The buses were en route Wednesday from Salt Lake City to Denver with a scheduled stop in Fort Collins.
Sheriff's spokesman John Schulz says 66-year-old Roland Arel, of Sacramento, Calif., was detained. Schulz says Arel is believed to be a transient who boarded the bus in Salt Lake City.
Schulz says authorities got a call about the passenger, contacted the man on a cellphone and he came out voluntarily.
The two buses were rerouted to a bus stop and deputies evacuated 96 passengers. The buses were searched and later cleared to leave.
