Drivers often feel various kinds of emotions in the context of driving. This research was conducted due to the difficulty of expressing the emotions in driving contexts. At first, throughout driver observation and survey it was found that existing interface in car is not enough to express drivers’ emotion to other drivers. Also most representative emotions drivers want to express while driving were identified, which were made into emoticons. Interactive prototypes which display emoticons were installed in the front and back of vehicles so that drivers can express their emotions while driving. Experiments were conducted to verify whether drivers’ stress was reduced when the prototype was installed in the vehicle, thereby enabling them to share their feelings with other drivers. The results showed that stress was indeed reduced in drivers compared to their original state.