Illinois Truck Idling Law
Illinois has a statewide diesel idling limit, but it only applies in the affected areas that fail federal air standards: Cook, DuPage, Lake, Kane, McHenry, Will, Madison, St. Clair, and Monroe counties, plus Aux Sable and Goose Lake townships in Grundy County and Oswego Township in Kendall County. There, a diesel truck over 8,000 pounds may not idle more than 10 minutes per hour, with up to 30 minutes to weigh, load, or unload (625 ILCS 5/11-1429). It is waived below 32F or above 80F, and an APU is fine. Chicago is stricter at 3 minutes per hour with a $250 fine.
When you can keep idling
- Traffic
- Mechanical work
- Sleeper-berth rest
- Below 32F or above 80F
- PTO and accessory power
APUs and idle-reduction gear
The statute lets you run an APU or gen-set instead of the main engine. Idle-reduction equipment also earns up to a 550-pound weight allowance, or the certified unit weight, whichever is less (625 ILCS 5/15-112(e-5)); carry written certification of the APU weight.
City and county ordinances
- Chicago: 3 minutes per hour, $250 (Municipal Code 9-80-095).
Illinois Idling Law FAQ
Is there a truck idling law in Illinois?
How long can a truck idle in Illinois?
What is the fine for idling in Illinois?
Does an APU count as idling in Illinois?
Reference information for planning, not legal advice. Traffic laws change and this can be out of date, so always confirm the current statute and obey posted signs before you rely on it. Last reviewed July 2026. Source: https://afdc.energy.gov/fuels/laws/IR?state=IL. See our Terms & Disclaimer.
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