While there are safety issues involved, some states that allow passenger to ride in fifth-wheel trailers while being towed.
All states allow turning on red after stopping unless posted. Some states require your headlights to be on if your windshield wipers are engaged. This should be connected to your trailer or car as well.
All states have height restrictions for your own safety; you wouldn't want to go under a 12-foot-tall bridge with a 14-foot-tall RV or under low hanging power lines. If you attach a car with a trailer, this law is the same.
Legal lengths vary due to shape and style of the roads. Some cannot accommodate the larger RVs because of hills and curves. The length of a car being towed also is a dded to the total length.
When looking into laws, you likely will find laws in your own state that you did not know existed. A good place to find the basic RV laws is in Woodall's or Trailer Life Campground Guide.
