A Stony Plain man was killed Tuesday, after his transport truck was struck by a pickup on Hwy. 813 near TR 691 while he was clearing snow from his trailer, Athabasca RCMP said.The incident occurred around 3:30 p.m. as the 57-year-old truck driver had pulled over to assist another motorist who had gone into the ditch. While clearing accumulated snow from the back of his semi-trailer, a southbound pickup collided with the rear of the truck, pinning the driver.Emergency Medical Services, Athabasca County Fire Department and RCMP responders attempted life-saving measures at the scene, but the truck driver succumbed to his injuries en route to hospital. The 41-year-old Edmonton man driving the pickup was treated at the scene and released with no injuries.RCMP said the investigation is ongoing. Preliminary reports indicate weather and road conditions, including blowing snow and poor visibility, likely contributed to the collision.