Amphibious Trailer

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)).