Volume List  / Volume 10 (2)



DOI: 10.7708/ijtte.2020.10(2).09

10 / 2 / 236 - 251 Pages


Moise Bitangaza - Department of Civil, Environmental and Geomatic Engineering, College of Science and Technology-University of Rwanda, Rwanda -

Hannibal Bwire - Department of Transportation and Geotechnical Engineering, College of Engineering and Technology-University of Dar es Salaam, Tanzania -


Providing efficient mobility is the cornerstone of the socio-economic development, however, the performance of the road transport systems in the developing countries’ cities has been reduced and affected continuously due to the increase in road users both motorized and non-motorized and roadside friction elements. Recent researches revealed that efficiency in urban transport is affected by different factors associated with roadside activities. In most developing countries, cities, including Kigali City, a proliferation of roadside friction elements affect travel performance measures in the locations where these elements occur. This study attempts to analyze the effect of dynamic roadside friction factors on traffic performance measures such as speed and level of service using data collected from Kigali urban roads. Data collected included spot speed data, road condition data, traffic, and roadside elements data. All data were collected in the field over six road-stretches covering different functional classes of roads in Kigali City. Key roadside friction (RSF) elements that affect traffic performance were selected based on ANOVA results and a sensitivity analysis was carried out to quantify the impact of roadside friction factors on speed and level of service. Moreover, relationships of speed, density, and flow were developed taking into account typical dynamic roadside friction elements. Overall, it was found that roadside friction factors affect travel performance in the locations where they occur and their effects are not only on two-lane roads but also on four-lane roads. The models developed in this study take into consideration roadside friction factors, and therefore they can be used to predict operating mean vehicle speed and density. To minimize the effects of roadside friction factors on traffic performance, the research-based information and findings from this study can be used in setting out guidelines while imposing some restrictions to eradicate an occurrence and the proliferation of roadside friction elements.

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The authors would like to acknowledge the Office of the City of Kigali for the provision of permission of collecting data in Roads of Kigali City.
The authors also would like to acknowledge the contributions of Trained Enumerators, Isaie Habanabashaka and Innocent Bizimana both Civil Engineering graduates, from Department of Civil, Environmental and Geomatic Engineering of the University of Rwanda-College of Science and Technology for assisting in the collection of the field traffic count, speed and roadside friction data for the study.
All data collection, the analysis and the compilation of the entire manuscript were done by the lead author, Moise Bitangaza who is a Tutorial Assistant in Civil, Environmental and Geomatic Engineering Department of the University of Rwanda-College of Science and Technology, Rwanda. Proofreading and editing of the manuscript were done by Hannibal Bwire, Senior Lecturer in the Department of Transportation and Geotechnical Engineering, College of Engineering and Technology-University of Dar es Salaam, Tanzania.
No funding received for this project. All the costs incurred were borne by the authors.


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