Police statewide are encountering more drivers who are either under the influence of marijuana or are carrying the drug illegally with them in their vehicle, according to the Colorado Department of Transportation and local police. Drug evaluations of impaired drivers that turned up positive for marijuana increased 35 percent from 2009 to 2010, according to state numbers.
New data from the National Highway Traffic Safety administration shows that legal and illegal drugs are impairing 16 percent of nighttime drivers nationwide. Colorado authorities say drug evaluations of impaired drivers that turned up positive for marijuana increased from 2009 to 2010. State Department of Transportation reports that from 2009 to 2010, the number jumped from 391 positive tests for marijuana to 599.
Part of the problem with establishing a metric for unacceptable levels of the drug in drivers resides in a lack of relative consensus about the drug’s impact, and how long it may impact behavior. While the drug can remain in a user’s system for weeks, many say that its effects are gone in a matter of hours. And while studies of alcohol use and impairment have been conducted for decades, there has been far less research of marijuana impairment. With the growing numbers of legal users joining the illegal users on the road, further research is clearly needed.