Please ensure Javascript is enabled for purposes of website accessibility
Contact Us for a Free Consultation 510.785.1444

Drug and Alcohol Combined DUIs

Driving under the influence of alcohol is a per se violation if the driver has a blood alcohol content (BAC) of 0.08% or higher. However, how do the police evaluate drivers who are under the influence of drugs, a combination of drugs, or a combination of drugs and alcohol? To be arrested for a drug DUI, the driver only has to be considered to be "under the influence of a drug or a combination of alcoholic beverage and drugs."

Drug DUIs Can Involve Multiple Drug Combinations

Under California Vehicle Code Section 23152(f), "It is unlawful for a person who is under the influence of any drug to drive a vehicle." Similarly, Under California Vehicle Code Section 23152(g), "It is unlawful for a person who is under the combined influence of any alcoholic beverage and drug to drive a vehicle."

Some police officers receive additional training to evaluate drivers who may be impaired by drugs or a combination of drugs. These advanced DUI programs include: 

  • Advanced Roadside Impaired Driving Enforcement - ARIDE
  • Drug Evaluation and Classification (Preliminary School) - DECP
  • Drug Recognition Expert - DRE

Drug Combinations and Driving

Under California Vehicle Code Section 312, a drug can be any substance or combination of substances that impair a driver's ability to drive the vehicle in an ordinarily prudent and cautious manner. Impairing drugs can affect the nervous system, brain, or muscles of the driver. 

Under this definition, drugs could include illegal narcotics, prescription drugs, over-the-counter drugs, and other substances that have an impairing effect.

Part of the National Highway Traffic Safety Administration (NHTSA) ARIDE training includes a section on "The Effects of Drug Combinations." Popular combinations of drugs include cannabis as a general mixer, the "speedball" combination of cocaine and heroin, or any other polydrug combinations. 

Polydrug means ingesting two or more different drugs. This can include poly-category drug combinations, which include drugs from two or more different drug categories. The NHTSA generally divides drugs types up into the following categories: 

  • Opioids/narcotic analgesics
  • Cannabis  
  • Stimulants 
  • Depressants, including benzodiazepines
  • Hallucinogens 
  • Dissociative drugs  
  • Inhalants 

Effects of Driving Under Drug Combinations 

Different drug combinations can have different effects on drivers. Generally, using two or more drugs or drug types can have the following potential effects: 

  • Null effect
  • Overlapping effect
  • Additive effect
  • Antagonistic effect

Null Effect of Combining Drugs

The null effect of combining drugs is like saying "nothing plus nothing equals nothing." For example, if one drug does not impair balance and another drug does not impair balance, combining them is not likely to cause a loss of balance in a roadside field sobriety test (FST). 

According to the NHTSA, a dissociative anesthetic and a central nervous system (CNS) depressant neither tend to affect pupil size. Combining these drugs, like combining ketamine and Xanax, would not likely reflect a change in the driver's pupil size. 

Drug Combinations and Overlapping Effects

An overlapping effect means that one drug causes a type of impairment and the other does nothing, which would have little effect on the impairment signs of the first drug. 

For example, a narcotic analgesic like Percocet generally does not impact a driver's horizontal gaze nystagmus (HGN) in an FST. However, a CNS depressant like Valium will likely show up in an HGN test. Combining the drugs will reflect in an HGN test similar to Valium alone. 

Additive Effect

The additive effect generally means where there is some reaction with one drug and a similar reaction to another type of drug, the combined effects can result in a greater reaction. For example, depressants generally cause HGN and vertical gaze nystagmus (VGN). Using inhalants like spray paint fumes can also result in HGN and VGN. Combining inhalants with a depressant like Klonopin can result in increased HGN and VGN presence in roadside testing.

Antagonistic Effect

The antagonistic effect of combining drugs can happen when drugs have opposite reactions in people, with unpredictable outcomes. The result of an antagonistic drug combination may depend on the amount of each type or category of drug and other factors. For example, opioids like fentanyl tend to constrict pupils. Stimulants, like cocaine, tend to dilate pupils. A combination of fentanyl and cocaine could show up as dilated pupils, constricted pupils, or pupils that appear normal, depending on the amount of the drugs involved, time passage, and the individual's metabolism.  

Drugs Combined With Alcohol and Driving

Alcohol alone or drugs alone are enough to lead to a DUI in California if the driver is considered to be "impaired." However, a small amount of drugs and a small quantity of alcohol, while separate may not be impairing, combined may be enough to impair a driver's abilities. According to the NHTSA, "alcohol is the most popular 'mixer' with other drugs." 

Criminal Penalties for Drug Combination DUI

The penalties for drunk driving in California are generally the same whether the driver was impaired by alcohol, drugs, or some combination of drugs and alcohol. For a first-offense misdemeanor DUI, the penalties generally include: 

One of the differences between a drug DUI and an alcohol DUI is that a driver arrested for drunk driving can generally get an IID-restricted license so they can drive as long as they pass the IID test. Drivers with a drug DUI may have to wait out their license suspension before they can get their driving privileges reinstated. 

There are increased penalties for multiple DUIs, DUIs causing bodily injury or DUIs with a high BAC. Talk to your California DUI defense lawyer about what penalties you may be facing after a drug DUI arrest in the East Bay

Contact an Experienced Oakland Drug DUI Defense Attorney

East Bay attorney Lynn Gorelick has more than 39 years of DUI and drug DUI defense experience and understands the challenges involved in California impaired driving cases. Talk to a local criminal defense lawyer who understands defense strategies and plea bargain negotiations for drivers in Oakland and Alameda County.

Serving The Bay Area

We strive to make the highest quality legal representation accessible and affordable.