I make no claim for the veracity of this information...
I posed this question on rv.net and located this pdf. It is old, but I think you will get the jist....
I found out that in Illinois it is only legal IF you are towing either an enclosed utility trailer WITH electric brakes, OR a non-commercial personal use vehicle WITH electric brakes....
But I got that from a state trooper....
I have a pdf I tried to attach but apparently I am not smart enough to figure that out. PM me and I have the US Road Use file you are looking for....
per ISP commercial vehicle division
I talked to the ISP & this is what they said,
60' maximum length, no laws against towing a boat behind a travel trailer.
Looks like I am going to have to get a really short boat.
Doubles and Triples in TX
This is an old thread, resurrected, but I’ll throw out some things here. Road Regulations start with Federal and most states adopt these as their own, with some having additional limitations to fit the conditions of their State.
As to Texas, the Interstates are full of UPS and FED-EX trucks pulling doubles, legal, everyone does it.
Limitations for any vehicle or combination vehicles, private or otherwise begin at the Commercial overall weight limit of 26k lbs.
No combination of vehicles, other than a truck tractor-trailer combination may exceed 65 feet. (Exceptions for logging and construction, but this does not apply to the OP)
Vehicle Combinations. No passenger vehicle or other motor vehicle with an unloaded weight of less than 2,500 pounds may be coupled with more than one other vehicle. Not more than three vehicles may be operated in a combination.
Therefore, your overall weight and length are the limiting factors.
Many people consider these huge fivers as being exempt from commercial status, not true. There are exemptions in place for RV’s but, From the manual: “A recreational vehicle that is driven for personal use.” I read this literally as an RV that is DRIVEN, not a trailer pulled.
As a member mentioned earlier, even with exempt status, you still have to pass and obtain a NON-COMMERCIAL Class ‘A’, or ‘B’ license to operate an exempt Vehicle exceeding 26k lbs. In addition, as mentioned, when the overall length of a Motor Home exceeds the limits in place, you must also comply with these rules for a NON-COMMERCIAL operators permit.
Take a 3500-drw pickup and hook a 6-lug tandem axle trailer behind, followed by a 5-lug tandem axle trailer and your Combined Gross Vehicle Weight of all three exceeds 28k lbs.
Try to hook most any trailer to a large Fiver behind a 1-ton, and your combined weight rating exceeds the 26k limit.
Many new F-450 pickup owners are shocked to get their first overweight fines. With it’s GVWR exceeding 16k lbs, anything larger than a 6-lug tandem axle trailer hooked behind puts you in the Commercial Class, whether for private use or not.
There are of course exemptions for farm, agriculture, and well digging but you STILL need to have the proper operator’s license, as stated above.