Just because Marijuana is legal in Washington State doesn’t mean that it’s legal for your day-trip to Powell’s Books, Portland Timbers match, or one of Portland’s brew pubs or McMenamins. Portland Police Department put out a great video talking about the difference between the laws for Oregon and Washington. DUI for marijuana in the two states are different, Oregon does not yet have a standard in place for “Active THC” like Washington State’s 5 nanograms, “impaired to a perceptible degree” is the legal standard in Oregon. Both Oregon and Washington, and local law enforcement, enforce DUI as a high priority.
FYI Marijuana DUI can include riding your bicycle, fixie or otherwise.