Two people were seriously injured Monday morning when a tractor-trailer sideswiped a tour bus parked on the westbound shoulder of Interstate 70 in Blue Springs. The bus, which was headed from St. Louis to Overland Park, had pulled over after a tire went flat, said Sgt. Collin Stosberg, a spokesman for the Missouri Highway Patrol. A tractor-trailer apparently veered out of its lane about 10:45 a.m. and sideswiped the bus, which got pushed part way down an embankment along the interstate between Missouri 7 and Adams Dairy Parkway.