# Illinois — Vehicle emissions testing: which counties require it, in which states

For Illinois, counties where testing is required is these areas of Illinois; program / authority is vehicle emissions inspection program, verified against its source on 2026-08-18.

- **State:** Illinois _(our reading, not quoted from the source)_
- **Counties where testing is required:** these areas of Illinois _(verified: appears in the quote below)_
- **Program / authority:** vehicle emissions inspection program _(verified: appears in the quote below)_
- **How often:** even model-year vehicles are inspected during even years, and odd model-year vehicles are inspected in odd years _(per epa.illinois.gov, not stated by the source above)_
- **Vehicles covered / exempt:** Most 1996 and newer gasoline-powered passenger vehicles are subject to emissions inspections after they are four years old _(per epa.illinois.gov, not stated by the source above)_

## What the source says

> Additionally, the Illinois Vehicle Emissions Inspection Law of 2005 (625 ILCS 5/13C) requires a vehicle emissions inspection program to reduce air pollution from motor vehicles in these areas of Illinois. For these reasons, the vehicle emissions inspection program is part of Illinois EPA’s strategy to reduce air pollution in Illinois and bring the Chicago and Metro-East areas into attainment of the ozone NAAQS.

## What epa.illinois.gov says

> Most 1996 and newer gasoline-powered passenger vehicles are subject to emissions inspections after they are four years old (e.g. 2012 vehicles are being inspected in 2016 for the first time). The inspection month coincides with the expiration date of the vehicle license plate. Typically, even model-year vehicles are inspected during even years, and odd model-year vehicles are inspected in odd years.

Source: https://epa.illinois.gov/topics/air-quality/mobile-sources/vehicle-emissions-testing.html

## Source

- https://epa.illinois.gov/topics/air-quality/mobile-sources/vehicle-emissions-testing.html

Last verified: 2026-08-18. Review by: 2027-08-18.
Part of [Vehicle emissions testing: which counties require it, in which states](https://referencesource.org/vehicle-emissions-testing-by-state/).