The present invention relates to a warning system mounted on a vehicle comprising detection means for detecting an object, and signalling means connected to said detection means, wherein said detection means are arranged to remotely detect an object in the vicinity of the vehicle and that said detection means is connected to said signalling means to automatically emit a signal that is detectable from at least one other side of the vehicle than the one where said object is present, and wherein said detection means (4) are arranged to avoid detecting objects lower than 0.5 m, preferably lower than 0.25 m from the ground.