Section 39.03.01.308 - MAXIMUM OVERWEIGHT LEVELS FOR ANNUAL OVERWEIGHT/OVERSIZE PERMITS01.Allowable Gross Vehicle Weight. The gross vehicle weight allowable by overweight permit is subject to the seasonal stability of the roadway and the capacity of the structures on the route of travel. For the purpose of issuing special permits, seven (7) levels of overweight are established, based on the weight formula of w = 500((ln/n-1) + 12n + 36) and routes for carrying the various levels of overweight are designated by color coding. The weight formula ("w") is the maximum weight in pounds (to the nearest five hundred (500) pounds) carried on any group of two (2) or more consecutive axles. "l" is the distance in feet between the extremes of any group of two (2) or more consecutive axles, "n" is the number of axles under consideration. The load factor based on the most critical bridge on the highway route will also be used in determining allowable weights.02.Red Routes. The red routes contain posted bridges and require approval or analysis from the Department. A vehicle configuration may be issued an annual overweight/oversize permit for travel on red routes only, upon completion of an analysis verifying the requested weights are acceptable. The annual permit will be issued for a specific vehicle configuration, operating on a specific route, at specific weights. All information will be listed on the annual permit and will be subject to revocation at such time the vehicle configuration changes (such as axle spacings), the approved weights change, or a bridge rating changes.03.Yellow Routes. The yellow overweight level is based on a single axle loading of twenty-two thousand five hundred (22,500) pounds, a tandem axle loading of thirty-eight thousand (38,000) pounds, and a tridem axle loading of forty-eight thousand (48,000) pounds or the equivalent loading as determined by spacings and the number of axles and computed by applying the formula W = 560 ((LN/N-1) + 12N + 36).04.Orange Routes. Orange overweight level is based on a single axle loading of twenty-four thousand (24,000) pounds, a tandem axle loading of forty-one thousand (41,000) pounds, and a tridem axle loading of fifty-one thousand five hundred (51,500) pounds or the equivalent loading as determined by spacings and the number of axles and computed by applying the formula W = 600 ((LN/N-1) + 12N + 36).05.Green Routes. The green overweight level is based on a single axle loading of twenty-five thousand five hundred (25,500) pounds, a tandem axle loading of forty-three thousand five hundred (43,500) pounds, and a tridem axle loading of fifty-four thousand five hundred (54,500) pounds or the equivalent loading as determined by spacings and the number of axles and computed by applying the formula W = 640 ((LN/N-1) + 12N + 36).06.Blue Routes. Blue overweight level is based on a single axle loading of twenty-seven thousand (27,000) pounds, a tandem axle loading of forty-six thousand (46,000) pounds, and a tridem axle loading of fifty-seven thousand five hundred (57,500) pounds or the equivalent loading as determined by spacings and the number of axles and computed by applying the formula W = 675 ((LN/N-1) + 12N + 36).07.Purple Routes. The purple overweight level is based on a single axle loading of thirty thousand (30,000) pounds, a tandem axle loading of fifty-one thousand five hundred (51,500) pounds, and a tridem axle loading of sixty-four thousand five hundred (64,500) pounds or the equivalent loading as determined by spacings and the number of axles and computed by applying the formula W = 755 ((LN/N-1) + 12N + 36).08.Black Routes. The black overweight level is based on a single axle loading of thirty-three thousand (33,000), pounds a tandem axle loading of fifty-six thousand (56,000) pounds, and a tridem axle loading of seventy thousand five hundred (70,500) pounds or the equivalent loading as determined by spacings and the number of axles and computed by applying the formula W = 825 ((LN/N-1) + 12N + 36).Idaho Admin. Code r. 39.03.01.308