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:
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?
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,
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.
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.
A former Los Angeles prosecutor, attorney Neil Shouse graduated with honors from UC Berkeley and Harvard Law School (and completed additional graduate studies at MIT). He has been featured on CNN, Good Morning America, Dr Phil, The Today Show and Court TV. Mr Shouse has been recognized by the National Trial Lawyers as one of the Top 100 Criminal and Top 100 Civil Attorneys.