Abstract:
By increasing use of vehicles in cities with the growth of population, traffic congestion occurs mainly at intersections. To solve the problems created at the intersection one of the best method is traffic signal control. Traffic signal control allows vehicle movements to be controlled by allocating time intervals, during which separate traffic demands for each approach of the intersection can make use of the available road space. But only traffic signal is not the best, it needs optimization depend on the problems of traffic occurs at the intersection.
All of traffic signal control used at signalized intersections in Ethiopia is Fixed Time Control (FTC). Fixed time control, all signal timing parameters are pre-computed and kept constant cycle time. These automated system do not provide an optimal control for fluctuating traffic volumes.fluctuating traffic volumes.
A fuzzy logic model based traffic light controller can be proposed for optimum control of fluctuating traffic volumes such as oversaturation or unusual load conditions. Fuzzy logic model allows the implementation of real-life rules similar to the way humans would think. The controllers is designed to be responsive to real-time traffic demands. To obtain the optimized signal timing and effective green times, Fuzzy logic toolbox is used to solve the model by MATLAB software.
The proposed model uses as an input queue length and traffic volume in order to estimate (output) the number of seconds of green time required by each of signal phase approaches.
Generally, the fuzzy logic model shows an average control delay were reduced by 10.61% and 36.26% of Banco di Roma and Gofa isolated intersection respectively, and overall the queue lengths are decreased from 0.29% to 10% for all approach of both intersection. The capacity of intersection for both intersection shows also increased from 1.92% to 7.69%.
Therefore this fuzzy logic model is expected to contribute and to give alternative handling for optimum intersection for a fixed time signal
