Browsing by Author "Kabanga, Deo"

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    A Mathematical Model for Traffic Congestion at Unsignalized Roundabouts Using Microscopic Traffic Flow Model
    (Kenyatta University, 2025-11) Kabanga, Deo
    Traffic flow in many urban centres continue to rise as mobility needs grow, especially at unsignalised roundabouts where vehicles must enter and circulate without the aid of traf f ic lights. These junctions form a key part of transport infrastructure in many developing countries and understanding how they function is essential for effective traffic management. This study develops and analyses a mathematical representation of vehicle movement at an unsignalised roundabout using a microscopic car-following framework based on the Intelligent Driver Model (IDM). To investigate how straight-through and turning movements influence vehicle behaviour, nu merical experiments were carried out in MATLAB. The simulation employed the fourth-order Runge–Kutta method preceded by a Fast Fourier Transform (FFT) to solve the system dynam ics. Four vehicles were introduced into the model and observed over a defined time horizon. From these simulations, the velocity ranges associated with the three types of movement, as well as the different manoeuvres performed at the roundabout, were identified and used as indicators of traffic capacity and operational performance. The findings reveal distinctive patterns in vehicle speed and acceleration. In particular, the emergence of V-shaped and W-shaped profiles reflects a rapid rise and subsequent drop in both velocity and acceleration as vehicles approach, enter, and exit the roundabout. These patterns consistently appeared in the simulated environment and align well with behaviour typically seen in real traffic conditions.