The State’s policing watchdog has launched an independent investigation into a collision on the M50 in Dublin that saw nine people hospitalised.A car carrying eight teenagers drove towards traffic after travelling in the wrong direction on the motorway at about 5.30am on Sunday.It collided with a car near Junction 12 at Firhouse.All eight teenagers were taken to different hospitals for treatment, one of whom was in a critical condition.The driver of the second car, a man aged in his 20s, was also taken to hospital with serious injuries.In a statement on Monday morning, Fiosrú, which investigates incidents involving contact with gardaí where a member of the public has died or been seriously injured, confirmed it received a referral regarding the incident.It said a team of investigators attended the scene and an independent investigation is ongoing.“A referral does not necessarily mean a garda or gardaí have been accused of wrongdoing.“Instead, it means that Fiosrú should independently investigate the incident to ascertain whether or not the act or omission of a garda or gardaí may have resulted in the death of, or serious harm to, a person,” it said.The section of the M50, from Junction 12 to Junction 11 southbound, was closed for a number of hours on Sunday while a forensic collision examination was carried out.Following the collision, gardaí appealed for witnesses to the incident to come forward, including those who were travelling in either direction between both junctions at the time.