TL;DR
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Prosecutors cannot secure a DUI conviction without evidence, as they must prove beyond a reasonable doubt that the defendant drove while impaired or with a prohibited blood alcohol content.
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Common evidence includes officer observations, chemical breath or blood test results, field sobriety tests, and physical items like open alcohol containers.
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Drivers can still be charged without breath or blood test results, as prosecutors can rely on video footage, officer testimony, and driving behavior, though refusing a chemical test triggers automatic penalties.
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Successful DUI convictions carry penalties such as jail time, fines, license suspensions, mandatory DUI school, and increased insurance rates.
Prosecutors typically have to have some type of evidence of impaired driving before they can file charges against a person for driving under the influence (DUI). This is because prosecutors can only secure a DUI conviction by showing evidence that a person drove or was in control of a motor vehicle while impaired or with a blood alcohol concentration (BAC) above a certain legal limit (for example, at or above .08% in most states). Further, prosecutors must show enough evidence, for a conviction, to convince a judge or jury beyond a reasonable doubt that a driver was guilty of DUI.
Some common types of evidence that a prosecutor may use to help prove DUI include:
- testimony from an arresting officer,
- breath test results and/or blood test results,
- results from field sobriety tests (which typically includes results from a horizontal gaze nystagmus test), and
- open containers of alcohol in a defendant’s vehicle.
If a prosecutor is able to convict a defendant of DUI, then the person may face such penalties as:
- jail time,
- a driver’s license suspension,
- community service,
- misdemeanor probation,
- fines, and
- completion of alcohol counseling or a DUI school.
1. Can you face DUI charges with no evidence of drunk driving?
DUI cases usually have to have some type of underlying evidence of drunk driving before a prosecutor will file DUI charges.
Keep in mind that state DUI laws say that prosecutors can only convict a person of drunk driving if they successfully prove certain “elements of the crime.”
For example, under California law, a prosecutor has to prove the following elements before a DUI arrest will rise to a conviction:
- the defendant drove a vehicle, and
- when he/she drove, the defendant was under the influence of an alcoholic beverage, a drug, or an alcoholic beverage and a drug, or
- when he/she drove, the defendant’s blood-alcohol level was 0.08% or more by weight.1
Note that a prosecutor must prove each of these elements with actual evidence, as opposed to mere assertions or uncorroborated claims. Further, there has to be enough evidence to convince a judge or jury, beyond a reasonable doubt, that a defendant was guilty of DUI/DWI.
2. What evidence can help prove a DUI charge?
When a prosecutor tries to prove a DUI case, he/she can use several types of evidence. Some of the most common types of DUI evidence include:
- an arresting officer’s report (which usually includes a police officer’s observations),
- breathalyzer test results, blood test results, or urine test results (to help show a driver’s blood alcohol content or BAC level),2
- statements that a defendant made to a law enforcement officer,
- an officer’s observations or opinions regarding field sobriety tests (or, FSTs), and
- open containers of alcohol in an accused’s vehicle.
3. Can you get charged for DUI without breath or blood test results?
Yes. People sometimes refuse to submit to a breath or blood test either before or after a DUI arrest.
In these cases, prosecutors can still file DUI charges, even without evidence of the driver’s blood-alcohol level. Prosecutors will just have to rely on other types of evidence to support their case.
For example, a prosecutor may rely on:
- field sobriety test results,
- an officer’s testimony that he/she spotted the defendant swerving,
- video evidence taken during the arrest, and/or
- any of the other evidence mentioned above.
Note that most state laws say that drivers who refuse a breath or blood test will face serious penalties for a chemical test refusal.
The major consequences of a chemical test refusal are:
- increased penalties in addition to the standard DUI penalties, and
- a mandatory driver’s license suspension that will occur regardless of the outcome in your DUI case.3
4. What are the common penalties for a DUI conviction?
If a prosecutor presents enough evidence of drunk driving to secure a DUI conviction, the defendant will face a series of potential penalties.
Common penalties for a DUI conviction include:
- jail time of up to six months,
- fines,
- increases in insurance rates,
- a driver’s license suspension, and
- completion of a DUI school.4
Given these penalties, people charged with DUI should contact an experienced criminal defense attorney or DUI defense attorney for help.
A skilled criminal defense lawyer or DUI lawyer can help a defendant raise a legal defense to contest any DUI charges that a prosecutor or state files.
Legal References:
- CALCRIM No. 2110 and No. 2111, Judicial Council of California Criminal Jury Instructions (2020 edition). Note that while 49 states follow a .08% per se legal BAC limit, Utah is the only state where the per se BAC limit is not 0.08% – but rather 0.05%. See Utah Traffic Code 41-6a-502.
- Note that during a DUI investigation in most states, the police may ask you to take up to two different types of tests to determine your BAC. These are a preliminary alcohol screening test (PAS test) and a post-arrest DUI blood test/chemical test or DUI breath test.
- See, for example, Florida Motor Vehicles Code 316.1932.
- See, for example, ARS 28-1381.