A three-vehicle crash closed the southbound lanes of Interstate 25 in Douglas County on Saturday night. A Colorado State Patrol spokesperson said the crash was reported around 7:22 p.m. near the 182 mile marker, south of Castle Rock. Two southbound lanes reopened around 9 p.m.One driver was extricated from their vehicle and airlifted to a local hospital in serious condition, the spokesperson said. A second driver and their passenger were also taken to the hospital in serious condition. The third driver was not injured, CSP said.Southbound traffic was diverted at mile marker 181 while crews cleared the scene. The Douglas County Sheriff's Office, Larkspur Fire Protection District and Castle Rock Fire Departments were also on scene. The cause of the crash is under investigation.