When a Blood Alcohol Level of .10 After Driving Is Not a DUI

As one of my clients would tell you, it is not illegal to have a .10 blood alcohol concentration (BAC) 30 minutes after driving.  What matters for a DUI is your BAC being below the California limit of .08 at the time of driving.    

Here’s how my client, whose blood alcohol level was .10 after driving, was able to avoid a DUI and maintain his driver’s license.

Client Pulled Over for a Suspected DUI

A few months ago, I represented a client who finished his last cocktail at a local bar in Downtown Auburn, California just before driving.  Five minutes later, he was pulled over for weaving. 

How the Next 30 Minutes Were Spent

He talked to the officers for 10 minutes and then performed 5 separate field sobriety tests for the next 20 minutes.  

Afterward, he took a breath test on scene, which showed a blood alcohol level of .10.

Related: Why a Failed Field Sobriety Test Might Not Mean a DUI

Now We Only Know His BAC 30 Minutes After Driving

The result of this test told us his BAC 30 minutes after driving.  But what was it at the time of driving? 

In a DMV hearing, we were able to show that it was below California’s legal DUI limit of .08 BAC.  This is because of a phenomenon known as rising blood alcohol concentration.  

What Can Rising Blood Alcohol Concentration Tell Us About His BAC When He Was Driving? 

As we ingest alcohol into our bodies, it travels through the esophagus, then to the stomach.  While alcohol is in the stomach, it doesn’t impair driving or raise BAC very much because it hasn’t reached the brain.  

After it leaves the stomach, it enters the small intestine, then gets absorbed into the bloodstream and travels to the brain where it impairs mental and physical abilities and raises BAC.  The time it takes to do this is often 15-60 minutes after ingestion. 

What Was His BAC When He Was Driving?

In the case of my client, he was below a .08 BAC (which is not a DUI) at the time of driving because most if not all of the drink he just finished was still in his stomach at the time of driving, which did not raise his BAC or impair him.  

However, because he was pulled over, spoke to police, and then completed field sobriety tests, the alcohol had time to leave his stomach, absorb into the bloodstream, travel to the brain, and raise his blood alcohol level to a potential DUI level of .10.  

What If He Weren’t Pulled Over?

If he weren’t pulled over, he would have made it to his home near downtown Auburn before he reached a DUI alcohol level of .08. 

The Result of His DMV Hearing

Because my client would have made it home before his BAC reached the legal limit for a DUI, the DMV did not suspend his license after we held a hearing.

If you suspect your BAC was rising when you were pulled over, you should consult a DUI lawyer.  I, along with the team of DUI lawyers at the Cohen Defense Group are intimately familiar with the science of DUIs, including rising blood alcohol concentration. Contact us today.

About Zachary Merliss

Zachary MerlissZach Merliss focuses his practice on DUI law in Placer County. He teaches the “legal aspects” lecture at a First Offense DUI School in Auburn, and successfully completed the 3-day Standardized Field Sobriety Test Academy, which is the same course police must pass before conducting a DUI investigation. He has litigated dozens of DMV hearings, DUI trials, and motions to suppress evidence. During his time at the Cohen Defense Group, he has worked hard for clients to obtain reduced sentences and dismissals.