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Marijuana DUI Laws

Marijuana Blood Testing Laws Explained

As of December 1, 2012, people in the state of Washington are allowed to possess up to 1oz of marijuana for personal use. In addition, the new law set a “per se,” or maximum, threshold THC level that drivers cannot exceed while driving.  As stated in the law, A person is guilty of driving while under the influence of intoxicating liquor, marijuana, or any drug if the person drives a vehicle within this state:

  1. And the person has, within two hours after driving, an alcohol concentration of 0.08 or higher as shown by analysis of the person’s breath or blood made under RCW46.61.506; or
  2. The person has, within two hours after driving, a THC concentration of 5.00 or higher as shown by analysis of the person’s blood made under RCW 46.61.506; or
  3. While the person is under the influence of or affected by intoxicating liquor, marijuana, or any drug; or
  4. While the person is under the combined influence of or affected by intoxicating liquor, marijuana, and any drug.

The impact of marijuana legalization on state DUI Laws

Linda M. Callahan

Marijuana Detection

  • With recent testing being done by neighboring Colorado law enforcement professionals, Washington state troopers have even more reason to consider similar technology designed to keep drivers who are high on marijuana off the road.
  • Currently, state officers use nothing more than job-related skills and standard field sobriety tests to “detect” marijuana and other drugs on individuals suspected of driving under the influence. No actual device for detecting pot exists at this time (despite nationwide efforts currently underway by state officials across the country).
  • In Washington, it’s the Marijuana Breathalyzer developed by Washington State University; in Colorado, it’s the Nasal Ranger (an olfactometer designed to identify strong marijuana odors among users); in other jurisdictions, it’s saliva detection.

The Rush for a Testing Device

  • States across the country are fervently identifying, developing, and testing new methods of marijuana detection; however, a standard device with proven results has yet to surface.
  • According to Lt. Rob Sharpe of the Washington State Patrol (WSP), all types of methods are being considered: “Whether it’s measuring THC on the breath or in the saliva, some are looking at transdermal applications, so just measuring off of sweat from the body.”
  • An impaired driving section commander at the WSP, Sharpe is personally invested in the detection efforts currently underway – but he’s not ready to commit to any one method just yet: “If we’re going to adopt something in Washington, we want to make sure it’s very reliable and doesn’t suffer from false positives or false negatives that could occur.”

Use caution

  • With marijuana detection testing on the rise, recreational and medicinal users alike should take extra precautions.
  • While an official device has not yet been developed, regulating marijuana DUIs is at the forefront of efforts being made by Washington law enforcement officers. In fact, the WSP has employed a full-time librarian to collect studies from around the world pertaining to testing machines that might be useful to state troopers.

“Tough DUI Laws Require Tough DUI Lawyers”

Linda M. Callahan

Drugged DUI
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5 Nanograms Per Milliliter of Blood

  • Before the passage of I-502 which legalized marijuana, Washington had a zero-tolerance policy regarding driving under the influence of marijuana’s active ingredient, delta-9 tetrahydrocannabinol (THC), which many believe impairs driving ability.
  • Prior to the law’s effective date of December 1, 2013, any level of THC in a driver’s blood was prohibited.
  • Furthermore, drivers under the age of 21 were prohibited from having any active THC in their blood.
  • Now, drivers 21 or older are permitted a very low amount of the active THC in their blood—up to 5 ng (nanograms) per milliliter of blood. Driving under the influence of more than 5 ng per milliliter of blood is punishable by law.

The Affected By Element of DUI Laws

  • There is much controversy over whether any particular driver will be impaired by 5 ng of delta-9 THC.
  • Even the National Highway Traffic Safety Administration (NHTSA) has published materials that cast doubt upon the fairness of establishing a bright line “per se” level of impairment.
  • In their 2004 publication Drugs and Human Performance Fact Sheets, the authors state that it is “difficult to establish a relationship between a person’s THC blood or plasma concentration and [driving] performance impairing effects. . . .concentrations of the parent drug [marijuana] and the metabolite [delta-9 THC] are very dependent on patterns of use as well as dose.” Thus, they conclude that “it is inadvisable to try and predict effects based on blood THC concentrations alone, and currently impossible to predict specific effects based on THC-COOH [inactive THC metabolite] concentrations.”
  • The reason for this is that people become tolerant to any drug, including THC, after time. Thus, an individual may have a seemingly high level of THC in their blood, but not be too impaired to drive. In fact, in 1983, NHTSA published Marijuana and Actual Driving Performance, where they concluded, “THC’s adverse effects on driving performance appear relatively small.”
  • Everyone reacts to marijuana differently. If the driver in question did not drive in an impaired manner, the jury can reject a prosecutor’s case and find the driver not guilty.

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Washington State has some of the toughest DUI laws in our nation. These laws carry increasingly severe penalties for those who drink and drive. Washington lowered the BAC limit from .10 to 0.08 in January of 1999. Drivers with a blood-alcohol concentration (BAC) at .08 or above can now be convicted of driving under the influence of alcohol. In addition, because public sentiment is so very negative toward drunk drivers, prosecutors will often pursue a DUI conviction even when the driver’s test result is well under .08! This is possible because they can obtain a conviction if they can show the person drove while “affected by” alcohol, and/or marijuana or any drug, including prescription or over-the-counter medications.

We Challenge The Following Evidence On Every Case.


Probable Cause

Before you were asked to step out of your vehicle, the officer has been gathering evidence to support the arrest.


Field Sobriety Tests

As Ms. Callahan likes to call them “Bad Science”, FST’s are virtually impossible to pass, especially if the officer is the one grading you.


Breath Test - BAC

Factory trained, Linda M. Callahan understands the science behind breath testing most attorneys don’t.


Blood Test

With extensive training at Axion Labs in Chicago, Linda M. Callahan has the relevant experience to challenge Blood test evidence.

Snohomish County DUI Attorney

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