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Size and Weight Limits
(207) 624-9000 ext. 52134

Gross Weight Limits

Maine General Law

Maine's General Law gross weight limit applies to the following highways:

  • Interstate 95 from the New Hampshire State Line to the southern terminus of the Maine Turnpike;
  • The Maine Turnpike (designated Interstate 95);
  • All non-Interstate highways.

Maine's General Law provides that the total weight of a vehicle or combination of vehicles, plus their load, is limited by the number of axles to:

Table 1 - General Law Gross Weight Limits

2 Axles

..........34,000 pounds

3 Axles

..........54,000 pounds

4 Axles

..........69,000 pounds *

5 Axles

..........80,000 pounds

6 Axles

..........100,000 pounds **

*Also applies to all single unit vehicles over 4 axles.

**Applies only to a combination vehicle consisting of a 3 axle truck tractor towing a triaxle semitrailer unit that is operating on the General Law highways listed above. The 80,000 pound limit applies to all other combination vehicles over 4 axles, except for certain vehicles carrying special commodities which are allowed additional weight tolerances. (53 foot semitrailer vehicles are restricted to 80,000 pounds GVW on the Maine Turnpike.)

Interstate Highway System

For operation on the Interstate Highway System, excluding those segments of the Interstate Highway System listed above, the weight of the vehicle or combinations of vehicles, plus their load, is limited by Bridge Formula B, modified. In addition, the Bridge Formula also limits the total weight of any group of consecutive axles of a vehicle or combination of vehicles according to the distance between the centers of the extreme axles in a group. The greatest load allowed is 80,000 pounds.

The following are exceptions to the use of the Bridge Formula on the Interstate System:

  • Single axles are limited to 20,000 pounds for vehicles over 73,280 pounds GVW, and 22,000 pounds for vehicles 73,280 pounds GVW or less.
  • Tandem axles are limited to 34,000 pounds.
  • Two consecutive tandem axles may carry 34,000 pounds each if there are at least 36 feet between centers of extreme axles.
  • All 3 axle trucks with brakes on the wheels of all axles may be operated with a gross weight of 48,000 pounds if the distance between extreme axles is at least 16 feet when hauling construction materials or 18 feet when hauling forest products or hauling raw ore from mine or quarry to place of processing.

Axle Weight Limits

Groups of closely spaced axles are treated as follows:

  • Axles whose centers are less than 4 feet apart shall be considered a single axle unit.
  • A single axle whose center is closer than 10 feet, or if it is a steering axle 9 feet, to a triaxle unit shall be considered part of that triaxle and not add to the allowable load capacity of that triaxle unit.

The axle weights and distance limits for axle units are:

Table 2 - Axle Unit Weight Limits
  Single Axle Tandem Axle Triaxle
Interstate 22,000 lbs (1) 34,000 lbs
(2)
Non Interstate (3) - General 22,400 lbs 38,000 lbs (4) 48,000 lbs (5)
Non Interstate (3) - Special Products 24,200 lbs 46,000 lbs (6) 54,000 lbs (7)

(1) 20,000 pounds for GVW over 73,280 pounds;
(2) Controlled by Bridge Formula (see Table 3 below)
(3) For the following roads: Interstate 95 from the New Hampshire State Line to the southern terminus of the Maine Turnpike, the Maine Turnpike (designated Interstate 95 and 495) and all non-Interstate highways;
(4) Exceptions - 41,000 lbs on a six axle combination;
(5) Exceptions - 50,000 lbs on a six axle combination;
(6) 44,000 pounds tandem limit for 5 or more axle combinations.
(7) 64,000 pounds for 4 axle single unit vehicles hauling forest products.
All loads are limited to 600 pounds per inch of tire width, manufacturer's rating, excepting farm trucks transporting potatoes directly from the field to the place of storage or to a processing facility during the potato harvesting season.

Table 3 - Interstate Axle Group "Bridge Formula" Weight Limits
Distance (FT) Between Centers of Extreme Axles in Axle Group
Gross Weight Limit On Any Group of Consecutive Axles
2
Axles
3
Axles
4
Axles
5
Axles
6
Axles
7
Axles
4..................................
34,000
5..................................
34,000
6..................................
34,000
7..................................
34,000
AXLE
GROUPS
IN
8..................................
34,000
34,000
More than 8.................
38,000
42,000
THESE
SPACINGS
9..................................
39,000
43,000
10................................
40,000
43,500
IMPRACTICAL
11................................
41,000*
44,500
12................................
42,000*
45,000
50,000
13................................
43,000*
46,000
50,500
14................................
44,000*
46,500
51,500
15..............................................
47,500
52,000
16..............................................
48,000
52,500
58,000
17..............................................
49,000
53,500
58,500
18..............................................
49,500
54,000
59,500
19..............................................
50,500
54,500
60,000
20..............................................
51,000
55,500
60,500
66,000
21..............................................
52,000
56,000
61,000
66,500
22..............................................
52,500
56,500
62,000
67,000
23..............................................
53,500
57,500
62,500
68,000
24..............................................
54,000
58,000
63,000
68,500
74,000
25..............................................
55,000
58,500
63,500
69,000
74,500
26..............................................
55,500
59,500
64,500
69,500
75,000
27..............................................
56,500
60,000
65,000
70,000
76,000
28..............................................
57,000
60,500
65,500
71,000
76,500
29..............................................
58,000
61,500
66,000
71,500
77,000
30..............................................
58,500
62,000
67,000
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
79,500
34............................................................
64,500
69,500
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**
72,000
,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
74,500
79,000
43............................................................
71,000
75,000
80,000
44............................................................
71,500
75,500
45............................................................
72,000
76,000
46............................................................
77,000
47............................................................
Greater
77,500
48............................................................
Loads
78,000
49............................................................
Not
78,500
50............................................................
Practical
79,500
51............................................................
80,000

*40,000 lbs. if GVW is 73,280 lbs. or more. ** If two tandems, 68,000 lbs.

Tolerances and permits (Excluding the Interstate System)

General Tolerance

Provided that gross, axle, and tire limits are not exceeded, vehicles may operate at a gross weight exceeding the current registration by the greater of 2 1/2 percent or 500 pounds.

A three axle truck tractor (not truck) and triaxle semitrailer combination vehicle (Special 6) may operate at a maximum of 100,000 pounds GVW if:

  • The vehicle is registered or apportioned for 100,000 pounds;
  • The distance* between extreme axles, excluding the steering axle, is at least 36 feet to the nearest foot;
    *The 100,000 pound maximum GVW shall be reduced 2,000 pounds for each foot this distance is less than 36 feet, to the nearest foot.
  • The minimum distance between steering axle and the first axle of the tandem is at least 10 feet to the nearest foot;
  • The maximum weight shall not exceed 41,000 pounds on the tandem axle and 50,000 pounds on the triaxle;
  • For all vehicles manufactured, modified, or retrofitted with liftable or variable load suspension axles after October 30, 1991, such axles are permitted only under the following conditions:
    • Only one liftable or variable load axle may be present on the truck tractor unit, and such axle must be legally part of the tandem axle group.
    • Only one liftable or variable load axle may be present on the semitrailer unit, and such axle must be legally part of the triaxle group.
    • The axle weight rating of the lift axle must conform to the expected loading of the suspension and be at least 20,000 pounds or more.

 

Special Limits for Certain Commodities

While actively engaged in the exclusive transport of the commodities listed below, vehicles will be allowed special weight tolerances.

The special weight tolerances are:

  • 10% over the maximum gross weights (up to 80,000 pounds) listed in Table 1;
  • 85,000 pounds GVW for certain six axle single unit trucks carrying only forest products;
  • 94,000 pounds GVW for certain four axle single unit truck trailer combination vehicles;
  • 100,000 pounds GVW for combination vehicles consisting of a three-axle truck-tractor (not truck) with triaxle semitrailer that is registered or apportioned for at least 90,000 pounds GVW; and
  • Axle weight limits: See Table 2.

Restrictions include:

  • Wheelbase reductions for 4 or more axle combinations;
  • 600 pounds per inch of tire width, manufacturer's rating;
  • Unless otherwise indicated in this section, the vehicle must be registered or apportioned for the maximum legal weight allowed for that vehicle configuration under Maine law;
  • For operation at 100,000 pounds gross weight, the distance between the extreme axles of the vehicle, excluding the steering axle, must be at least 32 feet to the nearest foot.

The vehicle must be loaded entirely with the following commodities:

  • Materials or unset concrete intended for highway construction and carried in dump or transit mix trucks;
  • Manufacturer's concrete products;
  • Raw ore from mine or quarry to place of processing;
  • Unprocessed milk;
  • Refrigerated products when they constitute the majority of products carried in a sealed vehicle;
  • Building materials that absorb moisture during delivery originating and terminating within the State;
  • Incinerator ash;
  • Unconsolidated rock materials, including limestone, and: bark; pulpwood; firewood; logs; sawed lumber; bolts; soils; dimension lumber; road salt; solid waste; farm produce; sawdust; and wood chips.

A four axle single unit truck, two axle trailer combination vehicle carrying the commodities listed above may operate at the maximum gross vehicle weight of 94,000 pounds under either of the following conditions:

  • The trailer unit is registered for at least 28,000 pounds gross weight and the combined registered weight for the truck and trailer is at least 94,000 pounds gross weight; or
  • The truck is registered for at least 94,000 pounds.

Other restrictions apply. Contact the Bureau of Motor Vehicles, Motor Carrier Services Office for further information.

Projecting Objects & Trailers

Vehicles carrying objects that project more than 4 feet from the rear of the vehicle must, during the period of 1/2 hour after sunset to 1/2 hour before sunrise, carry a red light at or near the rear end of the projecting objects. At all other times, the vehicle must carry a clean red cloth of the dimensions 12 x 12 inches attached at or near the end of the projecting object.

During the hours when lights are required, a vehicle carrying logs that project more than 4 feet from the rear of the vehicle is required to display a red reflector or to paint reflectorized paint on the end of the log projecting furthest to the rear. The reflector or reflectorized paint must be properly maintained, and must be located and be the size which is sufficient to reflect at night on an unlighted highway the undimmed headlights of a vehicle approaching the rear of the vehicle from a distance of at least 200 feet.

A load must be covered or otherwise secured or confined to prevent any portion of the load from falling from or spilling out of the vehicle.

Trailers, semitrailers, or vehicles being towed must, in addition to the tow bar or coupling device, have a safety chain or steel cable made of not less than 1/4 inch wire so attached as to prevent breakaway from the towing vehicle. (This requirement does not apply to truck tractor and semitrailer units equipped with a fifth wheel mechanism.)

Trailers that are wider then the towing vehicle must be equipped with reflective material or a lamp on each front corner that is visible to oncoming traffic.

Questions or comments can be sent to Francis Fox, Chief, Motor Carrier Services.