Under Colorado law, drivers with five nanograms of active tetrahydrocannabinol (THC) in their blood can be prosecuted for driving under the influence (DUI). However, because there is no roadside device to detect THC, law enforcement officers—many trained as drug recognition experts (DREs)—base arrests on observed impairment. Even people who use marijuana for medicinal purposes can be arrested for DUI.Consuming any amount of marijuana before driving puts you at risk for DUI, which can cost more than $13,500, in addition to jail time and loss of license.Many Colorado law enforcement officers are trained to detect drug impairment. On average, more than 60 people are arrested each day in Colorado for DUI, including drugs, alcohol or a combination of both. Retail marijuana is intended for private, personal use. Such use is only legal in certain locations not open or accessible to the public. Marijuana may not be consumed openly or publicly. Click the image to learn more about City of Fort Collins FAQs regarding marijuana consumption and possession!