Road-projection technology has been developed to improve traffic safety, in which symbols or patterns are projected onto the road surface from a vehicle. The response times of cyclists when a vehicle direction indicator flash with and without road-projection were obtained to verify alerting effects of the road-projection lamp linked to the direction-indicator of the vehicle. When cyclists could not see the direction-indicator lamp flashing on the vehicle or when they were moving by a bicycle, the response times with road-projection were shorter than those without it. Favorable responses were received from participants through the questionnaire used in this study regarding the road projection of the direction-indicator. Even when cyclists were operating smartphones, the response times with road-projection were shorter than without it. However, this suggested that delays caused by operating smartphones were longer than the time saved by road-projection.