All but two of the northbound lanes were blocked at the scene, causing a three-mile backup as of 8:20 a.m. Arriving at the scene, they found a school bus off the roadway. At least one person was reported to be seriously injured, but it wasn't immediately clear which vehicle they were in. Troopers and medics responded to the scene, near the South 272nd Street interchange, at about 7:50 a.m. after receiving reports of a bus crash. Officials said it doesn't appear any students were on the bus at the time of the crash.