Six people were hurt in a two-vehicle accident on U.S. 54 at Route E in Cole County, Monday afternoon.
Missouri Highway Patrol reports show the accident occurred just before 2 p.m.
James O'Brien, 59, Creve Couer, was going east on 54 while Dylan Evers, 16, Henley, was stopped in the median crossover to turn south onto Route E.
O'Brien travelled off the left side of the road, went into the median and continued going eastbound, striking two road signs and the side of Evers' vehicle.
O'Brien was later arrested for operating a motor vehicle in a careless and imprudent manner resulting in an accident as well as six felony counts of second-degree assault for operating a vehicle while intoxicated.
O'Brien had no reported injuries, but two passengers, his wife Rita Graham, 53, and his son James, 14, both of Creve Coeur, were treated for moderate injuries.
Evers was treated for minor injuries while his brother, Joseph, seven, was treated for serious injuries. Two other passengers with Evers, Jaylin McKinney, 15, Eugene, and Gavin Reed, six, Jefferson City, were also treated for serious injuries.
All those involved in the accident were wearing seat belts.