Traffic Lights Control System #Group 10

    Traffic Lights Control system for Emergency vehicles

                                 

-by C. Khaleel Basha, GK. Deepak Sharma, S. Hemanth Kumar,D.Prakash

Abstract:

Traffic congestion problem is a phenomena which has a huge impact on the transportation system in our country. This causes many problems especially when there are emergency cases at traffic light intersections which are always busy with many vehicles. A traffic light controller system is designed in order to solve these problems. This system was designed to be operated when it receives signal from emergency vehicles based on radio frequency (RF) transmission and by using the micro controller we can change the traffic lights sequence back to the normal sequence before the emergency mode was triggered. In future, this prototype system can be improved by controlling the real traffic situation, in fact improving present traffic light system technology.

Introduction:
Many countries in the world are facing the problem at traffic light intersection that causes accident between emergency vehicle and other public vehicle. The traffic control system in Malaysia specifically has not been equipped with appropriate method when emergency case occurs. This will cause the emergency vehicles such as ambulances difficult to reach the destination on time because of the traffic congestion. Moreover, the situation is getting worse when emergency vehicles have to wait for other vehicles to give way at intersections with traffic lights. This causes a delay of time and may affect the emergency case. Besides, the collisions with other vehicles from other direction might occur at intersections when emergency vehicles had to override the red traffic lights. All these difficulties faced by emergency vehicles can be avoided using this traffic light control system based on radio frequency.

Implementation:

The RF module comprises of an RF Transmitter and an RF Receiver. The transmitter/receiver (TX/RX) pair operates at a frequency of 434 MHz. An RF transmitter receives serial data and transmits it wirelessly through RF through its antenna connected at pin 4. The transmission occurs at the rate of 1 Kbps - 10 Kbps. The transmitted data is received by an RF receiver operating at the same frequency as that of the transmitter.This RF transmission system employs Amplitude Shift Keying.The transmitter module takes serial input and transmits these signals through RF. 

Circuits involved in the Implementation are:

RF Transmitter Circuit:
The transmitter circuit consists of a RF transmitter module, an encoder, a set of four push-on switch and a power supply.

Push-ON Switches:
A set of four push-on switches is used in the RF transmitter circuit. Each switch labeled with number 1, 2, 3, and 4 to indicate which traffic light at the intersection(geometric directions can also be used instead of numbering convention). These switch need to be push (switch on) in order to trigger the emergency sequence mode of the traffic light intersection.When any of these switch is being pushed-on, the RF transmitter send a signal that have been coded to the receiver which then will be used to override the traffic light sequence.

RF Receiver Circuit:
The RF receiver circuit consists of a RF receiver module, a decoder, relays and LEDs. A LED is connected to pin 14 of the decoder to indicate that the RF transmitter is in the range with the RF receiver. A LED is connected to each relay to indicate which traffic light has been triggered by the signal transmitted from the RF transmitter.

Traffic Light Circuit:
A circuit of four traffic light intersection has been designed for this project using a PIC 16F877A micro controller. The sequence of the traffic lights is generated by the PIC 16F877A. The input from the RF receiver circuit has been used to override the sequence.

Simulation : 

• The simulation model is developed by using Simulink, Fuzzy logic controller, Simevents tool boxes and Matlab workspace environment.

• The Fuzzy Logic Controller(FLC) utilizes two sets of inductive loop sensors on each approach to the junction. One just before the junction and the other at a predetermined distance from the intersection to gather data information about the vehicle arrival and retrieval.

• The traffic data information received is utilized by the fuzzy logic controller which alters the traffic lights sequence.

• When the vehicle is at 250 meters from the traffic light junction ,the Fuzzy logic controller sends the signal to the PLC (Programmable logic controller) and it starts controlling the traffic lights.If there is a red light, it turns it to green and if there is a green light it just extends the timer till the vehicle crosses.

• The fuzzy logic controller determines the time taken by the ambulance to cross the signal and when the vehicle crosses the predetermined distance,signal is lost the FLC alters the traffic lights to the normal sequence.

The Emergency Mode Sequence 
The emergency mode is triggered when the RF receiver has received the transmitted signal from the RF transmitter(which is present in the vehicle) to override the normal sequence of the traffic light. The lane in which the signal is received is given a green light and the remaining lanes are given red so that the vehicle path is clear.

After a certain time the emergency vehicle travels out of the range and the receiver disconnects from the transmitter and the normal traffic light sequence gets resumed.

Challenges Faced:

• When multiple emergency vehicles are present at the same junction,both the vehicles are given green but the priority goes to the vehicle that comes first i.e., priority given to the vehicle whose transmitted signal is received first.

• Every traffic light at the junction needs to be modified and should be implanted with a receiver which isn't possible at present.Though it is difficult, we can try this system in a small area and if the results match our expectations, extending this to all areas may be possible. 

Future Works:

• Intimating the next upcoming traffic junction about this emergency condition in order to clear the traffic early.