## 2 Materials and Methods
### Evaluation Methodology
#### 2.1.3 Evaluation and Assessment  
The last phase is the evaluation and assessment of all obtained data in three evaluation areas: user acceptance, safety impact, and functional evaluation. Four basic questionnaires were prepared for user acceptance (in accordance with WG3):  
* Driver's profile,
* General questions regarding C-ITS,
* Questionnaire related to a specific use-case:  
Pre-ride,  
Post-ride. For most questions in the driver's profile questionnaire, the driver ticked off the appropriate option. The questions are from the following areas:  
Type of driver,  
Sex,  
Age (in ranges),  
Education,  
Number of citizens in hometown (in range),  
Type of a driving license,  
The length of driver's license ownership,  
Number of driven kilometers annually,  
Frequency of driving vehicle,  
The number of (caused and uncaused) traffic accidents, penalty points,  
Current sources of traffic information,  
Preferred traffic information based on C-ITS. General questions related to C-ITS focused mainly on two areas: willingness to pay for these services (regularly or once) and the opinion of drivers on the HMI and its distraction while driving. Specific pre-ride questionnaires related to a given use-case do not always have the same questions, however, they focus on driver perceived perception in the following areas:  
Safety,  
Overview of a situation,  
Comfort of driving. Specific post-ride questionnaires aim at all previous areas and further:  
Usefulness of the service,  
Satisfaction with the information obtained. Samples of the results are shown in Section 3.1.3 User Acceptance. The impact assessment for different use-cases in C-Roads follows the recommendation and general guidelines in the Evaluation and assessment plan [20], proposed by WG3 within the C-Roads platform. These specifications were designed to unify the process of evaluation and assessment and the results of the individual sub-states at their pilot sites in order to be as transparent and comprehensible as possible for all C-ITS stakeholders. Furthermore, it proposes general recommendations at the level of individual use-cases but leaves the method of implementation to individual states. In the Evaluation and assessment plan [20], the main three impact areas covering the expected benefits and impact of the C-ITS services are in line with national and European policies to increase safety and reduce the environmental impact of transportation. Each area of impact brings a slightly different view of the evaluation of changes in driver behavior and is linked to subsequent analysis and individual statistical methods that use the captured data. Within the proposed methodology, impact area safety was selected as the main part. For each use case, an analytical method was chosen based on the true nature of each evaluated use case and the ability of the recording equipment to capture the difference in driver behavior using C-ITS as opposed to driving without C-ITS. The main comparison of individual passage for all use-cases was the comparison of speeds and comparison of accelerations. To determine the significance of the differences between the two mean values (situations with and without C-ITS), a two-sided, paired T-Test was used when comparing speed and acceleration. Such a test evaluates whether there is a possibility that the difference in the mean value of the two selections is due to chance. [PERSON]\({}^{\prime}\)s test was performed on the same comparison of speed and acceleration to determine if there was a statistical difference in the variances with and without C-ITS. Functional evaluation in this methodology covers aspects of evaluation that are based on the experience of evaluators, evaluation drivers, and other stakeholders. It also deals with some problematic properties of use-cases. Functional evaluation is therefore divided into three areas:  
* lessons learned,
* HMI,
* quality of service. Lessons learned are primarily designed from the user\({}^{\prime}\)s point of view.