Using a handsfree telephone in a car leaves the driver, who has to phone or who receives a phone call, free to move. However, the driver's speech mixes with noise like in every telephone conversation. Moreover, the caller in the network hears a disturbing acoustic echo. The object of this study is to assess perturbances in the communication caused by noise (for the two subscribers) and echo (for the caller in the network). An experimental test was carried out on a simulator equipped with a handsfree telephone which provides full interactivity between the audio-visual function and the driving task. Twenty-four pairs of subjects, familiar with the phone use, were recruited. Under a given pretext, the caller in the network had to phone his partner inside the vehicle. After each test, a self-estimation was made by answering a questionnaire. This research gives prominence to disturbances closely connected with noise and, to a lesser extent, with echo, in terms of declared annoyance, effort to listen, effort to speak, quality and acceptability of communication, tiredness, difficulties during the conversation or linked to the driving task. (A)
Abstract