New Hampshire Revised Statutes 266:18 – Weight on Interstate and Defense Highway System
I. Maximum tire and axle gross weights allowable:
Terms Used In New Hampshire Revised Statutes 266:18
- Combination vehicle: shall mean a combination of truck-tractor and semi-trailer, or a combination of truck-tractor, semi-trailer, and full trailer, being driven together as an articulated unit. See New Hampshire Revised Statutes 259:11-a
- Commissioner: shall mean the commissioner of safety. See New Hampshire Revised Statutes 259:13
- following: when used by way of reference to any section of these laws, shall mean the section next preceding or following that in which such reference is made, unless some other is expressly designated. See New Hampshire Revised Statutes 21:13
- Full trailer: shall mean any trailer being towed behind a semi-trailer as part of a combination vehicle also known as twin-trailers or "double bottoms. See New Hampshire Revised Statutes 259:37-a
- Heavy duty recovery vehicle: shall mean a wrecker that:
I. See New Hampshire Revised Statutes 259:40-b - Semi-trailer: shall mean a vehicle of the trailer type so designed and used in conjunction with a self-propelled vehicle that a considerable part of its own weight or that of its load rests upon and is carried by the towing vehicle, and not including a pair or set of wheels commonly used as an implement for other purposes than transportation, provided, however, that the word "semi-trailer" shall not include any vehicle as described in this section if used exclusively for agricultural purposes unless said vehicle be of the type constructed specifically to be towed by a tractor-type truck. See New Hampshire Revised Statutes 259:98
- Single unit vehicle: shall mean a truck consisting of cab, chassis and body capable of carrying a load and not primarily designed for drawing other vehicles. See New Hampshire Revised Statutes 259:100-a
- State: shall mean :
I. See New Hampshire Revised Statutes 259:106 - Tandem axle: shall mean 2 consecutive axles whose centers may be included between parallel vertical planes spaced at least 4 feet and not more than 10 feet apart, extending across the full width of the vehicle, except that for vehicles being driven on the interstate and defense highway system with a gross weight in excess of 73,280 pounds a tandem axle shall be limited to 2 or more consecutive axles whose centers may be included between parallel vertical planes spaced not less than 40 nor more than 96 inches apart, extending across the full width of the vehicle. See New Hampshire Revised Statutes 259:107-a
- Trailer: shall mean any vehicle without motive power designed for carrying property or passengers wholly on its own structure and for being drawn by a self-propelled vehicle, except those running exclusively on snow or on stationary tracks and vehicles used exclusively for agricultural purposes. See New Hampshire Revised Statutes 259:113
- Tridem: shall mean 3 consecutive axles, the centers of which, when measured between the first and third axles, may be included between parallel vertical planes spaced more than 8 feet apart, and which tridem unit measures less than 12 feet overall between the centers of extreme axles, extending across the full width of the vehicles; except that for vehicles being driven on the interstate and defense highway system with a gross weight in excess of 73,280 pounds, a tridem shall measure not less than 40 inches nor more than 96 inches between the parallel vertical planes. See New Hampshire Revised Statutes 259:115-a
- Truck: shall mean every motor vehicle designed, used or maintained primarily for the transportation of property. See New Hampshire Revised Statutes 259:115-b
- Truck-tractor: shall mean any vehicle designed and intended primarily for drawing other vehicles and not so constructed as to carry a load other than a part of the vehicle and load so drawn, except that a truck-tractor engaged in the transportation of automobiles may transport motor vehicles on a part of the power unit. See New Hampshire Revised Statutes 259:116
- Vehicle: shall mean :
I. See New Hampshire Revised Statutes 259:122
(a) The manufacturer’s load rating for the tires.
(b) When being driven with a gross weight in excess of 73,280 pounds:
(1) 20,000 pounds per axle on axles more than 8 feet apart;
(2) 17,000 pounds per axle on axles not more than 8 feet apart;
(c) When being driven with a gross weight not in excess of 73,280 pounds:
(1) 22,400 pounds per axle on 3-axle single unit vehicles and on all other vehicles with axles 10 feet or more apart, including combination vehicles;
(2) 18,000 pounds per axle on axles of vehicles less than 10 feet apart, except 3-axle single unit vehicles.
(d) Two axles less than 40 inches apart shall be considered as a single axle unit.
II. Maximum allowable vehicle gross weights:
(a) For 2-axle vehicles, 33,400 pounds.
(b) For single unit 3-axle vehicles, 47,500 pounds, or a gross weight not in excess of that produced by application of the weight formula as defined in subparagraph (h), whichever is greater, as shown in table III.
(c) For single unit 4-axle vehicles, provided that such vehicles shall have drive on 2 rear axles, and the tridem may contain not more than one retractable axle and, if not factory installed and load equalizing, must provide a system of load equalization by hydraulic, pneumatic, or mechanical means, and be equipped with brakes:
(1) 47,500 pounds, or a gross weight not in excess of that produced by application of the weight formula as defined in subparagraph (h), whichever is the greater; or
(2) If a heavy duty recovery vehicle, 75,000 pounds, or a gross weight not in excess of that produced by application of the weight formula as defined in subparagraph (h), whichever is the greater.
(d) For a single unit 5-axle heavy duty recovery vehicle, 80,000 pounds, or a gross weight not in excess of that produced by application of the weight formula as defined in subparagraph (h), whichever is the greater. Such vehicles shall have drive on 2 rear axles, and the tridem may contain not more than one retractable axle and, if not factory installed and load equalizing, must provide a system of load equalization by hydraulic, pneumatic, or mechanical means, and be equipped with brakes.
(e) For a combination of truck-tractor and semi-trailer equipped with 3 axles, the gross weight shall not exceed that set forth in table I as follows:
| Table I. | |
|---|---|
| Distance Between Extreme Axles in Feet | Maximum Gross Weight in Pounds |
| 25 | 54,500 |
| 26 | 55,500 |
| 27 | 56,000 |
| 28 | 57,000 |
| 29 | 57,500 |
| 30 | 58,500 |
| 31 | 59,000 |
| 32 | 60,000 |
Further provided that the maximum tire and axle gross weights as provided in paragraph I shall apply and the maximum load in pounds carried on any group of 2 or more consecutive axles shall not exceed that produced by application of the weight formula as defined in subparagraph (h).
(f) For a combination of truck-tractor and semi-trailer equipped with 4 axles, the gross weight shall not exceed that set forth in table II as follows:
| Table II. | |
|---|---|
| Distance Between Extreme Axles in Feet | Maximum Gross Weight in Pounds |
| 28 | 60,500 |
| 29 | 61,500 |
| 30 | 62,000 |
| 31 | 62,500 |
| 32 | 63,500 |
| 33 | 64,000 |
| 34 | 64,500 |
| 35 | 65,500 |
| 36 | 66,000 |
| 37 | 66,500 |
| 38 | 67,500 |
| 39 | 68,000 |
Further provided that the maximum tire and axle gross weights as provided in paragraph I shall apply, and the maximum load in pounds carried on any group of 2 or more consecutive axles shall not exceed that produced by application of the weight formula as defined in subparagraph (h).
(g) For a combination of truck-tractor and single semi-trailer with 5 or more axles with gross weight not in excess of 73,280 pounds, the weight on any single axle shall not exceed 22,400 pounds and the weight on any tandem axle shall not exceed 36,000 pounds.
(h) For a combination of truck-tractor and single semi-trailer equipped with 5 or more axles with a gross weight in excess of 73,280 pounds or a combination of truck-tractor and more than one trailing unit, the total gross weight shall not exceed 80,000 pounds including all law enforcement tolerances, and the overall gross weight on a group of 2 or more consecutive axles shall not exceed that produced by application of the following formula, known as the weight formula:
——
N − 1
(In which W equals overall gross weight on any group of 2 or more consecutive axles to the nearest 500 pounds; L equals the distance measured to the nearest foot between the extreme of any group of 2 or more consecutive axles; and N equals the number of axles in the group under consideration.) Except that 2 consecutive sets of tandem axles may carry a gross load of 34,000 pounds each, provided the overall distance between the first and last axles of such consecutive sets of tandem axles is 36 feet or more and provided that such gross weight shall not exceed 80,000 pounds, including all law enforcement tolerances.
——
N − 1
when expressed in tabular form results in maximum allowable load in pounds carried on any group of 2 or more consecutive axles as follows in table III.
| Table III. | ||||||
|---|---|---|---|---|---|---|
| Distance* | 2 axles | 3 axles | 4 axles | 5 axles | 6 axles | 7 axles |
| 4 | 34,000 | |||||
| 5 | 34,000 | |||||
| 6 | 34,000 | |||||
| 7 | 34,000 | |||||
| 8 and less | 34,000 | 34,000 | ||||
| more than 8 | 38,000 | 42,000 | ||||
| 9 | 39,000 | 42,500 | ||||
| 10 | 40,000 | 43,500 | ||||
| 11 | 44,000 | |||||
| 12 | 45,000 | 50,000 | ||||
| 13 | 45,500 | 50,500 | ||||
| 14 | 46,500 | 51,500 | ||||
| 15 | 47,000 | 52,000 | ||||
| 16 | 48,000 | 52,500 | 58,000 | |||
| 17 | 48,500 | 53,500 | 58,500 | |||
| 18 | 49,500 | 54,000 | 59,000 | |||
| 19 | 50,000 | 54,500 | 60,000 | |||
| 20 | 51,000 | 55,500 | 60,500 | 66,000 | ||
| 21 | 51,500 | 56,000 | 61,000 | 66,500 | ||
| 22 | 52,500 | 56,500 | 61,500 | 67,000 | ||
| 23 | 53,000 | 57,500 | 62,500 | 68,000 | ||
| 24 | 54,000 | 58,000 | 63,000 | 68,500 | 74,000 | |
| 25 | 54,500 | 58,500 | 63,500 | 69,000 | 74,500 | |
| 26 | 55,500 | 59,500 | 64,000 | 69,500 | 75,000 | |
| 27 | 56,000 | 60,000 | 65,000 | 70,000 | 75,500 | |
| 28 | 57,000 | 60,500 | 65,500 | 71,000 | 76,500 | |
| 29 | 57,500 | 61,500 | 66,000 | 71,500 | 77,000 | |
| 30 | 58,500 | 62,000 | 66,500 | 72,000 | 77,500 | |
| 31 | 59,000 | 62,500 | 67,500 | 72,500 | 78,000 | |
| 32 | 60,000 | 63,500 | 68,000 | 73,000 | 78,500 | |
| 33 | 64,000 | 68,500 | 74,000 | 79,000 | ||
| 34 | 64,500 | 69,000 | 74,500 | 80,000 | ||
| 35 | 65,500 | 70,000 | 75,000 | |||
| **36 | 66,000 | 70,500 | 75,500 | |||
| **37 | 66,500 | 71,000 | 76,000 | |||
| **38 | 67,500 | 71,500 | 77,000 | |||
| 39 | 68,000 | 72,500 | 77,500 | |||
| 40 | 68,500 | 73,000 | 78,000 | |||
| 41 | 69,500 | 73,500 | 78,500 | |||
| 42 | 70,000 | 74,000 | 79,000 | |||
| 43 | 70,500 | 75,000 | 80,000 | |||
| 44 | 71,500 | 75,500 | ||||
| 45 | 72,000 | 76,000 | ||||
| 46 | 72,500 | 76,500 | ||||
| 47 | 73,500 | 77,500 | ||||
| 48 | 74,000 | 78,000 | ||||
| 49 | 74,500 | 78,500 | ||||
| 50 | 75,500 | 79,000 | ||||
| 51 | 76,000 | 80,000 | ||||
| 52 | 76,500 | |||||
| 53 | 77,500 | |||||
| 54 | 78,000 | |||||
| 55 | 78,500 | |||||
| 56 | 79,500 | |||||
| 57 | 80,000 | |||||
* Distance in feet between the extremes of any group of 2 or more consecutive axles.
**Distance in feet between the extremes of 4 axles. (2 sets of 2 axles) 68,000 gross weight exception. The permissible loads are computed to the nearest 500 pounds.
(i) The following loaded vehicles shall not be driven over H15-44 bridges:
(1) A combination vehicle equipped with 5 axles in the configuration of 3-axle truck-tractor and 2-axle semi-trailer with wheel base less than 38 feet or 2-axle truck-tractor with 1-axle semi-trailer and 2-axle full trailer with wheel base less than 45 feet.
(2) A loaded single unit vehicle with full trailer equipped with axles with wheel base less than 45 feet.
(3) Vehicles with 7, 8, or 9 axles.
(j) Coupled vehicles consisting of a truck together with a trailer attached to the truck by a pintle hook or similar coupling device with adequate breakaway protection as provided in N.H. Rev. Stat. § 266:63 may be driven, provided the total combined gross weight of the vehicles does not exceed 80,000 pounds and provided that each unit of the coupled vehicles shall be limited to the maximum permissible axle weights and gross weights of the individual units, and further provided that the weight of 2 or more consecutive axles of the coupled vehicle shall not be in excess of that produced by application of the weight formula as defined in subparagraph (h) and shall be limited to a total combined gross weight not in excess of 80,000 pounds, a single axle limit of 20,000 pounds and a tandem axle limit of 34,000 pounds.
III. Notwithstanding paragraphs I and II, for as long as exemptions exist in 23 U.S.C. § 127 that allow maximum gross weights of up to 99,000 pounds on interstate routes 89, 93, and 95 of the interstate and defense highway system, the provisions of N.H. Rev. Stat. § 266:18-a regarding weight on the non-interstate and general highway system shall also apply to vehicles or combination vehicles while being operated on any sections of interstate routes 89, 93, or 95 not posted by the commissioner of transportation for lower weights. Such vehicles shall not exceed the weight limits in paragraphs I and II unless they have been certified pursuant to N.H. Rev. Stat. § 266:18-d for the higher weights and paid the required fee the same as vehicles operating on the non-interstate highways as provided in N.H. Rev. Stat. § 266:18-d.