Fifth-wheels, referred to as “fivers” in transport slang, provide the largest living area and usually the greatest comfort. The raft of legislation that covers their use should not cause too much consternation for owners accustomed to the ways of the road, but rules do vary from state to state. Since fifth-wheels are towed behind a truck rather than attached permanently to the driver’s cabin, size limits and passenger safety are of key concern.

Passenger Restrictions

As a general rule, passengers are not allowed to travel in a fifth-wheel trailer while it is being towed, but 21 states do allow it, including California, New York and Pennsylvania. Restrictions apply, however, usually stipulating that there must be one unlocked exit that can be opened from inside or outside, or that passengers must be over 14 years old. Some states require that safety glass be fitted in windows of trailers carrying passengers, and that all passengers wear seat belts.

Size Limits

Just because a dealership touts the virtues of a particular fifth-wheel does not mean it is welcome in all states. North Carolina, for example, does not allow trailers longer than 35 feet. Most states set the bar at either 40 or 53 feet, while big rig drivers should head to Wyoming, which allows a 60-foot “fiver.” More importantly, the combined length of both towing vehicle and trailer must be taken into account. In Mississippi, the total length cannot exceed 53 feet, while Wyoming again allows the longest rigs at up to 85 feet. Other states are in between. Width restrictions also apply. All but three states set the maximum at 8 ½ feet, which is a standard width for most fifth-wheels.

Safety Equipment

One of the biggest risks when towing a fifth-wheel is loss of control over the trailer. To mitigate the dangers of uncoupling during a trip, many states require that the trailer be fitted with a safety chain, and a separate braking system must usually be fitted for trailers over a certain weight, typically 1,000 pounds but as high as 3,000 or 5,000 pounds in some states. The breakaway switch activates the brakes if the trailer becomes separated from the towing vehicle. For larger RVs, brakes must be fitted to each wheel. Only 14 states require a fifth-wheel to carry a fire extinguisher, but common camping sense demands one there, with or without legal enforcement.

Driving Rules

Most states allow overnight parking with fifth-wheels in rest areas if indicated, but the dwindling availability of places to stay legally is a major concern among full-time RVers. While underway, trucks towing fifth-wheels will have to stay in the right-hand lane in states including California, and some states prohibit a right turn on a red light. Forget the carpool lane in Connecticut, and stay away from the tunnels in Maryland and Massachusetts if you are carrying propane tanks on board. While few drivers would want to drive without windshield wipers and headlights on, in some states it is obligatory. The wicked pleasure of driving with the support of a radar detector or police scanner is banned in many states.