Amphibious Trailer

Some specialized brands of trailer, such as the hi-lo trailer, have an upper half (slightly larger than the lower half) that can be folded down over the lower half to a total height of about five feet for reduced wind resistance during travel; these otherwise contain everything other travel trailers have (except for a full-height closet).
An innovation in the travel trailer types is the "toy box" or "toy hauler". Half living area and half garage, these trailers allow 'toys' to be brought to the countryside. A folding rear ramp give access for motorcycles, ATVs, personal watercraft or racecars. A generator provides power for the equipment.
Another innovation is the hybrid travel trailer, combining the features of a pop-up trailer and a hard-sided trailer. In its camping configuration, one or more bunks fold down from the side with canvas tent covers. When in travel, the bunks fold up into the side of the trailer leaving four hard sides. Larger models allow the hybrid travel trailer to be used while "turtled", that is with the sides up. The primary advantage of a hybrid travel trailer is that it offers a greater space-to-weight ratio. A disadvantage is that the tent ends are not insulated and subject to heat loss and condensation.
In the United States, it is generally illegal for passengers to ride in a travel trailer, while in motion, unlike horse-drawn trailers and coaches. Triple towing is not allowed in some states, such as California, Alabama, Florida, or New York; however, triple towing is permitted in Texas if the combined length does not exceed 65 feet (20 m)).