Update at 3 p.m.: The U.S. Department of Transportation has released a statement about its order that Lucky Star cease operations, "declaring that its vehicles and drivers pose an imminent hazard to public safety (PDF)."

The release adds:

Federal investigators found that Lucky Star’s fleet of 21 motor coaches did not meet minimum safety standards as the company failed to systematically and properly inspect, repair or maintain the vehicles. Investigators also found that the owners of Lucky Star failed to monitor and ensure that its drivers complied with controlled substances and alcohol use and testing regulations. Drivers were employed before receiving negative pre-employment drug and alcohol test results as required by federal law. Drivers were not required by the company to turn in hours-of-service records or other required documentation such as driving itineraries and fuel receipts.

Original post:

Lucky Star, which provides bus service between Boston's South Station and New York City, has halted service.

A statement on the company's website reads:

Per the order of [the U.S. Department of Transportation], Lucky Star Bus has temporary [sic] ceased operations. All affected e-ticket customers will be receiving a refund automatically. Thanks!

There's no official word yet as to why federal regulators halted Lucky Star service.

In February, transportation officials ordered another Chinatown bus carrier, Fung Wah, to cease operations. The company's operating license was then revoked for not cooperating with safety inspectors.