# Does the Driver Understand the Warning? Comprehension of the Request to Intervene
## 3 Results
### ITS Results  
The results of the CT (comprehension test) are shown below. Figure 3 provides information about the understanding of the RtI message conveyed by each of the icons presented in Figure 1. Correct answers are marked with a green rectangle. Almost half of the respondents stated that the \"red hands on steering wheel\" icon warned about the need  
Figure 1: RtI icons tested in the ITS laboratory: (**a**) “red hands on steering wheel” icon, (**b**) “natural hands on steering wheel” icon, (**c**) orange wheel icon.  
Figure 2: RtI icons tested by Solaris: (**a**) red car icon (MobilEye), (**b**) red pedestrian icon (MobilEye), (**c**) leaving-the-lane icon (MobilEye), (**d**) warning triangle in yellow (Solaris), (**e**) warning triangle in red (Solaris), (**f**) steering wheel in yellow (Solaris).  
to intervene, and this was the best result. Somewhat fewer participants, 31%, indicated that the same icon in natural color signaled Rtl. The drop in comparison to the red icon may be due to drivers becoming accustomed to the way information is encoded on the dashboard. According to ISO 2575 \"Road vehicles--Symbols for controls, indicators, and tell-tales\" [26], red color is used to warn drivers. This type of lighting informs them about the car's potential problem, safety issues, or immediate failure points. On the other hand, the orange wheel icon was not regarded as Rtl-signaling. Respondents tended to think that the symbol suggested driving in automated mode, the system is in control of the vehicle (38%), locked steering wheel (30%), or had no idea what it meant (22%). This is also reflected on the right panel of Figure 3, showing that drivers either had no idea what they should do when noticing such a symbol (26%) or thought they should relax because the vehicle was in automated mode (44%). Both answers were incorrect.  
Respondents reported that when noticing the \"hands on wheel\" icons, they were supposed to put their hands on the steering wheel (red 47%, natural 47%). Although this was not the best answer, it might be considered half-correct because regaining control (correct answer; red 30%, natural 12%) necessitates putting one's hands back on the steering  
Figure 3: Comprehension Test, assessing the comprehension of the message conveyed by the icons: (a) What does this icon mean? (b) What should you do when you see this icon? The correct answer is marked with a green rectangle. ITS icons only.  
wheel. It should also be noted that some drivers misunderstood the meaning of the symbols by reading the pictogram as conveying the hand-off-wheel message. This was the case for 21% of respondents interpreting the natural-colored icon.  
Next, participants were familiarized with the meaning of the symbols and asked to assess the extent to which each icon warned about Rtl (Figure 4). It was the red icon that turned out to communicate such a warning most effectively, with the largest proportion of respondents (80%) indicating answers 4 (26%) and 5 (54%).  
Participants did not rate the orange icon well. According to 41% of respondents (the second highest number of answers), the icon reflected its intended meaning to a very small extent.