DUI “Legal Limit” Myth
A lot of people use the term “legal limit" in reference to a blood-alcohol content of .08, however, this is a myth! A BAC of .08 is not where you cross into the not legal to drive category in Colorado.
Anyone who drives a vehicle while their ability to drive is substantially impaired by the consumption of alcohol (and/or drugs) is guilty of Driving Under the Influence (DUI). This means a test result is not even necessary to prove DUI (although submitting to a test is required under Colorado law when an officer has probable cause to believe you may be impaired by alcohol while driving). A level of .08 or more, as measured by a statutorily approved test within 2 hours of driving, is considered a “ DUI per se." DUI per se means there is a “permissible inference" that your ability to drive was substantially impaired, meaning it is something the prosecution does not need to prove (they only need to prove you were driving with a BAC of .08 or higher).
Further, anyone driving while their ability to drive is impaired to the slightest degree by the consumption of alcohol (and/or drugs) is guilty of Driving While Ability Impaired (DWAI). A level of .05 up to .08, as measured by a statutorily approved test within 2 hours of driving, is considered a DWAI per se. The permissible inference of being DWAI at this level works both ways, meaning the prosecution doesn't need to prove impaired driving, but they also would have to overcome this inference to prove DUI (which is unlikely). There is also a permissible inference that a BAC of under .05 is not DUI or DWAI. For anyone under the age of 21, there is also a charge of Under Age Drinking and Driving for levels of .02 up to .05.
The difference in penalties between DUI and DWAI in Colorado are not that much. The primary difference on a first offense is a DWAI conviction does not require DMV to revoke you license, while a DUI conviction takes it away for a year; however, DMV will take away your license based on an administrative decision if your BAC was tested at .08 or more, or you refused to take a test.
In summary, you can be criminally charged at .05 BAC (.02 if under 21 years old), and could be charged based on evidence of alcohol related driving impairment with or without a test result. Therefore, .08 is not the “legal limit."