Efficient Real Time Traffic Signal Control

CHAPTER – 1

INTRODUCTION

The increase in urbanization and traffic congestion creates an urgent need to operate our transportation systems with maximum efficiency. As traffic volume continues to increase, the streets become more and more congested. One of the most cost-effective measures for dealing with this problem is traffic signal control. Traffic signal retiming and coordination of existing signals have been proven to bring about substantial reductions in traffic delay, considerable energy savings, and consequently, huge reduction in travel time and increased safety for the public. Control of traffic signals for efficient movement of traffic on urban streets constitutes a challenging part of an urban traffic control system (UTCS). Traffic signal control varies in complexity, from simple systems that use historical data to determine fixed timing plans, to adaptive signal control, which optimizes timing plans for a network of signals according to traffic conditions in real time. Real-time systems responding automatically to the prevailing traffic conditions, are potentially more efficient than clock-based fixed-time control settings, possibly extended via a simple traffic-actuated logic.

The traffic flow behaviour in the network depends on control inputs that are directly related to corresponding control devices, such as traffic lights, variable message signs, etc., and disturbances, whose values cannot be manipulated but may possibly be measurable (e.g., demand) or detectable (e.g., incident). The function of the control strategy module is to specify the control inputs in real time based on available measurements (e.g., from loop detectors or traffic cameras).Surveillance system provides real time status to the control algorithm which decides control inputs. A human interface is required to monitor or change the control strategy.

An intersection