Records show the bus involved in the crash was cited eight times for maintenance problems in October and seven times in July. Overall, the bus recorded 22 safety violations in five inspections conducted between October 2011 and October 2012, including problems with brakes, the windshield and tires.
Stephen Keppler of the Commercial Vehicle Safety Alliance, a group with industry and government members, said buses and trucks average about two violations for each inspection.
Jackie Gillan, president of Advocates for Highway and Auto Safety, a Washington-based advocacy group, said the crash points to the need for improved roof strength and other safety measures.
"We have a long way to go before we can say boarding a motor coach is as safe as boarding an airplane," she said. Bus passengers "are often riding blindfolded."