The people of Washington have spoken, and it is yet another example of “going green!” While this proves to be a victory for the will of the People, the potential challenges to states’ rights versus federalism will have to be tabled for a different discussion. 1 Understanding the legal limits for Marijuana in Washington State is easy to follow.
Washington’s Initiative 502 placed Washington at the forefront of the legalization of recreational marijuana use. However, just because marijuana is now legal in Washington does not mean there are not limitations on where it can be used, how much you can possess, and of course, potential punishments for driving under the influence (DUI). Thus, especially with DUI implications and open-container laws, it helps to think of marijuana like alcohol. For example, it is a traffic infraction to operate a motor vehicle on a highway with an open alcohol container2. Similarly, it is also a traffic infraction to operate a motor vehicle on a highway with an open container of marijuana.3
Just as with mixing alcohol and/or prescription medication and driving, you can be cited for a DUI after consuming marijuana. Most people are familiar with .08 legal limit for alcohol consumption and driving, however, the legal limit for marijuana consumption and driving is a little more vague. The legal limit for marijuana is 5.0 nanograms of delta-9 tetrahydrocannabinol or THC.4 There is an important distinction between THC, which is active and causes impairment, versus carboxy-TCH which is stored in a person’s body and does not contain active TCH.5 If you drive with 5.0 nanograms or more of THC in your system, you place yourself at risk of being charged with a DUI.
Marijuana is legal, but there are restrictions regarding age, how much you can possess, where you can purchase it, and where you can consume it. No one under the age of twenty-one (21) may use or possess marijuana. You can purchase and possess up to one (1) once (or 28 grams) of “useable” marijuana – the green stuff you smoke – up to sixteen (16) ounces of marijuana-infused edibles in solid form, seventy-two (72) ounces in liquid form, and seven (7) grams of marijuana concentrates. Marijuana, in all forms, can only be sold and purchased at state-licensed retail stores. Use of marijuana is restricted to private property; it is illegal to consume marijuana in public.6
Marijuana is legal in Washington, but know the laws and use common sense and moderation so as to not run afoul of these laws. In sum, you must be 21 to have it, do not use it in public, you cannot have more than an ounce of it, and you should not drive on it. Understanding the legal limits for Marijuana in Washington State is of utmost importance for Washington State residents.
 See http://lcb.wa.gov/mj2015/faqs_i-502 for a brief discussion of federal law concerning marijuana.
 See RCW 46.61.519, http://app.leg.wa.gov/rcw/default.aspx?cite=46.61.519.
 See RCW 46.61.745, http://app.leg.wa.gov/RCW/default.aspx?cite=46.61.745. Per the statute, unless the marijuana in your car is in the trunk or inaccessible, the marijuana must be in a sealed, unopened package or container.
 See RCW 46.61.502, http://app.leg.wa.gov/RCW/default.aspx?cite=46.61.502.
 See RCW 46.04.586, http://app.leg.wa.gov/RCW/default.aspx?cite=46.04.586.