Thats not rice thats sugar cane and in the harvest season there are hundreds of grossly overloaded truck and trailer units on the road to the mills and waiting at the mills to be unloaded. I have a photo of 13 rows of units 6 deep waiting at a mill in one of 3 full parking areas with dozens more trucks on the roads to the mill.
These that are being modified are for carting the chopped cane that is harvested by harvester. This photo shows trucks with both chopped cane and whole cane which is cut then picked up and loaded on to the units on the right of the photo.