Max Legal Weight for GVW under 80,000 lbs and Max Permitted Weight for GVW over 80,000 lbs
The Gross Vehicle Weight 80,000 pounds maximum.
The Gross Weight imposed on the highway by the wheels of any one axle of a vehicle shall not exceed 22,400 pounds.
It shall be unlawful to transport or operate over or upon any public highway in this state any vehicle equipped with two axles the gross weight of which including its load exceeds 32,000 pounds when equipped with rubber tires if the front and rear axles are less than 6 feet apart, or 36,000 pounds if such axle spacing is less than 12 feet apart, or any single vehicle equipped with 3 or more axles the gross weight of which including its load exceeds 40,000 pounds if the front and rear axles are less than 16 feet apart, or 44,000 pounds if such axle spacing is less than 20 feet apart, or any vehicle of the tractor semi-trailer class equipped with 3 or more axles the gross weight of which including its load exceeds 46,000 pounds if the front and rear axles of the combined unit are less than 22 feet apart, or 50,000 pounds if such axle spacing is less than 27 feet apart provided, however, that the weight of a tag-along trailer secured to such vehicle by a pin and pintel hook shall not be considered in determining the above loads, so long as said trailer, when loaded, does not exceed its manufacturers weight limits, and as long as the vehicle towing said trailer and/or the trailer itself possesses the proper braking capacities for said trailers.
32,000 pounds (if the front and rear axles less than 6 feet apart)
36,000 pounds (less than 12 feet apart)
40,000 pounds (if the front and rear axles less than 16 feet apart)
44,000 pounds (less than 20 feet)
46,000 pounds (less than 22 feet)
50,000 pounds (less than 27 feet)
Gross Vehicle Weight
It shall be unlawful to operate over or upon any public highway in this state any vehicle equipped with tandem axles, should the gross weight of said axles exceed 44,000 pounds if such axle spacing does not exceed 8 feet.
With respect to all public highways, the overall gross weight on a group of two or more consecutive axles of a vehicle or combination of vehicles, shall be determined by the following bridge gross weight formula:
where:W = the overall gross weight on any group of two or more consecutive axles to the nearest 500 pounds;
Such overall gross weight of any vehicle or combination of vehicles may not exceed 80,000 pounds except as specified in Sections 31-25-1, 31-25-2 and 31-25-21. In any calculation using the above formula in which the multiple axle limit is less than 44,000 pounds, 44,000 pounds shall be considered the legal limit.
The State Department of Transportation with respect to highways under their jurisdiction may in their discretion upon application in writing and good cause being shown therefor, issue a special permit in writing authorizing the applicant to operate or move a vehicle or combination of vehicles of a size or weight of vehicle or load exceeding 80,000 pounds or otherwise not in conformity with the provisions of chapters 1-27, inclusive, of this title upon any highway under the jurisdiction of the party granting such permit and for the maintenance of which said party is responsible. Provided, however, that neither the State Department of Transportation nor the local authorities may issue permits for divisible loads weighing in excess of 104,800 pounds gross vehicle weight for 5 axle vehicles and 76,650 pounds, gross vehicle weight, for 3 axle vehicles.
Source of information: http://sos.ri.gov/documents/archives/regdocs/released/pdf/DMV/DMV_1673_.pdf