Answer: Submit to sobriety tests, roadside chemical tests, or both.
If an officer reasonably suspects cannabis impairment, the driver must take field sobriety tests, validated roadside chemical tests, or both.
Easy to get wrong: Refusing because cannabis is legal, or thinking only an alcohol breath test can be required.
Illinois Rules of the Road 2026 (2026, DSD A 112.47, printed July 2026), Chapter 6, p.48