# Towards Understanding Driver Acceptance of C-ITS Services--A Multi-Use Case Field Study Approach
## 4 Discussion
### Desired Free of Charge Information  
The ranking of desired _free-of-charge information_ begins with \"Warnings for actual traffic jams,\" which ranked first in both field studies. Nearly 90% to 93% of respondents want access to this type of information in their vehicle. The second most important type of information, with an approval rate of 75% to 86%, is \"Warnings for specific situations such as bad weather, roadworks, and emergency vehicles.\" In third place is \"The regulatory speed limit,\" with 75% to 82% of respondents finding it important. The newly introduced ESRIUM use case, \"Information about poor surface quality (e.g., potholes, ruts),\" is relevant for roughly 50% of respondents.  
These findings suggest that drivers prioritize real-time traffic jam alerts to adjust their driving strategy. There is also strong consensus on the importance of situational awareness and adhering to speed limits. The top three types of information have been widely used for years, traditionally delivered through technologies like dynamic road signs or radio. In contrast, the ESRIUM use case is a newer concept, which may explain its lower approval rate.  
Furthermore, research indicates that dynamic road signs, such as overhead gantries, when combined with in-vehicle systems, enhance compliance with speed regulations and improve driver situational awareness [32]. Studies also indicate that while IVIS can complement traditional traffic management systems, they should not replace them entirely, as drivers currently trust traditional signage more [31]. This indicates that in-vehicle information systems alone are less effective than an integrated approach that combines external and in-vehicle guidance [32]. However, road signs remain an effective means of warning drivers about non-critical or non-urgent events in terms of safety [31].  
Figure 13: Current use of information in both field studies.  
Additionally, drivers recognize the benefits of IVIS and V2X communication in providing real-time updates that improve driving efficiency [33]. The actual effectiveness of connected vehicle safety features depends on their adoption rate and the quality of the infrastructure. Therefore, further studies are needed to better understand their long-term impact on safety and driver behaviour [31]. C-ITS is anticipated to improve vehicle safety, mitigate congestion causes, and foster efficient, eco-friendly driving [34]. Additionally, drivers recognize the benefits of IVIS and V2X communication in providing real-time updates that improve driving efficiency [33].  
In summary, both field studies and literature agree that a key benefit of IVIS is the provision of real-time updates to the drivers. This is a clear advantage compared to traditional infrastructure, such as dynamic road signs. However, drivers are used to signage on the road and see IVIS as an add-on for traffic information. Looking at the user groups in both field studies, other reasons for preferring signage information may be that most of the participants are experienced drivers with an age of 35+.