BOSTON (CBS) – Some travelers were left stranded at South Station Wednesday after the Lucky Star bus line abruptly shut down.

READ MORE: Bryan Purdie Charged In Falmouth Home Invasion, Kidnapping

Lucky Star posted signs that it was forced to close after an inspection.

The signs read, “Due to DOT inspection all buses are temporarily out of service until further notice. We apologize for any inconvenience.”

The buses travel between Boston and New York. The shutdown follows a massive nationwide effort to improve safety in the bus industry.

It all started in February with the Fung Wah bus line. The I-Team shot exclusive video as inspectors hauled Fung Wah buses out of service. There were so many problems that the company was permanently shut down.

READ MORE: Federal Regulators Say Weymouth Compressor Site Should Not Have Been Approved

In a letter to the bus company from the Department of Transportation, investigators say “Lucky Star fails to ensure that its motor coaches are systematically and properly inspected, repaired and maintained and meet minimum safety standards; indeed, Lucky Star, through the actions of Qiao M. Chen, dispatched a motor coach that had an approximate 4 foot by 2 foot hole in the bottom of the motor coach and significant frame damage.”

In the last year, investigators say Lucky Star buses broke down 80 times on its Boston to New York City route.

Investigators also found a bus that was placed out of service one day, drove the route the next day – not being repaired for days after it was supposedly placed out of service.

“Investigation uncovered egregious regulatory violations demonstrating Lucky Star’s flagrant disregard for motor coach passenger safety,” the letter says.

In addition to equipment problems, the investigation also uncovered the fact drivers were over the maximum amount of driving time allowed, on several occasions and failed to comply with mandatory alcohol and drug testing.

MORE NEWS: McAvoy's Late Goal Lifts Bruins To 4-3 Win Over Capitals

“Individually and cumulatively, these violations and conditions of dispatch and operation substantially increase the likelihood of serious injury or death to Lucky Star drivers and the motoring public,” the letter said.