(2) “Single axle weight” means the total weight transmitted by all wheels whose centers may be included between 2 parallel transverse vertical planes 40 inches apart extending across the full width of the vehicle.

(3) “Tandem axle weight” means the total weight transmitted to the road by 2 or more consecutive axles whose centers may be included between parallel vertical planes spaced more than 40 inches apart but not more than 96 inches apart extending across the full width of the vehicle.

(b) An over-the-road bus or any vehicle that is regularly and exclusively used as an intrastate public agency passenger bus:

(1) Is exempt from tandem axle weight limits provided in this section; but

(2) Shall comply with the vehicle and combination of vehicles weight limits provided in this section that are not tandem axle weight limits.

(c) Notwithstanding any other provisions of this title, the overall gross weight on a group of 2 or more consecutive axles may not exceed an amount produced by application of the following formula:

( LN )
W = 500 ( ————– + 12N + 36 )
( N – 1 )

where “W” = overall gross weight on any group of 2 or more consecutive axles to the nearest 500 pounds, “L” = distance in feet measured horizontally between the vertical centerlines of the extreme of any group of 2 or more consecutive axles, and “N” = number of axles in group under consideration, except that 2 consecutive sets of tandem axles may carry a gross load of 34,000 pounds each providing the overall distance between the first and last axles of such consecutive sets of tandem axles is 36 feet or more; provided, that such overall gross weight may not exceed eighty thousand (80,000) pounds, including any enforcement or statutory tolerances.

(d) The following table indicates the permissible overall gross weights based upon the above formula:

Distance in
feet between
the extremes of
any group of 2
or more
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
8
and less 34,000 34,000

More than
8 38,000 42,000
75,000 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
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 72,500 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 Exception
See
subsection
(c),
This
section (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 74,000 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

(e) The gross weight of any vehicle or combination of vehicles may not exceed the following limits:

Gross
Number of weight
axles (in pounds)
Three or less 55,000
Four 66,000
Five as provided for in § 13-916 or § 13-923 of this
article 80,000

(f) A trailer with metal tires and a gross weight of more than 6,000 pounds may not be moved on a highway.

(g) (1) Except on interstate highways, a single unit vehicle with 3 axles, or a combination of vehicles with a trailer less than 32 feet long or a semitrailer less than 45 feet long, either registered as a farm vehicle or carrying farm products as defined under § 10-601 of the Agriculture Article that were loaded in fields or other off-highway locations, is permitted an axle load limit tolerance of 5% from subsections (c) and (d) of this section, except during harvest time when an axle load limit tolerance of 15% or, subject to paragraph (2) of this subsection, a gross vehicle weight tolerance of 5% from subsections (c) and (d) of this section is permitted for a vehicle carrying the following agricultural products:

(i) Wheat, for the period from June 1 to August 15;

(ii) Corn, for the period from July 1 to December 1;

(iii) Soybeans, for the period from September 1 to December 31; and

(iv) Vegetable crops, for the period from June 1 to October 31.

(2) The harvest time gross vehicle weight limit tolerance of 5% under paragraph (1) of this subsection applies only to a vehicle traveling within 100 miles of the field or other off-highway location where the vehicle was loaded.

(3) (i) Except on interstate highways, a single unit vehicle with at least 3 axles or a combination of vehicles with a trailer length of less than 32 feet carrying forest products that have been loaded in forests or other similar off-highway locations is permitted an axle load limit tolerance of 10% from subsections (c) and (d) of this section, except for the period from June 1 through September 30 when an axle load limit tolerance of 15% from subsections (c) and (d) of this section is permitted.

(ii) Except on interstate highways, a combination of vehicles with a semitrailer length of 45 feet or less carrying forest products that have been loaded in forests or other similar off-highway locations is permitted an axle load limit tolerance of 5% from subsections (c) and (d) of this section, except for the period from June 1 through September 30 when an axle load limit tolerance of 15% from subsections (c) and (d) of this section is permitted.

(h) (1) Any vehicle that uses an auxiliary power unit or an idle-reduction technology unit in order to promote reduction of fuel use and emissions from engine idling shall be allowed up to an additional 550 pounds total in gross, axle, tandem, or bridge formula weight limits.

(2) To be eligible for the additional weight limit allowed under paragraph (1) of this subsection, the vehicle operator must:

(i) Obtain and make available to law enforcement officers written certification of the weight of the auxiliary power unit or idle-reduction technology unit; and

(ii) By demonstration or certification, prove that the idle-reduction technology unit is fully functional at all times.

(3) The additional weight limit allowed under paragraph (1) of this subsection may not exceed the certified weight of the auxiliary power unit or idle-reduction technology unit.

(i) Notwithstanding any other provision of this section, the gross vehicle weight of a vehicle for which a permit is issued under § 24-113.3 of this subtitle for traveling along a designated heavy weight port corridor may not exceed 100,000 pounds.