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Driving While Intoxicated Laws

The effects of alcohol can increase the risk of drunk-driving crashes. Driver impairment can include difficulty steering, delayed reaction time, and impaired perception. According to the National Highway Traffic Safety Administration (NHTSA), about 28 people die every day in alcohol-related crashes in the U.S. Fatal crashes involving drunk drivers kill over 10,000 people a year. As a result, drunk driving prosecution is taken very seriously.


Each state has its own way to refer to impaired driving. One of the confusions with a DWI is how it differs from a DUI (Driving Under the Influence) or an OUI (Operating Under the Influence). Some states also have laws against driving while ability impaired (DWAI).

Other states make a distinction based on whether the driver is impaired over the legal limit (generally, 0.08% blood alcohol concentration), or under the limit but still impaired. The terms for impaired driving may be different but these all generally refer to driving after you have been drinking or using drugs.

States With Driving While Intoxicated Laws

The majority of states use the term DUI to refer to impaired driving. About 10 states use DWI, including:

Blood Alcohol Level and DWI

States generally have multiple ways to charge a driver with a DWI. A per se DWI means the driver is impaired just by having a blood alcohol content (BAC) that is over the limit. Even if the driver passes the field sobriety tests and does not break any other traffic laws, the driver is considered impaired just because of their BAC. In most states, drivers are considered under the influence of alcohol with an alcohol level of 0.08% or above.

Other drivers may be subject to different limits. Commercial drivers with a CDL cannot have a BAC of 0.04% or higher while operating a commercial motor vehicle. The limit for underage drivers is even lower. Many states have a zero-tolerance policy for under-21 drivers, with an underage DWI for a BAC of 0.01% or 0.02%.

Drug DWI

Drivers can also face a DWI for driving while under the influence of drugs or the combined influence of alcohol and drugs. Drug DWIs are not limited to illegal drugs. A drug DWI can also apply to medical marijuana, prescription drugs, and even over-the-counter medication, if it impairs the driver’s ability to safely operate a motor vehicle.

Drunk Driving Traffic Stop

Generally, a police officer needs a reason to make a traffic stop. This can include even a minor traffic violation, like speeding, driving at night with the headlights off, or weaving on the road. Once the police stop the vehicle, they may look for signs of an impaired driver, including:

  • Slurred speech
  • Open container of alcohol in view
  • Smell of alcoholic beverages on the driver’s breath
  • Admitting to drinking alcoholic beverages

When the police suspect impaired driving, they may conduct a further investigation, including field sobriety tests and a Breathalyzer. Field sobriety testing is supposed to look for signs the driver is physically impaired by alcohol. Depending on the driver’s alcohol consumption, the driver may fail one or all 3 of the standard tests, which include:

  • Walk-and-Turn Test
  • One-Leg-Stand Test
  • Horizontal Gaze Nystagmus Test (eye movement reaction)

The preliminary alcohol screening device, preliminary breath test, or “Breathalyzer,” is a roadside breath test device that provides an indication of the driver’s breath alcohol level. The law enforcement officer can use this evidence to gain probable cause to arrest a driver. However, Breathalyzer and field sobriety tests may not be required. Check your state laws or talk to your criminal defense attorney about the laws in your state.

Arrest for a DWI

When the driver is arrested and taken to the police station, they may be required to submit a chemical test. Blood alcohol testing or breath alcohol testing is generally required under the state’s implied consent law. Drivers who have a license and have driving privileges have given their implied consent to submit to chemical testing if they are arrested for impaired driving.

Breath tests can analyze the driver’s blood alcohol content. Blood tests can sample blood alcohol content and look for the presence of drugs, including prescription drugs and recreational drugs. Refusal to submit to a chemical test could result in a suspended license for a year. Evidence of refusal could also be used as evidence against you in your criminal case.

Criminal Penalties for DWI Offenses

Even though a DWI is a common criminal offense, they are some of the most harshly prosecuted crimes, even for first-offense DUI. The criminal penalties for a DWI conviction depend on a number of factors, including the level of alcohol, subsequent offenses, and if anyone was injured. Penalties for an impaired driving offense can include:

There are other consequences of a drunk driving criminal offense, which can include points on your driving record, higher insurance rates, and a permanent criminal record.

Alternatives to Maximum Jail Time

Many states offer alternatives to jail time, especially for first-time DWIs, which may include probation, suspension of sentence, diversion, or an alcohol or drug abuse program. Probation generally requires the defendant complete the terms of probation to avoid spending days in jail. If the defendant violates a condition of probation, they may be sent to jail to serve out the rest of their sentence.

DWI and DUI Laws are State Specific

DWI and DUI laws differ widely from one state to the next. Some states will make you use an ignition interlock device to get your driving privileges reinstated. Some states classify certain criminal offenses as misdemeanors while others increase the criminal charge to a felony. Make sure that you know the specific laws and regulations in your state.

If you are facing charges for operating a motor vehicle under the influence of alcohol or under the influence of drugs, you may be facing harsh criminal and administrative penalties. Each case is different and you should have an experienced attorney review the facts of your case. A qualified DWI lawyer can address your particular legal needs, explain the law, and represent you in court. Contact a DWI attorney to discuss your specific legal situation.

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