundabout performance. VISSIM’s results are often considered to be closer to real-world conditions due to its ability to simulate complex traffic scenarios. Still, it requires accurate input data and proper calibration for reliable outcomes. The HCM6 offers theoretical estimations based on well-established formulas and is a quick estimation method but might lack the precision of simulation-based models.
Development of a cost-effective method to implement traffic management principles to a small city environment
(Stellenbosch : Stellenbosch University, 2021-03) Ebrahim, Riyaaz; Bruwer, Megan; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
ENGLISH ABSTRACT: Small cities, defined as cities with a population of at most 300,000 people, would benefit from a Traffic Management Centre (TMC) to improve traffic operations but the model used for larger cities is often too expensive to implement. This research therefore investigates a cost effective traffic management model for a small-city environment. This traffic management model would be able to provide the necessary functionality of traffic management inherited from TMCs for a larger city. Two Test Models (TMs) were investigated which assessed the difference in functionality provided by conventional TMC practices (TM 1) and a proposed “minimal infrastructure model” (TM 2) to determine an optimal traffic management method that is cost-effective. The four core Intelligent Transport Systems (ITSs) that were identified for a small-city include: Arterial Management System (AMS), Incident Management System (IMS), Urban Traffic Management (UTM) and Transport Information Management (TIM). These four systems were tested within the study area of Stellenbosch. The level of functionality of the two TMs were compared. Unmanned Aerial Vehicles (UAVs), also known as drones, and Floating Car Data (FCD) were additional tools used in TM 2 in the attempt to achieve effective traffic management with minimal fixed infrastructure requirements. The TMs were investigated for the town of Stellenbosch, in the Western Cape of South Africa. This is a small city environment with significant traffic challenges, and which currently does not have a TMC. It was found that the level of detail in TMC operations required for larger cities is not the same as for smaller cities. In addition to this, effective traffic management can be provided to a small city by implementing the minimal infrastructure model (TM 2). Furthermore, it was found that by reducing the number of components on the roads of the study area and including FCD and UAVs to aid traffic management, the TMC capital and first year of operation cost could be reduced by 37% for the minimal infrastructure model, when compared to the traditional TMC setup used in large cities in South Africa.
Establishing and applying road classification and access management techniques on Bird street in Stellenbosch, South Africa
(Stellenbosch : Stellenbosch University, 2020-03) Snyman, Jacobus Petrus; Bruwer, Megan; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
ENGLISH ABSTRACT: Bird Street is one of the roads in Stellenbosch with the slowest movement of traffic and the highest level of congestion during peak hour periods (06:00 to 09:00 and 16:00 to 19:00). The optimum functioning of the transport network cannot be achieved, due to outdated transport systems and changes that have occurred over the past few decades. The purpose of this study is to investigate the traffic operation along the road, with the intention of establishing whether there is a discrepancy between the actual and intended road classification and access management of Bird Street, and to determine the impact of this potential discrepancy on traffic parameters. Vehicle movement and traffic volume data were analysed for further use in other components of the study. From the analysed data, Bird Street was classified according to the functional classification system techniques. These techniques were used to classify Bird Street under two conditions, namely the current designed condition and the current operating condition. Thereafter, different scenarios were developed based on the classification of the two conditions and by representing different techniques identified for each of them within the context of the literature. A microscopic traffic modelling software package from PTV Group was used to construct a traffic model (static) for the simulation of different scenarios and to obtain results for further analysis. From the results, the impact of jaywalking activities within the network, current signal plans vs optimised signal plans, functional classification and functional classification vs without jaywalking were determined. Ultimately, the economic impact and the change in emissions for the best-case scenario category were compared to the base scenario. From the results, it was concluded that jaywalking activities and the optimisation of the current implemented signal plans had a minor impact on the current traffic conditions. It was also concluded that by redesigning outdated road networks within a realistic context and according to the standards identified by the literature, the same outcome can be achieved as within a utopian context. For the realistic design condition, an average percentage speed and volume increase of 66% and 100%, respectively, was determined. The total cost saving was determined as R11 951 548.76 per year and the improved design proved to be more environmentally friendly by reducing the carbon footprint. Overall, it was concluded that the main cause of the current traffic conditions along Bird Street was the outdated functional classification and access management thereof.
Factors affecting modal choice for long-distance travel in South Africa with a focus on improving rail patronage
(Stellenbosch : Stellenbosch University, 2023-02) Kühn, Justin; Bruwer, Megan; Asekun, Olabanji; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
ENGLISH ABSTRACT: The patronage of long-distance passenger rail in South Africa has decreased by 90.3% between the 2009/10 and 2019/20 financial years (Passenger Rail Agency of South Africa, 2020a). The decline in rail passenger patronage was largely due to the decrease in the number of trains running as a result of a dispute between the Passenger Rail Agency of South Africa (PRASA) and Transnet over service prices and access to the rail network (Passenger Rail Agency of South Africa, 2011). PRASA has plans to revitalize the long-distance passenger rail sector. Some of the plans include upgrading selected long-distance corridors to high-speed rail and expanding the current network (Passenger Rail Agency of South Africa, 2019a). High-speed rail and network expansion projects are expensive and long-term solutions. Short- to medium-term solutions should also be considered to attract more passengers. To recommend solutions that can improve rail patronage, a better understanding of desired services of long-distance travellers is required. This study aims to determine the desired services of long-distance travellers to establish short- to medium-term solutions to improve long-distance rail patronage. This study evaluated the needs of long-distance travellers by asking South Africans what factors influence their long-distance modal choice through a travel survey. A study was also done to identify high-demand travel corridors in South Africa where new or improved rail services could be implemented. The modes on the corridors were investigated to identify how rail can compete against other long-distance transport modes. The information gathered from the two investigations were used to recommend solutions to improve rail services based on new strategies and strategies designed by PRASA. The survey participants identified safety as the most important factor that influenced their modal choice for long-distance transport. Participants also identified punctuality and cost as important factors, while the distance to and from stations was indicated to be the least important. The investigation of high-demand travel corridors and the information from the survey determined that the shorter corridors (between 300 to 600 km) should be the first routes to reinstate and implement the improved services on. In conjunction with reinstating long-distance passenger rail services on the identified travel corridors, PRASA should increase security. Improving the safety onboard the trains and at the stations would increase the attractiveness of rail the most. A list of more recommended solutions was given that PRASA could use to improve the other factors identified too and further increase the attractiveness of long-distance rail services.
The Impact of Covid-19 pandemic on traffic generation and parking demand at hospitals
(Stellenbosch : Stellenbosch University, 2021-03) Mariti, Thato Monica; Bruwer, Megan; Stellenbosch University. Faculty of Engineering. Dept. of Civil Engineering.
ENGLISH ABSTRACT: This study investigates the impact of COVID-19 pandemic on the traffic generation and parking demand on hospitals. Coronavirus disease first started in Wuhan, China and was reported as the global pandemic by World Health Organization (WHO) in December 2019. The virus was found to be highly contagious and could be transmitted very easily from person to person such as by spending time with an infected person. The global village opted to closing borders and shutting down of the international travel either by air, land or sea to contain the viral transmission throughout the world. South Africa also implemented similar measures in regard to the international travel ban in March 2020. The ban was not only on the travel between countries, but restrictions were also imposed between provinces and even with towns. The country implemented a complete shutdown on businesses, schools and all services with the exception of essential services such as retail and hospitals. The essential providers also operated under strict regulations to minimise the viral transmission. The research looked at both private and public hospitals in Johannesburg and Ekurhuleni Metros in Gauteng province, South Africa. The study found variation in traffic flow patterns at each hospital investigated which was done by traffic and pedestrian count at the hospital access gate during the COVID-19 pandemic Lockdown Level 3. The study found that traffic at private hospitals was lower during the midday which was expected due to the regulations implemented by hospitals. The traffic during the morning was, however unusually, higher than the normal period prior COVID-19 pandemic lockdown. Trip generation rates are used to estimate the number of trips produced and attracted by the hospitals. These trip generation rates are provided in the South African Trip Generation Rates and the South African Trip Data manuals which are based on the South African land use characteristics. The Institute of Transportation Engineers manual is also used mostly by international countries. The research found that the trip generation rates measured at both the private and public hospitals are lower than the trip generation rates recommended in the two existing local manuals. Similar results were established even with the historical data received from the private hospitals records. It is possible that the vehicles trips estimated by the existing trip generation rates are an overestimate. Pedestrians’ volumes (from Public Transport) at public hospitals were almost 80% of the vehicle volumes, signifying a high percentage of pedestrians and lower vehicle ownership. Due to the virus rapidly spreading throughout the country, it was expected that the parking demand at hospitals would be higher with patients seeking medical assistance. The research however found that the parking demand was very low and this could be as a result of strict regulations for hospital visits and travel restrictions during the lockdown. Overall, it was concluded that COVID-19 pandemic and the imposed restrictions had an impact on hospital traffic generation and the parking demand. The traffic flow patterns were slightly lower compared to the time before COVID-19. The parking demand was less due to the restrictions and the additional parking time due to screening had an insignificant impact on the parking demand.
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.

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