What does DUI “Per Se” mean?

“Per Se” means “by or in itself.”

California Vehicle Code 23152(b) makes it a crime to drive a motor vehicle with a blood alcohol concentration (“BAC”) of 0.08% or higher.  Often referred to as California’s “per se” DUI law, this section means that someone driving “at or over the BAC limit” of .08% or more, the person can be found guilty of DUI, even if it cannot be proven that he or she is actually “under the influence” of the alcohol.  Thus, the BAC level itself is an illegal level.

In other words, a person can be “sober as day” but if the government can prove that at the time of driving the person’s blood alcohol concentration was .08% or more, with evidence that is accurate and reliable, then the person is guilty of DUI.

VC235152(b) states:

“It is unlawful for a person who has 0.08 percent or more, by weight, of alcohol in his or her blood to drive a vehicle.”

Vehicle Code 23152(b) is almost always charged together with Vehicle Code 23152(a) which states:

“It is unlawful for a person who is under the influence of any alcoholic beverage to drive a vehicle.”

The VC23152(a) charge is the basic driving under the influence charge.  With this charge the actual blood alcohol concentration level does not matter.  The question is, was the person under the influence of alcohol when driving.  Theoretically a person could have a .03% blood alcohol concentration level and still be convicted of the (a) charge if there is enough evidence that the person was driving while under the influence of alcohol.

What does “under the influence” mean?  For the definition we look to CalCrim jury instruction # 2110, which states:

“as a result of drinking alcohol, a person’s mental or physical abilities are so impaired that he or she is no longer able to drive a vehicle with the caution of a sober person, using ordinary care, under similar circumstances.”

That is an incredibly vague definition, especially when taking into consideration the phrase “so impaired.” Thus, the standard is not simply “impaired,” or even “a little impaired.”  The standard is “so impaired.”  You must ask yourself – what does the phrase ‘so impaired’ mean?

This is why DUI cases often go to Trial, because being “under the influence “ can be incredibly subjective. Everything turns on what evidence is presented at Trial, how the evidence is presented, and how a jury perceives it.

Although the Per Se charge discussed above seems to be black and white, it is not.    Blood or breath samples are often taken after the person was stopped by the police, sometimes an hour or more later, so it does not tell us exactly what the person’s BAC was at the time of driving.  This is because alcohol levels are either rising or falling, depending on when the person drank.

The other issue is whether the alleged result itself is accurate and reliable.  In other words, was the analysis of the blood sample done correctly? Was it done in accordance with accepted scientific practices or was it a sloppy analysis?

As for the breath machine, were all the required protocols followed prior to the breath test being administered on the person?  Was the machine itself in proper working order? Were the necessary accuracy and calibration checks completed as required?

As you can see, there are many factors that can affect the accuracy and reliability of a breath or blood test result.  This is why it is essential to have an expert DUI defense attorney defending your case.