Halifax Regional Police is currently on scene at a head-on motor vehicle collision that occurred in the vicinity of 1250 Old Sambro Road in Halifax at approximately 5:20 p.m. It appears that three vehicles were involved. The collision occurred between a passenger vehicle and a Metro Transit bus, with a third vehicle rear-ending the initial passenger car involved. The bus had five passengers on board who were examined by EHS at the scene and released. The lone occupant of the rear-end vehicle was not injured. The female driver of the car involved in the head on collision with the bus had to be extracted from the vehicle by Fire personnel; she has been transported to the QE2 with serious injuries. Traffic is currently shut down on the Old Sambro Road in the vicinity of the collision both inbound and outbound. HRP Accident investigators and identification personnel are on scene and the police investigation is underway.