Last verified: March 2026
VC 23152(f): Impairment-Based Prosecution
Driving under the influence of cannabis is prosecuted under Vehicle Code §23152(f), which makes it unlawful to drive a motor vehicle while under the influence of any drug. Unlike alcohol DUI, where a blood alcohol concentration of 0.08% creates an automatic legal presumption of impairment, California has no per se THC blood concentration limit.
This means prosecutors must prove actual impairment — that the drug affected the driver's ability to operate a vehicle with the caution characteristic of a sober person. A positive THC blood test alone is not sufficient for conviction. This is a significantly higher evidentiary bar than alcohol cases and makes cannabis DUI prosecutions both more complex for the state and more defensible for defendants.
Several states have adopted per se THC limits — Colorado and Washington set the threshold at 5 ng/mL of active THC per milliliter of blood. California has repeatedly declined to adopt a per se standard, reflecting the scientific consensus that THC blood levels do not correlate reliably with impairment the way BAC does for alcohol. Regular users can have elevated THC levels without being impaired, while infrequent users may be impaired at lower concentrations.
How Cannabis DUI Cases Are Built
Without a per se limit, California law enforcement builds cannabis DUI cases through multiple evidence streams:
- Driving behavior: Erratic driving, lane departures, failure to maintain speed, delayed responses to signals, and other observable driving impairment documented on dashcam or bodycam
- Officer observations: Bloodshot and watery eyes, cannabis odor, slow or confused speech, impaired coordination, dilated pupils, and disorientation during the traffic stop
- Field sobriety tests: Modified Romberg balance, walk-and-turn, one-leg stand, and finger-to-nose tests. While not scientifically validated for cannabis the way they are for alcohol, these tests contribute to the overall evidence picture
- Drug Recognition Expert (DRE) evaluation: Specially trained officers conduct a standardized 12-step evaluation that includes vital signs (pulse, blood pressure, body temperature), pupil measurements under different lighting, muscle tone examination, and divided-attention tasks. DRE officers are trained to identify seven categories of drug impairment
- Blood testing: If arrested, a blood draw can establish the presence and concentration of active delta-9-THC. Blood tests are more useful when drawn promptly — THC levels drop rapidly after consumption, and delays reduce evidentiary value
Penalties for Cannabis DUI
Cannabis DUI penalties under VC 23152(f) mirror alcohol DUI penalties. For a first offense:
| Penalty | First Offense | Second Offense (within 10 years) |
|---|---|---|
| Jail time | 96 hours – 6 months | 96 hours – 1 year |
| Fines | $1,800 – $3,500 (with assessments) | $1,800 – $4,000 (with assessments) |
| License suspension | 6 months | 2 years |
| DUI program | 3-month AB 541 program | 18-month SB 38 program |
| Probation | 3 – 5 years informal | 3 – 5 years informal |
The base fine for a first-offense DUI is $390, but penalty assessments multiply the actual cost to approximately $1,800–$3,500. California's assessment structure adds state, county, court security, DNA, and emergency medical surcharges that roughly quadruple the base fine.
A first offense is a misdemeanor. It becomes a felony if the DUI causes injury (VC 23153), if it is a fourth offense within 10 years, or if the driver has a prior felony DUI conviction.
Open Container: VC 23222(b)
California's cannabis open container law under Vehicle Code §23222(b) is separate from the DUI statute. It is unlawful for any person to have an open container or open package of cannabis or cannabis product while driving or riding as a passenger in a vehicle.
- Penalty: $100 infraction — no criminal record, no arrest, comparable to a seatbelt violation
- Storage requirement: Cannabis products must be in a sealed, unopened container stored in the trunk or an area of the vehicle not accessible to the driver or passengers. If your vehicle has no trunk (SUV, hatchback), store products in a locked container behind the last row of seats
- This applies to all occupants: The driver, front-seat passengers, and rear-seat passengers are all subject to the open container law
Practical Advice
Cannabis impairs driving ability. The absence of a per se THC limit does not mean driving after consuming cannabis is safe or consequence-free. Reaction time, attention, and judgment are all affected.
- Use rideshare or taxi: Uber, Lyft, and taxis are widely available across California. Many consumption lounges actively encourage rideshare use and some offer discount codes
- Wait before driving: THC impairment peaks within the first 1–3 hours of inhalation. Edibles can take 4–6 hours before effects fully subside. When in doubt, wait longer
- Seal and store products properly: After purchasing from a dispensary, keep products in their sealed dispensary bag and place them in the trunk. Never open cannabis products in the passenger area
- Refusal consequences: Refusing a blood test after a lawful DUI arrest triggers an automatic 1-year license suspension under California's implied consent law (VC 23612)
Cannabis impairs driving. There is no safe amount for driving. California has a 10-year lookback for prior DUI offenses, and a cannabis DUI carries the same penalties as alcohol DUI. Use rideshares, taxis, or a designated driver.
For in-depth cannabis education, dosing guides, safety information, and research summaries, visit our partner site TryCannabis.org