One of the pioneers of fast, cheap bus service between Boston and New York City has been ordered off the roads because of structural problems with the buses.

Federal officials have ordered the entire Fung Wah bus fleet to cease carrying passengers immediately, following a WBZ I-Team report that found cracks in 21 out of the company’s 28 buses.

The U.S. Department of Transportation’s Federal Motor Carrier Safety Administration said in a press release Tuesday that the service must shut down, according to several media outlets.

“FMCSA’s safety investigators are continuing their examination of Fung Wah’s operations, including examining the safety records of its vehicles, drivers and other company safety performance requirements prescribed by federal regulations, and may consider additional actions against the company if warranted,” the statement says.

The service transports passengers between South Station in Boston and Canal Street in New York City for $15 per one-way ticket.

Have you ever taken the Fung Wah? How was your experience?