# A Systematic Literature Review of Autonomous and Connected Vehicles in Traffic Management
## 3 Research Analysis
### Traffic Management Methodologies Consisiting of Primary Goals
#### 3.2.1 Efficiency
They also used a k-shift optimization approach to facilitate the junction passage of unlucky automobiles. The suggested technique surpasses FCFS and conventional traffic-light management strategies in conditions of average delay and the amount of traffic that successfully navigated the intersection in an hour while modeling balanced and unbalanced traffic. Additionally, ref. [54] suggested a junction system based on an auction that decides how many ideas there are for changing the sequence of the vehicles at the junction in all directions. It considers fostering justice while tolerating travel time for drivers on a restricted budget. Except for Baton Rouge, the recommended auction-based technique outperformed base cases on the road networks of four significant cities regarding trip time. Another study that uses automated vehicles to improve traffic flow on circular highways is [87], which used the cellular automation model to study the mixed traffic system at the micro level. Each AV in this system will have a \"far-sightedness\" and be capable of knowing the speeds and locations of the vehicles thanks to the use of sensors or mutual information exchange. They investigated how the extent of far-sightedness, the proportion of autonomous to human-driven vehicles, vehicle density, and the likelihood of random HV deceleration affect the traffic capacity in the circular road scenario. These formulae were shown to be essential for regulating the density and the proportion of HVs and AVs in future smart traffic systems, which will aid in preventing severe traffic congestion. Recent work [88] focused on the trajectory control of autonomous vehicles at traffic crossings using a newly developed non-linear tracking approach. The Newton-Raphson approach is used in this technique to direct an anticipated system output to a future reference goal. In considering the effectiveness of traffic flow at single-lane roundabouts, ref. [8] proposed seven dispute resolution techniques. It prioritizes approaching vehicles using demand-dependent techniques and modifies their trajectories to consider the roundabout's shape. The first technique arranges arriving vehicles based on their Shortest-Remaining-Time-First (SRTF, i.e., the quickest period until the vehicle reaches the first dispute portion it will confront) to the dispute segments within the circular roadway. In contrast, the other techniques adjust the SRTF regulations to satisfy highly unbalanced traffic flows with frequent right- or left-turning maneuvers. It was determined that the technology provides greater throughput with a more negligible average control latency than conventional vehicles' operation. Under full CAV traffic flow, the roundabout's capacity is enhanced by 58 to 73% (with the increasing trend of conflicting flow, respectively). In all demand situations, the approach that prioritizes vehicles that must pass through more dispute locations and those that exit the system first performs better than the other strategies, making it the best method for coordinating CAVs at roundabouts. According to procedures from the Highway Capacity Manual, this method minimizes the average control latency by 75 to 95% when compared to traffic with conventional vehicles. Reference [55] offers a cellular automata model based on many agents. The model can effectively simulate complicated traffic scenes using multi-agent theory to replicate complex traffic elements because cellular automata have simple rules and good simulation efficiency. The simulation's outcomes demonstrate that the issue of swollen traffic volume-caused road congestion may be successfully prevented. A generalized macroscopic model was developed by [56] to predict the average connected autonomous vehicle (CAV) platoon length for a given traffic demand and CAV penetration rate. This model was used to analyze the capacity of roadways while taking mixed traffic into account to improve efficiency. The cooperative and opportunistic car-sharing strategies, representing the best- and worst-case outcomes, were contrasted.