All trucks in China are required by law to have their license plate number printed on the back of the cargo area. Plates often get obscured by dirt or by the carried cargo. The lower beam is obligatory too, to prevent cars from ending up under the truck in case of a crash. Sadly, most of these beams are poorly constructed at best, so they don’t save a lot of lived in reality.
Happily, the driver of this truck doesn’t have to worry too much about this, with such lucky 6666 plates his business will boom in any way.