Road safety is influenced by an interrelated number of factors, whereby a large proportion of traffic accidents is considered to be caused by a human factor. Recent scientific research suggests that human error is not always the real cause of an accident, that is, to a certain extent, caused by a lack of adequate information related to road elements and its environment. This is especially evident in night conditions when drivers must make decisions relatively quickly and based on less visual information than the daily conditions. Namely, under night conditions, the driver has limited sources of visual traffic information and makes most of the decisions based on the traffic signaling visibility, which is a key element of road traffic and driver communication. This doctoral thesis has determined connection between driver’s psychophysical load and traffic signalization night quality (visibility) using driving simulator, eye tracking glasses (ETG glasses) and electroencephalograph (EEG device). Research, due to security risk, was conducted in the Department of Traffic Signalization laboratory, Faculty of Transport and Traffic Sciences, University of Zagreb on a driving simulator involving 45 respondents of different age groups who were familiar with the research equipment, but not with the research aim to avoid affect on the results. The research was conducted in the so-called "black room" where all the walls were painted black to simulate night conditions. Previously prepared scenario simulated night driving conditions and included, for traffic safety, the most risky situations such as: dangerous bends, intersections, encounters with pedestrians, connections between rural and urban road parts, etc. During respondent’s test drive, data related to driving speed, acceleration and deceleration, lateral position, characteristic eye movements (fixations and saccades) and cognitive load were recorded for each subject. Statistical analysis and comparison of driving results enabled the identification of factors that affect on driver’s psychophysical condition at driving in night conditions. The results and findings after the research confirm the positive impact of the traffic signalization visibility level on the psychophysical condition (driver behavior) at night driving. The observed changes are visible in driving speed changes, deceleration, cognitive load and eye movement changes (number of views on traffic signs and the percentage of observed traffic signs) and represents useful guidelines for improving traffic signaling elements to increase road safety.