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Marijuana DUI: Cannabis and Cars, VC 23152(e)

Marijuana is now legal in California for those over 21-years of age. However, law enforcement in San Diego and around the State of California has increased the number of stops for suspicion of driving under the influence of marijuana, VC 23152(e). The DUI investigation for marijuana is the same as they are for alcohol, with a few changes. There are three phases for the investigation.


The first phase is observation. Law enforcement will observe the vehicle in motion to determine if there is sufficient reason to stop the vehicle for suspicion of DUI. Examples that law enforcement will look for are the following: straddling lanes, weaving, swerving, almost hitting another vehicle, following too closely, braking, stopping erratically, turning with a wide radius, driving without headlights, improperly using turn signals, and driving in the opposing lane.

This list is not exhaustive, and law enforcement can and do rely on many other indicators to stop a vehicle to investigate the driver for suspected marijuana DUI


The second phase consists of the officer observing the driver after the stop and deciding whether to ask the driver to step out of the vehicle. After the initial stop, the officer may ask the driver for things at the same time, ask interrupting or distracting questions, and/or unusual questions. If the officer suspects the driver is impaired, they will ask the driver to step out of the vehicle – making observations of unusual reactions, problems opening the car door, leaving the car in gear, using the vehicle for balance, etc.


Once out of the vehicle, the last phase of the marijuana DUI investigation has begun. The officer will ask the driver to perform Standardized Field Sobriety Tests (SFSTs) – Horizontal Gaze Nystagmus (HGN), Walk-and-Turn, and One-Leg Stand. These standardized tests do not do very well when testing for marijuana presence or impairment. In the past, some officers have tried to rely on the infamous “green tongue syndrome” to establish that the driver had recently used marijuana. This hypothesis has been rejected by the courts, because there is no scientific validity that confirms the idea that smoking marijuana leads to a green tongue.

A Drug Recognition Expert (DRE) may try to detect marijuana presence by observing body temperature, muscle tone, pupil size, pulse rate, and blood pressure. These indicators are not very useful. The officer will also attempt to obtain a breath sample. The issue is that most devices only test for alcohol. The Draeger 5000, which is used to detect marijuana, cannot detect impairment – only presence.

These tests are optional – that is, the driver can refuse to perform these tests. The driver will have to comply with the officer’s requests for his or her license, registration, and insurance. If the driver refuses to perform SFSTs, the officer will then have to make a decision: he or she observed enough through driving and initial interactions, to establish the probable cause to arrest for marijuana DUI; or release the driver because there is insufficient probable cause to arrest.

If the driver is lawfully arrested, he or she will be advised by the officer of their obligation to provide a blood or breath sample, pursuant to Vehicle Code Section 23612. If the driver refuses, he or she can lose their license for up to one year or more.

Marijuana DUIs are very complex and require an experienced attorney. If you have been arrested for marijuana DUI, VC 23152(e), contact Kern Law, APC today. We provide a free consultation.