Application of Enhanced Triple Modular Redundancy (ETMR) Architecture and Markov Processes to Eliminate Operational Downtime in Traffic Light System

Expansion of road infrastructure to meet vehicular road usage demand is not sustainable due to some resource’s constraint. Remedying this problem made the use of Traffic Light System (TLS) popular because of its autonomous ability to coordinate traffic. However, common problem with the TLS is frequent downtime which are caused majorly by the Traffic Light Controller Unit. This downtime often culminates to traffic jam or accident at the affected road intersection. Despite the enormous negative consequence of its downtime only few studies have attempted improving the TLS available and dependable. They have been able to design a fail-safe mode of operation during downtime where TLS display all red light to all the connected roads, and some fault-tolerant features which still resulted in a single point of failure in its component design while the problem of TLS downtime still persist. Hence this study developed an Enhanced Fault-tolerant Traffic Light System (EFTLS) Model that utilizes an Enhanced Triple Modular Redundancy (ETMR) architecture and Markov processes to ensure the reliable operation of traffic lights, even in the presence of component failures. The model is also designed with two voters as against the single voter mechanism in existing Fault-tolerant TLS to control three Traffic Light Control Units (TLCUs), allowing for seamless switching between control units to maintain working status. This work was simulated using Proteus 8 professional because it supports both analogue and digital simulations, and real time analysis of designed circuit. This research results revealed the reliability of the EFTLS and the existing Fault-tolerant Traffic Light System (FTLS) to be 1.000 Units (100 %) and 0.97426 Units (97.426%) respectively. This translates to an average reliability increase of 2.574 %. These results indicated that this work significantly improves the continuous availability of existing FTLS.