Illinois moves to 80,000-pound truck weight allowance Effective January 1, 2010, Illinois will allow trucks weighing 80,000 pounds on most of its state roads. The previous allowance had been 73,280 pounds. The single-axle limit will increase from 18,000 to 20,000 pounds. The tandem-axle allowance will increase from 32,000 to 34,000 pounds. The state or its political subdivisions may still post roads and bridges for lower weight limits if needed, and the state doubled its fines for overweight violations to go with its new weight allowances. Illinois will also allow truck widths of 102 inches starting January 1, up from 96 inches.               return