The Federal Motor Carrier Safety Administration shut down three primary companies -- Apex Bus Inc.

CNN: STORY HIGHLIGHTS

It was the third shutdown of a passenger carrier this month following the motor carrier administration's deployment of more than 50 investigators to look at businesses considered to be high risk, the DOT said.

WSJ: Feds: NY bus company made drivers repair vehicles

Looking at five years of fatal crashes involving large trucks, 0.10 percent or one in a thousand involved the truck's couplings, hitches or chains, according to an analysis of federal data from 2007-2011 by the Federal Motor Carrier Safety Administration.

NPR: Runaway Trailer Crashes Rare; NY Accident Killed 7

"The crash and other fatal crashes like it that occurred along I-95 last year led our agency to conduct this unprecedented one-year investigation into dangerous and illegal bus companies operating in violation to our basic safety standards, " Federal Motor Carrier Safety Administrator Anne Ferro told reporters.

CNN: STORY HIGHLIGHTS

Among the problems discovered by inspectors were "four undercarriage frame cracks including at the drive axle, at the cross member for the motor mounts, and at the differential and over the right front steering axle, " according to a letter sent by Berwick to Federal Motor Carrier Safety Administration Administrator Anne Ferro.

WSJ: Mass. official: Buses pulled from road for safety