Arizona DUI Interlock Laws Have Changed: What You Need to Know

Ryan W. Cummings | January 7, 2026

Categories: Brother at Law, DUI

If you or someone you love has been charged with a DUI in Arizona, understanding ignition interlock requirements is critical.

Over the last few years, Arizona has made significant changes to its DUI interlock laws, and many people are still relying on outdated information.
At R&R Law Group, we frequently get questions like:

  • Do I need an ignition interlock for a drug DUI?
  • What happens if I refuse a breath test?
  • Can I get credit for the time I already had an interlock installed?

Below is a clear breakdown of how Arizona DUI interlock laws currently work and why these changes matter.

Drug DUI vs. Alcohol DUI: The Key Difference

Arizona law treats drug-related DUIs differently than alcohol-related DUIs when it comes to ignition interlock requirements.

A.R.S. § 28-1381(A)(3) – Drug or Metabolite DUI

If you are convicted of a DUI based solely on having a drug or its metabolite in your system (commonly referred to as an A(3) or A3 DUI), you are NOT required to install an ignition interlock device.
This is a major change from prior years. Lawmakers recognized that ignition interlock devices are designed to detect alcohol, not drugs and requiring them in drug-only DUI cases did not make practical or legal sense.
Bottom line: A drug DUI conviction alone does not trigger an interlock requirement.

Alcohol DUI Convictions Still Require an Interlock

If your DUI involves alcohol impairment, Arizona law still requires an ignition interlock device.
The length of time the interlock must remain installed depends on factors such as:

  • Whether it is a first or repeat offense
  • The blood alcohol concentration (BAC)
  • Whether aggravating factors were present

In alcohol-based DUI cases, interlock requirements remain strict, but recent changes can still work in your favor.

Refusing a Breath Test: A New Option

Under Arizona’s implied consent law, refusing a breath or blood test can result in a 12-month driver’s license suspension.
However, under newer laws, drivers now have an alternative.

Interlock Instead of Suspension

If you refuse a breath test, you may:

  • Avoid serving the full suspension
  • Install an ignition interlock device immediately
  • Continue driving legally as long as the interlock remains installed for at least 12 months.

This option can be crucial for people who rely on driving for work or family responsibilities.

Credit for Time Already Spent With an Interlock

One of the most important and beneficial changes in Arizona DUI law is that drivers can now receive credit for time already served with an ignition interlock device.

How This Works
For example:

  • You are arrested for an alcohol DUI
  • You install an interlock right away
  • Six months later, your case is resolved and results in a conviction

Under current law, those six months already count toward your required interlock period. This means you may only need to keep the device installed for the remaining balance, rather than starting over.
This change has saved many drivers months of time and money.

Why These Changes Matter

DUI interlock laws are technical and constantly evolving. A misunderstanding about whether you need an interlock or how long you need it, can result in:

  • Unnecessary expenses
  • License suspensions
  • Additional violations
  • Delays in restoring full driving privileges

Every DUI case is different, and small details can have a major impact on the outcome.

Talk to an Arizona DUI Attorney Before Making Decisions

DUI cases often involve multiple agencies, timelines, and exceptions. If you have been arrested or charged with a DUI in Arizona, it’s important to speak with an experienced attorney before making decisions about interlock installation, license suspension, or plea agreements.

At R&R Law Group, we offer free case evaluations to help you understand your legal rights and options, schedule now or give us a call at (602) 497-3088.
Reach out to our office for assistance. Contact R&R Law Group today to discuss your case and get clear guidance on your rights and options.

We’re here to help you navigate the process and move forward with confidence.

Disclaimer: This article by R&R Law Group does not constitute legal advice and is only for general informational purposes. For guidance about your specific situation, you should consult with a qualified attorney.