A communication system for a vehicle includes a vehicle speed sensor configured to emit a periodic function with a parameter correlated to the speed of the vehicle, an acceleration monitoring system, a braking system engagement detector to detect a braking status of the vehicle, an alerting device capable of signaling other drivers of a deceleration condition of the vehicle, and a control device. The acceleration monitoring system is configured to compute the acceleration of the vehicle from variations in the parameter of the periodic function of the vehicle speed sensor and to output a deceleration status of the vehicle. The control device is coupled to the acceleration monitoring system, the braking system engagement detector, and the alerting device, wherein the acceleration monitoring system sends signals to the control device and the control device operates the alerting device in a manner dependent on the deceleration status of the vehicle.