Effectiveness of a speed advisory traffic signal system for Conventional and Automated vehicles in a smart city

As the world population and the traffic demand are constantly inflating, there is a substantial need to procure a safe and effective method for traffic control and management. Thus, traffic signals operate to manage the flow of vehicles and vulnerable road users through intersections. Intelligent Transport Systems (ITS) technologies based on vehicle connectivity and information exchange may overcome the cons of fixed‐time traffic signals in coping with the unplanned traffic stream. The roadmap for operating connected vehicles in an urban environment is still in the planning phase and in order to achieve sustainable results, a proper management technique must control the flow of vehicles. Green Light Optimal Speed Advisory (GLOSA) utilizes infrastructure and vehicles communication through using current signal plan settings and updated vehicular information in order to influence the intersection approach speeds. This thesis presents a traffic microsimulation study that investigates the state‐of‐the‐art in traffic management (GLOSA) for vehicles in smart cities. The simulations are performed to analyze the effect on traffic performance when more drivers comply to the speed advice. The GLOSA management approach is also accessed for its capability to improve traffic efficiency in a mixed environment of conventional and automated vehicles, as well as in a full market penetration of only connected automated vehicles. The simulations in this thesis undergo a fixed time traffic management for a fictious case with only straight forward traffic flow. Results show that GLOSA has a great impact on reducing the waiting time and enhancing the traffic performance for conventional driving in addition to further possibilities for introducing automated vehicles onto the road alongside conventional vehicles. Moreover, enhancements of automated vehicle parameters show significant results singly independent on operating the GLOSA management algorithm, with minor improvements while accompanied with GLOSA. Full market penetration of connected conventional vehicles managed by the GLOSA technique results in achieving waiting time reduction of 66%, compared to having conventional vehicles without GLOSA connectivity. While increasing the percentage of GLOSA connectivity causes a decrease in trip delay ranging from 35 % to 70% reduction for 50% and 100% penetration rates respectively. Simulations results for 50% or more compliance rates showed waiting time of values very close to the full compliance mode, which indicates that even if only half of the drivers comply to the GLOSA speed recommendation, this should have a significant impact on the traffic performance. In a mixed traffic scenario, where automated vehicles share the road equally with conventional vehicles both having the same time gap, it was clear that there are no further benefits from introducing automated vehicles without decreasing their time headways. The best traffic performance results achieved by using GLOSA, goes for connected automated vehicles having the lowest simulated time gap. The waiting time reduction reaches 95% and trip delay lessens to 88%.