This document describes a density-based traffic light controller system that uses sensors to measure traffic load and detect emergency vehicles. The system uses a microcontroller to automatically adjust signal timing based on traffic density during normal operation. When an emergency vehicle is detected, the system overrides normal timing to provide a green light in the direction of the emergency vehicle while blocking other lanes. The system is intended to help reduce traffic jams by adapting to current traffic conditions. Key components include IR sensors to detect vehicles, a microcontroller to control signal timing, and an RF receiver to detect emergency vehicles like ambulances.

1. DENSITY BASED TRAFFIC LIGHT
CONTROLLER
MEPCO SCHLENK ENGINEERING COLLEGE
BY
SOPHIA DELSI R
SINTHUJA R
III ECE

2. INTRODUCTION
•Traffic congestion is a severe problem in
many major cities across the world.
•An adaptive traffic control system can be
developed where the traffic load and
emergency vehicles are continuously
measured by sensors connected to a
microcontroller-based system which also
performs all intersection control functions.
•Microcontroller based traffic control
system is an application specific project,
which is used to control the traffic.

3. DESCRIPTION
During normal time the signal
timing changes automatically
on sensing the traffic density at
the junction but in case of any
emergency vehicle like
ambulance, fire brigade etc.,
requiring priority are built in
with RF control to override the
set timing by providing
instantaneous green signal in
the desired direction while
blocking the other lanes by red
signal for some time.

4. BLOCK DIAGRAM

5. MICROCONTROLLER
89C51
• The AT89C51 is a low-
power, high-performance
CMOS 8-bit microcomputer
with 4K bytes of Flash
programmable and erasable
read only memory
(PEROM).
• The Atmel AT89C51 is a
powerful microcomputer
which provides a highly-
flexible and cost-effective
solution to many embedded
control applications.

6. ROAD MAP
•This project is implemented
by placing IR modules and
led’s at the 4 way junction,
the four paths are
represented as E,W,N,S.
• IR modules along four
paths, and LEDs are there
for indication purpose.

7. POWER SUPPLY
BUFFER

8. POWER SUPPLY CIRCUIT

9. IR SENSING CIRCUIT

10. DECODER
HT12D
BUFFER
4050
DECODER

11. AMBULANCE RECEIVER
SENSOR
PIN1:GND
PIN2:+Vcc
PIN3:OUTPUT

12. AMBULANCE CAR CIRCUIT

13. ADVANTAGES
• During normal time the signal timing changes
automatically on sensing the traffic density at the
junction but in case of any emergency vehicle
like ambulance, fire brigade etc., requiring
priority are built in with RF control to override
the set timing by providing instantaneous green
signal in the desired direction while blocking the
other lanes by red signal for some time.
• It reduces the possibilities of traffic jams caused
by traffic lights to an extent.

14. CONCLUSION
By using this system configuration we can
reduce the possibilities of traffic jams caused
by traffic lights to an extent. The number of
passing vehicles on the road decides the
density range of traffics and on the basis of
vehicle count microcontroller decides the
traffic light delays.

15. REFERENCES
[1] Muhammad Ridwan. „Development of a Low Cost
Smart Traffic Controller System”. Department of Mechanical
and Materials Engineering Faculty of Engineering and Built
Environment Universiti Kebangsaan Malaysia, 43600 Bangi
Selangor, Malaysia
[2] Marco Wiering. “Intelligent Traffic Light Control”.
Institute of information and computing sciences,
utrecht university
[3] W. Wen & C. L. Yang. “A dynamic and automatic
traffic light control system for solving the road congestion
problem”.
[4] “Automatic Traffic Control System”. SMEU Astana
Solutions Automatic Traffic Control System.htm