Motorcycle accidents caused by sudden deceleration or exceed maximum safe speed of vehicles are still common. There is no tool that can provide alerts when the speed has exceeded the safe speed limit for vehicles allowed. Hence, the study aims to design and manufacture implementation of ATmega16 as an indicator of the maximum speed. Output data is obtained in the form of increasing speed. Maximum speed indicator system consists of atmega 16 as the main processing unit, sensor optocoupler, 4x4 keypad, buzzer and LCD LM162. It includes the output of the transducer which is processed by a microcontroller keypad which is then forwarded to the buzzer and LCD LMB162. Testing is conducted by direct tests on the vehicle running, and the obtained results show the maximum speed indicator device made to work properly and in accordance with the specifications of the predetermined design, so that it can give a warning when the safe speed is being and has been exceeded