What is the “legal limit,” or the blood alcohol content limit, in South Carolina?

Technically, there is no such thing as a “legal limit” under SC’s DUI laws, although you can be charged with DUAC (driving with an unlawful alcohol concentration) if your blood alcohol content (BAC) is .08% or greater.

Below, we will go over the basics of the “legal limit” in SC and how your BAC result can affect your DUI case, including:

  • The legal limit if you are charged with DUI,
  • The legal limit if you are charged with DUAC,
  • How the police test your blood alcohol content, and
  • What the results mean for your case.

What Does “Legal Limit” Mean?

If you ask most people what the “legal limit” is for DUI in SC, they will probably say .08%. If you are a DUI defense lawyer, you know that’s technically not true – if you are charged with DUI, there is no set number above which you are guilty.

You can be charged with DUAC, though, based on a BAC of .08% or greater.

DUI & DUAC Laws in SC

DUI Law in SC

To get a conviction for driving under the influence (DUI) in SC, the prosecutor does not have to prove a specific BAC level. They don’t need a BAC level at all, although your Datamaster result may be used as evidence against you.

What do they need to prove to get a conviction?

SC Code § 56-5-2930 says that the state must prove you were:

  1. Driving a motor vehicle within this state,
  2. While under the influence of alcohol, drugs, or a combination of alcohol and drugs,
  3. To the extent that your faculties to drive a motor vehicle were materially and appreciably impaired.

That’s it. They don’t need to prove that your blood alcohol content was .08% or greater. They don’t have to prove a blood alcohol content at all.

On the other hand, you can be acquitted of DUI even if your blood alcohol content was .08% or greater. If you are a regular drinker with a high tolerance, for example, you could have a BAC of .10%, and yet your faculties to drive were not materially or appreciably impaired.

The results of any blood alcohol tests may be evidence at your trial if your attorney is unable to get them excluded, but it is only one piece of the evidence that the jury will consider when deciding whether your faculties to drive were materially and appreciably impaired.

Evidence of intoxication, or the lack of intoxication, in a DUI trial could include:

  • Breath, urine, or blood test results,
  • A roadside video that shows your performance on any field sobriety tests that were given,
  • A video from the Datamaster room that shows your behavior as you wait for the breath test,
  • The officer’s testimony as to their observations when they made the arrest,
  • Testimony of other witnesses, including sobriety witnesses, who testify as to their observations of your behavior at or near the time of the traffic stop,
  • Evidence of any irregularities in the testing process including the officer’s failure to follow SLED policy and procedures, or
  • Evidence of any medical conditions that would explain 1) an abnormally high test result or 2) what appears to be a poor performance on the field sobriety tests.

DUAC Law in SC

Driving with an unlawful alcohol concentration, or DUAC, is a bit different. You could say that DUAC has a “legal limit,” because, to get a conviction, the state must prove that your BAC was .08% or higher.

That’s it. They don’t have to prove that your ability to drive was impaired, only that you took a test, and your test result was .08% or higher. You could have a high tolerance for alcohol, or the test result could have been wrong, but you can be convicted solely based on the test results.

That doesn’t mean you don’t have any possible defense if you took the breathalyzer test and are charged with DUAC. For example, you can still present evidence that the test results were incorrect, based on data your attorney finds on SLED’s Datamaster database, expert testimony about the operation of the Datamaster machine, an independent BAC test, or other evidence of sobriety.

If your attorney can show that the officer did not follow SLED policy or if there were irregularities with the blood alcohol test, the results may be excluded from the trial. Or, if the officer did not comply with SC’s mandatory videotape law, your case could still be dismissed before it reaches trial.

One reason prosecutors often do not charge DUAC, although it appears to be easier to prove, is that the trial can become a battle of the experts – if your attorney can get the BAC results excluded, they no longer have a case, which means the prosecutor may need to bring their own Datamaster expert for the trial to counter your arguments.

How Does BAC (Blood Alcohol Content) Work? 

In most cases, the arresting officer will attempt to get you to take a Datamaster test – this is the breathalyzer machine used in SC. There are no roadside PBTs (portable breath tests) like they use in some other states – SC courts have found that roadside PBTs are not sufficiently reliable to use as evidence, although they will allow Datamaster results.

The breathalyzer is designed to first test itself with a “simulator solution” that should have a .08% alcohol content – if the simulated test is a success, it then tests your breath. It measures the “deep lung” air from the alveolar sacs in your lungs, but it must then convert the “breath alcohol content” into “blood alcohol content.”

The machine does this by taking your breath alcohol result and multiplying it by 2100 – an average multiplier that should not apply to every person. This means that, if there is any alcohol in your mouth, the result can be skewed – this is why there is a 20-minute observation period, and the officer is supposed to check inside the mouth to ensure there are no piercings, dentures, chewing gum, or other objects that could hold small amounts of alcohol.

The machine is subject to radio frequency interference, and there is a long list of other circumstances that can cause inaccurate results – your attorney will have the opportunity to research data on the machine that you were tested on as well as the officer that tested you to identify any anomalies that could have caused an inaccurately high result.

Blood or Urine Tests

In some cases, the officer may request a urine or blood sample instead of or in addition to the breathalyzer test. Although the testing procedure is different, the results will have the same impact on your case.

What effect do the blood alcohol test results have on your DUI case?

What the Results Mean for Your Case

There are two ways that the blood alcohol test results can affect your case – in implied consent proceedings and the criminal case for the DUI charges.

Administrative: If you refuse the test (in most cases, this is a good idea even if you do not think you are intoxicated), or if you take the test and the result is .15% or greater, your license will be immediately suspended, and you will need to request an implied consent administrative hearing to get your license reinstated.

Criminal: In your criminal case, SC DUI law sets out how your BAC test result can be used as evidence. SC Code § 56-5-2950 says:

  • If the BAC was .05% or less, it is conclusively presumed that you were not under the influence of alcohol (although they can still try to prove that you were under the influence of drugs),
  • If the BAC was higher than .05% but less than .08%, there is no inference either way (but it can still be considered when the jury is determining guilt or innocence), and
  • If the BAC was .08% or higher, it can be inferred that you were under the influence of alcohol.

Note the difference between a conclusive presumption (if your BAC result is less than .05%, you are not under the influence of alcohol and it cannot be rebutted) and an inference (if your BAC result is .08% or greater, jurors could reasonably conclude that you were under the influence of alcohol, but the inference is rebuttable – the jurors can still acquit you regardless of the BAC result).

Questions About the Legal Limit in SC? 

If you have been charged with a DUI-related offense in SC, including DUI, DUAC, or felony DUI, contact the SC DUI defense lawyers at Templeton, Mims & Ward at 843-285-5090 or by sending us an email through our website to set up a consultation and find out how we can help.

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