Public safety officials are warning motorists to be cautious after deer in the roadway contributed to a couple of serious motor vehicle accidents, including one that left an Oxford County man in critical condition. Stephen McCausland, spokesman for the Maine Department of Public Safety, said 50-year-old Gerald Pelletier of Mexico was seriously injured Monday evening after his car hit a dead deer in the road, causing his vehicle to veer into the path of a loaded pulp truck on Route 2 in Mexico. The collision, which was reported around 9:30 p.m., caused the six-axle pulp truck to overturn in the roadway, spilling a portion of its load of logs.