Government safety officials swooped down on more than two dozen curbside bus operations that mostly ferry passengers in the busy East Coast transportation corridor between New York and Florida, shuttering them for safety violations in the largest-ever single federal crackdown on the industry.

Teams of officials for the Federal Motor Carrier Safety Administration, armed with legal orders declaring the bus operations imminent hazards to public safety, fanned out to 26 companies based in six states: Georgia, Indiana, Maryland, New York, North Carolina and Pennsylvania. Officials withheld details about the operation until Thursday.

The crackdown is a blow to curbside buses — companies that sell tickets online and pick up and drop off passengers on street corners, rather than at terminals. Curbside operators’ cheap fares, made possible in part by low driver salaries and minimal overhead, have upended the economics of the long-distance bus industry over the past decade. They also have a fatal accident rate seven times higher than other types of interstate bus operators, federal accident investigators said in a report last year.

The shutdown orders were carried out at the headquarters and at bus pickup locations of 26 curbside companies. A majority of the 233 bus routes serviced by the companies either departed from or ended in New York City’s Chinatown district, transporting an estimated 1,800 passengers a day mostly along the busy Interstate 95 corridor.