Crossing the Street Across the Globe: A Study on the Effects of eHMI on Pedestrians in the US, Germany and China

Automated vehicles (AVs) will be integrated into mixed traffic within the next few years. To replace human-human communication, different external human machine interfaces (eHMI) have been proposed. Interpretation of HMIs can be subject to cultural influences. To examine the potential of eHMIs across different cultures, as well as research the transferability of study results, three virtual reality studies were conducted in Germany, the United Stated and China. In all studies, participants had the role of pedestrians and had to recognize if an AV is yielding or passing the pedestrian. Two eHMIs, a light-band and a display were used to inform pedestrians of the AV’s intention. When yielding to the pedestrian, eHMI showed benefits in terms of intention recognition in Germany and the United States. In China, however, eHMI did not show these effects. Results consistently show across all cultures, that eHMI deteriorates pedestrians’ recognition of the AVs intention to pass and not yield. The authors conclude that eHMI should only be used in already safe states of the AV, such as when yielding. In addition, eHMIs should not be introduced into a different culture without considering necessary cultural adaptations. For testing eHMIs internationally, there is a need to carefully select comparable traffic scenarios. These scenarios have to take into account habitual behavioral patterns of the current traffic and therefore the learned behavior of road users as to what they expect to happen in such situations.