Tachometer is an instrument capable of measuring the speed of rotation of an object that is not directly an indication of the safety of the engine rotation. Tachometer in this study is mounted on a fleet of Trans Jogja. The primary data collection, in the form of speed graph from tachometer data recording, was then conducted and secondary data were obtained from PT Denso Sales Indonesia. The results showed that the average speed of Trans Jogja fleet in the morning is 42.86 km/h, at noon 36.5 km/h, in the afternoon 35.2 km/h, and in the evening 37.39 km/h. The observed violation was a violation which occurs when the driver passes the speed limit of vehicles in the city, which is 50 km/h. This study shows that 27.45 % violation occurs in the morning, 12.6 % during the day, 13 % in the afternoon, and 17.46 % in the evening.