A detection system designed to be mounted in a first vehicle. The detection system has a detection device configured to detect the presence of a second vehicle in a detection zone of the first vehicle, an alert device configured to generate a first stimulus perceptible by the driver of the first vehicle if a second vehicle is present in the detection zone, and a monitoring device configured to detect a reaction by the driver of the first vehicle in response to the first stimulus. The alert device is configured to generate a second stimulus in case of reaction by the driver of the first vehicle in reaction to the first stimulus.