The death toll from a massive Wyoming traffic pileup climbed to two on Tuesday after collisions that involved 64 vehicles and injured dozens, authorities said. Wyoming Highway Patrol troopers arrested a Canadian motorist on Monday on suspicion of vehicular homicide, but authorities declined to provide details about the investigation involving Alex Dragaytsev, 45, of Quebec. Troopers initially blamed fog and slush for a pileup on U.S. Interstate 80 west of Laramie that began at 8 a.m. Monday when a semitrailer crashed into another truck and jackknifed over both lanes of the main east-west artery that crosses the southern part of the state, authorities said.