What Is a “Rising BAC” Defense?

A “rising BAC” defense applies to certain cases where someone is accused of Driving Under the Influence (DUI). The defense addresses the fact that everyone’s body metabolizes alcohol at a different rate. Sometimes, this means that your blood alcohol content (BAC) as indicated on a chemical test result is higher than it normally would be because your body has begun to process the alcohol and introduce it into your bloodstream.

In effect, the rising BAC defense argues that someone was not as intoxicated at the time of their arrest as the chemical test seems to indicate. This is an especially common consideration if the individual had their chemical test delayed for an hour or more after the time the individual was arrested.

Does the Rising BAC Defense Apply to My Case?

A rising BAC defense is not always a viable legal strategy when facing a DUI, and many judges and juries are skeptical of it. However, it may be a scientific fact that the chemical test used to prosecute DUI had one or more inaccuracies, including an inaccuracy caused by the body’s own metabolic process.

You can discuss how a rising BAC could affect your case and what other defense strategies you have available during a free, no-obligation consultation with a Pennsylvania DUI lawyer near you. Call the Law Offices of Steven E. Kellis today at (215) 977-4183 or contact us online to learn more and discuss your case.

How the Rising BAC Defense Works

BAC refers to how much a person’s body has metabolized the alcohol they’ve consumed over time. When an officer of the law stops a driver on suspicion of DUI, a BAC test is generally given unless the arresting officer believes the driver is so obviously intoxicated that they have all of the evidence they need.

 A BAC test can only be administered with the consent of the driver, but refusing a test can lead to separate criminal penalties

It takes longer for alcohol to leave a larger person’s body than a smaller person. Because of this fact of physiology, a good Pennsylvania DUI attorney can use this argument to help get their client off a charge of driving under the influence.

Note that, like many other states, Pennsylvania has two types of DUI charges: “per se” and general impairment. The difference between the two is how the prosecution proves the driver was “under the influence” during the trial. 

Conviction of a “per se” DUI occurs when the prosecution shows the defendant was driving with an amount of alcohol or drugs in their body that exceeded the legal limit. “Over the limit” in Pennsylvania is 0.08% for non-commercial drivers and 0.04% for commercial drivers. There are also different per se limits that can give you a higher penalty for more “aggravated” charges.

General impairment DUIs, on the other hand, concentrate on how the driver was handling the vehicle and how the alcohol (or drugs) actually affected their mental or physical abilities. Pennsylvania’s DUI law specifically states that anyone can be charged with DUI as long as they are, “rendered incapable of safely driving,” the vehicle (P.A.C.S. § 3802). 

Usually, an officer will want to prove that a “per se” limit has been violated so they can levy more specific charges. However, they don’t need to prove that you hit a certain DUI limit to argue that you were “less safe”. Instead, they can look to factors like slurred speech, lack of coordination, and failing roadside tests as evidence of impairment.

Rising BAC Defense

Defense attorneys will often use the “rising BAC defense” in DUI trials. The job of the prosecution is to prove the defendant was legally over the limit while operating the vehicle, while the defense attorney tries to cast doubt of the prosecution’s case. 

In a rising BAC defense case, the DUI defense lawyer will argue that their client’s BAC was technically under the limit while driving, but because of the way different bodies metabolize alcohol, it caused their BAC to rise above the legal limit by the time they were tested.

One way a defense attorney may argue this is to bring in an expert witness. The witness will look at the recorded BAC and estimate what the BAC was at the time of driving. If successful, their testimony could cast doubt on the prosecution’s claim enough to help the client beat the charge. 

Apart from how different people metabolize alcohol differently, other factors may play into determining BAC, such as:

  • Amount of alcohol driver consumed
  • How the alcohol was consumed, e.g. shots or sips
  • When and what the driver last ate. Starches and pasta, for example, will absorb more alcohol than most foods.
  • The passage of time between consumption and driving, consumption and test, and driving and testing
  • Any medical condition that affects how the driver’s liver functions

Any of these can play into how a driver’s BAC registers along with absorption and dissipation. A qualified expert witness can estimate where the driver’s BAC was at a given time.

How the Prosecution Can Use Falling BAC in a Case

The prosecution can use the variation in BAC against a defendant. They might argue that the defendant’s BAC was above the legal limit when they were pulled over but fell below the limit by the time any tests were administered. A qualified expert witness for the prosecution can use the same factors as a defense to convict a defendant of a “per se” DUI even though their BAC was below the legal limit when testing occurred.

Further, the prosecution can justify charges for a “general impairment” DUI even if the defense can convincingly argue that the BAC revealed on the test results was inaccurate compared to the BAC of the defendant at the time of driving. 

The rising BAC defense inherently admits that the defendant had not only been drinking but drinking enough to go over the per se BAC limit. Therefore, a rising BAC defense can present evidence of guilt just as much as it reveals flaws in the prosecution’s case. 

As a result of these tradeoffs, many DUI defense attorneys are reluctant to pursue a rising BAC defense strategy. They will only do so if it is highly relevant to the case at hand or the defendant feels as if it is their best option for beating or reducing DUI charges.

Defend Against a Pennsylvania DUI with an Experienced Attorney

The best way to avoid a DUI in Pennsylvania is to not drive after consuming any alcohol. If you’re going out for a night on the town, consider using a taxi, public transportation, or a driving service like Uber or Lyft to get to and from the bar or party. It’s not only the smart choice for you, it’s a safer choice for other drivers and pedestrians.
However, if you find yourself charged with a DUI and need someone to help you fight the charges, the law offices of DUI Attorney Steven E. Kellis have your back. With over 25 years of experience as well as time spent as a DUI prosecutor, Kellis has the knowledge and know-how to help you come up with a strong legal defense. Call us today at (215) 977-4183 or contact us online to schedule a free, no-obligation consultation.