Opacity testing is a core component of the Ontario DriveON emissions inspection for heavy-duty diesel commercial motor vehicles. The pass/fail threshold depends on the vehicle's model year — and understanding those limits before inspection day helps fleet managers avoid surprises at the yard. Ontario refers to the measured outcome as the overall opacity result.
The following table reflects Ontario's official opacity standards for commercial vehicle emissions inspections. Thresholds became stricter for 2011 and newer vehicles effective July 1, 2023.
| Model Year | Pass | Fail |
|---|---|---|
| 1990 and older (not school bus) | 0–40% | >40% |
| 1990 and older (school bus) | 0–30% | >30% |
| 1991 to 2007 | 0–30% | >30% |
| 2008 to 2010 | 0–20% | >20% |
| 2011 and newer (effective July 1, 2023) | 0–10% | >10% |
Before the opacity measurement, the inspector performs a pre-test check. A unit may not proceed to the opacity test if conditions such as the following are present:
For 2007 and newer commercial motor vehicles with a gross vehicle weight rating (GVWR) up to 6,350 kg, the emissions test includes an On-Board Diagnostics (OBD) system test in addition to the opacity measurement. Vehicles outside that published OBD system-test window still receive the applicable pre-test and opacity inspection. The current DriveON directive should be consulted for any additional data-collection requirements.
A passing emissions test report remains valid for 12 months from the date of inspection. Fleet managers should align opacity test scheduling with plate sticker renewals and ownership transfer timelines to avoid compliance gaps.
Pre-test check · Opacity test · OBD system test (2007+ with GVWR up to 6,350 kg, where applicable) · Pass report valid 12 months
Related guides: SAE J1667 snap test explained and common causes of high opacity.
