The Department of Transportation announced today that it was shutting down Washington DC Party Shuttle, a local tour bus operator that runs trips for tourists throughout D.C. and down to Mt. Vernon. It also operates in New York as OnBoard Sightseeing Tours. According to a press release from the department, the operator and its drivers violated safety standards:

An FMCSA investigation launched earlier this month revealed that the company had failed to monitor and ensure that its drivers comply with federal drug and alcohol testing requirements. Investigators found that one driver had repeatedly been permitted or required to operate a passenger vehicle even though it was known that the individual had tested positive for a controlled substance. The investigation also found that the carrier does not have an effective maintenance program, which results in significant safety problems with its vehicles. These violations and conditions of operations substantially increase the likelihood of serious harm to drivers, passengers and the motoring public.

The department said that this was the first shutdown of a passenger carrier since 50 investigators were deployed earlier this month to ensure that health and safety regulations were being followed.