A heavy hauler is a type of transport truck designed to move exceptionally heavy objects. Tractor trailer trucks are only allowed by law in many countries to operate under a certain amount of weight. If an object exceeds that weight and cannot be broken down into smaller portions for several trucks to carry, a heavy hauler is used to move the item. This truck features an extra long or wide trailer with many wheels for stability, and it is towed by a tractor strong enough to haul the weight. The truck must often be accompanied by guide vehicles.
The outward appearance of a heavy hauler is very similar to that of a flatbed truck, though the heavy hauler's flatbed trailer is usually much wider, longer, or otherwise overbuilt to handle excess weight. The load being hauled may extend off the sides of the trailer in any direction, which means the items being hauled may extend into another lane on a highway or road. For this reason, escort vehicles drive both ahead of and behind the heavy hauler, and sometimes even alongside it, to warn other motorists of the oversize vehicle. The escort vehicles may prevent other cars from coming near the heavy hauler for safety reasons. In some cases, a specially designed or equipped escort vehicle may drive ahead of the hauler to raise power lines and other obstructions that may become tangled when the hauler passes through.
It is not uncommon to see heavy haulers on roads and highways carrying a wide variety of goods. prefabricated houses are often hauled on these trucks, as are industrial equipment such as tanks, chambers, and so on. When factories or large buildings are built, they are often constructed with large sections of material that are then assembled onsite; a heavy hauler may be responsible for transporting these prefabricated pieces to the site for assembly.
Sometimes the flatbed trailer of the hauler can be articulated for greater mobility. Such trailers are usually reserved for especially large items that tend to be very long as well. The tractor used to haul such a trailer is usually more powerful than a normal tractor trailer unit. In some extreme cases, more than one tractor may be used to transport an especially large or heavy item, and in even fewer cases, a special hauler must be specifically designed and constructed to move an item across a short or long distance.