Arrested for a DUI: What to Expect

General information about DUI arrests and investigations.

By , Attorney University of Santa Clara Law School
Updated 10/25/2022

Every case is different. But this article discusses some of the more common features of DUI arrests and investigations, including how the law might apply to the various stage of a DUI arrest.

DUI Traffic Stops: Getting Pulled Over

Most DUI arrests start with the driver being pulled over or stopped by the police. Legally speaking, it's important that police had a valid reason for doing so.

Reasonable Suspicion Justifying a Traffic Stop

In most DUI cases, police pull the motorist over because of signs of impairment (such as swerving) or a traffic violation (even something minor like a broken taillight will suffice). Generally, a stop is legal so long as police had reasonable cause (sometimes called "reasonable suspicion") to believe the driver violated the law.

If the police truly had no reasonable cause to pull you over, later in your case you can bring a motion to suppress, which can result in the entire case being thrown out.

The legalities of DUI Checkpoints

A DUI checkpoint, where police stop all traffic on a certain roadway, is an exception to the general rule that police need evidence of wrongdoing to stop a vehicle. Basically, the U.S. Supreme Court ruled that the government's interest in having these types of checkpoints outweighs the inconvenience and intrusion to drivers.

However, some states have enacted laws that prohibit police from using DUI checkpoints.

How Police Conduct DUI Investigations

Every case is a little different. But most DUI investigations involve some or all of the components discussed below.

Police Observations of Intoxication

Traffic detentions typically begin with the officer asking for your license and registration. The officer is likely to take note if, during this interaction, you show signs of impairment—things like fumbling around with your documents or the odor of alcohol or marijuana.

Any such observations will undoubtedly show up in the police report, which you'll typically see for the first time at your arraignment.

Police Questioning of DUI Suspects

During a DUI stop, police almost always ask the driver if they've had anything to drink. In response, most motorists say something like, "just a beer or two with dinner"—usually an underestimation of what they actually drank.

Police have heard these types of responses innumerable times and aren't likely to stop there—especially if there are other indicators that you're drunk or have been using drugs. After receiving confirmation that you've been drinking—whatever the amount—most cops are going to want to investigate further.

You have the right to remain silent in response to police questioning. But whether it's a good idea to exercise that right, might depend on the specific circumstances.

DUI Roadside Testing

An officer who suspects someone of drunk driving will often seek to confirm the suspicions using some roadside tests: field sobriety tests (FSTs) and a "preliminary alcohol screening" (PAS) test (commonly called a "breathalyzer"). These prearrest tests are typically voluntary.

DUI Field Sobriety Tests

There are lots of different FSTs that police use. But the most common are the three "standardized" FSTs, the:

  • horizontal gaze nystagmus (HGN)
  • walk and turn, and
  • one-leg stand.

In the 1970s, the National Highway Traffic Safety Administration (NHTSA) developed these three tests—which together are called the "standardized FST battery"—for officers to gauge a motorist's level of impairment. After conducting studies, the NHTSA concluded the standardized FSTs were reliable indicators of when a driver's blood alcohol concentration (BAC) is .1% or above.

PAS Breathalyzer Tests

A PAS device (also called "portable breath test" (PBT) machine) is a handheld machine that police use to measure a driver's breath alcohol concentration. PAS results are sometimes less reliable than breath or blood tests conducted at a police station or hospital. But the advantage of these devices is that they give police a quick and easy way to estimate a driver's BAC.

The purpose of a PAS test is not to gather evidence for court, but to assess whether there's probable cause for a DUI arrest.

Mandatory DUI Blood, Breath, and Urine Tests

Chemical testing is crucial to DUI investigations. Every state has laws that make it illegal to drive with a BAC of .08% or more (.05% or more in Utah). But proving a driver's BAC requires test results. To aid in DUI prosecutions, all states have laws that make testing mandatory under certain circumstances. Below we discuss these laws and the consequences of refusing o test.

DUI Implied Consent Laws

All 50 states have "implied consent" laws that require motorists lawfully arrested for DUI to submit to chemical testing. The purpose of the testing—usually of the breath or blood—is to measure the amount of drugs or alcohol in the driver's system.

Penalties for Refusing a DUI Blood or Breath Test

Motorists who refuse testing normally face consequences that can include:

And if the case goes to trial, the prosecution can normally tell the jury about the defendant's refusal.

In some states, you can even be convicted of a separate crime for refusing a chemical test. In these states, a refusal can lead to two separate criminal convictions: one for DUI, and another for the refusal. However, in 2016, the U.S. Supreme Court held that laws criminalizing refusal to take a blood test were unconstitutional. But the Court did say that it's generally okay for a law to criminalize refusing to submit to a breath test.

When Police Can Search Your Car During a DUI Stop

Generally, if police have probable cause to believe there's incriminating evidence inside your car, they can search it without a warrant. For instance, an officer might see or smells things during a DUI stop that give them reason to suspect there are drugs in the car. If that's the case, police could be justified in not only searching the interior of your car, but also the glove box, trunk, and closed containers such as backpacks.

Another common justification for an automobile search is driver consent: Generally, police can look inside your car if you give them permission to do so.

However, in this area, the law is full of rules, exceptions, and nuances. So if you have a question about a car search, it's probably best to get in contact with an attorney.

DUI Arrest, Detention, and Release

Arrest and release procedures differ by area and the circumstances of the case. But here's how it normally works.

Getting Booked for a DUI

If police determine there's probable cause to arrest you for driving under the influence, you'll likely be cuffed and taken to the local jail or police station. At the jail or police station, police will book and cite you for the offense.

Temporary Driver's Licenses

When police arrest you for a DUI, they typically take your driver's license and give you a temporary paper driving permit. The temporary permit is normally effective until the court or department of motor vehicles makes a decision on whether to suspend your license.

Paying Bail and Getting Released from Jail

You'll normally stay in jail until someone bails you out or a judge releases you on your "own recognizance." If you were arrested on a Friday, and not bailed out, you might have to spend the entire weekend in jail. The good news is that you'll get credit against any future sentence imposed for the time you've already spent in jail.

DUI Police Reports

Most people are curious to see the DUI police report, which describes in the officer's words what happened. In most states, the police report isn't available until your first day in court, the arraignment.

Because the report describes the case against you, it's an important tool for deciding how best to handle your case. An experienced DUI attorney can often identify the strengths and weaknesses of the state's case by reviewing the police report.

Get Legal Help

If you've been arrested for driving under the influence, it's a good idea to get in contact with an experienced DUI attorney. DUI laws vary by state, and the facts of every case are different. A qualified DUI lawyer can help you understand what the law is in your state and explain any possible defenses you might have.

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