As long as you aint twisted and you stay in between the lines, you're straight.
Cops got more to worry about at that time of night than the 5 shots you had before you put the keys in the car. They dont even want to give you a DUI. They'd rather sit on their ass and not do any work and still get paid- like every other American. However it is their job to pull over drunk drivers, so even if you are a drunk driver- simply dont look like one and they wont pull you over.
I've come out of a bar intoxicated in Windsor, Ontario; Daytona Beach FL, Orlando FL, Saginaw MI, as well as Mt. Clemens MI and jumped into a car and drove home while police were outside the actual bars I left and patrolling the roads. MO area PD's can't be much different than any other cops.