The police pulled over more than a dozen tour buses at a surprise checkpoint on Friday night in Manhattan, and not one of them passed an inspection, state officials said.

Each of the 14 buses failed the inspection, said Deborah Sturm Rausch, a spokeswoman for the New York Department of Transportation.

Less than a week after a bus crash in the Bronx that left 15 dead, the authorities have stepped up enforcement of long-distance bus companies. The totals from Friday’s inspections suggest that operators have made little effort to comply with regulations.

According to a state official, Transportation Department inspectors determined that nine drivers should not have been behind the wheel: four because of lack of qualifications and five because they had been driving for too long. Ten buses were deemed unfit for the road and had to be towed, the official said.