Tomorrow, we will all be passengers (at least part-time) of autonomous cars. The fear of being a passenger in a car could interfere with its use, or lead to risky behaviors of humans in the car. A crucial issue of the autonomous car is the level of well-being of the passengers and the drivenger (contraction of driver and passenger). To this end, car interior design is already being considered (infotaitment) to keep passengers occupied, and reduce the processing of negative emotional thoughts related to the situation. Anxiety or fear are emotions that imply at risk behaviors (degradation of attentional processing, shouting, motion sickness, urge to go out, physical violence) in car (Taylor, Deane,& Podd, 2008). The study of the determinants and effects of the fear of being a passenger in a car (which we call Locomotiophobia) by researchers in Human Factors and Ergonomics will make it possible to provide appropriate solutions to reduce its incidence and thus promote the adoption of this new mode of transportation by their to-come-up users.The objective of this study is to investigate for the very first time the locomotiophobia. It then seeks to define the prevalence of this specific anxiety in a large group of individuals, and to identify the factors that influence it. 577 participants took part of our study. Based on the principle of the Driving Cognition Questionnaire (DCQ) developed by Ehlers et al. (2007), we constructed the Passenger Cognition Questionnaire (PCQ). This questionnaire is made up of 20 sentences summarizing a situation of concern in the car. It is divided into 3 sub-sections: "concerns related to panic feelings", "concerns related to accident risks", and "social concerns". Participants were asked to indicate how often they had experienced each situation on a 4-point Lickert scale ranging from 0: Never to 4: Always. The Anxiety-Treatment Scale (STAI ; Spielberger et al., 1983), is a classic psychopathology scale. It evaluates the feelings of apprehension, tension, nervousness and anxiety that the individual feels at the time of an anxietyprovoking situation. It contains 20 items too. Participants had here again rate the frequency they experienced the situation on a 4-point Lickert scale ranging from 0: Never to 4: Always. A questionnaire on the characteristics of the participants (driver's license, means of transport used, type of road used, victims/witnesses of a road accident), and the anxiety they feel regarding to the type of transportation (train, plane, bus, car) and the type of driver (unknown versus familiar) was finally constructed. It is named the Questionnaire of the general behavior. The analysis of the Questionnaire of the general behavior brings us that among the 577 participants of the study, 519 were women. 51.1% had a driving licence since 10 years, and 86.3% declared not loosing « points » in their driving licence since the last 12 monthes. Among the drivers, 56.1 % report to travel less than 100 km per week, and 43.9% more than 100 km per week. 85.8% of the participants reported using rather their personal car. 76.8% reported being, from often to always, passenger of a car whose driver they know ; while only 5.2% reported being from often to always passenger of a car whose driver they don’t know. The major result from this first questionnaire is that, 27.7% of participants declared feeling from often to always locomotiophobia when they are passengers in a car whose driver they know. This percentage reaches 44.9% when the car is driven by an unknown driver. The analysis of the PCQ revealed that participants with driving licence report less anxiety related to « panic feeling » and « risk of accident » than those without driving licence. The former may have a greater sense of control over the situation and consider that they could act in a critical situation. Finally, the fact to be part of or to be injured in a road accident drive to a significant increase in the three sus-sections of the PCQ. The objective of this study was to investigate the locomotiophobia of car passengers. The study revealed that this specific anxiety affected more than 25% of individuals. People who had been in a car accident or had been injured showed higher anxiety. Moreover, the study reveals that this anxiety decreases when the driver is a familiar person, when the passenger has his or her driver's license. Tomorrow's cars will be driven at least partially by artificial intelligence. It appears essential that FH/E searchers work on the understanding of the determinants the locomotiophobia to limit its at risk (cognitive and emotional) behavioral effects on the passengers and on the drivenger, by providing him/her with the means that will enable him/her to reduce his/her anxiety.