625 ILCS 5/1-105.6
Section 1-105.6
(625 ILCS 5/1-105.6) Sec. 1-105.6. Axle load. The total load transmitted to the road 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. (Source: P.A. 90-89, eff. 1-1-98.)