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What Is a Portable Breath Test (PBT)?

Posted on February 8, 2023 in

A fun night out with friends, a romantic dinner date with wine, or an evening watching the big game at a sports bar can be the highlight of your week. But if your good time turns into a DUI, the results of your night out can be life-altering. Police officers in Arizona need only a reasonable suspicion to pull over a driver they suspect of driving under the influence of alcohol or drugs. Any signs of erratic driving behaviors such as swerving within a lane, hugging the middle line, driving unreasonably slowly, or hitting a median are enough legal cause for reasonable suspicion as well as any error that violates a traffic law, such as running a red light. If the officers smell alcohol or witness you acting noticeably intoxicated during the traffic stop they could request that you submit to a portable breath test.

How Does a Breathalyzer Test Work?

A portable breath test or breathalyzer measures a person’s blood alcohol level (BAC) through the alcohol fumes on their breath. When the driver blows into the tube attached to the portable device for about 4 seconds, vapors from the alcohol the driver consumed react with potassium dichromate, which is an orange solution inside the breathalyzer tube. The presence of alcohol vapors turns the solution green and creates a current of electricity which registers as a numerical value on the device. If the device registers a BAC over .08% in Arizona, the police may charge the driver with a DUI.

While the PBT test delivers a clear indication of the test subject’s blood alcohol level, the level of impairment the amount of alcohol causes can vary a great deal between individuals.

Reasons An Officer Could Request That You Take a Portable Breath Test

Once you’ve been pulled over, an officer could ask you to take a portable breath test if you exhibit any of the following signs of intoxication:

  • Smelling of alcohol
  • Slurred speech
  • Delayed speech
  • Incoherent speech
  • Having bloodshot or red eyes
  • Open containers of alcoholic beverages

If any of the above signs are present the officer may ask you to take a breathalyzer test. They could also perform field sobriety tests. If you fail the roadside tests and/or register a BAC of .08% or higher, the officer will charge you with a DUI. Be prepared to take a second, more accurate BAC test at the police station.

Can I Refuse a Portable Breath Test?

Unless the police officer has a search warrant, you may legally refuse to take a portable breath test in Arizona during a traffic stop. Both Arizona courts and the U.S. Supreme Court define breathalyzer tests and other chemical tests as protected searches under the 4th Amendment, meaning the officer cannot force you to take a test. Instead, they can only ask for a driver’s express consent. You may refuse consent, but that action has the following mandatory consequences:

  • Reporting your refusal to the Department of Motor Vehicles
  • An automatic one-year license suspension
  • A two-year license suspension for a second refusal within 7 years of the first
  • The refusal will be used against you in a trial if the officers proceed with a DUI arrest which they may legally do despite the refused PBT test if they find probable cause that you are impaired

It’s important to understand that the breathalyzer test is meant to screen drivers who are NOT impaired in order to prevent false arrests. An officer can arrest you on a DUI charge on reasonable suspicion alone.

If you have questions about portable breath tests and your legal rights and protections under the law, contact an Arizona criminal defense attorney.