Drug DUI cases depend on interpretation, not a simple number. We make the prosecution prove impairment.
The short answer. In California you can be charged with DUI for marijuana, prescription medication or over-the-counter drugs if they impair your driving. There is no THC concentration that automatically proves impairment, so cases rest on officer observations, field tests, expert evaluations and toxicology. The prosecution must prove impairment at the time of driving.
Officers may use a Drug Recognition Expert (DRE), who evaluates suspected impairment through a 12-step protocol. Blood or urine tests may show the presence of a substance, but presence is not the same as impairment.
| When | What happens | What we do |
|---|---|---|
| Day of arrest | Evaluation, possible blood draw | You call us; avoid statements about dosage or intent |
| Within 10 days | The DMV hearing window | We request it and review the paperwork |
| Evidence stage | Lab results and officer reports arrive | We examine toxicology, timing and chain of custody |
| Resolution | Suppression, reduction, negotiation or trial | We push where the evidence cannot connect drug findings to driving |
We treat a DUID as the technical evidence case it is. We dissect how impairment was concluded (field sobriety methods, officer and DRE observations, body-cam gaps, report inconsistencies), then stress-test the toxicology: what was tested, when it was taken, chain of custody, and whether the results show impairment at the time of driving versus mere presence.
Local knowledge matters: Howard Williams is familiar with local judges, prosecutors, and court procedures at El Cajon Superior Court. You get direct access to your attorney, not a call center, and we are available 24/7 for emergencies. Over 20 years of experience.
Related services: Refused Chemical Test, High BAC DUI, First-Time DUI.
Call The Law Firm of Howard Williams now for a free consultation. Payment plans may be available for qualified clients.
Sources: California Vehicle Code impairment standard. The information on this page is general and does not create an attorney-client relationship.
Talk to the Law Firm of Howard Williams about your California DUID defense today – protect your license, challenge the evidence, and fight for the best outcome.
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Yes. Recreational cannabis is legal in California, but driving while impaired by it is not. The prosecution must prove impairment at the time of driving.
No. California has no THC concentration that automatically establishes impairment, unlike alcohol’s 0.08% standard. Cases rest on officer observations, field tests and expert evaluations.
Yes. California DUI law looks at impairment, not at whether a drug was prescribed. Over-the-counter medication that causes drowsiness or impaired coordination can also lead to charges.
A specially trained officer who evaluates suspected drug-impaired drivers using a 12-step protocol, including eye response, vital signs and behavior indicators.
Not by itself. THC can remain in the body after impairment has ended, and blood tests do not directly measure impairment at the time of driving. The defense separates presence from impairment.
Avoid statements about dosage or intent without legal counsel. These cases depend on medical interpretation and the timing of ingestion.
