1.1 General Background
Nowadays, controlling the traffic becomes major issue because of rapid increase in automobiles and also because of large time delays between traffic lights. Traffic congestion is a condition on road networks that occurs as use increases, and is characterized by slower speeds, longer trip times, and increased vehicular queuing. As demand approaches the capacity of a road (or of the intersections along the road), extreme traffic congestion sets in. When vehicles are fully stopped for periods of time, this is known as a traffic jam. In traffic environments, Traffic Sign Recognition (TSR) is used to regulate traffic signs, warn the driver, and command or prohibit certain actions. A fast real-time and robust automatic traffic density detection and recognition can solve traffic jams, and thus, significantly decrease fuel wastage and waiting time. Traffic congestion is now considered to be one of the biggest problems in the urban environments like Addis Ababa.In order to improve the transportation systems in cities we should have a traffic controlling system which fixes different time for different density of cars.
Automatic density based traffic control is a method of controlling the traffic jam automatically using density measuring sensors like infrared sensors. It assigns the waiting time of the cars in the road according to the number of cars present.
⦁ Density Based Traffic Light Control
If the number of cars in any side of the road is above the threshold value and higher than other side of the roads, less waiting time (RED light) and much longer passing time (GREEN light) is assigned to this road. Here the assigned waiting/passing time also varies depending on the density of the denser road.
This project could be implemented using IR sensors as a means of measuring the density. IR sensor has a Tx – Rx pair and when a car passes through this pair (IR sensors placed at opposite sides of the road) the receiver would be blocked from receiving the signal hence we count the number of car density. This value is given to the microcontroller from all sensors found in the four directions and the microcontroller compares these values. Finally the one with higher density would get the priority to pass.
1.3 Emergency override for traffic light control
This project also provide an additional functionality to free the road with an emergency vehicle. The system has facility for emergency vehicle detection system like ambulance, police car etc. By detecting the siren of emergency vehicle the corresponding road is cleared quickly. This condition has the highest priority above all conditions. After the vehicle passes the system tends to check if there is density. If two or more emergency cars are present the system decides based on their density.
⦁ General Objective
The objective of this project is to create an automatic density based traffic control system based so that to minimise the wastage of resources and waiting hours.
1.4.2 Specific Objective
⦁ To detect the presence of emergency vehicles and clear the corresponding road by giving priority.
⦁ To determine the position/direction of arrival of emergency vehicles
⦁ Noise cancelation of received signal
Our project solves some of the problems faced by using the traditional traffic system. The problems encountered are described below:-
1.5 Problems of Traditional Traffic Control System
1.5.1 Fixed Time Slot
Present day traffic light controlling system has a fixed time counter (mostly 60 sec). This is not a wise method because denser areas should be given more time than less dense ones.
1.5.2 No Emergency Override Mechanism
It is obvious that emergency vehicles such as ambulance are stuck in the high traffic density and wait until it is cleared. This could sever the patient’s condition and put his/her life in danger.
1.6 Proposed Solutions
1.6.1 Density based Dynamic Delay time for Traffic Lights
The counter time given for each road side should be proportional to the density of the cars. The denser the road the more time needed to clear the congestion.
1.6.2 Emergency Vehicle Override System
Emergency vehicles should be given priority by using a mechanism that detects their presence and frees the road with emergency vehicle. If more than one emergency vehicles are detected the system should decide based on their densities.