How Do You Measure Marijuana Impairment for DUIs?

Introduction to How Do You Measure Marijuana Impairment for DUIs?

More than half of the states in the United States allow for the use of medical marijuana, twenty eight states to be exact (including Washington DC).i On top of those twenty eight states, there are sixteen other states that have regulations in place to allow for a limited use of medical marijuana.ii That’s a total of forty four states that permit some use of marijuana for medical purposes in some manner. Where does one draw the line to measure marijuana impairment for DUIs?

measure marijuana impairment for duisOf those forty four states, six states permit marijuana for recreational use as well as medical use. Those states include California, Massachusetts, Nevada, Alaska, Colorado, Oregon, Washington, and Washington DC.iii Arizona voted on this issue in November 2016, but recreational use was not approved. In all states with marijuana use legalized in some form, there are laws in place to ensure safety, especially on the roadways. Measuring how much marijuana is in someone’s system and even determining what a safe amount would be are two questions that still do not have a clear answer.

What Legalized Marijuana Laws Look Like in Action

Last November, 2016, California, Massachusetts and Nevada legalized marijuana for recreational use.iv This new law limits marijuana use and possession to adults ages 21 and up, just like alcohol use.vResidents of these states are even permitted to grow up to six marijuana plants for their own personal use.vi In Nevada, people will only be able to grow their own marijuana plants if they live more than 25 miles from a retail marijuana store.vii

In California and Nevada, employers will have the right to enforce rules about how their employees use marijuana.viii In Massachusetts, the ballot measure states that employers will be permitted “to prohibit the consumption of marijuana by employees in the workplace.”ix It is important to note that marijuana use in public places, however, is still illegal in all states that have legalized recreational marijuana use.x

Now, even though many states have legalized marijuana either in the form of medical use or recreational use, these state laws still violate the federal law which prohibits marijuana use.xi This means that if the federal government wants to prosecute individuals in Washington or Colorado where recreational marijuana use is legalized at the state level, they can.xii The federal laws trump the state laws in this instance. However, personal use of marijuana in these states is not a high priority for enforcement from the federal government – at least not right now.

What DUI Laws for Marijuana Look Like in Other States

In states where marijuana use is illegal for recreational use, driving under the influence is easy enough to detect. Even if you have a medical marijuana card, if you are driving while impaired, you can still be charged with a DUI. If you do not have a medical marijuana card, you will certainly be charged with a DUI. It is a simple process, are you under the influence of marijuana or not. When it comes to alcohol, there is a defined threshold of 0.08% blood alcohol concentration – and anything above that will more than likely result in a DUI (you can obtain a DUI even if you are below the threshold if you are driving and appear impaired).

When it comes to detecting marijuana in the driver’s system, it is just not that simple. Colorado seems to be the leading pioneer in creating standards for detecting marijuana in the driver’s system, but many people still criticize the procedures. Currently, Colorado law specifies that drivers with five nanograms of active tetrahydrocannabinol (THC) in their blood can be prosecuted for a DUI.xiii This is a relatively small amount of marijuana but just like alcohol, it could affect some drivers much more drastically than others. Some argue that this amount is too low, while others argue it is too high.xiv

Research has shown that for individuals who use marijuana regularly, it can take much longer to dissipate in their system.xv With that being said, chronic marijuana users could have 5 nanograms of THC in their system basically at all times – even if they have not used TCH in two days.xvi The more regularly someone uses THC, the more nanograms there will be present in their system at all times. So while Colorado is doing their best to create a model for DUI enforcement in regards to marijuana use – there is still a very long way to go to accurately determine what level of THC will lead to the impairment of a driver.

The Use of Blood, Breath, or Urine Tests for Marijuana Detection

In California, a state where medical and recreational use of marijuana is legal, if an officer has probably cause to believe you were driving under the influence of marijuana, or any other drug, the officer can administer a blood, breath, or urine test.xvii However, the use of these tests to measure marijuana impairment for DUIs is a flawed system and will not provide accurate results. For habitual users, it is possible to have marijuana in your system for extended periods of time – and these tests do not differentiate WHEN the person used TCH. A person could be completely sober and yet have 7 nanograms in their system from long time use (even if they haven’t used THC in three days).

California is now utilizing a saliva swab test to detect not just marijuana, but crystal meth, methadone, cocaine, and some prescription drugs.xviii While these tests can detect these drugs, there are arguments over whether these tests are actually accurate. These tests cannot test the level of marijuana in your system, just that it is in your system. That is like police administering a test for detecting alcohol and finding alcohol is in your system – even if you just tasted the wine at Olive Garden. Should that really warrant a DUI?

Conclusion to How Do You Measure Marijuana Impairment for DUIs?

As of right now, even though forty four states permit some level of marijuana use, the state of the law for enforcing DUIs connected to marijuana is lagging far behind where it should be. Colorado is doing their best to create some form of guideline for determining how to enforce marijuana laws in connection with driving, but the methods of determining how much THC is in someone’s system is still lagging behind to measure marijuana impairment for DUIs. It will be a continued trial and error until the legal “sweet spot” is found.


i See 28 Legalized Medical Marijuana States and DC Pro Con.org (Accessed February 23, 2017) http://medicalmarijuana.procon.org/view.resource.php?resourceID=000881

ii See 3 More States Legalize Recreational use of Marijuana: How the Map Looks Now Live Science (Published November 09, 2016) http://www.livescience.com/56807-recreational-marijuana-california-massachusetts-nevada.html

iii Id.

iv Id.

v Id.

vi Id.

vii Id.

viii See 3 More States Legalize Recreational use of Marijuana: How the Map Looks Now Live Science (Published November 09, 2016) http://www.livescience.com/56807-recreational-marijuana-california-massachusetts-nevada.html

ix Id.

x Id.

xi See Federal Marijuana Use Americans for Safe Access (Accessed February 23, 2017) http://www.safeaccessnow.org/federal_marijuana_law

xii Id.

xiii See Marijuana and Driving Colorado The Official State Web Portal (Accessed February 23, 2017) https://www.codot.gov/safety/alcohol-and-impaired-driving/druggeddriving/marijuana-and-driving

xiv See The Difficulty of Enforcing Laws Against Driving while High National Public Radio (Published September 6, 2016) http://www.npr.org/sections/health-shots/2016/09/06/492810932/the-difficulty-of-enforcing-laws-against-driving-while-high

xv See 6 Things We Learned about Marijuana Blood Testing Defense Matters (Published March 11, 2014) https://www.duidefensematters.com/resources/blog/6-things-we-learned-about-marijuana-blood-testing

xvi Id.

xvii See How Police Test for Marijuana DUI in California Randy Collins (Accessed February 23, 2017) https://www.duiease.com/test-for-marijuana-california/

xviii Id.