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California Highway Patrol Testing Cannabis-Impaired Drivers

Drivers under the influence of marijuana are nothing new in California. However, there has always been a problem of determining when a driver who used marijuana is safety-impaired. The effects of marijuana usually wear off within a matter of hours but evidence of the drugs remains in the driver's body. 

Police officers in California may have to rely on faulty Drug Recognition Expert (DRE) evaluations of whether a driver is impaired. This can result in some drivers who are not impaired getting charged and convicted of a drug DUI. The DMV and CHP are testing impairment for drivers under the influence of cannabis in a study with UC San Diego. 

If you have questions about an Oakland marijuana DUI arrest and your best legal defense options, talk to an experienced East Bay DUI defense attorney for legal advice.

Increase in Drug-Impaired Driving Accidents

According to the Commissioner of the California Highway Patrol (CHP), "Throughout California, we are seeing an alarming increase in the number of crashes involving drivers impaired by drugs. Working in collaboration with our traffic safety partners and key stakeholders on this groundbreaking study will provide potentially lifesaving information, resulting in safer roadways in California for all who use them.”

In 2018, there were approximately 173 fatal crashes involving drug-impaired drivers. In 2021, the number of fatal drug-related accidents was 280—an increase of 62%. 

According to the National Highway Traffic Safety Administration (NHTSA), 56% of drivers involved in fatal and serious injury accidents tested positive for at least one drug. Like alcohol, marijuana can slow coordination, judgment, reaction time, and hurts a driver's ability to multitask. Drugs like methamphetamines and cocaine can make drivers less risk-averse and more aggressive. Combining drugs or drugs and alcohol can intensify the effects of the drugs. 

Many drivers also forget about the effects of prescription medications, which can cause drowsiness, dizziness, slow coordination, and reduced reaction time. Prescription drugs combined with even one or two drinks may affect the driver like having 5 or 6 drinks. 

California Has No Per Se Limit for THC and Drugged Driving

A number of states have tetrahydrocannabinol (THC) limits for impaired driving. California drivers are familiar with the per se limits for alcohol, where 0.08% BAC or higher is enough for a drunk driving arrest. The per se limit does not require the police to show the driver was unable to drive safely, only that their blood alcohol level was over the limit. 

There is no THC per se limit for marijuana-impaired driving in California. Other states with legal medical and recreational marijuana laws, like Colorado and Washington, have set the THC limit to more than 5 nanograms of active THC per milliliter of blood. Even if drivers have a medical card for marijuana, they can be arrested for impaired driving.  

CHP and UC San Diego Testing Marijuana Detection

The California Department of Motor Vehicles (DMV) and CHP are partnering with the University of California San Diego (UCSD) to study public safety and best practices for detecting driving impairment in cannabis users. The study will use volunteers in the Sacramento area to test different methods of cannabis-impairment detection.

The study will include random double-blind assignment of a cannabis product, placebo, or no substance. The volunteers will then drive a test course in a closed environment at the CHP Academy. The vehicles will evaluate and record driver actions and vehicle movements, including: 

  • Corrections to the steering wheel
  • Changes in acceleration
  • Changes in braking
  • Vehicle positioning

Police and CHP officers who are trained as Drug Recognition Experts (DRSs) use other clues for looking for drug-impaired drivers, including erratic driving behavior, standardized field sobriety tests (SFSTs), and other evaluations. 

Penalties for Drugged Driving in California

Without a THC limit, drivers who are under the influence of marijuana and other drugs are evaluated based on the impairment. Under California Vehicle Code 23152 f, "It is unlawful for a person who is under the influence of any drug to drive a vehicle."

Drugs include marijuana or any substance that can affect the nervous system, brain, or muscles of a person to impair their ability to drive a vehicle in a prudent and cautious manner. "Under the influence" means that as a result of taking a drug, the driver's mental or physical abilities are so impaired that they are no longer able to drive a vehicle with the caution of a sober person, using ordinary care.

To prove the driver was impaired, a prosecutor may use the police report, dashcam footage, police testimony, field sobriety test results, and drug test results. A blood test can show the presence of marijuana or THC in the driver's body, as well as other substances, including alcohol. 

The penalties for a drug DUI are generally the same as for an alcohol DUI, including: 

There is a major difference in penalties. Marijuana-impaired drivers generally can't get an IID-restricted license immediately after a DUI. Alcohol DUI drivers can get an ignition interlock device (IID) so they can still drive as long as they can blow an alcohol-free breath sample. Drug DUI drivers may have to wait out their license suspension before they can get their license back. 

Talk to an East Bay DUI Defense Lawyer About Your Drug DUI

Lynn Gorelick has more than 40 years of East Bay DUI defense experience and understands how much is at stake for drivers facing a drug-driving arrest. She understands how to approach the individual case and defense strategies to avoid a conviction. If you are a driver facing drug DUI charges anywhere in Oakland, Alameda County, or Contra Costa County, contact Lynn Gorelick for help

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