---
title: "What is the BAC limit for a CDL holder in Illinois?"
description: "Illinois follows federal 49 CFR 383.51 standards: 0.04% BAC is the CDL-specific DUI threshold while operating a commercial motor vehicle. That is half the standard 0.08% limit for non-commercial..."
url: https://chicagoduilawyer.net/faq-items/what-is-the-bac-limit-for-a-cdl-holder-in-illinois/
date: 2026-07-08
modified: 2026-07-08
author: "Chicago DUI Lawyer"
type: faq
lang: en
---

# What is the BAC limit for a CDL holder in Illinois?

Illinois follows federal 49 CFR 383.51 standards: 0.04% BAC is the CDL-specific DUI threshold while operating a commercial motor vehicle. That is half the standard 0.08% limit for non-commercial drivers under 625 ILCS 5/11-501. Any measurable alcohol in a CDL driver operating a commercial vehicle triggers an immediate 24-hour out-of-service order. The chicagoduilawyer.net brand emphasizes the second layer: even off-duty, a CDL holder driving a personal vehicle at 0.08% or above still triggers CDL disqualification. The commercial license is treated as an ongoing federal safety instrument, and the disqualification consequences follow the driver, not the vehicle.