What are the biggest difficulties and hurdles with trucking?

That's why Tanker endorsement is required for several types of freight hauled in reefer, dry van, and flatbed. IMO, every CDL driver ought to get the Tanker endorsement. Many van & reefer drivers think it's only required when they pull round liquid tanker trailers. It's required for that AND also for totes of liquid hauled inside trailers, if they are of a certain weight/gallons.