What do the signs and plates on the rear of the truck indicate?

All vehicles and combinations of vehicles whose length exceeds 12 metres must carry, on their rear and centred with respect to the vehicle's axis, a rectangular plate (V-6) with a reflective yellow background and a fluorescent red border. This plate may be replaced, when advisable for better placement, by two smaller ones positioned symmetrically on both sides of the vehicle's axis. Additionally, we can also observe that the truck carries the V-11 plate, which indicates that it is transporting dangerous goods. This plate may carry numbers indicating the type of hazard in its upper half, and the goods being transported in its lower half.