## 3 Results and Discussion
### The Most Influential Documents  
The final list \"A\" of 698 documents that was analyzed in the previous sections still contained some documents that were not exactly centered on the investigated field of study. Moreover, the cocitation analysis described above revealed a very sparse network that appeared unuseful to establish the most influential documents. For this reason, and in an attempt to establish the most influential papers in the field, the following procedure was applied in order to include important documents that may have been excluded from list \"A\":  
* The top 20 documents (considered belonging to the investigated field among documents of list \"A\") in order of received citations were manually selected. In this way, we created a list \"A20\" of influential documents. * All highly cited documents among the cited documents of the more recent papers of list \"A\" were considered in the following way: a list \"A20-restricted-to-2015-2020\" was extracted from list \"A\"; in the same way, a list \"A20\" was created but with only the documents published between 2015 and 2020. Then, all documents cited by the 20 documents in the list \"A20-restricted-to-2015-2020\" were added to a list \"C\" consisting of 736 documents. The list \"C\" was then ordered by citations, and all documents were manually examined reading the titles, abstracts and, in some cases, the full papers. The papers (all manually considered belonging to the investigated field) with a number of citations higher than 71 were added to the list \"A20\". The number 71 was used as a reference since it was the number of citations of the least-cited document in the list \"A20\". With this procedure, a list \"A31\" was created containing 31 documents that can be considered among the most influential in the sector. It must be noted that some general scope papers have been left in the list since they have been considered relevant. Moreover, papers on the following topics have also been left inside the list:  
* The use of floating car data as a means to establish traffic signal timings;
* The use of green light optimized speed advisory (GLOSA). The list \"A31\" includes [46; 50; 51; 52; 53; 54; 55; 56; 57; 58; 59; 60; 61; 62; 63; 64; 65; 66; 67; 68; 69; 70; 71; 72; 73; 74; 75; 76; 77; 78; 79; 80; 81; 82  
tion rate of the connected vehicles, the authors developed an algorithm that estimates the states of unequipped vehicles based on connected vehicle data. As in the paper of [PERSON] et al. (2007), the algorithms were validated in a simulation environment. In particular, a real-world intersection was modeled in VISSIM. Simulation results showed that the proposed control algorithm outperforms actuated control by reducing total delay in a high-penetration-rate case as well as in a low-penetration-rate case. [PERSON] [76] proposes a new framework for dynamic and automatic traffic light control systems for improving traffic congestion problems. The system consists of hardware and software components, including RFID tags and a backend server, and it is based on the transmission of radio signals. Once the vehicle data have been acquired, maximum flow, interarrival time and average car speed are calculated and used as the input parameters of the traffic light control simulation model built in the server. The system can automatically infer and provide different alternatives in terms of varieties of traffic situations and then set red or green light duration via a traffic light control interface for improving the traffic congestion problem. The simulation results prove the efficiency of the traffic system in an urban area, with a reduction in the average waiting times. [PERSON] et al. [78] developed arterial velocity planning algorithms maximizing the probability of drivers having a green light when approaching signalized intersections. The algorithms minimize the acceleration/deceleration rates of vehicles, ensuring that a single vehicle never exceeds the speed limit, passing through intersections without coming to a stop.