Department of Transportation and Geotechnical Engineering
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Item FACTORS CONTRIBUTING TO TRAFFIC FLOW CONGESTION IN HETEROGENOUS TRAFFIC CONDITIONS(International Journal for Traffic and Transport Engineering, 2019-05-15) Mahona, John; Mhilu, Cuthbert; Kihedu, Joseph; Bwire, HannibalMost of the urban roadways do experience traffic flow congestion at various road sections called critical traffic points, which is partly contributed by the presence of various factors on the roadways. A number of studies have used travel time indices to determine congested links of the road networks. However, the travel time-delay based indices have found less application in the identification and quantification of congestion levels in the road networks. As a result, a limited number of studies have examined the factors contributing to the propagation of congestions at various road sections using the travel time-delay indices. This paper aims to identify factors contributing to propagation of traffic congestions at frequently congested traffic critical points and to estimate their influence on the entire road network using travel time-delay data. Travel time-delay data were collected by using test moving cars.The results indicate that low travel-delay transition index below 0.70 signify the jam and crowded traffic flow condition, while higher values greater than 0.70 indicate free flow phenomena. On the other hand, high congestion index values indicate jam and crowded flow conditions whereas the low values below 0.5 signify free flow conditions. Further, the results showed that low transition index and high congestion index values were associated with roadway design factors such as T-joints, cross joints, bus stops, humps and traffic lights, which are considered to be static bottlenecks which impedes the vehicle flow.Item Severity of motorcycle crashes in Dar es Salaam, Tanzania(Taylor & Francis Group, LLC, 2019-05-19) Salum, Jimoku Hinda; Kitali, Angela E; Bwire, Hannibal; Sando, Thobias; Alluri, PriyankaObjective: Motorcycles are a common mode of transportation in low- and middle-income countries. Tanzania, in particular, has experienced an increased use of motorcycles in the last decade.In Dar es Salaam, motorcycles provide door-to-door travel and often operate where more conventional services are uneconomical or physically impossible to maneuver. Although motorcycles play a crucial role in improving mobility in the city, they have several safety issues. This study focuses on identifying factors influencing the severity of motorcycle crashes. Method: A multinomial logit analysis was conducted to identify factors influencing the severity of motorcycle crashes in Dar es Salaam, Tanzania. The severity categories were fatal, severe injury, minor injury, and property damage only (PDO). The analysis was based on a total of 784 motorcycle crashes that occurred from 2013 to 2016. Results: The following factors were found to increase the probability of a fatality: Speeding, driving under the influence, head-on impact, presence of horizontal curves, reckless riding, off-peak hours, violations, and riding without a helmet. The results indicate that crashes occurring on weekdays, during peak hours, at intersections, involving a rear-end impact, in daylight, on street roads, and under clear weather conditions decrease the probability of a fatality. However, minor injury and PDO crashes were found to be associated with crashes occurring during peak hours, at intersections, and on street roads, as well as failure to yield right-of-way. Conclusions: Several countermeasures are recommended based on the study findings. The recommended countermeasures focus on the holistic safety improvement strategies constituting the three Es of highway safety, namely, engineering, education, and enforcement.Item OPERATIONAL CHARACTERISTICS OF THE NEWLY INTRODUCED BUS RAPID TRANSIT IN DAR ES SALAAM, TANZANIA(Transportation Research Board’s 96th Annual Meeting, Washington, D.C., 2017) Matata, Flavius; Kitali, Angela E; Sando, Thobias; Bwire, HannibalIntroduction of Dar es Salaam Bus Rapid Transit (DART) in Dar es Salaam metropolitan city, Tanzania, which involves use of exclusive curbed median bus lanes, meant to reduce the congestion problem by reducing travel times reliability and variability. Improved travel time benefits offered by BRT system eventually attract commuters to public transit hence reducing congestion through modal shift from private transportation system. This paper aimed at analyzing the operational impact of the DART system in Dar es Salaam metropolitan city as well as challenges inhibiting efficient operation of the system. The performance of DART system was measured based on ridership, and travel time savings measures, while challenges which the system is facing were also investigated by interviewing various stakeholders.The drivers were interviewed together with the passengers in all routes at different times of the day. Along BRT routes, students either using BRT or other means of transport mode were interviewed concerning their perception towards BRT. With the use of questionnaires, the private car owners riding along the BRT routes were interviewed with the main focus being why they still use private cars instead of BRT. Descriptive analysis was then conducted on the data collected for different groups and exploring their views and opinions to determine the effect of BRT in the city. Findings from this analysis reveal the need for improving the current BRT system and all associated operations to have a better performing transportation system.Item FACTORS INFLUENCING THE SEVERITY OF MOTORCYCLE CRASHES IN DAR ES SALAAM(Transportation Research Board’s 97th Annual Meeting, Washington, D.C., 2018) Salum, Jimoku Hinda; Kitali, Angela E; Bwire, Hannibal; Sando, Thobias; Alluri, PriyankaMotorcycles are a common mode of transportation in low and middle-income countries. Tanzania, in particular, has experienced an increased use of motorcycles in the last decade. In Dar es Salaam, motorcycles provide door-to-door travel, and often operate where more conventional services are uneconomical or physically impossible to maneuver. Although motorcycles play a crucial role in improving mobility in the city, they have several safety issues. This study focuses on identifying factors influencing severity of motorcycle crashes. From 2013-2016, a total of 784 motorcycle crashes were extracted from the Tanzania police force records. The severity categories were fatality, severe injury, minor injury, and property damage only. A multinomial logit analysis was performed. The following factors were found to increase the probability of a fatality: speeding, driving under influence, head-on impact type, presence of horizontal curves, reckless riding, during off peak hours, violations, and riding without helmets. The results indicate that crashes occurring on weekdays, during peak hours, at intersections, rear-end impact type, in daylight, on street roads, and under clear weather conditions decrease the probability of a fatality. However, minor injuries and property damage only crashes are associated with crashes occurring during peak hours, at intersections, at street roads, and failure to yield right-of-way. From the findings, several countermeasures are recommended. The proposed countermeasures take the holistic safety improvement strategies encompassing the three E’s of highway safety, namely engineering, education, and enforcement.Item Effects of Residential Land Use on Trip Generation in Urban Areas: Comparison between Estimated Trip Generation Rates and Planning Practices in Dar es Salaam, Tanzania.(WORLD TRANSPORT POLICY AND PRACTICE, 41 CHURCH ST, CHURCH STRETTON, SHROPSHIRE SY6 6DQ, 2015-10) Wilfred, Gordian; Bwire, Hannibal; Mattsson, LarsGöran; Jonsson, DanielItem Strategies for Promoting the Use of Concrete Pavements in Tanzania: Technical and Institutional Considerations(Tanzania Journal of Engineering and Technology, 2008) Mfinanga, David A.; Bwire, HannibalHigh-type roads in Tanzania have been predominantly of asphaltic concrete construction. This ever enlarging and ageing asphaltic road network represents increasing resource requirements on the road agency in the form of maintenance. Limited resources coupled with the ever sky-rocketing costs of petroleum products and the competing demands of social economic developments, presupposes the need to look for alternative road onstruction technology that is more cost-effective and resource optimising. Experience gained from developed and some developing countries where concrete pavements have been widely used suggests the potential of this type of pavement in many developing countries. This paper discusses the technical aspects of design and construction- and maintenance-related aspects of concrete pavements. The discussion extends further to highlight issues pertaining to the performance of concrete pavements and strategies for promoting the use of concrete pavements in Tanzania. Conclusions and recommendations are made with suggestions on how to start implementing the proposed strategies.Item The Separate Effects of Traffic Loading and Environment on Rutting and Cracking Trends of Asphalt Pavements(Eighth International Conference on Asphalt Pavements, 1997) Mfinanga, David A.; Ochiai, Hidetoshi; Yasufuku, Noriyuki; Yokota, HiroshiRoad pavements deteriorate with traffic loading and environment but the separate effects of these factors are not yet well defined especially with age or environment. This paper aims at finding the separate effects of these two factors on asphalt pavement rutting and cracking. It is believed that this will lead to better modeling of pavement deterioration by clearly understanding and treating the two factors as separate entities. A methodology was devised to separate the two effects, in which pavement age is used to represent the cyclic effect of environmental forces, and analysis was carried out. Results show how each of these factors influence pavement rutting and cracking and provide a further understanding of the influence of some pavement parameters on pavement rutting.Item Unsafe Driving Actions as a Contributory Factor to Road Accidents in Dar es Salaam(Botswana Journal of Technology, 2007) Mfinanga, David A.Item A Simulation Study of Flexible Pavement Design Parameters on Pavement Performance for Application in Tanzania(University of Mississippi, International Journal of Pavements, 2008-01) Mfinanga, David A.; Salehe, JumaThis research aimed to improve pavement performance at the design stage by evaluating the effect of several input parameters used in pavement design. Three types of pavement structures were analyzed: asphalt concrete on granular base, asphalt concrete on bituminous base, and asphalt concrete on cemented base. Subbase for all 3 pavement structures was granular. In the analysis, pavement design input parameters were varied in terms of layer's moduli and thicknesses, axle load, and tire pressure; the mechanistic-empirical approach was used to determine pavement service life. The most influential parameters on pavement performance for all 3 types of pavements were found to be base modulus, axle load, AC thickness, subgrade modulus, and base thickness. It is recommended that these parameters be more accurately determined during design and measured during construction, and that pavement structures be more carefully selected to minimize the impact of uncontrollable factors.Item Intrussion Detection by Penetration Test in an Organization Network(IEEE xplore Digital Library, 2009) Ndyetabura, Hamisi Y.; Mvungi, Nerey H.; Mfinanga, David A.; Mwinyiwiwa, Bakari M. M.This paper presents a study made on network security in an organization's local area network (LAN). Intrusion detection test in a campus network was performed using penetration test methods and the results analyzed. The objectives were to identify different form of network attacks and methods used to capture the hacking. During the study, the risks and attacks caused by hackers to the network were evaluated. The results obtained are seen as a good indicator of the security state of the network. Hence, an organization network that responds well to penetration test can be given a certificate. Such certificate will provide a positive sign and confidence to the network users. The study was conducted in a dynamic situation by doing experiments during different periods of time. The case study was a campus LAN, The network administrator permitted network information like internet protocol (IP) address to be gathered and analyzed and to performed the penetration test that enabled , hackers and attackers methods to be dentified. It was realized that 90% of network the users has no fear of the network security risk inspite of the finding that network security rating of the case study is at 50 percent.Item Prospects of Pre-timed Arterial Traffic Control Systems in City Roads of a Typical Developing Country: A Case Study of Dar es Salaam City(IEEE xplore Digital Library, 2011-01-14) Ndyetabura, Hamisi Y.; Mvungi, Nerey, H.; Mfinanga, David A.; Mwinyiwiwa, Bakari M. M.This paper looks into prospects of pre-timed arterial traffic control systems for cities with limited infrastructures. The methodologies for designing a pre-timed arterial traffic controller system were researched. A prototype designed and implemented in Field Programmable Gate Arrays (FPGA) is presented. Dar es Salaam Roads have been used to provide data for the design and implementation whereby the neighboring road intersections within a logically computed radius of less than 250m qualified for pre-timed arterial traffic controller. One intersection is a master and the remaining ones act as slaves. Using Very High Speed Hardware Descriptive Language (VHDL), an algorithm has been developed for coordinating adjacent traffic signals along the arterial roads. The use of VHDL enabled the algorithm to be implemented and tested in Xilinx Spartan 2E Field Programmable Gate Array (FPGA) that functioned and served the purpose of real-time simulation of Arterial Traffic Controller.Item ICT as a tool for Development of Traffic Control Systems (2011) Ndyetabura, Hamisi Y.; Mwinyiwiwa, Bakari M. M.; Mvungi, Nerey. H.; Mfinanga, David A.The application of Intelligent Transportation Systems (ITS) in Intelligent Traffic Control System (ITCS), is expected to improve the performance of road transportation significantly. Public policy makers, among others, are therefore increasingly interested in the implementation possibilities of these systems. However, current knowledge ITS implementation issues is poor with respect to technological requirements for its implementation. The contribution of ITS to general transport policy goals and theItem A Methodology for Comparative Analysis of Public Transport Systems in Africa Cities(Document Transformation Technologies, 2011) Roux, Y. E.; Del Mistro, Romano F.; Mfinanga, David A.The large and mostly impoverished populations of African cities are dependant on public transport. In most African cities, private vehicle ownership and traffic is increasing rapidly, scheduled or formal public transport systems are declining or have disappeared altogether and the unscheduled or informal paratransit systems that have replaced them are unsafe and offer a low quality service. A problem with public transport planning in many African cities is that public transport is either poorly planned or not planned at all. This is due to the fact that there is a lack of adequate information and planning framework to guide decision makers and that they either select inappropriate systems based on those used in developed countries or allow private operators to decide. It is the responsibility of government to ensure that public transport systems meet the needs of the communities they serve and political decision-makers need to make the right decisions for the development of public transport. Precise and relevant performance indicators and statistics may give a clear overview of the public transport systems of cities and will help to monitor the benefits of implementing efficient systems. Therefore a need exits to develop a methodology to assess public transport systems in African cities. The aim of this paper is to set out a methodology to describe, discuss, and compare public transport systems in African cities. The paper will only discuss the assessment methodology, and the application of the methodology will be discussed in a future paper.Item Impact of Incidents on Traffic Congestion in Dar es Salaam City(Multi Science Publishing, 2013-06-01) Mfinanga, David A.; Fungo, EmmanuelPoorly managed traffic incidents have largely contributed to congestion and delay in the city of Dar es Salaam. A thorough understanding of travel delays caused by incidents is therefore essential for effective countermeasures against the increasing congestion. The method used to determine delays in this research is based on the deterministic queuing theory. Information on incidents was obtained from traffic surveys, traffic police and road users. Counting the number of vehicles passing the incident location was done on incident and incident-free days. The cumulative traffic counts on incident and incident-free days were then calculated and used to plot the queuing diagram used to determine incident induced delay. This method turned out to be a useful tool for estimating incident induced delay in areas with less sophisticated equipment i.e. where there are no sensors, closed circuit television (CCTV) cameras, etc. The method provided good estimates of incident induced delay which may help planners and transportation officials in better understanding incident related congestion and in selecting more effective countermeasures against incident related traffic congestion in the city. It was found out that the effects of incidents were different for the different zones, types of incidents and the periods the incident occurred. In addition to the incident duration and the number of vehicles affected, the impact of incidents also depended on availability of alternative routes, number of lanes on the road, discipline of the driver in manoeuvring at incident location and traffic control at the scene.Item Computation and Evaluation of 5’x 5’ Gravimetric Geoid of Northeastern Part of Tanzania(2001) Lubida, Alex; Saburi, JohnItem The SUA Method: Case Study from the Uluguru Mountains.(JICA/SUA Centre for Sustainable Rural Development (SCSRD), Morogoro, Tanzania, 2004) Matee, A. Z.; Tarimo, A. J. O.; Rwezimula, F.; Nkonoki, B. J.; Lubida, Alex; Ikeno, J.; Yasu, H.; Takeishi, M.; Higuchi, H.; Mizuno, K.; Tanaka, U.Item SDI Strategic Planning Using the System Dynamics Technique: A Case Study in Tanzania(AGILE Digital Editions, 2014) Mansourian, Ali; Lubida, Alex; Abdolmajidi, Ehsan; Pilesjö, Petter; Runnström, MicaelDevelopment of spatial data Infrastructure (SDI) is a long term process, which requires long-term plans. The complexity of SDI, which is a matter of technical, institutional and financial challenges and their interactions, makes the development of such a plan complicated. It is also generally hard to convince policy-makers about the reliability of a plan and the future effect of that to get their supports. The system dynamics technique has been shown to be a proper approach for SDI planning, responding to the above issues. This paper summarizes the application of the system dynamics technique for SDI modelling in Tanzania.Item SDI Planning Using the System Dynamics Technique within a Community of Practice: Lessons Learnt from Tanzania(Taylor & Francis, 2015-07-03) Mansourian, Ali; Lubida, Alex; Pilesjö, Petter; Abdolmajidi, Ehsan; Lassi, MonicaThere exist major challenges in accelerating the spatial data infrastructure (SDI) planning process in the developing countries as well as advocating for politicians to support the development of SDI, due to the high complexity of SDI, lack of knowledge and experience, and limited insight in the benefits. To address these challenges, a methodology for SDI planning in Tanzania, based on the system dynamics technique and the communities of practice concept, was adopted and applied within a community consisting of experts from stakeholder organizations. The groups gathered to develop an SDI plan, while they shared their knowledge and discussed their ideas that helped their understanding of SDI. By running the system dynamics model, the development of SDI over time could be simulated that gave the planning community an insight about the future effects of today’s plans and decisions. Finally, an optimum model could be developed by refinements and improvements done with the consensus of the SDI stakeholders. This model included the components and policies that are essential for a successful SDI implementation in Tanzania and can be used as a basis for SDI planning and help to gain political support. Lessons learnt from this research were promising regarding the usability of the methodology for SDI planning in comparable countries.Item Applying the Theory of Planned Behavior to Explain Geospatial Data Sharing for Urban Planning and Management: Cases from Urban Centers in Tanzania(Taylor & Francis, 2015-05-04) Lubida, Alex; Pilesjö, Petter; Espling, Margareta; Runnström, MicaelThis paper illustrates the potential use of the theory of planned behavior as a guiding framework for understanding intentions and behavior in geospatial data sharing in Tanzania. A structured questionnaire survey, was constructed and sent to local governments as well as academic and private organizations that are major producers and/or users of geodata. The questionnaire covered issues of how collection of geodata is financed, management of geospatial data, and compatibility of spatial data-sets. The theory was found to be generally effective in accounting for intentions to share geospatial data in Tanzania (p < .01). Results show potential for data sharing between local governments and other organizations in Tanzania, and it is suggested that creating awareness among spatial data stakeholders and the establishment of a spatial data infrastructure policy framework will speed up geospatial data sharing.