In this section the following words have the meanings indicated. “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. “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. An over–the–road bus or any vehicle that is regularly and exclusively used as an intrastate public agency passenger bus: Is exempt from tandem axle weight limits provided in this section; but Shall comply with the vehicle and combination of vehicles weight limits provided in this section that are not tandem axle weight limits. 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. 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 , 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 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 A trailer with metal tires and a gross weight of more than 6,000 pounds may not be moved on a highway. 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: Wheat, for the period from June 1 to August 15; Corn, for the period from July 1 to December 1; Soybeans, for the period from September 1 to December 31; and Vegetable crops, for the period from June 1 to October 31. 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. 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. 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. 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. To be eligible for the additional weight limit allowed under paragraph (1) of this subsection, the vehicle operator must: Obtain and make available to law enforcement officers written certification of the weight of the auxiliary power unit or idle–reduction technology unit; and By demonstration or certification, prove that the idle–reduction technology unit is fully functional at all times. 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. 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.