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Top Ten Tips > Fighting a DUI Arrest

7. The 3-Hour Presumption

Police officers are never able to test your breath or blood alcohol precisely at the time you are driving. Your Sonoma County DUI lawyer will explain to you that typically at least 10-40 minutes elapse before you were tested, sometimes more than an hour or more subsequent to driving, particularly in remote accident cases and during busy holidays. Therefore the law provides the government with a legal fiction (a "presumption") that as long as the breath, blood or urine test samples are obtained within three hours of driving, the law will presume that the results obtained subsequent to the DUI arrest relate back to (were the same as) your alcohol level at the time of driving (Vehicle Code Section 23152(b)). If the test sample was not obtained within 3 hours, then the government cannot rely on this presumption and you may very well have a winning case in Sonoma County Superior Court and at the Santa Rosa DMV.

Understand that the 3-hour rule is a rebuttable presumption which may be challenged with our own affirmative evidence, introduced in a Sonoma County court or at the DMV, that even though the tests were obtained within three hours of driving, the tests are not an accurate reflection of your alcohol level at the time of driving. The best example is evidence of drinking after driving, even if the drinking happens in the vehicle once it has been parked and stopped. Good Sonoma DUI attorneys will tell you that one of the most common mistakes in such circumstances is denying this defense of drinking after driving at the time of arrest out of fear that admitting to drinking in a parked car would make things look worse to the arresting officer. See this discussion under Tip #4 above.

Passed out Sonoma DUI arrestTime of Driving.

Obviously, in order to take advantage of this gift of a 3-hour presumption, the government (both the Sonoma County District Attorney and the Santa Rosa DMV) must be able to establish a time of driving with some degree of probability. Sonoma court and DMV cases may be winners if, for example, your Sonoma County DUI attorney can show that you were parked for more than a couple of hours, perhaps sleeping off some drinks, prior to encountering law enforcement, or you were involved in an an accident scene which remained undiscovered for a long time. Often your Sonoma DUI lawyer can use impartial witness testimony, bar receipts, phone messages, and cell phone records to establish driving outside three hours (see the Preserve Physical Evidence discussion in the Tips for the First 48 Hours articles on this site). Santa Rosa DUI attorneys can expect to encounter contrary government evidence of time-stamped dispatch records, evidence of the public visibility of an accident scene, evidence of recency of driving (you in the driver's seat, warm hood, keys in ignition, engine running, lights on), or records of an eye witness who may have called 911 to report erratic driving at a certain recorded time, all to challenge the defense argument that your vehicle had been stationary for a long time.


Any result portrayed was dependent on the facts of that case, and the results will differ if based on different facts.

Our DUI Lawyers

Dave Jake Schwartz is an Honors Graduate from UC Hastings Law School, and UC Davis, former Federal Judicial Clerk, and Nationally Qualified Sobriety Tests Practitioner. Member of the California Bar for 30 years, Sonoma County resident for over 20 years, handles only DUI cases, including thousands of Sonoma County DUIs and DMV hearings: first/multiple offenders, minors, seniors, tourists, undocumented immigrants, veterans, probation violations, suspended license, public intoxication, open container, minor in possession, child endangerment, collisions, hit and run, evading, resisting arrest.


Dave Jake Schwartz