This experiment aims to study the impact of the sonification of a hand gesture controlled system on the driver behavior. The principle is to give an auditory feedback to the driver, in addition to a visual screen, in order to assist in-car devices interface manipulation. A touchless interface has been tested with a panel of 24 subjects on a driving simulator. Different tasks (pick up the phone, select an item in a list) involving the screen and the interface had to be performed by the user while driving. To study the contribution of the sound feedback on the drivers’ behavior, two audio conditions were tested: with and without auditory feedback. The tasks were performed in lowly and highly demanding traffic conditions. Driving and gaze behavior as well as eye-tracking information were analyzed. Moreover, a questionnaire was used to obtain subjective measurements, such as ease of use and feeling of safety. The results show that the sonification helped drivers to feel safer and more focused on the road. This result was confirmed by gaze analysis, which shows that drivers look significantly less to the visual interface when a sound is present, leading to a safer use of the interface.