### State of the Art  
The essential document dealing with evaluation procedures is the FESTA Handbook [4]. It is a guideline document with intentions to gather all knowledge from experts, stakeholders, workshops, and seminars about Field operational tests (FOT) to create a common methodology. FOT follows evaluation and assessment methods for driver support systems testing newly developed or implemented systems to provide real-world impact and benefits. The evaluation processes are based on the so-called V diagram, which describes the individual steps recommended within the FOT. The evaluation framework used in the InterCor project is based on the above-mentioned document [5]. This framework defines \"what\" needs to be evaluated. It defines the artifacts for input and output for evaluation, such as the research questions and hypotheses to be tested and answered, and the required key performance indicators and measurements from pilot data. In this framework, it is also stated that it is necessary to adjust the recommendations provided by the FESTA handbook according to the evaluated use-cases. Another project dealing with C-ITS and thus its evaluation is the Nordicway project [6], which includes Finland, Sweden, and Denmark. The evaluation here was addressed in several different areas such as service ecosystem, user acceptance, or quality of service. For the methodology used in Nordicway 2, some steps defined in FESTA were used and adapted for the needs of evaluation. The next project to be mentioned is called COOPERS [7; 8]. Impact assessment is first determined on simulators, where it is possible to test some risks of the situation. The impact assessment was focused on the speed profiles, acceleration, lane-changing behavior, and car-following gaps. The drivers also filled in questionnaires after the drive aiming at the usefulness and, readiness of the information provided by C-ITS. There are also other projects dealing with cooperative systems, including their evaluation, such as DRIVE C2X [9] and SCOOP [10]. For the SCOOP project, for example, the evaluation focuses not only on vehicle drivers but also on road operators, while the DRIVE C2X project focuses on another area of journey quality evaluation. Another possibility of evaluation is the use of modeling tools. This approach is used, for example, in Italy [11] in the evaluation of platooning and its effects on safety or the environment. In addition to the above-mentioned documents and articles, research is also moving towards modification and expansion of the FESTA handbook, e.g., [12; 13]. In Australia, they are also working on evaluation based on cooperative awareness messages to assess safety impact [14]. Article [15] deals with a two-stage study including a structured interview with guidelines for assessing acceptance factors and an online study for their evaluation. The study is also focused on facilities that can be provided by the cooperative driver assistant systems in the future like braking, lane change, etc. The interesting conclusion reflects the different opinions of car and truck drivers on C-ITS problematic. Article [16] examines the user's consent to an automatic overtaking system based on cooperative systems. The user acceptance is focused on usefulness, ease of use, enjoyment, safety, etc. Article [17] is focused on transport factors that affect cooperative systems. These are solved and measured using simulation tools. Challenges and difficulties are also mentioned here, such as choosing the right indicators or defining proper scenarios for determining these factors. The next article [18] is aimed at the effect of HMI on driver perception. It compares two basic HMI modes: one-stage, i.e., informing about only one event (the one with the highest priority), or three-stage, i.e., informing about several events. Testing took place on a driving simulator. The bottom line is that drivers would prefer a 3-stage warning system. Another study [19] deals with the design of an interface to the infotainment systems in a vehicle.