DUI
Like every other state in the United States, driving under the influence is a crime in Missouri, and is subject to a great number of regulations outside of the Liquor Control Law. Missouri's maximum blood alcohol level for driving is .08% for persons over the age of 21 and .02% for minors and adults under age 21.
Ordinarily, DUI is a misdemeanor in Missouri, although the third DUI conviction becomes a felony. Refusal to take a chemical test (i.e. breathalyzer) when so requested by a law enforcement officer who has probable cause will result in a one-year suspension of the suspect's driver's license.
Read more about this topic: Alcohol Laws Of Missouri