9900 Revere Road
Clinton, IL
61727-2744

Phone: 217-935-2438

Weight Limits

Public roads in Illinois are classified by the size and weight of vehicles that are allowed to travel upon them without a permit from the highway authority. The size classification and the maximum legal vehicle weight limit that can operate upon a road or segment of road may be established by the highway authority having jurisdiction over the road or segment of road in accordance with state statutes. Signs erected on the road or segment of road display the classification and/or weight limits that have been established. A permit from the proper highway authority is required to operate a vehicle in excess of the size or weight limits posted.

In addition to establishing the size and weight of vehicles that are allowed to travel upon roads or segments of roads year round without a permit, a highway authority may also prohibit vehicles or establish vehicle weight restrictions for a period not to exceed 90 days to reduce the potential for damage or deterioration due to climatic conditions. This seasonal posting is widely used throughout Illinois during late winter and early spring when the frozen ground is thawing leaving roads soft and prone to damage.

The size classification and the maximum legal vehicle weight limit that can operate upon any road that is not posted otherwise is governed by state statute. For decades, the statute spelled out a state formula for vehicle gross weight that consisted of combinations of number of axles, axle weights and axle spacings which culminated in the heaviest allowable vehicle load being 73,280 pounds for a 5-axle semi-tractor trailer combination. The state statute was changed in 2009 and effective January 1, 2010 the state formula was replaced with a federal formula that consists of combinations of axles, axle weights and axle spacings which culminate in the heaviest allowable vehicle load being 80,000 pounds for either a 5-axle or 6-axle semi-tractor trailer combination. A permit from the proper highway authority is required to operate a vehicle in excess of the statutory size or statutory gross vehicle weight limits for specified combinations of axle weights and axle spacings on roads that are not otherwise posted.

Many county highways and township roads in DeWitt County are not posted and are therefore governed by the statutory limits year round. Many others are posted for seasonal weight limitations and some are posted for year round weight limitations. The map of weight limits on DeWitt County Highways may be viewed by clicking here. You will see that the DeWitt County Highways shown in red are posted seasonally and they are also posted year round. The seasonal posting on those DeWitt County Highways is a maximum legal weight limit of 4 Tons per Axle from February 1 to April 30 every year. The year round posting on those DeWitt County Highways is the state formula for vehicle gross weight as it existed prior to the legislative changes that took place in 2009 that consisted of combinations of axles, axle weights and axle spacings which culminated in the heaviest allowable vehicle load being 73,280 pounds for a 5-axle semi-tractor trailer combination as you can see in the 73,280 pound table by clicking here. You can click here to see the combination of signs used for the seasonal posting and year round posting. These signs are erected at each end of each posted county highway. You will also see that the remaining DeWitt County Highways shown in blue are limited to 80,000 pound maximum either by posting or by state statute. In either case the weight limitation is governed by combinations of axles, axle weights and axle spacings which culminate in the heaviest allowable vehicle load being 80,000 pounds for either a 5-axle or 6-axle semi-tractor trailer combination which you can see in the 80,000 pound table by clicking here. The posted 80,000 pound DeWitt County Highways include a classification which establishes limitations on the vehicle dimensions whereas state statutes govern the vehicle dimensions on those 80,000 pound DeWitt County Highways that are not posted.

A permit issued by the DeWitt County Engineer is required for any vehicle to operate on a DeWitt County Highway in excess of the statutory limitations or posted limitations, as applicable. You can see a sample form by clicking here. The information contained in the sample completed form is necessary in order for the County Engineer to determine whether it is appropriate to issue a permit.