North August Public Safety Officers went to mile marker No. 1 around 9:30 a.m. to assist Aiken County deputies with the pedestrian.
The man told police he was walking to Richmond, Va., but would only identify himself as "I am" and "I is," a report states.
A bus ticket in the man's pocket identified him as 20-year-old Tremain Johnson, a fact Johnson confirmed on the way to jail, according to a report.
He was charged with failure to obey a lawful order.