According to the 2013 annual report file by the Fatality Analysis Reporting System (FARS), 14 percent of all traffic fatalities and an estimated 3 percent of those injured in traffic crashes were pedestrians. Our approach is active safety system based on pedestrian detection. This paper proposes a traffic caution system for pedestrian safety whose objective is to give a warning using visual effect to both driver and pedestrian to solve a lack of driver's and pedestrian's road attentiveness. Our contributions are as follows: 1) pedestrian detection and vehicle speed estimation using low cost sensors, 2) spontaneous participation of a driver for risk awareness according to visual effects (e.g., if LEDs are turned on, the driver puts the phone down.), and 3) improvement of roadattentiveness of a pedestrian and a driver using visual effects (i.e., high attentiveness on the road if LEDs are red, and moderate attentiveness on the road if LEDs are yellow.).