Browsing by Author "Ndibatya, Innocent"
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- ItemCharacterizing the movement patterns of minibus taxis in Kampala’s paratransit system(Journal of Transport Geography, 2021) Ndibatya, Innocent; Booysen, M.J.Urban travelers in Africa depend on minibus taxis for their daily social and business commuting. This paratransit system is loosely regulated, self-organizing, and evolves organically in response to demand. Our study used floating car data to analyze and describe the movement characteristics of nine minibus taxis in Kampala, Uganda. We made three intriguing findings. Firstly, in searching for, picking up and transporting passengers, minibus taxi trajectories followed a heavy-tailed power-law distribution similar to a “L´evy walk”. Secondly, their routes’ topology and shape gradually changed. Thirdly, the extraordinary winding (expressed in terms of tortuosity) of the paths suggested the extreme determination of the drivers’ search for passengers. Our findings could help city planners to build on the self-organizing characteristics of the minibus taxi system, and improve the mobility of travelers, by optimizing routes and the distribution of public amenities.
- Iteme-Quantum leap on a data highway: Planning for electric minibus taxis in sub-Saharan Africa’s paratransit system(2021) Ndibatya, InnocentMinibus taxis are ubiquitous in the developing cities of the Global South. This versatile, if somewhat chaotic, public transport system is now faced with the need to move to renewable energy. But the looming roll-out of electric vehicles poses a threat to the already fragile electrical grids of African cities. This chapter evaluates the energy requirements of decarbonisation and evaluates two types of data, passenger-based and vehicle-based, from research in South Africa that has modelled these taxis. Using these two data capture methods, we assess the energy requirements and charging opportunities for electric minibus paratransit in three African cities and compare the results of the two methods to assess their suitability for planning minibus taxi electrification.
- ItemMapping the informal public transport network in Kampala with smartphones: making sense of an organically evolved chaotic system in an emerging city in sub-Saharan Africa(35th Southern African Transport Conference, 2016) Ndibatya, Innocent; Booysen, M.J.; Coetzee, JIn cities in the emerging world, public transport networks are governed by a large number of agents, each with their own agendas, priorities, incentives and resources, interacting nonlinearly through complex feedback loops. The transport system in these cities have developed into a semi-chaotic self-organizing structure with seemingly unpredictable behaviour to an outside observer. This is due to user agent actions by passengers, independent determination of operating plans and practices by transport operators, and a managing authority exhibiting a lack of will (both political and institutional), to implement adequate control measures to provide regulation and management of these systems. Based on the problems that face transport systems in developing cities and public transport in particular, this paper reports on an attempt to understand the supply of public transport in the Kampala area in a novel manner. We describe a mapping approach using a custom-developed smartphone application which was used to quickly and accurately capture informal transport systems for analysis and study of urban mobility where no dependable data was currently available. Secondly, based on the data created by the study project, to provide insights into the routes, operations, and characteristics of the minibus taxi network which convey the majority of Kampala’s travelers. Our hypothesis is that by understanding the network in geospatial terms, we will be able to create benefits for all role-players and improve the efficiency and effectiveness of the supply of public transport to more closely match the demand for public transport in an emerging world city.
- ItemMinibus taxis in Kampala's paratransit system: Operations, economics and efficiency(Journal of Transport Geography, 2020) Ndibatya, Innocent; Booysen, M.J.Most cities in sub-Saharan Africa rely for their public transport on paratransit in the form of fourteen- to twenty seater privately owned and mostly old minibus taxis. The system is often seen as disorganized, unregulated and inefficient. To assess the accuracy of this picture, we analyzed the operations and economics of Kampala's minibus taxi system and its efficiency from the passengers' and the drivers' perspectives, using ‘floating car data’. We found that the picture is largely accurate. Our findings suggest the need for moderate transformation: adequate enforcement of regulations, reorganization of ownership, renewal of fleets, and integration of ICT systems to facilitate scheduling, booking and fare collection. This will help to make the system safer, cleaner and more efficient for Kampala commuters and more stable, secure and profitable for the minibus taxi drivers and the mini industries that depend on them
- ItemModelling of inter-stop minibus taxi movements: Using machine learning and network theory(1st International conference on the use of Mobile ICT in Africa, 2014) Ndibatya, Innocent; Booysen, M.J.Minibus taxis provide affordable alternative transport for the majority of urban working population in Sub-Saharan Africa. Often, these taxis do not follow predefined routes in their endeavours to look for passengers. Frequently, they stop by roadsides to pick up passengers and sometimes go off the main route in an attempt to fill the taxi with passengers to make the trip profitable. In addition, the destinations are changed from time to time depending on the driver. This uncoordinated movement creates a web of confusion to would-be passengers. The key aspects that are not clear to the passengers include; where to get a taxi, the waiting time and the travel time to the destination. These conditions leave taxi passengers at a very big disadvantage. In this research, we applied the concepts of machine learning and network theory to model the movements of taxis between stops. The model can be used to compute the waiting times at the stops and the travel times to a specified destination. Twelve minibus taxis were tracked for 6 months. Density-based clustering was used to discover the formal and informal taxi stops, which were modelled into a flow network with the significant stops as nodes and the frequency of departures between nodes as edges representing the strength of connectivity. A data driven model was developed. From the model, we can predict the time a passenger will have to wait at a stop in order to get a taxi and the trip duration
- ItemRay of hope for sub-Saharan Africa's paratransit: Solar charging of urban electric minibus taxis in South Africa(Energy for Sustainable Development, 2021) Ndibatya, Innocent; Booysen, M.J.; Abraham, C.J.Minibus taxi public transport is a seemingly chaotic phenomenon in the developing cities of the Global South with unique mobility and operational characteristics. Eventually this ubiquitous fleet of minibus taxis is expected to transition to electric vehicles, which will result in an additional energy burden on Africa's already fragile electrical grids. This paper examines the electrical energy demands of this possible evolution, and presents a generic simulation environment to assess the grid impact and charging opportunities. We used GPS tracking and spatiotemporal data to assess the energy requirements of nine electric minibus taxis as well as the informal and formal stops at which the taxis can recharge. Given the region's abundant sunshine, we modelled a grid-connected solar photovoltaic charging system to determine how effectively PV may be used to offset the additional burden on the electrical grid. The mean energy demand of the taxis was 213kWh/d, resulting in an average efficiency of 0.93kWh/km. The stopping time across taxis, a proxy for charging opportunity, ranged from 7.7 h/d to 10.6 h/d. The energy supplied per surface area of PV to offset the charging load of a taxi while stopping, ranged from 0.38 to 0.90kWh/m2 per day. Our simulator, which is publicly available, and the results will allow traffic planners and grid operators to assess and plan for looming electric vehicle roll-outs.
- ItemTransforming Paratransit in Africa's congested Cities: An ICT- enabled Integrated Demand Responsive Transport (iDRT) approach(IST-Africa 2020 Conference Proceedings Miriam Cunningham and Paul Cunningham (Eds) IST-Africa Institute and IIMC, 2020) Ndibatya, Innocent; Booysen, M.J.Developing cities in Africa and the Global South are grappling with the problem of inadequate public transport provision. The informal privately-run paratransit system consisting of mini- and micro-buses, shared taxis (jitneys), motorcycle and bicycle taxis has seen substantial growth since the early nineties. This loosely-regulated transport system is associated with many challenges that include congestion, high crash rates, high levels of noise and air pollution. In this paper we describe the origin and current status of this structurally unique paratransit system. We then reviewed the transport master plans of four East African cities (Dar es Salaam, Kampala, Kigali, and Nairobi) and identify remaining planning gaps. We found that all the four cities reviewed lacked satisfactory plans for multi-modal public transport integration, demand responsiveness, and ICT integration which are essential to every modern and efficient public transport system. We then proposed a conceptual organised public transport system (ICT-enabled iDRT). We described how it could be adapted for a highly congested city like Kampala in order transform its existing chaotic paratransit system into an efficient public transport system that could make commuters happier and safer, reduce costs and considerably reduce pollution
- ItemWalking on sunshine: Pairing electric vehicles with solar energy for sustainable informal public transport in Uganda(Energy Research and Social Science, 2021-11) Ndibatya, Innocent; Booysen, M.J.; Abraham, C.J.; Rix, A.J.Minibus taxi public transport is a seemingly chaotic phenomenon in the developing cities of the Global South with unique mobility and operational characteristics. Eventually this wide-spread effect of minibus taxis will have to transition to electric vehicles. This paper examines the impact of this inevitable evolution on a city-wide scale in Kampala, Uganda. We present a generic simulation environment to assess the grid impact and charging opportunities, given the unique paratransit mobility patterns. We used floating car data to assess the energy requirements of electric minibus taxis, which will have a knock-on effect on the region's already fragile electrical grid. We used spatio-temporal and solar photovoltaic analyses to assess the informal and formal stops that would be needed for the taxis to recharge from solar PV in the region's abundant sunshine. The results showed that the median energy demand across all simulated days of the effect of taxis was 220kWh=d. This ranged to a maximum of 491kWh=d, with a median charging potential (stationary time) across taxis of 8 h=d to 12 h=d. The median potential for charging from solar PV ranged from 0:24kWh=m2 to 0:52kWh=m2 per day, across the taxis. Our simulator and results will allow traffic planners and grid operators to assess and plan for looming electric vehicle roll-outs to the most-used mode of transport in Africa.