Traffic Controltion In Botswana

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Traffic congestion has become a global problem due to the rapid rise in car ownership. Because of this, the need for an efficient and reliable traffic system arose. An efficient control of traffic results in increased safety and a reduction of time lost. While an efficient control of traffic signals alone cannot solve traffic congestion in its entirety, it serves as a significant step toward remedying the problem, especially in large cities. Gaborone, the capital city of Botswana, is no exception to the car ownership boom, and the problems that come with it, which is what this thesis works to solve. Most countries, especially developing ones, use Pre-timed controllers on traffic junctions. Pre-timed controllers are inexpensive, and relatively…show more content…
The advantage of actuated controllers is that they quickly adapt to conditions on the road and act accordingly. This system has three basic parts; a detector, controller unit, and signal heads (traffic lights), which will be explained in detail in the chapters to follow. There are challenges, however, to an actuated controlled network. It is highly sophisticated, and implementation may be hard and expensive, especially in Botswana, a third world…show more content…
Logic types can be categorized into two (FHWA, 1996). The first being how the controller responds to traffic. The logic here being pre-timed, actuated, or adaptive. The second is the scope (area) that the control strategy is applied. These strategies can be isolated intersection control, arterial control, and network control. Pre-timed control is the most common and basic type of control logic. The duration of each interval within each phase is fixed, and historical data is used to determine the values used. Pre-timed control is not demand responsive, in the sense that the signals work without regard to traffic fluctuations. Actuated control which is the focus of this thesis is demand responsive. Phase durations are set based on traffic demand, and this data is gathered by detectors on intersections. The interval might be extended, for instance, when a car is approaching a signal that is about to change to yellow, allowing the car to pass without stopping. The figure below shows how the green interval phase can be extended by vehicle actuation (Dunn Engineering Associates, 2005). The main three parameters used are the minimum green period, maximum period, and extension period. No matter the demand, the green time is retained for at least the specified minimum green period. If a vehicle is detected and less than the extension period remains in the interval, the interval is extended from the time

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