With the rapid increase of urban development and the surge in vehicle ownership, urban roadrntransport problems like traffic accident and congestion caused huge waste of time, propertyrndamage and environmental pollution in recent years. To address these problems, use ofrnInformation Communication Technologyâ€“based transport systems that can support maximumrnutilization of the existing road transport infrastructure has been proposed by differentrnresearchers. Road monitoring systems are one of these solutions which support road users tornmake informed decisions. However, the current road traffic monitoring systems use road siderninfrastructures for road traffic data collection and these technologies lack accurate and up-to-daterntraffic data covering the whole road network. By comparison, cellular networks are alreadyrnwidely deployed and can provide large road network coverage. Besides, 3G and 4G cellularrnnetworks provide mobile phone positioning facility with better performance accuracy and thisrnopportunity can help to obtain accurate traffic flow information in cost effective manner on thernentire road networks. Mobile positioning technologies which aim to collect road traffic data inrncellular networks can be either Handset-based or Network-based. Each of these technologiesrndiffer in their positioning accuracy as well as area coverage. But, there is no single cellularrnnetwork positioning technology that can support wide area coverage with high accuracyrnsimultaneously. To improve positioning accuracy, coverage and communication latency ofrnivrnpositioning technologies, combination (hybrid) of Handset-based and Network-based positioningrntechniques has been proposed. The objective of this research is, therefore, to develop a real-timernroad traffic estimation framework, which utilizes a hybrid cellular network positioningrntechnology as a source of road traffic data.rnTo achieve this objective, the study uses a design science research approach. Detail literaturernreview on past and current research studies was conducted to identify the need for better roadrntraffic flow estimation accuracy together with improved performance of the procedures. With thernhelp of systematic literature review better understanding on road traffic flow estimationrnprocedures and tools was identified.rnThe results of literature review on the different positioning principles and state estimationrnmodels formed a base to design a hybrid mobile phone positioning and tracking algorithm andrnreal-time road traffic state estimation framework. An experimental research method is employedrnin evaluating the accuracy of the proposed hybridized positioning technology and validating thernperformance of road traffic state estimation framework. To evaluate the operational effectivenessrnof the framework sample road networks of Addis Ababa city are used. Data is gathered based onrnsimulation experiment and also from field test conducted using J2ME location API (JSR-179)rnsoftware installed on A-GPS enabled mobile phone moving in all journey of a moving vehicle.rnThe evaluation of the framework using both simulation data and real-world data indicated thatrnthe developed estimation model could help to generate reliable traffic state information on urbanrnroads.rnrnTo validate the research process and evaluate practical utility of the research result, a theoreticalrnliterature support and expert survey were employed respectively. Accordingly, both the processrnand result are found to be valid, reliable and practical.