Drunk Driving Basics

Drunk Driving Basics

Whether it’s called driving under the influence (DUI,) driving while intoxicated (DWI,) operating while intoxicated (OWI,) operating a vehicle while intoxicated (OVI,) or operating under the influence (OUI,) drunk driving is against the law in every state of the union. Drunk drivers can face criminal charges and have their driver’s license suspended by the state Department of Motor Vehicles. Most DUI cases are charged as misdemeanors, but based on what happened and the driver’s past, felony charges may be brought. Drunk drivers can go to jail, have to pay fines and lose their license. Conviction often leads to substantially higher insurance premiums or outright policy cancellation. The following is an overview of the legal issues a DUI suspect faces.

Under the influence

If a driver operates a vehicle after drinking alcohol, their senses can be impaired in a way that makes driving more difficult. DUI laws also include driving while under the influence of illegal drugs and also prescription drugs. It is against the law to drive while under the influence of any substance that impairs the senses.

Per se laws

In addition to driving under the influence statutes, all states have per se laws. A driver with a blood alcohol content of 0.08 or higher is presumed to be guilty of DUI. There is no need prove the driver was under the influence or impaired to support a per se DUI conviction.

Police contact and reasonable cause

The evidence necessary to arrest and bring charges against a DUI suspect is acquired primarily after the vehicle has been stopped, and the officer makes contact with the driver. In many cases, the police stop a driver for a simple infraction, such as a broken tail light, or a more serious violation, like an unsafe lane change or following too closely. In other instances, the police may suspect the driver has been drinking. In any case, the police must have reasonable cause to believe a vehicle code violation has occurred.

Field sobriety tests

A field sobriety test (FST) is a method used by a police officer to determine if a person that is suspected of driving while impaired is indeed intoxicated with alcohol or other drugs. There are several standardized tests used by police officers. A breathalyzer test, whereby the drive blows into a hand-held device, is among the most common FSTs. Other FSTs typically used by the police are the horizontal gaze nystagmus (HGN) test, the walk-and-turn test, and the one leg stand test. Each FST must be performed according to standardized procedures. Contrary to what many people believe, FSTs are voluntary. Although there are no legal consequences for refusing a FST, the officer may arrest the driver based on other objective signs of alcohol consumption, such as an odor of alcohol, slurred speech, and red or watery eyes.

Probable cause for arrest

Based on the results of the FSTs and the driver’s responses, the police may make the determination the driver was under the influence while driving. If so, this gives the officer probable cause to make an arrest for DUI. Probable cause for arrest is a higher legal standard than the reasonable cause required for a stop.

Blood alcohol content testing

After arrest, suspects are taken to a local precinct and given either a breath or blood test to determine their blood alcohol content. Unlike the roadside breathalyzer test, this BAC test is mandatory and refusal brings separate criminal penalties. Under what are known as implied consent laws, every driver, as a condition for the privilege of driving, must take a BAC test if arrested on a suspicion of DUI.

DMV administrative action

If a BAC of 0.08 or greater is returned, the state Department of Motor Vehicles immediately begins an administrative action to suspend the driver’s license. The suspension will occur automatically unless the driver or their legal representative requests a hearing. This is completely separate from the criminal case.

Criminal case

The district attorney in the county where the arrest was made will pursue the criminal case. If the BAC test result was 0.08 or greater, the driver will be charged under both the driving under the influence law and the per se law. If the result was under 0.08, the driver will be charged under only the driving under the influence law.


The potential penalties depend on the facts of the present case and the defendant’s prior history. Jail time, fines and fees, license suspension and remedial classes are typical. But if the individual has prior convictions for DUI, the penalties become increasingly harsh. The most severe penalties are possible if someone else was injured as a result of driving while under the influence. Increasingly common is the requirement for the installation of an ignition interlock device on the vehicle. A driver must blow into this device before the vehicle can be started and intermittently while driving. If the device senses alcohol in the breath, the vehicle will be inoperable.


As with all criminal charges, the defendant has a right to counsel and constitutional protections apply. An experienced criminal defense lawyer can review the evidence and determine if the proper procedures were followed. Possible areas of challenge, based on the individualized facts and circumstances of the specific case, may involve the nature of the stop, the interaction between the police officer and the driver, any FSTs performed, the arrest, post-arrest interaction while being transported to and at the police station, the BAC testing at the station, plus any other irregularities that may have occurred.

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