While both food trucks and food trailers provide a mobility option to food sellers, there is a difference between the two options. A food truck is a complete unit that can be driven around, the food vending portion is built into the vehicle - the use of the vehicle would in general be restricted to that one purpose.

A food trailer on the other hand, is just a trailer with no auto mobility capability. Simply put a food trailer would have to be driven around - pulled by another vehicle. So a food seller using a food trailer would be in a fixed position until a vehicle arrives to pull the trailer around. The cost of a food trailer could be a bit lower than that of a food truck. This would depend on the equipment fitted into the food trailer and food truck. It is quite obvious that there is no need to engage a vehicle all through the time that, the food trailer is in operation.

More information on this topic at: https://www.saw2day.org/food-trucks-trailers-thailand-01-0921.php