Authorities have ordered Double Happyness Travel Inc. to immediately cease operations.
U.S. Transportation officials say they found numerous violations of rules governing vehicle maintenance and driver safety, including drug and alcohol testing and records on how long drivers were working.
Double Happyness takes passengers from Albany, N.Y., Baltimore, Md., and Wilmington, Del., to stops in midtown Manhattan and Chinatown in New York City.
The company did not immediately return a message Thursday at its corporate office in Huntingdon Valley, near Philadelphia.
The Federal Motor Carrier Safety Administration says it has doubled inspections and safety reviews of the nation's 4,000 bus lines in recent years.