## 4 Results  
The measurement data from the data logger were subjected to a summation filter in the data analysis software and correlated with the corresponding events obtained by the video recorder. An example of the oscillogram obtained during tests is shown in Figure 3. It represents the level of concentration of a driver during two short trips. Four events were listed that could have affected his/her level of concentration. Figure 3: Level of driver concentration. Figure 2: Block diagram of the operator’s concentration measurement system model. Events 1, 2 and 3 occurred in the evening when there was little traffic on the road. Locations were identified where the driver reacted to passing vehicles (events 1, 2 and 3), as shown in Figure 4. Increased levels of concentration were observed when approaching a junction, recorded as event number 4. The recording of concentration levels was repeated on route 2, which is characterized by increased traffic (motorway). Elevated levels were recorded on 9 occasions. One of these was an access to a section where there were difficulties due to ongoing road works, as shown in Figure 5.  
The study found that the system detects the test driver's reaction to certain driving situations in the form of an increased level of concentration. Tests were also carried out on a route of about 700 km long. Drivers drove in mixed areas, including built-up areas, expressways and motorways. Figure 6 shows the time intervals during which the drivers drove on motorways and expressways. In case of interval 1, a decrease in the average concentration level of the drivers up to the stop was observed. For intervals 2 and 3, a decrease in the average concentration level was also observed (after a stop, the vehicle was driven by the same person). It was found that the average concentration level for compartment 1 increased in a short period of time when there was a change of driver (person). Figure 4: Example of recorded event—passing another vehicle. Figure 5: Example of a recorded event—unexpected road works. The average concentration level recorded on the motorway (Section 1) was equal to 45.8% (driving time of approx. 1 h 12 min), while the average concentration level calculated at the same time on the mixed section (urban expressways) was equal to 50.3%, as shown in Figure 7.  
The average concentration level calculated on motorway (Sections 2 and 3) was equal to 50% and 49% respectively. The corresponding average value of the concentration level recorded in the urban area was equal to 58%, as shown in Figure 8.  
The level of concentration of drivers with varying levels of driving skills was also verified, as shown in Figures 9-11. As observed, the average level of concentration while driving for inexperienced drivers was equal to 53.6%. Figure 6: Average concentration level of drivers on a motorway or expressway. Figure 3:0 Average concentration level of drivers on a motorway or expressway—first data part. The average level of concentration while driving in case of an experienced driver, as shown in Figures 11 and 12, was equal to 39.5%. Figure 3:1 Average concentration level of drivers on a motorway or expressway—second data part. Figure 3:2 Concentration level of an experienced driver. Figure 3:3 Concentration of a less experienced drivers. It was found that the system was able to detect differences in driving in urban areas (more driving events occurring) and motorway areas (fewer driving events occurring) after averaging the focus level values. The system also detected a difference in focus between experienced and inexperienced drivers. During long, monotonous driving sessions, there was a large drop in the driver's average concentration levels. A study was also carried out on the concentration of people performing the activity of moving small objects from one container to another using tweezers. As shown in Figure 12, the task lasted 3 min, where the concentration level of those performing simple activities rose to a peak and then fell.