Ill. Admin. Code tit. 92, § 554.503
b) Length limitations in Section 15-107(a) through (f) of the Code do not apply to the following:
2) Vehicles and loads operated by a public utility while en route to make emergency repairs to public service facilities or properties, but during night operation every vehicle and its load must be equipped with a sufficient number of clearance lamps on both sides and marker lamps upon the extreme ends of any projecting load to clearly mark the dimensions of the load. (Section 15-107(g)(2) of the Code)\
c) The following vehicles may exceed the 8 feet 6 inches (width) limitation during the period between ½ hour before sunrise and ½ hour after sunset:
3) Portable buildings designed and used for agricultural and livestock raising operations that are not more than 14 feet wide and with not more than a 1 foot overhang along the left side of the hauling vehicle. However, the buildings shall not be transported more than 10 miles and not on any route that is part of the National System of Interstate and Defense Highways. All buildings when being transported shall display at least 2 red cloth flags, not less than 12 inches square, mounted as high as practicable on the left and right side of the building. A State Police escort shall be required if it is necessary for this load to use part of the left lane when crossing any 2 lane State highway bridge. (Section 15-102(b)(3) of the Code)
e) Often a question arises as to whether a piece of equipment is exempted or whether a permit must be obtained for its movement. A guide is found in an Attorney General's Opinion, dated November 15, 1949, concerning an overwidth bulldozer used occasionally for farm conservation work. The opinion reads in part:
"It would seem that the bulldozer is used chiefly for a commercial operation and in view of such use would probably not be within the exemption. There are many items which could be used for commercial purposes in aid of a farming operation or to conserve the soil, but of course, all such items do not fall within the exemption of the statute. The character of their use must necessarily be a determining factor."
(Source: Amended at 36 Ill. Reg. 13254, effective August 1, 2012)