A devastating highway collision west of St. Paul has left two people dead and two others fighting for their lives after a garbage truck veered into oncoming traffic in an apparent attempt to avoid another crash.On Monday at 1:09 p.m., officers with the Royal Canadian Mounted Police in St. Paul responded to an iPhone crash alert on Hwy. 29, roughly one kilometre west of town between RR 105 and RR 110.Mounties say preliminary findings indicate a garbage truck travelling eastbound was unable to stop for a semi-truck that was turning south onto a range road. In an effort to avoid striking the semi, the garbage truck swerved into the westbound lane, where it collided head-on with an approaching SUV.The 36-year-old female driver of the SUV and her 44-year-old male passenger were pronounced dead at the scene. Two women seated in the rear of the SUV, aged 29 and 38, had to be extricated from the wreckage and were transported to hospital with life-threatening injuries. The 53-year-old male driver of the garbage truck was treated at the scene and later released.An RCMP forensic collision reconstructionist from the Eastern Alberta District has been called in to assist.No further details have been released as investigators continue to determine the exact sequence of events leading up to the fatal crash.