# Risk Assessment for the Development of Emergency Scenarios for Tram Driver Training
## 2 Theoretical Background
In addition, these systems are equipped with audio, haptic, and sensory interfaces that enhance the feeling of being inside a virtual world. * Semi-immersive virtual environment (Fish Tank VR)--these systems are a post-medium form between the abovementioned environments. Training scenarios are implemented using a conventional monitor, but the system does not support sensory output. However, the tool supports head tracking and improves the feeling of 'being there' thanks to the motion parallax effect. The research results described in this article relate to solutions using IVR. IVR enables the creation of a scalable tool that can provide a full range of sensory stimuli, access to a 360\({}^{\circ}\) virtual interface, and the ability to manipulate virtual objects during training [24; 25]. It is also possible to isolate the trainee from the environment and uncontrolled external stimuli that distract them and prevent them from fully interacting with the digital world [26]. By using IVR, it is also possible to achieve, to a greater extent, the benefits of VR technology in training reported in the literature. These benefits are outlined in Table 2.  
Summarizing the benefits reported in the literature regarding using VR solutions in training processes, the research findings are worth noting [28]. In this article, 184 publications on the use of virtual reality in training programs were analyzed. The results indicate that the most typical rationale for using VR in training is to reduce the limitations of traditional training methods, provide an immersive and attractive form of training, improve motivation, and increase participant engagement. Despite the numerous benefits of using VR technology in training systems, the limitations of its use should also be kept in mind. The biggest problem associated with using VR tools in the training process is the potential for simulation sickness (also known as VR sickness or cybersickness [29]). Simulation sickness encompasses a set of symptoms occurring in a virtual reality user, i.e., general discomfort, fatigue, headache, eye strain, difficulty concentrating, increased saliva, sweating, nausea, blurred vision, and dizziness [30]. Simulation sickness is the body's reaction to discrepancies between visual information and proprioceptive and vestibular signals. The triggers of cybersickness fall into three categories [31]: individual, technological, and task-related factors. A research challenge related to virtual reality is the occurrence of simulation sickness in a changing environment. Two different driving environments of an autonomous car were analyzed: driving on a country road and driving on a motorway [32]. In the second scenario, the user had to perform fewer maneuvers than driving on a dynamic country road. The study participants were verified by visualizing the electrogastrography (EGG) signals. In most cases considered in the study, signal amplitude and nausea were increased in the more dynamic driving environment. Changing the virtual reality environment leads to a recurrence of simulation sickness, as different training environments can elicit different sensory and physiological responses. In a study by [PERSON] and [PERSON] [33], whose considerations are based on three driving environments, including motorway, rural, and urban, vehicle speed was shown to be a factor in the possibility of simulation sickness. Selected publications also highlight the impact of environmental complexity on cybersickness. In a helicopter flight simulation, two scenarios were verified, including a flight in cloudless conditions and a flight in stormy conditions, to determine the effect of simulation on cybersickness [34]. The results confirmed that the change in environment significantly increased the simulator sickness questionnaire (SSQ) total score from cloudless to stormy conditions. Increased tolerance to cybersickness is achieved by gradually adapting the user to the virtual environment. In [35], the optic flow strength of the virtual environment was improved, reducing cybersickness symptoms.