A serious accident has closed Colorado Highway 85 just north of Brighton on Thursday afternoon.Colorado State Patrol Trooper David Hall said four people were injured in the two-vehicle accident, including two children. The accident, which happened at 2:30 p.m., closed the roadway for nearly two hours. Highway 85 has since reopened to traffic.Preliminary reports state a 2006 white Kia sedan was traveling south on Hwy 85 and attempted a left turn to 168th St. A 2004 blue Chevrolet Cavalier was traveling north on Hwy 85 when the two cars collided.The two children, who were passengers in the Cavalier, were flown by Flight For Life helicopter to The Children's Hospital in Aurora. The two female drivers in each vehicle were each taken by ambulance to Platte Valley Medical Center in Brighton.An accident reconstruction crew is on the scene to determine the cause of the crash. Also State Patrol is investigating who had the right of way at the traffic light.