## 4 Planning and Design of Studies of Driver Behavior at Pedestrian Crossings Using Simulators
### Selection of the Type of the Driving Simulator  
The selection of the type of driving simulator included several aspects. One of them was the main purpose for which the research is to be carried out, as it is to study the behavior of drivers approaching pedestrian crossings, and the results can then be used to create solutions to support the safety of vulnerable road users. The main requirement was first and foremost the realism of the research itself, to replicate real conditions in a simulated environment as much as possible. Another aspect concerned its complementarity with regard to the functionality of the device. When planning a behavioral study, research parameters are determined that will be crucial to the simulation study. The research parameters in the case of driving simulator research may be: driving speed, any kind of reaction time relating to the devices in the driving simulator, eye tracking, and movement of the research participant in the vehicle. The final selection of the phenomena to be studied and the resulting measurement parameters are always determined by the specific context of dedicated research. When identifying hazards at pedestrian crossings, it is crucial to consider the driver's perception of the traffic scene, concentration, and correctness of reaction. The factors influencing these observations should include driving speed, behavior of vulnerable road users, attention distractors, and weather conditions. When analyzing these factors, it is necessary to determine the measurement signals recorded during tests. Following an analysis of the available driving simulators and consideration of the context and research problems, it was determined that the high-end simulator AutoSim AS 1200-6 (AutoSim AS, Tromso, Norway) was an appropriate choice. The high-end simulator AutoSim AS 1200-6 is built from a full-size cabin of an Opel Astra IV passenger car and equipped with a system of four projectors displaying images on a screen covering a 200\({}^{\circ}\) field of vision, as well as a system of three screens acting as car mirrors (Figure 3). The simulator sits on a six-degree-of-freedom moving platform, allowing the simulation of angular and linear movements of the cabin during actual driving. The simulator's software (v.2016.10) allows full control of weather conditions, lighting conditions, and the behavior of other road users. An additional advantage of the solution is the minimization of the risk of simulator sickness by not using directly worn VR goggles. The simulator has a number of relevant cameras to record activity in the cab, and it is also crucial that the simulator has six degrees of freedom, which also has a great impact on the ability to minimize the occurrence of symptoms of simulator sickness among study participants, which is crucial for reliable results after the completion of the study, as extensively described in the previous section of the article. The last aspect concerns the availability of such an advanced solution. Simulators of the class described in this study are available for use only at specialized research institutes. The selection of the type of driving simulator is a key stage of research planning and must result from the specific research problem and scope of experiments. In the case of research focusing on, for example, reaction time, driving bucks are often used as cheaper solutions than professional full-vehicle cabin simulators. These types of simulators are often additionally equipped with actual adjustable seat bucks with a head-mounted display (HMD) as a visualization system [35]. Desktop simulators or even VR are being used more often because they are definitely the cheapest methods [36]. However, significant differences in this case include even the observed motion scene and surface area. However, the most important difference in these solutions is the lack of perception of dynamic phenomena (acceleration, braking, tilting, and even collisions) [37].