This research is to get a better understanding of what kind of intention is needed to communicate between drives and autonomous car. Whattypes of communication methods should be used to offer a better user experienceto drivers and passengers. In this study, we examined the effects of informationtype (“why”message,“how”message) and speaker gender (female voice, malevoice) voice messages that provide communication about the car operations inadvance before the autonomous car’s action. 30 participants took part in thisexperiment. Results showed that female voice was more trustworthy, acceptableand pleasure than the male voice, because participants were more familiar withfemale voice as it was widely used in smart device and navigation system. Also,the female voice is easier to hear than the male voice in the noisy condition.More than half of the participants changed their preference for the speakergender, which reminds researchers to be cautious about the results of an onlinesurvey of drivers’attitude to speaker gender. How message is preferred byparticipants. It is considered to be more intelligent and interesting than whymessage as it described what automated activity it is undertaking directly,participants didn’t need to take part in the decision process which may add theircognitive load. Additionally, how message uses the first person word like“I”“we”or“us”to communicate with the drivers increase participants’ trust and satisfaction.