Congestion at intersections is an ever-present headache, and road authorities across the globe have sought to develop and adopt Intelligent Transport System (ITS) solutions to reduce such congestion. The application of ITS is seen as a proactive approach to reduce traffic congestion, improve journey times and improve the safety of motorists.
ITS is a broad field including many applications and sub-systems, and leading transport authorities have adopted an ITS concept known as Intelligent Traffic Signal Control Systems (ITSCS) at signalized intersections to improve congestion. So how can ITSCS help in reducing traffic jams at signalized junctions and improving safety?
One of the frustrations drivers face each day when reaching a signalized intersection is the waiting time, particularly when there are no cars on other approaches. This results in lost time, increased fuel consumption and air pollution and non-reliable journey times. ITSCS seeks to improve the operation of intersections by using detectors (triggered by vehicles approaching the signalized intersection) which then send the information to the local Intelligent Traffic Signal Controller (LITSC). The LITSC then analyzes the received information to determine an optimum green time for each approach, thus optimizing the throughput of each intersection.
ITSCS also contributes to reducing the number of accidents at intersections. The Federal Highway Administration (FHA) reports approximately 2.5 million intersection accidents every year. Many of these accidents occur as drivers doubt whether they should stop before the stop line or proceed through the intersection during the amber interval – known as the dilemma zone in traffic engineering. In such circumstances, a vehicle might be involved in a right-angle crash, rear-end collision, or receive a traffic fine. This uncertainty can be reduced by providing an Advanced Dilemma Zone Detection System which requests the LITSC to extend the green time of a signal head upon detecting any vehicle in the dilemma zone and allowing the vehicles to pass safely.
There have also been instances where ambulances and other emergency vehicles have been delayed on their journeys through signalized intersections. A study by George et al (2017) outlined that ambulance delays were linked to 30% of deaths in India. It is reasonable to assume that delays at signalized intersections is a contributor to this percentage. An ITS sub-system called Emergency Vehicle Signal Preemption (EVSPS) permits emergency vehicles to pass through congested intersections by requesting the LITSC to assign priority to the vehicle for a limited amount of time until the vehicle crosses the junction.
The above are just some of the ways in which smart traffic signals impact our lives in a positive way, and for more interesting discussion about this subject, please do not hesitate to contact me on: Laith.firstname.lastname@example.org