This paper addresses the problem of the development, implementation and testing of a Lane Change Decision Aid System on a motorcycle, by using a short range radar sensor and a set of LEDs to interface with the driver. First, a feasibility analysis for such application is performed, then the algorithm is described, and finally the results of on-road tests are presented to illustrate and validate the method. The algorithm is composed by a first block for stabilizing the detected objects through a finite state machine and filtering the data coming from the sensor by implementing a Kalman filter that reduces the sensors inaccuracies. A decision block sets the state of the system by checking the position and speed of the detected objects, and finally an HMI block computes the Hazard Level considering position and Time-To-Collision of the detected objects and delivers a warning to the driver