How Idaho DUI Laws Apply to Commercial Drivers (CDL Holders)

Driving a commercial vehicle in Idaho comes with serious responsibility—and even higher legal expectations. For commercial driver's license (CDL) holders, a DUI charge can do more than just put your license at risk. It can jeopardize your career, limit future job opportunities, and even lead to disqualification from commercial driving entirely.

Whether you're a long-haul trucker passing through Boise or a local delivery driver, understanding how Idaho DUI laws apply to CDL holders is critical. In this post, we break down the key differences in the law, the harsher penalties commercial drivers face, and how even off-duty incidents can impact your CDL status.

Lower BAC Thresholds for Commercial Drivers

Under Idaho law, the standard blood alcohol concentration (BAC) limit for non-commercial drivers is 0.08%. But for CDL holders, the threshold is significantly lower.

If you're operating a commercial vehicle, such as a semi-truck, school bus, or hazardous materials transport, the legal BAC limit is 0.04%. That's half the limit for regular drivers.

Even a single drink with dinner could potentially put you over the limit, depending on your size, gender, and metabolism. Because of the size and potential danger posed by commercial vehicles, the law applies stricter standards to promote safety on Idaho roads.

DUI in a Commercial Vehicle: What Happens?

If you're stopped and tested while operating a commercial vehicle and your BAC is 0.04% or higher—or you show signs of impairment from drugs or alcohol—you can be:

• Arrested and charged with DUI

• Immediately removed from service for 24 hours

• Reported to the Idaho Transportation Department (ITD) and your employer

Following a DUI arrest, your CDL is typically disqualified for a minimum of one year, even if the offense occurred in your personal vehicle.

DUI in a Personal Vehicle Still Affects Your CDL

Many commercial drivers don't realize that DUI convictions don't have to happen in a commercial vehicle to affect your license.

Even if you're driving your personal car, a DUI conviction—or even a refusal to submit to a chemical test—can result in:

• Disqualification of your CDL for one year

• Three-year disqualification if you were transporting hazardous materials

• Lifetime disqualification for a second DUI offense or refusal

The law applies broadly because the state holds CDL holders to a higher standard, regardless of the vehicle involved.

CDL DUI Penalties Under Idaho Law

In addition to the standard DUI penalties (jail time, fines, license suspension, mandatory treatment), CDL holders face specific consequences tied to their commercial driving privileges.

First DUI Offense (CDL)

• Criminal penalties: Same as for non-commercial drivers—up to 6 months in jail, fines up to $1,000, mandatory substance abuse evaluation

• Driver's license suspension: Minimum of 90 days

• CDL disqualification: Minimum one year, even if you were off-duty

• No restricted CDL permits: Idaho does not allow any form of limited or hardship CDL—if your CDL is suspended, you cannot work

Second DUI Offense (CDL)

• CDL disqualification for life: No exceptions under Idaho law. Some states allow reinstatement after 10 years with proof of rehabilitation, but Idaho typically does not.

This makes a second offense essentially career-ending for most commercial drivers.

Drug and Prescription Medication DUIs

Driving under the influence of drugs—whether illegal, prescription, or over-the-counter—can also lead to a DUI charge and CDL disqualification. Idaho law treats drug impairment the same as alcohol impairment.

Common substances that have led to CDL DUI charges include:

• Marijuana (even from legal-use states)

• Prescription painkillers (e.g., oxycodone, hydrocodone)

• Benzodiazepines (e.g., Xanax, Valium)

• Sleep aids and muscle relaxants

CDL holders should be especially cautious with any substance that could impair reaction time, coordination, or alertness.

Impact on Employment

CDL disqualification isn't just a legal issue—it's a job-killer.

Most trucking companies have strict zero-tolerance DUI policies. Even a first offense can lead to:

• Immediate termination

• Loss of insurance coverage

• Denial of employment from future employers

And once a DUI is on your record, it becomes part of your PSP (Pre-Employment Screening Program) file through the FMCSA (Federal Motor Carrier Safety Administration). Employers use this to vet applicants, and a DUI can make you an uninsurable risk.

What You Should Do If You're a CDL Holder Facing DUI Charges

If you're a commercial driver accused of DUI, the stakes couldn't be higher. The risk isn't just a license suspension—it's your livelihood.

Important steps include:

• Do not drive: Driving during a disqualification can lead to jail time and permanent license loss.

• Comply with testing and evaluations: Failing to do so makes the situation worse.

• Avoid second offenses at all costs: A second DUI conviction typically means lifetime CDL loss.

• Stay proactive: Ask for a hearing with the ITD within 7 days to challenge administrative suspensions.

Final Thoughts

For commercial drivers in Idaho, a DUI is more than a traffic offense—it's a career-defining event. The law imposes stricter limits and harsher penalties because of the risks associated with commercial vehicles. Whether you're hauling freight, driving a school bus, or delivering goods locally, the responsibility is heavy—and so is the legal burden.

If you're facing a DUI as a CDL holder, your best strategy is early, informed action. Understanding the law, complying with all requirements, and avoiding repeat mistakes are critical to protecting your career and future.