Drugged Driving Laws

All 50 states and the District of Columbia have laws that target impaired drivers. Unfortunately, many driving under the influence (DUI) laws do not discriminate between alcohol-impaired drivers and drug-impaired drivers. While there should be no difference between the two with regard to rates of apprehension, conviction and sentencing, states have no means to track these potential differences. An essential first step to improved laws is to include a distinction between alcohol- and drug-impaired driving.


Per Se Laws 

Under per se laws it is illegal to drive with specific levels of drugs or metabolites. Across the US there is a clear per se standard for alcohol: If a driver has a blood alcohol concentration (BAC) of 0.08g/dL or more that driver is a violation of the per se alcohol law. US commercial drivers are held to a lower per se standard of 0.02g/dL for alcohol. Some states have per se laws for drugs where a specified amount of a controlled substance or metabolite is a violation. Importantly, not all per se drug laws are created equal in terms of highway safety. 

Zero Tolerance Per Se

Under a zero tolerance per se law it a violation for drivers to have any illegal drugs or  their metabolites present. There is abundant precedent for using the zero tolerance per se standard for drugs. There is no acceptable level of BAC for an underage drinker in the US because any alcohol consumption under the age of 21 is illegal. For the same reason, the per se standard has been used for illegal drugs among commercial drivers for nearly three decades with great success and little controversy. This zero tolerance standard is used in federally-mandated workplace drug testing for safety-sensitive jobs. There is no more safety sensitive common human activity than driving a motor vehicle, regardless of whether or not a federal mandate is involved. For this reason the Institute for Behavior and Health, Inc. supports the use of zero tolerance per se drug laws with effective enforcement and active public education. “Don’t Drink and Drive” is widely accepted. We need to add the message “Don’t Drug and Drive.” 

Zero tolerance per se drug laws are widely used in the developed world outside the US, including Western European nations, Canada, Australia and New Zealand. The benefit of a zero tolerance per se drug law for alcohol and drugs is that prosecutors do not have to meet more complex and difficult to use standards of guilt. 

A common argument against zero tolerance per se laws is that the presence of drugs and metabolites does not prove impairment. As described in the Enforcement page of this website, drivers are tested for drugs after they have been arrested for suspicion of impaired driving, and/or after a crash when there is suspicion of impairment. One way to reduce concerns about identifying the presence of drugs that are not presently causing impairment is to use drug testing methods with shorter windows of detection, in particular oral fluid. 

Another common argument against zero tolerance per se drug laws - specifically for marijuana - is that in some states marijuana use is legal for adults. As a result, some states have set arbitrary legal blood limits on THC for drivers. For more analysis on marijuana-impaired driving, read about Impairment Thresholds: A Fool's Errand.

Tandem Per Se DUID

The American Automobile Association has proposed using a two-component structure for addressing marijuana-impaired driving of behavioral and physiological evidence of impairment and evidence of recent marijuana use. Framed as “tandem per se DUID” legislation by Ed Wood, founder of DUID Victim Voices and advocate for victims of drugged driving, this law allows the prosecution to prove someone guilty of DUID by showing that evidence of impairment coupled with a positive drug test. 

Impairment Thresholds: A Fool's Errand

There is no 0.08 BAC equivalent for any drug, including marijuana. This is because, unlike alcohol, drug levels do not consistently correlate with specific levels of impairment. A drug concentration that produces no observable impairment in one individual may be profoundly impairing to another. There are currently no laboratory tests that identify tolerance, one of several factors that determine impairment after drug use. Another key factor that prevent the identification of simple impairment thresholds is drug-to-drug interactions because of the increasingly common finding of multiple drug use by drivers.

A widely suggested but misguided proposal is for states to address marijuana-impaired driving by using an arbitrary limit for drivers of 5ng/ml tetrahydrocannabinol (THC), the main psychoactive ingredient in marijuana. A 2016 comprehensive AAA study demonstrated that 5ng/ml THC is not a usable impairment threshold for marijuana. This complements the position that the Institute for Behavior and Health, Inc. has held for years that a limit of 5ng/ml THC gives most marijuana-impaired drivers a free pass to drive stoned.

It is commonly assumed that the challenge of finding the specific level of each drug that causes impairment, including marijuana, is simply a matter of additional research. It is not. While further study of alcohol and other drugs in driving contexts is needed, it is imperative that action be taken now, based on more than four decades both of active research on drugs and driving and compiling the statistics on drug-related motor vehicle crashes and fatalities. Waiting for more research while drugged driving injuries and fatalities mount is tragically irresponsible.


Administrative License Revocation

The Foundation for Alcohol Responsibility reports that as of 2016, 42 states and the District of Columbia have administrative license revocation (ALR) laws for alcohol: "These laws allow law enforcement officers to confiscate a driver’s license if that individual fails or refuses to take a breath test. The suspension/revocation typically occurs immediately with the arresting officer taking the license at roadside and is classified as an administrative sanction (i.e., it is not a criminal punishment)." 

ALR is an effective deterrent for alcohol-impaired driving. It also should be applied for drugs. 


Model Laws

The following model laws were developed by the Institute for Behavior and Health (IBH) and the National Partnership on Alcohol Misuse and Crime (NPAMC).  The first iterations of these laws were created in 2010 following input from a committee of prosecutors, toxicologists and other traffic safety experts from across the United States. They have since been updated and include provisions defining the crimes of alcohol and/or drugged driving and "internal possession" of chemical and controlled substances. A PDF is also available.

Section _____
Prohibiting Driving Under the Influence (DUI) of Alcohol or Drugs; definition. 

(1) A person is guilty of the offense of driving under the influence and is subject to punishment as provided in subsection (2) if the person is driving or in actual physical control of a vehicle anywhere within this state and: 

  • (a) The person is under the influence of alcoholic beverages, a chemical or controlled substance as defined in s. _______, any other impairing substance or any combination of two or more of these substances while impaired to the slightest degree; or
  • (b) The person has an alcohol concentration of 0.080 or more grams of alcohol per 100 milliliters of blood, 0.080 or more grams of alcohol per 210 liters of breath at the time of driving; or
  • (c) The person has an alcohol concentration of 0.080 or more grams of alcohol per 100 milliliters of blood or 0.080 or more grams of alcohol per 210 liters of breath at the time of driving or any time after driving as a result of alcohol consumed before or during driving; or
  • (d) There is any amount of a Schedule 1 chemical or controlled substance as defined in s. _______* or one of its metabolites or analogs in the person’s blood, saliva, urine, or any other bodily fluid; or
  • (e) There is any amount of a Schedule 2, 3 or 4 chemical or controlled substance as defined in s. _______ or one of its metabolites or analogs in the person’s blood, saliva, urine or any other bodily fluid. The fact that a person charged with violating this provision consumed the drug pursuant to a prescription issued by a licensed health professional authorized to prescribe it and injected, ingested, or inhaled the controlled substance in accordance with the health professional's directions shall constitute an absolute affirmative defense against any charge of violating this provision related to that particular drug, but no other substance and not any other provision under subsection 1.
  • (f) With the exception of (1)(e), the fact that any person charged with violating this subsection is or was legally entitled to consume alcohol or to use a controlled substance, medication, drug or other impairing substance, shall not constitute a defense against any charge of violating subsection 1.
* Pursuant to 21 USC Sec. 812, Schedule 1 drugs or substances have a “high level of abuse” and “no currently accepted medical use in treatment in the United States.”

Section _____
Prohibiting the Internal Possession of Chemical or Controlled Substances

Any person who provides a bodily fluid sample containing any amount of a chemical or controlled substance as defined in s. _________ commits an offense punishable in the same manner as if the person otherwise possessed that substance.** The fact that a person charged with violating this provision consumed the drug pursuant to a prescription issued by a licensed health professional authorized to prescribe it and injected, ingested, or inhaled the controlled substance in accordance with the health professional's directions shall constitute an absolute affirmative defense against any charge of violating this provision.

** This crime would be the equivalent of possession of a controlled substance and would be punished in the same manner.

NOTE: This provision is not a DUI specific law. Rather, it applies to any person who tests positive for chemical or controlled substances. Because so many DUI offenders are tested for drugs, we include this provision in our model.

Recommended Reading + Resources

The following is not a comprehensive list of related reading and resources but serves as a starting point for more information on these drugged driving issues. Be sure to also check out the Resources page.

Drugged Driving Laws

Impairment thresholds

Administrative License Revocation

To request materials email the Institute for Behavior and Health at ContactUs@IBHinc.org.

Back to Top ↑